天体物理学学术速递[1.10]
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astro-ph天体物理学，共计49篇
【1】 Forecasts for WEAVE-QSO: 3D clustering and connectivity of critical points with Lyman-$α$ tomography
标题：编织类星体预报：用LYMAN-$α$层析成像术对临界点的3D聚类和连通性
链接：https://arxiv.org/abs/2201.02606
备注：26 pages, 22 figures, submitted to MNRAS
摘要：The upcoming WEAVE-QSO survey will target a high density of quasars over a
large area, enabling the reconstruction of the 3D density field through
Lyman-$\alpha$ tomography over unprecedented volumes smoothed on intermediate
scales ($\approx$ 16 Mpc/$h$). We produce mocks of the Lyman-$\alpha$ forest
using LyMAS, and reconstruct the 3D density field between sightlines through
Wiener filtering in a configuration compatible with the future WEAVE-QSO
observations. The fidelity of the reconstruction is assessed by measuring one-
and two-point statistics from the distribution of critical points in the cosmic
web. In addition, initial Lagrangian statistics are predicted from first
principles, and measurements of the connectivity of the cosmic web are
performed. The reconstruction captures well the expected features in the auto-
and cross-correlations of the critical points. This remains true after a
realistic noise is added to the synthetic spectra, even though sparsity of
sightlines introduces systematics, especially in the cross-correlations of
points with mixed signature. Specifically, for walls and filaments, the most
striking clustering features could be measured with up to 4 sigma of
significance with a WEAVE-QSO-like survey. Moreover, the connectivity of each
peak identified in the reconstructed field is globally consistent with its
counterpart in the original field, indicating that the reconstruction preserves
the geometry of the density field not only statistically, but also locally.
Hence the critical points relative positions within the tomographic
reconstruction could be used as standard rulers for dark energy by WEAVE-QSO
and similar surveys.
【2】 Integration and qualification of the Mini-EUSO telescope on board the ISS
标题：国际空间站上Mini-EUSO望远镜的集成与鉴定
链接：https://arxiv.org/abs/2201.02597
摘要：Mini-EUSO is a compact telescope ($37 \times 37 \times 62$~cm$^3$) currently
hosted on board the International Space Station. Mini-EUSO is devoted primarily
to study Ultra High Energy Cosmic Rays (UHECR) above $10^{21}$~eV but also to
search for trange Quark Matter (SQM), to observe Transient Luminous Event (TLE)
in upper atmosphere, meteoroids, sea bioluminescence and space debris tracking.
Mini-EUSO consist of a main optical system, the Photo Detector Module (PDM),
sensitive to UV spectrum ($300\div400$~nm) and several ancillary sensors
comprising a visible ($400\div780$~nm) and NIR ($1500\div1600$~nm) cameras and
a $8 \times 8$ channels Multi-Pixel Photon Counter Silicon PhotoMultiplier
(MPPC SiPM) array which will increase the Tecnological Readyness Level of this
ultrafast imaging sensor. Mini-EUSO belongs to a novel set of missions
committed to evaluate, for the first time, the capability of observing Cosmic
Rays from a space-based. The instrumentation, space-qualified tests will be
shown.
【3】 Sub-surface granular dynamics in the context of oblique, low-velocity impacts into angular granular media
标题：倾斜低速撞击角状颗粒介质背景下的地下颗粒动力学
链接：https://arxiv.org/abs/2201.02585
摘要：Oblique, low-velocity impacts onto extraterrestrial terrain are an inevitable
occurrence during space exploration. We conduct two-dimensional discrete
simulations to model such impacts into a bed of triangular grains. Finite
element method provides the basis for simulation, enabling the angular grain
geometry. Our findings re-create the three classes of impact behavior
previously noted from experiments: full-stop, rollout, and ricochet
\citep*{Wright2020}. An application of Set Voronoi tessellation assesses
packing fraction at a high resolution, revealing how grains shift relative to
each other during an impact event. Calculation of Von Mises strain
distributions then reveal how grains shift relative to the overall system,
leading to the notion of the 'skin zone'. Intuition would suggest that the
region of perturbed grains would grow deeper with higher velocity impacts,
results instead show that increasing velocity may actually evoke a change in
the grains' dissipative response that boosts lateral perturbation. Finally, we
consider as a whole how sub-surface response could link with impactor dynamics
to deepen our understanding of oblique, low-velocity impact events and help to
improve mission outcomes.
【4】 Magnetic field topology, chemical spot distributions and photometric variability of the Ap star phi Draconis
标题：AP星Phi Draconis的磁场拓扑、化学黑子分布和光度变率
链接：https://arxiv.org/abs/2201.02554
备注：13 pages, 13 figures; accepted for publication in MNRAS
摘要：The primary component of the multiple star phi Dra is one of the brightest
magnetic chemically peculiar stars in the northern sky. Here we report results
of a comprehensive study of the rotational photometric variability, binarity,
magnetic field geometry, and surface chemical spot structure for this star. We
derived a precise photometric rotational period of 1.71650213(21) d based on
one year of TESS nearly continuous space observations and discovered modulation
of the stellar light curve with the phase of the 127.9-d binary orbit due to
the light time travel effect. We revised parameters of the binary orbit and
detected spectroscopic contribution of the secondary. A tomographic mapping
technique was applied to the average intensity and circular polarisation
profiles derived from Narval high-resolution spectropolarimetric observations.
This analysis yielded a detailed map of the global magnetic field topology
together with the surface distributions of Si, Cr, and Fe abundances. Magnetic
mapping demonstrates that the surface field structure of phi Dra is dominated
by a distorted dipolar component with a peak field strength of 1.4 kG and a
large asymmetry between the poles. Chemical maps show an enhancement of Cr, Fe
and, to a lesser extent, Si in a series of spots encircling intersections of
the magnetic and rotational equators. These chemical spot geometries do not
directly correlate with either the local field strength or the field
inclination.
【5】 HST observations of the globular cluster NGC 6402 (M14) and its peculiar multiple populations
标题：球状星团NGC6402(M14)及其特殊多种群的HST观测
链接：https://arxiv.org/abs/2201.02546
备注：23 pages; accepted for publication in AAS Journals
摘要：We present Hubble Space Telescope (HST) photometric results for NGC 6402, a
highly reddened very luminous Galactic globular cluster (GC). Recent
spectroscopic observations of its red giant stars have shown a quite peculiar
behavior in the chemistry of its multiple populations. These results have
prompted UV and optical HST observations aimed at obtaining the cluster's
"Chromosome map" (ChM), an efficient tool to classify GCs and characterize
their multiple populations. We find that the discontinuity in the abundance
distributions of O, Mg, Al and Na inferred from spectroscopy is more nuanced in
the ChM, which is mostly sensitive to nitrogen. Nevertheless, photometry in
optical bands reveals a double main sequence, indicating a discontinuity in the
helium content of the populations. The population with the largest chemical
anomalies (extreme) peaks at a helium mass fraction Y~0.31. This helium content
is consistent with results from the analysis of the distribution of
horizontal-branch stars and the spectrophotometry of the red giants. The ChM
and the color magnitude diagrams are compared with those in NGC 2808, a
prototype GC with helium abundances up to Y > 0.35, and both confirm that NGC
6402 does not host stellar populations with such extreme helium content.
Further, the ChM reveals the presence of a group of stars with larger
metallicity, thus indicating that NGC 6402 is a Type II cluster. The modalities
of formation of the multiple populations in NGC 6402 are briefly surveyed, with
main attention on the Asymptotic Giant Branch and Supermassive star models, and
on possible clusters' merging.
【6】 The historic Ks light curve of the FUor PGIR20dci
标题：FUOR PGIR20dci的历史Ks光曲线
链接：https://arxiv.org/abs/2201.02541
备注：This paper has been accepted for publication as a AAS Research Note. We have added Table 1 with our Ks-band photometry so that this arXiv submission is self-contained
摘要：We report a historic Ks-band light curve spanning over three decades of the
FUor PGIR20dci recently discovered by Hillenbrand et al. (2021) . We find some
minor variability of the object prior to the FUor outburst, an initial rather
slow rise in brightness, followed in 2019 by a much steeper rise to the
maximum.
【7】 Microlensing constraints on clustered primordial black holes
标题：簇状原始黑洞的微透镜约束
链接：https://arxiv.org/abs/2201.02521
备注：9 pages, 1 figure. Comments are welcome!
摘要：The discovery of black-hole-binary mergers through their gravitational wave
(GW) emission has reopened the exciting possibility that dark matter is made,
at least partly, of primordial black holes (PBHs). However, this scenario is
challenged by many observational probes that set bounds on the relative PBH
abundance across a broad range of viable PBH masses. Among these bounds, the
ones coming from microlensing surveys are particularly severe in the mass range
from $\sim 10^{-10}$ to a few M$_{\odot}$. The upper part of this range
precisely corresponds to the mass window inside which the formation of PBHs
should be boosted due to the QCD phase transition in the early Universe, which
makes the microlensing probes particularly important. However, it has been
argued that taking into account the inevitable clustering of PBH on small
scales can significantly relax or entirely remove these bounds. While the
impact of PBH clustering on the GW event rate has been studied in detail, its
impact on the microlensing event rate has not yet been fully assessed. In this
Letter, we address this issue, and show that clusters arising from PBH formed
from Gaussian initial curvature perturbations do not alter the current
microlensing constraints, as they are not sufficiently dense nor massive.
【8】 Rediscussion of eclipsing binaries. Paper VIII. The doubly-eclipsing quadruple star system V498 Cygni
标题：关于食双星的再讨论。文件VIII.双食四星系统V498天鹅座
链接：https://arxiv.org/abs/2201.02516
备注：Accepted for publication in the April 2022 edition of The Observatory. 16 pages, 7 black and white figures, 5 tables
摘要：V498 Cyg is an early-B-type binary known to show eclipses on a period of 3.48
d, and two sets of spectral lines. We present the discovery of a second set of
eclipses, on a 1.44-d period, in the light curve of this object from the
Transiting Exoplanet Survey Satellite (TESS). We develop a model of the light
curve to simultaneously fit the properties of both eclipsing binaries and apply
this to the TESS observations. We are able to fit the light curve of the
fainter system well, but the light curve fit for the brighter system is unable
to reproduce either its asymmetric primary eclipse or its changing light curve
shape. The available eclipse timing measurements are extremely scattered so we
determine orbital ephemerides based only on the TESS data. We infer the
physical properties of all four stars, estimating the masses of the components
of the brighter binary to be 10 Msun and 11 Msun, and of the fainter binary to
be 6.5 Msun and 3.5 Msun. The properties of the system may be reliably
determined in future by obtaining radial velocity measurements of the component
stars.
【9】 The transiting planetary system WASP-86/KELT-12: TESS provides the casting vote
标题：凌日行星系统WASP-86/KELT-12：TESS投决定票
链接：https://arxiv.org/abs/2201.02515
备注：Accepted for publication in the February 2022 edition of The Observatory. 11 pages, 4 black and white figures, 3 tables
摘要：A transiting planetary system was discovered independently by two groups,
under the names WASP-86 (Faedi et al. 2016) and KELT-12 (Stevens et al. 2017).
The properties of the system determined in these works were very different,
most tellingly a variation of a factor of three in the measured radius of the
planet. We suggest that the system be named WASP-86/KELT-12 to better apportion
the credit for discovery between the two groups. We analyse the light curve of
this system from the Transiting Exoplanet Survey Satellite, which observed it
in two sectors, following the Homogeneous Studies approach. We find properties
intermediate between the two previous studies: the star has a mass of 1.278 +/-
0.039 Msun and a radius of 2.02 +/- 0.12 Rsun, and the planet has a mass of
0.833 +/- 0.049 Mjup and a radius of 1.382 +/- 0.089 Rjup. The discrepancy in
the two previous sets of measured properties of the system arises from a
disagreement over the transit depth and duration, caused by the transit being
long and shallow so not well suited to follow-up photometry from ground-based
telescopes. We also update the orbital ephemeris to aid future work on this
system, which is a good candidate for characterising the atmosphere of a planet
through transmission spectroscopy.
【10】 A spectral hardening in the Fermi-LAT Data of 1ES 0502+675
标题：1ES 0502+675费米数据的谱硬化
链接：https://arxiv.org/abs/2201.02508
备注：Accepted by MNRAS
摘要：The $\gamma$-ray spectral feature of the blazar 1ES 0502+675 is investigated
by using Fermi Large Area Telescope (Fermi-LAT) Pass 8 data (between 100 MeV
and 300 GeV) covering from 2008 August to 2021 April. A significant
($\sim4\sigma$) hardening at $\sim$ 1 GeV is found in the $\gamma$-ray spectrum
during a moderately flaring state (MJD 55050-55350). The photon index below and
above the break energy is $\Gamma_1=2.36\pm0.31$ and $\Gamma_2=1.33\pm0.11$,
respectively. In the rest of the observations, the $\gamma$-ray spectrum can be
described by a power-law form with the photon index of $\approx1.6$. In the
frame of a one-zone synchrotron self-Compton (SSC) model, the spectral
hardening is interpreted as the transition between the synchrotron component
and the SSC component. This could be the result of a slight increase of the
break/maximum Lorentz factor of the electrons.
【11】 ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): A Hot Corino Survey toward Protostellar Cores in the Orion Cloud
标题：猎户座普朗克星系冷团(ALMASOP)的ALMA调查：猎户座星云中原恒星核心的热科里诺调查
链接：https://arxiv.org/abs/2201.02497
备注：34 pages. 14 figures. 1 figure set. 1 machine-readable table. Accepted for publication in ApJ
摘要：The presence of complex organic molecules (COMs) in the interstellar medium
(ISM) is of great interest since it may link to the origin and prevalence of
life in the universe. Aiming to investigate the occurrence of COMs and their
possible origins, we conducted a chemical census toward a sample of
protostellar cores as part of the ALMA Survey of Orion Planck Galactic Cold
Clumps (ALMASOP) project. We report the detection of 11 hot corino sources,
which exhibit compact emissions from warm and abundant COMs, among 56 Class 0/I
protostellar cores. All the hot corino sources discovered are likely Class 0
and their sizes of the warm region ($>$ 100 K) are comparable to 100 au. The
luminosity of the hot corino sources exhibits positive correlations with the
total number of methanol and the extent of its emissions. Such correlations are
consistent with the thermal desorption picture for the presence of hot corino
and suggest that the lower luminosity (Class 0) sources likely have a smaller
region with COMs emissions. With the same sample selection method and detection
criteria being applied, the detection rates of the warm methanol in the Orion
cloud (15/37) and the Perseus cloud (28/50) are statistically similar when the
cloud distances and the limited sample size are considered. Observing the same
set of COM transitions will bring a more informative comparison between the
cloud properties.
【12】 What drives galaxy quenching? A deep connection between galaxy kinematics and quenching in the local Universe
标题：是什么驱使星系熄灭？星系运动学与局地宇宙猝灭的深层联系
链接：https://arxiv.org/abs/2201.02484
备注：Accepted to MNRAS; 29 pages; 17 figures
摘要：We develop a 2D inclined rotating disc model, which we apply to the stellar
velocity maps of 1862 galaxies taken from the MaNGA survey (SDSS public Data
Release 15). We use a random forest classifier to identify the kinematic
parameters that are most connected to galaxy quenching. We find that kinematic
parameters that relate predominantly to the disc (such as the mean rotational
velocity) and parameters that characterise whether a galaxy is rotation- or
dispersion-dominated (such as the ratio of rotational velocity to velocity
dispersion) are not fundamentally linked to the quenching of star formation.
Instead, we find overwhelmingly that it is the absolute level of velocity
dispersion (a property that relates primarily to a galaxy's bulge/spheroidal
component) that is most important for separating star forming and quenched
galaxies. Furthermore, a partial correlation analysis shows that many commonly
discussed correlations between galaxy properties and quenching are spurious,
and that the fundamental correlation is between quenching and velocity
dispersion. In particular, we find that at fixed velocity dispersion, there is
only a very weak dependence of quenching on the disc properties, whereby more
discy galaxies are slightly more likely to be forming stars. By invoking the
tight relationship between black hole mass and velocity dispersion, and noting
that black hole mass traces the total energy released by AGN, we argue that
these data support a scenario in which quenching occurs by preventive feedback
from AGN. The kinematic measurements from this work are publicly available.
【13】 A Possible Explanation for the Blue Spectral Slope Observed on B-type Asteroids
标题：B型小行星上观测到的蓝色光谱斜率的一种可能解释
链接：https://arxiv.org/abs/2201.02459
摘要：In an effort to better understand the role dark material plays in the
reflectance spectrum of carbonaceous asteroids, we performed laboratory studies
focusing on quantifying how the addition of relevant dark material (graphite,
magnetite and troilite) can alter the ultraviolet-visible and near-infrared
spectrum of a neutral silicate mineral. We find that addition of graphite,
magnetite and troilite all darken the reflectance spectrum of our forsterite
samples and cause the spectral slope to decrease (become blue). These spectral
changes can be caused by both nm- and micron-sized grains. In the
ultraviolet-visible region, we find that graphite is most efficient at altering
the spectral slope, while in the near-infrared, magnetite is the most
efficient. At all wavelengths studied, graphite is the most efficient at
darkening our sample spectrum. However, the observation that troilite also
alters the slope and albedo of our samples suggests that the spectral changes
caused by magnetite and graphite may not be unique. In addition, we find that
the spectral slopes in our mixtures compare generally well to what has been
observed on Bennu suggesting that a significant portion of fine-grained dark
material, including sulfides, present in the regolith can cause the observed
negative (blue) slope found on B-type asteroids.
【14】 Stellar rotation rates in Kepler eccentric (heartbeat) binaries obtained from r-mode signatures
标题：从r模签名获得开普勒偏心(心跳)双星的恒星自转速率
链接：https://arxiv.org/abs/2201.02458
备注：13 pages, to appear in MNRAS
摘要：R-mode oscillations in a rotating star produce characteristic signatures in a
Fourier amplitude spectrum at frequencies related with the rotation frequency,
which can be, in turn, used to obtain the surface rotation rate of the star.
Some binary stars observed by Kepler indicate the presence of r~modes that are
probably excited by the tidal effect. In this paper, we have obtained stellar
rotation periods in 20 eccentric (heartbeat) binaries with r-mode signatures.
The majority of the rotation periods are found to be comparable to
pseudo-synchronous periods, in which the angular velocity of rotation is
similar to the angular orbital motion of the companion at periastron. In
particular, for the heartbeat stars with orbital periods longer than about
8\,d, all but one agree with pseudo-synchronous rotation. In contrast to a
previous investigation by Zimmerman et al., our result supports the
pseudo-synchronisation theory developed by Hut.
【15】 Absorption features in sub-TeV gamma-ray spectra of BL Lac objects
标题：BL Lac天体的亚TeVγ能谱吸收特性
链接：https://arxiv.org/abs/2201.02454
备注：Accepted for publication in ApJ
摘要：The production site of gamma rays in blazars is closely related to their
interaction with the photon fields surrounding the active galactic nucleus. In
this paper, we discuss an indirect method that may help to unveil the presence
of ambient structures in BL Lac objects through the analysis of their gamma-ray
spectrum. Gamma rays, passing through structures at different distances from
the black hole, interact via $\gamma\gamma$ pair production with the
corresponding photon fields and produce absorption features in their spectral
energy distribution. An interaction with a putative broad-line region may
reduce the gamma-ray flux only if its production site were very close to the
central engine. However, if jet photons interact with a bath of optical-UV seed
photons produced by a narrow-line region extended over the parsec scale, the
consequent $\gamma\gamma$ process may cause absorption features detectable at a
few hundreds GeV. The detection of such absorption features is facilitated in
sources with spectra reaching TeV energies, and specifically HBLs and EHBLs
(extreme blazars) may represent exceptional probes to investigate this topic.
We discuss recent observations of an extreme blazar named 2WHSP
J073326.7+515354 (or PGC 2402248), which shows evidence of such an absorption
feature in its gamma-ray spectrum and narrow emission lines in the optical
spectrum, suggesting the presence of narrow-line regions in its large-scale
environment. Finally, we discuss how sub-TeV absorption features in the spectra
of BL Lac objects may affect their broadband modeling, and eventually represent
a powerful diagnostic tool to constrain the gamma-ray production site and the
jet environment.
【16】 Efficient modeling of correlated noise. III. Scalable methods for jointly modeling several observables' time series with Gaussian processes
标题：相关噪声的高效建模。三、高斯过程联合建模多个观测值时间序列的可伸缩性方法
链接：https://arxiv.org/abs/2201.02440
备注：Accepted for publication in A&A
摘要：The radial velocity method is a very productive technique used to detect and
confirm extrasolar planets. The most recent spectrographs, such as ESPRESSO or
EXPRES, have the potential to detect Earth-like planets around Sun-like stars.
However, stellar activity can induce radial velocity variations that dilute or
even mimic the signature of a planet. A widely recognized method for
disentangling these signals is to model the radial velocity time series,
jointly with stellar activity indicators, using Gaussian processes and their
derivatives. However, such modeling is prohibitive in terms of computational
resources for large data sets, as the cost typically scales as the total number
of measurements cubed.
Here, we present S+LEAF 2, a Gaussian process framework that can be used to
jointly model several time series, with a computational cost that scales
linearly with the data set size. This framework thus provides a
state-of-the-art Gaussian process model, with tractable computations even for
large data sets.
We illustrate the power of this framework by reanalyzing the 246 HARPS radial
velocity measurements of the nearby K2 dwarf HD 138038, together with two
activity indicators. We reproduce the results of a previous analysis of these
data, but with a strongly decreased computational cost (more than two order of
magnitude). The gain would be even greater for larger data sets.
【17】 Discovery of C5H+ and detection of C3H+ in TMC-1 with the QUIJOTE line survey
标题：TMC-1中C_5H~+的发现及用吉若特线测量检测C~3H~+
链接：https://arxiv.org/abs/2201.02434
备注：Accepted for publication in A&A Letters on January 5th
摘要：We report the discovery of the C5H+ cation toward TMC-1 with the QUIJOTE line
survey. Four lines from J=7-6 up to J=10-9 have been identified in perfect
harmonic frequency relation that can be fit with B=2411.94397 +/-0.00055 MHz
and D=138+/-3 Hz. The standard deviation of the fit is 4.4 kHz. After
discarding potential candidates, C5H- among them, we conclude that the carrier
is C5H+, for which accurate ab initio calculations provide B=2410.3 MHz. We
also report for the first time in a cold starless core the detection of the
C3H+ cation. The column densities we derive for C5H+ and C3H+ are
(8.8+/-0.5)e10 cm-2 and (2.4+/-0.2)e10 cm-2, respectively. Hence, the C5H+/C3H+
abundance ratio is 3.7+/-0.5. The fact that C5H+ is more abundant than C3H+ is
well explained by dedicated chemical models and is due to the slow reactivity
of C5H+ with H2, while C3H+ reacts with H2.
【18】 Substructure in the stellar halo near the Sun. II. Characterisation of independent structures
标题：太阳附近恒星晕中的子结构。II.独立结构的特性
链接：https://arxiv.org/abs/2201.02405
备注：22 pages (12 extra pages in appendix), 16 figures, 13 tables. Submitted to A&A. This paper is the second of a series of papers. Paper I, by L\"ovdal et al., has been submitted simultaneously and can be found in this listing
摘要：Context: In an accompanying paper by L\"ovdal et al, we presented a
data-driven method for clustering in Integrals of Motion space and applied it
to a large sample of nearby halo stars with 6D phase-space information. Aims:
Our goal is to establish the reality of the clusters and groups through a
combined study of their stellar populations to gain insights into the accretion
history of the Milky Way. Methods: We develop a procedure that quantifies the
similarity of clusters based on the Kolmogorov-Smirnov test using their
metallicity distribution functions, and an isochrone fitting method to
determine their average age, which is also used to compare the distribution of
stars in the Colour-Absolute magnitude diagram. Considering their distributions
in Integrals of Motion space as well, this allows us to group clusters into
substructures, and to compare substructures with one another. Results: We find
that the 67 clusters identified by our algorithm can be merged into 12 extended
substructures, while eight small clusters remain as such. The large
substructures include the previously known Gaia-Enceladus, Helmi streams,
Sequoia, and Thamnos 1 and 2. We identify a few overdensities that can be
associated with the hot thick disc and which host a small metal-poor
population. Especially notable is the largest substructure in our sample which,
although peaking at the metallicity characteristic of the thick disk has a very
well populated metal-poor component, and dynamics intermediate between the hot
thick disc and the halo. We also identify additional debris in the region
occupied by Sequoia with clearly distinct kinematics. Although only a small
subset of the stars in our sample have chemical abundance information, we are
able to identify different trends of [Mg/Fe] vs [Fe/H] for the various
substructures confirming our dissection of the nearby halo. Conclusions: We
find... [abridged version]
【19】 Substructure in the stellar halo near the Sun. I. Data-driven clustering in Integrals of Motion space
标题：太阳附近恒星晕中的子结构。I.运动空间积分中的数据驱动聚类
链接：https://arxiv.org/abs/2201.02404
备注：15 pages, 14 figures, 2 tables Submitted to A&A. This is the first in a series of papers, the second (Ruiz-Lara et al.) can be found in this listing
摘要：Aims: Develop a data-driven and statistically based method for finding such
clumps in Integrals of Motion space for nearby halo stars and evaluating their
significance robustly. Methods: We use data from Gaia EDR3 extended with radial
velocities from ground-based spectroscopic surveys to construct a sample of
halo stars within 2.5 kpc from the Sun. We apply a hierarchical clustering
method that uses the single linkage algorithm in a 3D space defined by the
commonly used integrals of motion energy $E$, together with two components of
the angular momentum, $L_z$ and $L_\perp$. To evaluate the statistical
significance of the clusters found, we compare the density within an
ellipsoidal region centered on the cluster to that of random sets with similar
global dynamical properties. We pick out the signal at the location of their
maximum statistical significance in the hierarchical tree. We estimate the
proximity of a star to the cluster center using the Mahalanobis distance. We
also apply the HDBSCAN clustering algorithm in velocity space. Results: Our
procedure identifies 67 highly significant clusters ($ > 3\sigma$), containing
12\% of the sources in our halo set, and in total 232 subgroups or individual
streams in velocity space. In total, 13.8\% of the stars in our data set can be
confidently associated to a significant cluster based on their Mahalanobis
distance. Inspection of our data set reveals a complex web of relationships
between the significant clusters, suggesting that they can be tentatively
grouped into at least 6 main structures, many of which can be associated to
previously identified halo substructures, and a number of independent
substructures. This preliminary conclusion is further explored in an
accompanying paper by Ruiz-Lara et al., where we also characterize the
substructures in terms of their stellar populations. Conclusions: We find...
(abridged version)
【20】 The Dynamic Coupling of Streamers and Pseudostreamers to the Heliosphere
标题：流光和假流光与日光层的动态耦合
链接：https://arxiv.org/abs/2201.02388
摘要：The slow solar wind is generally believed to result from the interaction of
open and closed coronal magnetic flux at streamers and pseudostreamers. We use
3-dimensional magnetohydrodynamic simulations to determine the detailed
structure and dynamics of open-closed interactions that are driven by
photospheric convective flows. The photospheric magnetic field model includes a
global dipole giving rise to a streamer together with a large parasitic
polarity region giving rise to a pseudostreamer that separates a satellite
coronal hole from the main polar hole. Our numerical domain extends out to 30
solar radii and includes an isothermal solar wind, so that the coupling between
the corona and heliosphere can be calculated rigorously. This system is driven
by imposing a large set of quasi-random surface flows that capture the driving
of coronal flux in the vicinity of streamer and pseudostreamer boundaries by
the supergranular motions. We describe the resulting structures and dynamics.
Interchange reconnection dominates the evolution at both streamer and
pseudostreamer boundaries, but the details of the resulting structures are
clearly different from one another. Additionally, we calculate in situ
signatures of the reconnection and determine the dynamic mapping from the inner
heliosphere back to the Sun for a test spacecraft orbit. We discuss the
implications of our results for interpreting observations from inner
heliospheric missions, such as Parker Solar Probe and Solar Orbiter, and for
space weather modeling of the slow solar wind.
【21】 The prototype X-ray binary GX 339-4: using TeV gamma-rays to assess LMXBs as Galactic cosmic ray accelerators
标题：原型X射线双星GX339-4：用TeV伽马射线评估LMXB作为银河系宇宙线加速器
链接：https://arxiv.org/abs/2201.02379
备注：13 pages, 12 figures, accepted to MNRAS
摘要：Since the discovery of cosmic rays (CRs) over a century ago, their origin
remains an open question. Galactic CRs with energy up to the knee ($10^{15}$
eV) are considered to originate from supernova remnants, but this scenario has
recently been questioned due to lack of TeV $\gamma$-ray counterparts in many
cases. Extragalactic CRs on the other hand, are thought to be associated with
accelerated particles in the relativistic jets launched by supermassive
accreting black holes at the center of galaxies. Scaled down versions of such
jets have been detected in X-ray binaries hosting a stellar black hole (BHXBs).
In this work, we investigate the possibility that the smaller-scale jets in
transient outbursts of low-mass BHXBs could be sources of Galactic CRs. To
better test this scenario, we model the entire electromagnetic spectrum of such
sources focusing on the potential TeV regime, using the `canonical' low-mass
BHXB GX 339-4 as a benchmark. Taking into account both the leptonic radiative
processes and the $\gamma$-rays produced via neutral pion decay from inelastic
hadronic interactions, we predict the GeV and TeV $\gamma$-ray spectrum of GX
339-4 using lower-frequency emission as constraints. Based on this test-case of
GX 339-4 we investigate whether other, nearby low-mass BHXBs could be detected
by the next-generation very-high-energy $\gamma$-ray facility the Cherenkov
Telescope Array, which would establish them as additional and numerous
potential sources of CRs in the Galaxy.
【22】 Energy transfer, discontinuities and heating in the inner solar wind measured with a weak and local formulation of the Politano-Pouquet law
标题：用波利塔诺-普奎定律的弱局域公式测量内太阳风中的能量转移、间断和加热
链接：https://arxiv.org/abs/2201.02377
备注：13 pages, 9 figures, submitted to The Astrophysical Journal
摘要：The solar wind is a highly turbulent plasma for which the mean rate of energy
transfer $\varepsilon$ has been measured for a long time using the
Politano-Pouquet (PP98) exact law. However, this law assumes statistical
homogeneity that can be violated by the presence of discontinuities. Here, we
introduce a new method based on the inertial dissipation $\Dis$ whose
analytical form is derived from incompressible magnetohydrodynamics (MHD); it
can be considered as a weak and {\it local} (in space) formulation of the PP98
law whose expression is recovered after integration is space. We used $\Dis$ to
estimate the local energy transfer rate from the \textit{THEMIS-B} and
\textit{Parker Solar Probe} (PSP) data taken in the solar wind at different
heliospheric distances. Our study reveals that discontinuities near the Sun
lead to a strong energy transfer that affects a wide range of scales $\sigma$.
We also observe that switchbacks seem to be characterized by a singular
behavior with an energy transfer varying as $\sigma^{-3/4}$, which slightly
differs from classical discontinuities characterized by a $\sigma^{-1}$
scaling. A comparison between the measurements of $\varepsilon$ and $\Dis$
shows that in general the latter is significantly larger than the former.
【23】 A model of double coronal hard X-ray sources in solar flares
标题：太阳耀斑中的双冕硬X射线源模型
链接：https://arxiv.org/abs/2201.02293
备注：Submitted to ApJL
摘要：A number of double coronal X-ray sources have been observed during solar
flares by RHESSI, where the two sources reside at different sides of the
inferred reconnection site. However, where and how are these X-ray-emitting
electrons accelerated remains unclear. Here we present the first model of the
double coronal hard X-ray (HXR) sources, where electrons are accelerated by a
pair of termination shocks driven by bi-directional fast reconnection outflows.
We model the acceleration and transport of electrons in the flare region by
numerically solving the Parker transport equation using velocity and magnetic
fields from the macroscopic magnetohydrodynamic simulation of a flux rope
eruption. We show that electrons can be efficiently accelerated by the
termination shocks and high-energy electrons mainly concentrate around the two
shocks. The synthetic HXR emission images display two distinct sources
extending to $>$100 keV below and above the reconnection region, with the upper
source much fainter than the lower one. The HXR energy spectra of the two
coronal sources show similar spectral slopes, consistent with the observations.
Our simulation results suggest that the flare termination shock can be a
promising particle acceleration mechanism in explaining the double-source
nonthermal emissions in solar flares.
【24】 Properties of Molecular Gas in Galaxies in Early and Mid Stages of Interaction. III. Resolved Kennicutt-Schmidt Law
标题：相互作用早期和中期星系中分子气体的性质。III.解决的Kennicutt-Schmidt定律
链接：https://arxiv.org/abs/2201.02270
备注：40 pages, 15 figures, 10 tables; accepted for publication in PASJ
摘要：We study properties of the interstellar medium, an ingredient of stars, and
star formation activity, in four nearby galaxy pairs in the early and mid
stages of interaction for both a galaxy scale and a kpc scale. The galaxy-scale
Kennicutt-Schmidt law shows that seven of eight interacting galaxies have a
star formation rate within a factor of three compared with the best-fit of the
isolated galaxies, although we have shown that molecular hydrogen gas is
efficiently produced from atomic hydrogen during the interaction in the
previous paper. The galaxy-scale specific star formation rate (sSFR) and star
formation efficiency (SFE) in interacting galaxies are comparable to those in
isolated galaxies. We also investigate SFE and the Kennicutt-Schmidt law on a
kpc scale. The spatial distributions of SFE reveal that SFE is locally
enhanced, and the enhanced regions take place asymmetrically or at off-centre
regions. The local enhancement of SFE could be induced by shock. We find that
the index of the Kennicutt-Schmidt law for the interacting galaxies in the
early stage is 1.30$\pm$0.04, which is consistent with that of the isolated
galaxies. Since CO emission, which is used in the Kennicutt-Schmidt law, is a
tracer of the amount of molecular gas, this fact suggests that dense gas, which
is more directly connected to star formation, is not changed at the early stage
of interaction.
【25】 Strong H$_2$O and CO emission features in the spectrum of KELT-20b driven by stellar UV irradiation
标题：恒星紫外辐射驱动的KELT-20b光谱中强H$_2$O和CO发射特征
链接：https://arxiv.org/abs/2201.02261
备注：9 pages, 3 figures, 1 table, accepted to ApJL
摘要：Know thy star, know thy planetary atmosphere. Every exoplanet with
atmospheric measurements orbits around a star, and the stellar environment
directly affects the planetary atmosphere. Here we present the emission
spectrum of ultra-hot Jupiter KELT-20b which provides an observational link
between host star properties and planet atmospheric thermal structure. It is
currently the only planet with thermal emission measurements in the
$T_{eq}\sim$2200K range that orbits around an early A-type star. By comparing
it with other similar ultra-hot Jupiters around FGK stars, we can better
understand how different host star types influence planetary atmospheres. The
emission spectrum covers 0.6 to 4.5 $\mu m$ with data from TESS, HST WFC3/G141,
and Spitzer 4.5 $\mu m$ channel. KELT-20b has a 1.4 $\mu m$ water feature
strength metric of S$_{H_2O}$ = -0.097$\pm$0.02 and a blackbody brightness
temperature difference of 528K between WFC3/G141 (T$_b$=2402$\pm$14K) and
Spitzer 4.5 $\mu m$ channel (T$_b$=2930$\pm59$K). These very large H$_2$O and
CO emission features combined with the A-type host star make KELT-20b a unique
planet among other similar hot Jupiters. The abundant FUV, NUV, and optical
radiation from its host star (T$_{eff}=8720\pm250$K) is expected to be the key
that drives its strong thermal inversion and prominent emission features based
on previous PHOENIX models calculations.
【26】 New binary black hole mergers in the LIGO--Virgo O3a data
标题：LIGO中新的双星黑洞合并--室女座O3a数据
链接：https://arxiv.org/abs/2201.02252
备注：13 pages, 6 figures, 2 tables, 4 appendices (15 pages, 15 figures)
摘要：We report the detection of ten new binary black hole (BBH) merger signals in
the publicly released data from the the first half of the third observing run
(O3a) of advanced LIGO and advanced Virgo. Candidates are identified using an
updated version of the IAS pipeline (Venumadhav et al.), and events are
declared according to criteria similar to those in the GWTC-2.1 catalog (Abbott
et al.). The updated search is sensitive to a larger region of parameter space,
applies a template prior that accounts for different search volume as a
function of intrinsic parameters, and uses an improved coherent detection
statistic that optimally combines data from the Hanford and Livingston
detectors. Among the ten new events, we find interesting astrophysical
scenarios including sources with confidently large effective spin in both the
positive and negative directions, high-mass black holes that are difficult to
form in stellar collapse models due to (pulsational) pair instability, and
low-mass mergers bridging the gap between neutron stars and the lightest
observed black holes. We detect events populating the upper and lower black
hole mass gaps with both extreme and near-unity mass ratios, and one of the
possible neutron star--black hole mergers is well localized for electromagnetic
counterpart searches. We see a substantial increase in significance for many of
the events previously reported by other pipelines, and we detect all of the
GWTC-2.1 BBH mergers with coincident data in Hanford and Livingston except for
three loud events that get vetoed (compatible with the false-positive rate of
our veto procedure) and three that fall below the detection threshold. We also
return to significance the event GW190909_114149, which was reduced to a
sub-threshold trigger in GWTC-2.1. This makes a total of 42 BBH mergers
detected by our pipeline's Hanford--Livingston coincident search of the O3a
data.
【27】 Magnetic fields in the formation of the first stars.--II Results
标题：第一批恒星形成过程中的磁场--II结果
链接：https://arxiv.org/abs/2201.02225
备注：31 pages, 30 figures, submitted to MNRAS
摘要：Beginning with cosmological initial conditions at z=100, we simulate the
effects of magnetic fields on the formation of Population III stars and compare
our results with the predictions of Paper I. We use Gadget-2 to follow the
evolution of the system while the field is weak. We introduce a new method for
treating kinematic fields by tracking the evolution of the deformation tensor.
The growth rate in this stage of the simulation is lower than expected for
diffuse astrophysical plasmas, which have a very low resistivity (high magnetic
Prandtl number); we attribute this to the large numerical resistivity in
simulations, corresponding to a magnetic Prandtl number of order unity. When
the magnetic field begins to be dynamically significant in the core of the
minihalo at z=27, we map it onto a uniform grid and follow the evolution in an
adaptive mesh refinement, MHD simulation in Orion2. The nonlinear evolution of
the field in the Orion2 simulation violates flux-freezing and is consistent
with the theory proposed by Xu & Lazarian. The fields approach equipartition
with kinetic energy at densities ~ 10^10 - 10^12 cm^-3. When the same
calculation is carried out in Orion2 with no magnetic fields, several
protostars form, ranging in mass from ~ 1 to 30 M_sol with magnetic fields,
only a single ~ 30 M_sol protostar forms by the end of the simulation. Magnetic
fields thus suppress the formation of low-mass Pop III stars, yielding a
top-heavy Pop III IMF and contributing to the absence of observed Pop III
stars.
【28】 Modeling the γ-ray Pulsar Wind Nebulae population in our Galaxy
标题：模拟我们银河系中γ射线脉冲星风星云的数量
链接：https://arxiv.org/abs/2201.02221
备注：15 pages, 8 figures, 2 tables. Accepted for publication in Monthly Notices of the Royal Astronomical Society
摘要：Pulsar wind nebulae (PWNe) represent the largest class of sources that
upcoming {\gamma}-ray surveys will detect. Therefore, accurate modelling of
their global emission properties is one of the most urgent problems in
high-energy astrophysics. Correctly characterizing these dominant objects is a
needed step to allow {\gamma}-ray surveys to detect fainter sources,
investigate the signatures of cosmic-ray propagation and estimate the diffuse
emission in the Galaxy. In this paper we present an observationally motivated
construction of the Galactic PWNe population. We made use of a modified
one-zone model to evolve for a long period of time the entire population. The
model provides, for every source, at any age, a simplified description of the
dynamical and spectral evolution. The long term effects of the reverberation
phase on the spectral evolution are described, for the first time, based on
physically motivated prescriptions for the evolution of the nebular radius
supported by numerical studies. This effort tries to solve one of the most
critical aspects of one-zone modeling, namely the typical overcompression of
the nebula during the reverberation phase, resulting in a strong modification
of its spectral properties at all frequencies. We compare the emission
properties of our synthetic Pulsar Wind Nebulae population with the most
updated catalogues of TeV Galactic sources. We find that the firmly identified
and candidate PWNe sum up to about 50% of the expected objects in this class
above threshold for detection. Finally, we estimate that CTA will increase the
number of TeV detected PWNe by a factor$\geq3$.
【29】 LRG-BEASTS: sodium absorption and Rayleigh scattering in the atmosphere of WASP-94A b using NTT/EFOSC2
标题：LRG-BESTS：使用NTT/EFOSC2在WASP-94A b大气中的钠吸收和瑞利散射
链接：https://arxiv.org/abs/2201.02212
备注：16 pages, 15 figures, 6 tables, accepted for publication in MNRAS
摘要：We present an optical transmission spectrum for WASP-94A b, the first
atmospheric characterisation of this highly-inflated hot Jupiter. The planet
has a reported radius of $1.72^{+0.06}_{-0.05}$ R$_{\textrm{Jup}}$, a mass of
only $0.456^{+0.032}_{-0.036}$ M$_{\textrm{Jup}}$, and an equilibrium
temperature of $1508 \pm 75$ K. We observed the planet transit
spectroscopically with the EFOSC2 instrument on the ESO New Technology
Telescope (NTT) at La Silla, Chile: the first use of NTT/EFOSC2 for
transmission spectroscopy. We achieved an average transit-depth precision of
$128$ ppm for bin widths of $\sim200$ Angstrom. This high precision was
achieved in part by linking Gaussian Process hyperparameters across all
wavelength bins. The resulting transmission spectrum, spanning a wavelength
range of $3800 - 7140$ Angstrom, exhibits a sodium absorption with a
significance of $4.9\sigma$, suggesting a relatively cloud-free atmosphere. The
sodium signal may be broadened, with a best fitting width of $78_{-32}^{+67}$
Angstrom in contrast to the instrumental resolution of $27.2 \pm 0.2$ Angstrom.
We also detect a steep slope in the blue end of the transmission spectrum,
indicating the presence of Rayleigh scattering in the atmosphere of WASP-94A b.
Retrieval models show evidence for the observed slope to be super-Rayleigh and
potential causes are discussed. Finally, we find narrow absorption cores in the
CaII H&K lines of WASP-94A, suggesting the star is enshrouded in gas escaping
the hot Jupiter.
【30】 Imprints of fermionic and bosonic mixed dark matter on the 21-cm signal at cosmic dawn
标题：宇宙黎明时分21厘米信号上费米子和玻色子混合暗物质的印记
链接：https://arxiv.org/abs/2201.02210
备注：18 pages, 9 figures, comments welcome
摘要：The 21-cm signal from the epoch of cosmic dawn prior to reionization consists
of a promising observable to gain new insights into the dark matter (DM)
sector. In this paper, we investigate its potential to constrain mixed (cold +
non-cold) dark matter scenarios that are characterised by the non-cold DM
fraction ($f_{\rm nCDM}$) and particle mass ($m_{\rm nCDM}$). As non-cold DM
species, we investigate both a fermionic (sterile neutrino) and a bosonic
(ultra-light axion) particle. We show how these scenarios affect the global
signal and the power spectrum using a halo-model implementation of the 21-cm
signal at cosmic dawn. Next to this study, we perform an inference-based
forecast study based on realistic mock power spectra from the Square Kilometre
Array (SKA) telescope. Assuming inefficient, yet non-zero star-formation in
minihaloes (i.e. haloes with mass below $10^8$ M$_{\odot}$), we obtain
stringent constraints on both $m_{\rm nCDM}$ and $f_{\rm nCDM}$ that go well
beyond current limits. Regarding the special case of $f_{\rm nCDM}\sim 1$, for
example, we find a constraint of $m_{\rm nCDM}>15$ keV (thermal mass) for
fermionic DM and $m_{\rm nCDM}>2\times10^{-20}$ eV for bosonic DM. For the
opposite case of dominating cold DM, we find that at most one percent of the
total DM abundance can be made of a hot fermionic or bosonic relic. All
constraints are provided at the 95 percent confidence level.
【31】 A 2-3 mm high-resolution molecular line survey towards the centre of the nearby spiral galaxy NGC 6946
标题：对附近螺旋星系NGC6946中心的2-3毫米高分辨率分子线测量
链接：https://arxiv.org/abs/2201.02209
备注：38 pages, 23 figures, accepted for publication in A&A
摘要：The complex physical, kinematic, and chemical properties of galaxy centres
make them interesting environments to examine with molecular line emission. We
present new $2-4$" (${\sim}75{-}150$ pc at $7.7$ Mpc) observations at 2 and 3
mm covering the central $50$" (${\sim}1.9$ kpc) of the nearby double-barred
spiral galaxy NGC 6946 obtained with the IRAM Plateau de Bure Interferometer.
We detect spectral lines from ten molecules: CO, HCN, HCO$^+$, HNC, CS,
HC$_3$N, N$_2$H$^+$, C$_2$H, CH$_3$OH, and H$_2$CO. We complemented these with
published 1mm CO observations and 33 GHz continuum observations to explore the
star formation rate surface density ${\Sigma_{\mathrm{SFR}}}$ on 150 pc scales.
In this paper, we analyse regions associated with the inner bar of NGC 6946 $-$
the nuclear region (NUC), the northern (NBE), and southern inner bar end (SBE)
and we focus on short-spacing corrected bulk (CO) and dense gas tracers (HCN,
HCO$^+$, and HNC). We find that HCO$^+$ correlates best with
${\Sigma_{\mathrm{SFR}}}$, but the dense gas fraction ($f_{\mathrm{dense}}$)
and star formation efficiency of the dense gas (${\mathrm{SFE_{dense}}}$) fits
show different behaviours than expected from large-scale disc observations.The
SBE has a higher ${\Sigma_{\mathrm{SFR}}}$, $f_{\mathrm{dense}}$, and shocked
gas fraction than the NBE. We examine line ratio diagnostics and find a higher
CO(2-1)/CO(1-0) ratio towards NBE than for the NUC. Moreover, comparison with
existing extragalactic datasets suggests that using the HCN/HNC ratio to probe
kinetic temperatures is not suitable on kiloparsec and sub-kiloparsec scales in
extragalactic regions. Lastly, our study shows that the HCO$^+$/HCN ratio might
not be a unique indicator to diagnose AGN activity in galaxies.
【32】 Quasar Feedback Survey: Multi-phase outflows, turbulence and evidence for feedback caused by low power radio jets inclined into the galaxy disk
标题：类星体反馈调查：低功率射电喷流倾斜进入星系盘引起的多相外流、湍流和反馈证据
链接：https://arxiv.org/abs/2201.02208
备注：Accepted for publication in MNRAS. Main manuscript has 21 pages with 8 figures. Supplementary material is available for download under "Ancillary files" or by downloading the source file listed under "Other formats"
摘要：We present a study of a luminous, z=0.15, type-2 quasar (log
[L([OIII])/(erg/s)]=42.8) from the Quasar Feedback Survey. It is classified as
'radio-quiet' (log [L(1.4 GHz)/(W/Hz)]=23.8); however, radio imaging reveals ~1
kpc low-power jets (log [Pjet/(erg/s)]=44) inclined into the plane of the
galaxy disk. We combine MUSE and ALMA observations to map stellar kinematics
and ionised and molecular gas properties. The jets are seen to drive
galaxy-wide bi-conical turbulent outflows, reaching W80 = 1000-1300 km/s, in
the ionised phase (traced via optical emission-lines), which also have
increased electron densities compared to the quiescent gas. The turbulent gas
is driven perpendicular to the jet axis and is escaping along the galaxy minor
axis, reaching 7.5 kpc on both sides. Traced via CO(3-2) emission, the
turbulent material in molecular gas phase is one-third as spatially extended
and has 3 times lower velocity-dispersion as compared to ionised gas. The jets
are seen to be strongly interacting with the interstellar medium (ISM) through
enhanced ionised emission and disturbed/depleted molecular gas at the jet
termini. We see further evidence for jet-induced feedback through significantly
higher stellar velocity-dispersion aligned, and co-spatial with, the jet axis
(<5 deg). We discuss possible negative and positive feedback scenarios arising
due to the interaction of the low-power jets with the ISM in the context of
recent jet-ISM interaction simulations, which qualitatively agree with our
observations. We discuss how jet-induced feedback could be an important
feedback mechanism even in bolometrically luminous 'radio-quiet' quasars.
【33】 The nebular properties of star-forming galaxies at intermediate redshift from the Large Early Galaxy Astrophysics Census
标题：星系早期天体物理普查中红移的恒星形成星系的星云特性
链接：https://arxiv.org/abs/2201.02207
备注：Submitted to ApJ; main text 19 pages, 12 figures and 5 tables
摘要：We present a detailed study of the partial rest-optical
($\lambda_{\mathrm{obs}} \approx 3600-5600\,\r{A}$) spectra of $N = 328$
star-forming galaxies at $0.6 < z < 1.0$ from the Large Early Galaxy
Astrophysics Census (LEGA-C). We compare this sample with low-redshift ($z \sim
0$) galaxies from the Sloan Digital Sky Survey (SDSS), intermediate-redshift
($z \sim 1.6$) galaxies from the Fiber Multi-Object Spectrograph (FMOS)-COSMOS
Survey, and high-redshift ($z \sim 2$) galaxies from the Keck Baryonic
Structure Survey (KBSS). At a lookback time of $6-8\ \mathrm{Gyr}$, galaxies
with stellar masses $\mathrm{log}(\mathrm{M_{\ast}/M_{\odot}}) > 10.25$ appear
remarkably similar to $z \sim 0$ galaxies in terms of their nebular excitation,
as measured using $\mathrm{[O\,III]}\lambda5008 / \mathrm{H}\beta$. There is
some evidence that $0.6 < z < 1.0$ galaxies with lower $\mathrm{M_{\ast}}$ have
higher $\mathrm{[O\,III]}\lambda5008 / \mathrm{H}\beta$ than $z \sim 0$
galaxies and are more similar to less evolved $z \sim 1.6$ and $z \sim 2$
galaxies, which are offset from the $z \sim 0$ locus at all
$\mathrm{M_{\ast}}$. We explore the impact selection effects, contributions
from active galactic nuclei, and variations in physical conditions (ionization
parameter and gas-phase oxygen abundance) have on the apparent distribution of
$\mathrm{[O\,III]}\lambda5008 / \mathrm{H}\beta$ and find somewhat higher
ionization and lower enrichment in $0.6 < z < 1.0$ galaxies with lower
$\mathrm{M_{\ast}}$ relative to $z \sim 0$ galaxies. We use new near-infrared
spectroscopic observations of $N = 53$ LEGA-C galaxies to investigate other
probes of enrichment and excitation. Our analysis demonstrates the importance
of obtaining complete rest-optical spectra of galaxies in order to disentangle
these effects.
【34】 Finding Evidence for Inflation and the Origin of Galactic Magnetic Fields with CMB Surveys
标题：用CMB观测寻找暴涨的证据和银河系磁场的起源
链接：https://arxiv.org/abs/2201.02204
备注：7 pages, 2 figures
摘要：The origin of the $\mu\mathrm{G}$ magnetic fields observed in galaxies is
unknown. One promising scenario is that magnetic fields generated during
inflation, larger than 0.1 $\mathrm{nG}$ on Mpc scales, were adiabatically
compressed to $\mu\mathrm{G}$ strengths in galaxies during structure formation.
Thus, detecting a scale-invariant primordial magnetic field (PMF) above
$0.1\,\mathrm{nG}$ on Mpc scales just after recombination would indicate an
inflationary origin of galactic magnetic fields. This would also provide
compelling evidence that inflation occurred since only an inflationary
mechanism could generate such a strong, scale-invariant magnetic field on Mpc
scales. In contrast, constraining the scale-invariant PMF strength to be below
$0.1\,\mathrm{nG}$ would imply an inflationary scenario is not the primary
origin, since such weak PMFs cannot be amplified enough via adiabatic
compression to produce the strength of the galactic fields we observe today. We
find that measurements of anisotropic birefringence by future CMB surveys will
be able to improve the sensitivity to Mpc-scale inflationary PMFs by an order
of magnitude, and, in particular, that CMB-HD would lower the upper bound to
$0.072\,\mathrm{nG}$ at the $95\%$ CL, which is below the critical
$0.1\,\mathrm{nG}$ threshold for ruling out a purely inflationary origin. If
inflationary PMFs exist, we find that a CMB-HD survey would be able to detect
them with about $3\sigma$ significance or higher, providing evidence for
inflation itself.
【35】 Cosmology with one galaxy?
标题：只有一个星系的宇宙学？
链接：https://arxiv.org/abs/2201.02202
备注：20+6 pages, 15 figures, data and codes to reproduce the results publicly available at this https URL
摘要：Galaxies can be characterized by many internal properties such as stellar
mass, gas metallicity, and star-formation rate. We quantify the amount of
cosmological and astrophysical information that the internal properties of
individual galaxies and their host dark matter halos contain. We train neural
networks using hundreds of thousands of galaxies from 2,000 state-of-the-art
hydrodynamic simulations with different cosmologies and astrophysical models of
the CAMELS project to perform likelihood-free inference on the value of the
cosmological and astrophysical parameters. We find that knowing the internal
properties of a single galaxy allow our models to infer the value of
$\Omega_{\rm m}$, at fixed $\Omega_{\rm b}$, with a $\sim10\%$ precision, while
no constraint can be placed on $\sigma_8$. Our results hold for any type of
galaxy, central or satellite, massive or dwarf, at all considered redshifts,
$z\leq3$, and they incorporate uncertainties in astrophysics as modeled in
CAMELS. However, our models are not robust to changes in subgrid physics due to
the large intrinsic differences the two considered models imprint on galaxy
properties. We find that the stellar mass, stellar metallicity, and maximum
circular velocity are among the most important galaxy properties to determine
the value of $\Omega_{\rm m}$. We believe that our results can be explained
taking into account that changes in the value of $\Omega_{\rm m}$, or
potentially $\Omega_{\rm b}/\Omega_{\rm m}$, affect the dark matter content of
galaxies. That effect leaves a distinct signature in galaxy properties to the
one induced by galactic processes. Our results suggest that the low-dimensional
manifold hosting galaxy properties provides a tight direct link between
cosmology and astrophysics.
【36】 Fieldable Muon Momentum Measurement using Coupled Pressurized Gaseous Cherenkov Detectors
标题：用耦合加压气态切伦科夫探测器测量可场µ子动量
链接：https://arxiv.org/abs/2201.02591
备注：Transactions of American Nuclear Society Winter meeting, 125 (1), 400-403, 2021
摘要：Cosmic ray muons present a large part of the radiation background and
depending on the application of interest muons can be seen as background noise,
e.g., radiation mapping, radiation protection, dosimetry, or as a useful
interrogation probe such as cosmic ray muon tomography. It is worth noting
recent developments on muon scattering tomography which has emerged as a
prospective noninvasive monitoring method for many applications including spent
nuclear fuel cask monitoring and geotomography. However, it is still very
challenging to measure muon momentum in the field, despite the apparent
benefits, without resorting to large and expensive calorimeters, ring imagers,
or time of flight detectors. Recent efforts at CNL and INFN have developed
large prototypes based on multiple Coulomb scattering coupled with the muon
momentum reconstruction algorithms. While these efforts show promise, no
portable detectors exist that can measure muon momentum in the field. In this
work, we present a new concept for measuring muon momentum using coupled
pressurized gaseous Cherenkov radiators. By carefully selecting the gas
pressure at each radiator we can optimize the muon momentum threshold for which
a muon signal will be detected. This way, a muon passing through the radiators
will only trigger those radiators with momentum threshold less than the actual
muon momentum. By measuring the presence of Cherenkov signals in each radiator,
our system can then estimate the muon momentum. The primary benefit of such a
concept is that it can be compact and portable enough so that it can be
deployed in the field separately or in combination with existing tomography
systems.
【37】 Merger rate of charged black holes from the dynamical capture
标题：动态俘获的带电黑洞合并率
链接：https://arxiv.org/abs/2201.02581
备注：19 pages, 1 figures, Comments are welcome
摘要：We consider the dynamical capture of black holes carrying U(1) charge which
can not only correspond to electric or magnetic charge but also have other
physical interpretations such as dark or hidden charge. In the low-velocity and
weak-field regime, we study gravitational and electromagnetic radiations from
point masses with U(1) charges in a hyperbolic orbit, and we develop a
formalism to derive the merger rate of charged black holes from the dynamical
capture. We apply the formalism to find the effects of the charge-to-mass ratio
on the merger rate for possible different cases and discover that the effects
depend on the models.
【38】 Constraints on Einstein-dilation-Gauss-Bonnet gravity from Black Hole-Neutron Star Gravitational Wave Events
标题：黑洞-中子星引力波事件对爱因斯坦膨胀高斯引力帽引力的制约
链接：https://arxiv.org/abs/2201.02543
备注：11 pages, 5 figures
摘要：Recent gravitational wave observations allow us to probe gravity in the
strong and dynamical field regime. In this paper, we focus on testing
Einstein-dilation Gauss-Bonnet gravity which is motivated by string theory. In
particular, we use two new neutron star black hole binaries (GW200105 and
GW200115). We also consider GW190814 which is consistent with both a binary
black hole and a neutron star black hole binary. Adopting the leading
post-Newtonian correction and carrying out a Bayesian Markov-chain Monte Carlo
analyses, we derive the 90\% credible upper bound on the coupling constant of
the theory as $\sqrt{\alpha_{GB}} \lesssim 1.33\,\rm km$, whose consistency is
checked with an independent Fisher analysis. This bound is stronger than the
bound obtained in previous literature by combining selected binary black hole
events in GWTC-1 and GWTC-2 catalogs. We also derive a combined bound of
$\sqrt{\alpha_{GB}} \lesssim 1.18\,\rm km$ by stacking GW200105, GW200115,
GW190814, and selected binary black hole events. In order to check the validity
of the effect of higher post-Newtonian terms, we derive corrections to the
waveform phase up to second post Newtonian order by mapping results in
scalar-tensor theories to Einstein-dilation Gauss-Bonnet gravity. We find that
such higher-order terms improve the bounds by $14.5\%$ for GW200105 and $6.9\%$
for GW200115 respectively.
【39】 Inflation -- a Comparative Study Amongst Different Modified Gravity Theories
标题：膨胀--不同修正引力理论的比较研究
链接：https://arxiv.org/abs/2201.02473
备注：None
摘要：In the recent years, a host of modified gravity models have been proposed as
alternatives to the dark energy. A quantum theory of gravity also requires to
modify `General Theory of Relativity'. In the present article, we consider five
different modified theories of gravity, and compare inflationary parameters
with recent data sets released by two Planck collaboration teams. Our analysis
reveals that the scalar-tensor theory of gravity is the best alternative.
【40】 Ghost instability in the teleparallel gravity model with parity violations
标题：具有宇称破缺的遥平行引力模型中的鬼不稳定性
链接：https://arxiv.org/abs/2201.02357
备注：9 pages, 0 figure, teleparallel gravity, parity violation
摘要：In this paper we consider the parity violating gravity model within the
framework of teleparallel gravity. The parity violations are caused by the
couplings of a scalar field to the scalar invariants which are parity-odd and
quadratic in the torsion tensor. Totally there are two such type independent
invariants, and one of them is the Nieh-Yan density. Through investigations on
the cosmological perturbations of this model, we find that in general it
suffers from the difficulties of ghost instability in the scalar and vector
perturbations. But in the special case only the coupling to the Nieh-Yan
density exists, this model is ghost free and reduces to the Nieh-Yan modified
Teleparallel Gravity model.
【41】 Gravitational Reheating
标题：重力加热
链接：https://arxiv.org/abs/2201.02348
备注：5 pages, 4 figures
摘要：In this letter, we show for the first time that the perfect state of our
present universe can be obtained through gravitational interaction between
inflaton and all fundamental fields during reheating without invoking new
physics. Our analysis revealed that gravitational reheating is consistent for a
very restricted class of inflation models and narrow ranges of reheating
temperature and dark matter mass.
【42】 Gravitational wave background from non-Abelian reheating after axion-like inflation
标题：类轴子膨胀后非阿贝尔再加热的引力波背景
链接：https://arxiv.org/abs/2201.02317
备注：18 pages
摘要：A pseudoscalar inflaton $\varphi$, coupled to the topological charge density
$F\tilde{F}$ of a non-Abelian sector, can decay to gauge bosons ($\varphi\to g
g $), which may thermalize rapidly. The friction felt by $\varphi$ is then
increased by non-Abelian "strong sphalerons", leading to a self-amplifying
process that can efficiently heat up the medium. We determine a lower bound for
the gravitational wave production rate from such a process, originating via
hydrodynamic fluctuations and particle collisions, in terms of a minimal number
of parameters. Only a moderate fraction of energy density is converted to
gravitational waves, suggesting that non-Abelian models may avoid the
overproduction observed in some Abelian cases.
【43】 Constraining dark matter-nucleon scattering cross section by the background electron anti-neutrino flux data
标题：用背景电子反中微子通量数据约束暗物质-核子散射截面
链接：https://arxiv.org/abs/2201.02315
备注：Accepted for publication in Physics Letters B
摘要：Celestial objects such as stars and planets might be able to capture a large
amount of dark matter particles through dark matter-nucleon scattering. Many
previous studies have considered different celestial objects such as the Sun
and the Earth as natural dark matter detectors and obtained some stringent
bounds of the dark matter-nucleon scattering cross section. In this study, we
use the $\sim 10$ MeV electron neutrino flux limits obtained by the
Super-Kamiokande experiment and consider the Earth as a large natural dark
matter detector to constrain the dark matter-nucleon scattering cross section.
We show that this method can generally get more stringent limits. For certain
ranges of dark matter mass annihilating via the $b\bar{b}$ channel, the limits
of cross section for the isospin-independent scattering and proton-only
scattering could be more stringent than that obtained in the PICO
direct-detection experiment.
【44】 Dynamical evolution of dark matter admixed neutron stars
标题：暗物质混合中子星的动力学演化
链接：https://arxiv.org/abs/2201.02274
备注：None
摘要：We dynamically evolve for the first time dark matter admixed neutron stars
with fermionic dark matter. These systems are mixtures of the ordinary nuclear
matter of a neutron star and dark matter. To perform our dynamical evolutions,
we derive the equations of motion, in conservation form, for spherically
symmetric systems with an arbitrary number of perfect fluids. Using finite
volume and high-resolution shock-capturing methods, we dynamically evolve the
two-fluid case, with the first fluid modeling ordinary matter and the second
fluid modeling dark matter. We use our dynamical solutions to study nonlinear
stability, radial oscillation frequencies, and a dynamical formation process.
【45】 Swiss-cheese cosmologies with variable $G$ and $Λ$ from the renormalization group
标题：重整化群中具有变量$G$和$Λ$的瑞士奶酪宇宙论
链接：https://arxiv.org/abs/2201.02251
备注：15 pages, 3 figures
摘要：A convincing explanation for the nature of the dark energy and dark matter is
still missing. In recent works a RG-improved swiss-cheese cosmology with an
evolving cosmological constant dependent on the \sch radius has been proven to
be a promising model to explain the observed cosmic acceleration. In this work
we extend this model to consider the combined scaling of the Newton constant
$G$ and the cosmological constant $\Lambda$ according to the IR-fixed point
hypothesis. We shall show that our model easily generates the observed recent
passage from deceleration to acceleration without need of extra energy scales,
exotic fields or fine tuning. In order to check the generality of the concept,
two different scaling relations have been analysed and we proved that both are
in very good agreement with $\Lambda$CDM cosmology. We also show that our model
satisfies the observational local constraints on $\dot{G}/G$.
【46】 Black Hole Superradiance in Dynamical Chern-Simons Gravity
标题：动力Chern-Simons引力中的黑洞超辐射
链接：https://arxiv.org/abs/2201.02220
备注：19 pages, 4 figures
摘要：Black hole superradiance provides a window into the dynamics of light scalar
fields and their interactions close to a rotating black hole. Due to the
rotation of the black hole, the amplitude of the scalar field becomes
magnified, leading to a "black hole bomb" effect. Recent work has demonstrated
that rotating black holes in dynamical Chern-Simons gravity possess unique
structures, the "Chern-Simons caps," which may influence the behavior of matter
near the black hole. Motivated by the presence of these caps, we study
superradiance in dynamical Chern-Simons gravity in the context of a slowly
rotating black hole. We find that additional modes are excited and contribute
to the superradiance beyond what is expected for a Kerr black hole. Studying
the superradiant spectrum of perturbations, we find that the Chern-Simons
contributions give rise to small corrections to the angular dependence of the
resulting scalar cloud. Finally, we comment on potential observable
consequences and future avenues for investigation.
【47】 Well Tempered Cosmology: Scales
标题：温文尔雅的宇宙学：尺度
链接：https://arxiv.org/abs/2201.02211
备注：6 pages
摘要：Well tempered cosmology provides a well defined path for obtaining cosmology
with a low energy cosmic acceleration despite a high (Planck) energy
cosmological constant $\Lambda$, through a scalar field dynamically canceling
$\Lambda$. We explore relations between the mass scales entering the various
Horndeski gravity terms, and focus on the cases of only one or only two mass
scales, obtaining general solutions for the form of the action. The resulting
cosmology can be natural and viable, and as one of the only paths to dealing
with the cosmological constant problem it has a rationale to be a benchmark
cosmology.
【48】 Bubble universes and traversable wormholes
标题：泡沫宇宙和可穿越的虫洞
链接：https://arxiv.org/abs/2201.02203
备注：24 pages, 8 figures
摘要：Bubble universes and traversable wormholes in general relativity can be
realized as two sides of the same concept. To exemplify, we find, display, and
study in a unified manner a Minkowski-Minkowski closed universe and a
Minkowski-Minkowski traversable wormhole. By joining two 3-dimensional flat
balls along a thin shell two-sphere of matter, i.e., a spherical domain wall,
into a single spacetime one gets a Minkowski-Minkowski static closed universe,
i.e., a bubble universe. By joining two 3-dimensional complements of flat balls
along a thin shell two-sphere of matter, i.e., a spherical throat, into a
single spacetime one gets a Minkowski-Minkowski static open universe which is a
traversable wormhole. Thus, Minkowski-Minkowski bubble universes and wormholes
can be seen as complementary. It is also striking that these two spacetimes
have resemblances with two well-known static universes. The Minkowski-Minkowski
static closed universe resembles the Einstein universe, a static closed
spherical universe homogeneously filled with dust matter and with a
cosmological constant. The Minkowski-Minkowski static open universe resembles
the Friedmann static universe, a static open hyperbolic universe homogeneously
filled with negative energy density dust and with a negative cosmological, a
universe with two disjoint branes that can be considered a failed wormhole. In
this light, the Einstein and Friedmann universes are also two sides of the same
concept. A linear stability analysis for all these spacetimes is performed. The
complementarity between bubble universes and traversable wormholes, that exists
for these static spacetimes, can be can carried out for dynamical spacetimes,
indicating that such a complementarity is general. The study suggests that
bubble universes and traversable wormholes can be seen as coming out of the
same concept, and thus, if ones exist the others should also exist.
【49】 A $p$-Adic Matter in a Closed Universe
标题：a$p$-封闭宇宙中的阿迪克物质
链接：https://arxiv.org/abs/2201.02200
备注：None
摘要：In this paper, we introduce a new type of matter that has origin in $p$-adic
strings, i.e., strings with a $p$-adic worldsheet. We investigate some
properties of this $p$-adic matter, in particular its cosmological aspects. We
start with crossing symmetric scattering amplitudes for $p$-adic open strings
and related effective nonlocal and nonlinear Lagrangian which describes tachyon
dynamics at the tree level. Then, we make a slight modification of this
Lagrangian and obtain a new Lagrangian for non-tachyonic scalar field. {Using
this new Lagrangian in the weak field approximation as a matter in Einstein
gravity with the cosmological constant, one obtains an exponentially expanding
FLRW closed universe.} At the end, we discuss the obtained results, i.e.,
computed mass of the scalar $p$-adic particle, estimated radius of related
closed universe and noted $p$-adic matter as a possible candidate for dark
matter.
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