23 Apr24
Title: Constraints on Cosmological Models from Quasars Calibrated with Type Ia Supernova by a Gaussian Process
Authors: Haixiang Zhang, Yang Liu, Hongwei Yu, Xiaodong Nong, Nan Liang, Puxun
Wu
https://arxiv.org/pdf/2404.15913
.pdf
Abstract:
In this paper, we use quasars calibrated from type Ia supernova (SN Ia) to
constrain cosmological models. We consider three different X-ray luminosity
($L_{X}$) - ultraviolet luminosity ($L_{UV}$) relations of quasars, i.e., the
standard $L_{X}$-$L_{UV}$ relation and two redshift-evolutionary relations
(Type I and Type II) respectively constructed from copula and considering a
redshift correction to the luminosity of quasars. Only in the case of the Type
I relation, quasars can always provide effective constraints on the
$\Lambda$CDM model. Furthermore, we show that, when the observational Hubble
data (OHD) are added, the constraints on the absolute magnitude $M$ of SN Ia
and the Hubble constant $H_0$ can be obtained. In the $\Lambda$CDM model, the
OHD measurements plus quasars with the Type I relation yields $M$
=$-19.321^{+0.085}_{-0.076}$, which is in good agreement with the measurement
from SH0ES ($M=-19.253\pm{0.027}$), and $H_0$ =
$70.80\pm3.6~\mathrm{km~s^{-1}Mpc^{-1}}$, falling between the measurements from
SH0ES and the Planck cosmic microwave background radiation data.
22 Apr24
Title: Impact of main-sequence mass loss on the appearance, structure and evolution of Wolf-Rayet stars
Authors: Joris Josiek, Sylvia Ekstr\"om, Andreas A. C. Sander
https://arxiv.org/pdf/2404.14488
.pdf
Abstract:
Stellar winds are one of the most important drivers of massive star evolution
and a vital source of chemical, mechanical, and radiative feedback. Despite its
significance, mass loss remains a major uncertainty in stellar evolution
models. Particularly the interdependencies of different approaches with
subsequent evolutionary stages and predicted observable phenomena are far from
being systematically understood. In this study, we examine the impact of main
sequence mass loss on the structure of massive stars throughout their
evolution. A particular focus is placed on the consequences for entering the
Wolf-Rayet (WR) regime and the subsequent evolution. Using the Geneva stellar
evolution code, we compute grids of single, non-rotating stellar models at
solar and Large Magellanic Cloud (LMC) metallicity of initial masses between 20
and 120 solar masses, with two representative prescriptions for high and low
main sequence mass loss. We obtain detailed numerical predictions regarding the
structure and evolution of massive stars, and infer the role of main sequence
mass loss by comparison of the mass-loss rate prescriptions. We present
implications for the overall evolutionary trajectory, including the evolution
of WR stars, as well as the effect on stellar yields and stellar populations.
Mass loss during the main sequence plays an important role due to its ability
to affect the sequence and duration of all subsequent phases. We identify
several distinct evolutionary paths for massive stars which are significantly
influenced by the chosen main sequence mass-loss description. We also discuss
the impact of uncertainties other than mass loss on the evolution, in
particular those relating to convection. We further demonstrate that not just
the total mass loss, but the specific mass-loss history throughout a star's
life is a crucial determinant of many aspects, such as the resulting stellar
yields.
Title: The SAGA Survey. III. A Census of 101 Satellite Systems around Milky
Way-mass Galaxies
Authors: Yao-Yuan Mao (1), Marla Geha (2), Risa H. Wechsler (3), Yasmeen Asali
(2), Yunchong Wang (3), Erin Kado-Fong (2), Nitya Kallivayalil (4), Ethan O.
Nadler (5 and 6), Erik J. Tollerud (7), Benjamin Weiner (8), Mithi A. C. de
los Reyes (9), John F. Wu (7 and 10) ((1) U Utah, (2) Yale, (3)
Stanford/SLAC/KIPAC, (4) U Virginia, (5) Carnegie Obs., (6) USC, (7) STScI,
(8) U Arizona/Steward, (9) Amherst College, (10) Johns Hopkins)
https://arxiv.org/pdf/2404.14498
.pdf
Abstract:
We present the third Data Release (DR3) of the Satellites Around Galactic
Analogs (SAGA) Survey, a spectroscopic survey characterizing satellite galaxies
around Milky Way (MW)-mass galaxies. The SAGA Survey DR3 includes 378
satellites identified across 101 MW-mass systems in the distance range 25-40.75
Mpc, and an accompanying redshift catalog of background galaxies (including
about 46,000 taken by SAGA) in the SAGA footprint of 84.7 sq. deg. The number
of confirmed satellites per system ranges from zero to 13, in the stellar mass
range 10^6 to 10^10 solar masses. Based on a detailed completeness model, this
sample accounts for 94% of the true satellite population down to a stellar mass
of 10^7.5 solar masses. We find that the mass of the most massive satellite in
SAGA systems is the strongest predictor of satellite abundance
Title: The CO-to-H$_2$ Conversion Factor in the Barred Spiral Galaxy M83
Authors: Amanda M Lee, Jin Koda, Akihiko Hirota, Fumi Egusa, Mark Heyer
https://arxiv.org/pdf/2404.14503
.pdf
Abstract:
We analyze the CO-to-H$_2$ conversion factor ($\alpha_{\rm{CO}}$) in the
nearby barred spiral galaxy M83. We present new HI observations from the JVLA
and single-dish GBT in the disk of the galaxy, and combine them with maps of
CO(1-0) integrated intensity and dust surface density from the literature.
$\alpha_{\rm{CO}}$ and the gas-to-dust ratio ($\delta_{\rm{GDR}}$) are
simultaneously derived in annuli of 2 kpc width from R = 1-7 kpc. We find that
$\alpha_{\rm{CO}}$ and $\delta_{\rm{GDR}}$ both increase radially, by a factor
of $\sim$ 2-3 from the center to the outskirts of the disk. The
luminosity-weighted averages over the disk are $\alpha_{\rm{CO}} = 3.14$ (2.06,
4.96) M$_{\odot}$ pc$^{-2}$[K$\cdot$ km s$^{-1}$]$^{-1}$ and
$\delta_{\rm{GDR}}$ = 137 (111, 182) at the 68% (1$\sigma$) confidence level.
These are consistent with the $\alpha_{\rm{CO}}$ and $\delta_{\rm{GDR}}$ values
measured in the Milky Way. In addition to possible variations of
$\alpha_{\rm{CO}}$ due to the radial metallicity gradient, we test the
possibility of variations in $\alpha_{\rm{CO}}$ due to changes in the
underlying cloud populations, as a function of galactic radius. Using a
truncated power-law molecular cloud CO luminosity function and an empirical
power-law relation for cloud-mass and luminosity, we show that the changes in
the underlying cloud population may account for a factor of $\sim 1.5-2.0$
radial change in $\alpha_{\rm{CO}}$.
Title: A Blueprint for the Milky Way's Stellar Populations. V. 3D Local Dust
Extinction
Authors: Deokkeun An, Timothy C. Beers, Anirudh Chiti
https://arxiv.org/pdf/2404.14626
.pdf
Abstract:
Using a grid of empirically calibrated synthetic spectra developed in our
previous study, we construct an all-sky 3D extinction map from the large
collection of low-resolution XP spectra in Gaia DR3. Along each line of sight,
with an area ranging from $0.2$ to $13.4$ deg$^2$, we determine both the
reddening and metallicity of main-sequence stars and model the foreground
extinction up to approximately $3$ kpc from the Sun. Furthermore, we explore
variations in the total-to-selective extinction ratio in our parameter search
and identify its mean systematic change across diverse cloud environments in
both hemispheres. In regions outside the densest parts of the clouds, our
reddening estimates are validated through comparisons with previous reddening
maps. However, a notable discrepancy arises in comparison to other independent
work based on XP spectra, which can be attributed to systematic offsets in
their metallicity estimates. On the other hand, our metallicity scale exhibits
reasonable agreement with the high-resolution spectroscopic abundance scale. We
also assess the accuracy of the XP spectra by applying our calibrated models,
and we confirm an increasing trend of flux overestimation at shorter
wavelengths below $400$ nm.
Title: Isochrone Fitting of Galactic Globular Clusters -- VI. High-latitude
Clusters NGC5024 (M53), NGC5053, NGC5272 (M3), NGC5466, and NGC7099 (M30)
Authors: G.A.Gontcharov, S.S.Savchenko, A.A.Marchuk, C.J.Bonatto, O.S.Ryutina,
M.Yu.Khovritchev, V.B.Il'in, A.V.Mosenkov, D.M.Poliakov, A.A.Smirnov
https://arxiv.org/pdf/2404.14797
.pdf
Abstract:
We fit various colour-magnitude diagrams (CMDs) of the high-latitude Galactic
globular clusters NGC\,5024 (M53), NGC\,5053, NGC\,5272 (M3), NGC\,5466, and
NGC\,7099 (M30) by isochrones from the Dartmouth Stellar Evolution Database and
Bag of Stellar Tracks and Isochrones for $\alpha$-enrichment
[$\alpha$/Fe]$=+0.4$. For the CMDs, we use data sets from {\it Hubble Space
Telescope}, {\it Gaia}, and other sources utilizing, at least, 25 photometric
filters for each cluster. We obtain the following characteristics with their
statistic uncertainties for NGC\,5024, NGC\,5053, NGC\,5272, NGC\,5466, and
NGC\,7099, respectively: metallicities [Fe/H]$=-1.93\pm0.02$, $-2.08\pm0.03$,
$-1.60\pm0.02$, $-1.95\pm0.02$, and $-2.07\pm0.04$ dex with their systematic
uncertainty 0.1 dex
Title: Interacting Dark Energy after DESI Baryon Acoustic Oscillation
measurements
Authors: William Giar\`e, Miguel A. Sabogal, Rafael C. Nunes, Eleonora Di
Valentino
https://arxiv.org/pdf/2404.15232
.pdf
Abstract:
We investigate the implications of the Baryon Acoustic Oscillation
measurements released by the Dark Energy Spectroscopic Instrument (DESI) for
Interacting Dark Energy (IDE) models characterized by an energy-momentum flow
from Dark Matter to Dark Energy. By combining Planck-2018 and DESI data, we
observe a preference for interactions exceeding the 95% confidence level,
yielding a present-day expansion rate $H_0=71.4\pm1.5$ km/s/Mpc, in agreement
with SH0ES. This preference remains robust when including measurements of the
expansion rate $H(z)$ obtained from the relative ages of massive, early-time,
and passively-evolving galaxies, as well as when considering distance moduli
measurements from Type-Ia Supernovae sourced from the Pantheon-plus catalog
using the SH0ES Cepheid host distances as calibrators. Overall, high and low
redshift data can be equally or better explained within the IDE framework
compared to $\Lambda$CDM, while also yielding higher values of $H_0$ in better
agreement with the local distance ladder estimate.
19 Apr24
Title: SED Analysis of the Old Open Cluster NGC 188
Authors: Deniz Cennet Dursun, Seval Ta\c{s}demir, Seliz Ko\c{c}, Srishti \.Iyer
https://arxiv.org/pdf/2404.13115
.pdf
Abstract:
In this study, we investigate the fundamental astrophysical parameters of the
old open cluster NGC 188 through two complementary methods: isochron-fitting
and spectral energy distribution (SED) analysis. Using photometric,
astrometric, and spectroscopic data from the Gaia Data Release 3, we identify
868 most likely member stars with membership probabilities $P \geq 0.5$. The
mean proper-motion components and trigonometric parallaxes of the cluster are
derived as ($\mu_{\alpha}\cos \delta$, $\mu_{\delta}$) = (-$2.314 \pm 0.002$,
-$1.022 \pm 0.002$) mas yr$^{-1}$ and $\varpi = 0.550 \pm 0.023$, respectively.
From this initial selection of high probable member stars, we proceed with the
determination of astrophysical parameters using the isochron-fitting method.
Simultaneously estimating the colour excess, distance, and age of the cluster,
we employee PARSEC isochrones to observational data on Gaia based
colour-magnitude diagrams. These findings were obtained as
$E(G_{BP}-G_{RP})=0.066\pm 0.012$ mag, $d=1806 \pm21$ pc, and $t=7.65 \pm 1.00$
Gyr, respectively. Additionally, we identify and detected 19 previously
confirmed blue straggler stars within NGC 188. Subsequently, we performed SED
analyses for 412 out of the 868 cluster members. We obtained colour excess,
distance and age of the cluster as $E(B-V)=0.034\pm 0.030$ mag, $d=1854\pm 148$
pc, and $t=7.78\pm 0.23$ Gyr, respectively. The analysis of member stars was
revealed patterns of extinction in the $V$-band, with higher values of A(V)
observed in the lower right quadrant of the cluster. By comparing our results
of SED analysis with models of stellar evolution, particularly in terms of
temperature and surface gravity, we confirm agreement with theoretical
predictions. This comprehensive investigation sheds light on the astrophysical
properties of NGC 188, contributing to our understanding of stellar evolution
within open clusters.
Title: Exploring the Orbital Alignments of Galactic Close White Dwarf Binaries
with LISA
Authors: Naoki Seto
https://arxiv.org/pdf/2404.13313
.pdf
Abstract:
Using the proposed space gravitational wave detector LISA, we will be able to
measure the geometrical configurations of $\sim 10^4$ close white dwarf
binaries in our Galaxy. The obtained data will be an entirely new resource to
examine the randomness of their orbital orientations. Partly motivated by a
recent reported on the systematic alignments of bulge planetary nebulae, we
discuss the outlook of the orientational analysis with LISA. We find that a
quadrupole pattern as small as $\sim 0.05$ can be detected for bulge white
dwarf binaries, owing to their large available number. From such a pattern
analysis, we might geometrically explore fossil records in our Galaxy billions
of years ago.
Title: Exploring Detached Eclipsing Binary Systems from TESS Observations:
Insights into OBA-type Systems and Orbital Circularization
Authors: L. Siqueira and B. W. Freitas and D. B. de Freitas
https://arxiv.org/pdf/2404.13374
.pdf
Abstract:
This study presents photometric solutions for a carefully selected sample of
181 detached eclipsing binary systems recently observed by the Transiting
Exoplanet Survey Satellite (TESS) mission. Our findings contribute to
discussions about OBA-type systems and the orbital circularization influenced
by tidal interactions. The results encompass crucial parameters, including the
sum of radii fraction ($r_{\rm a}\,+\,r_{\rm b}$), radii ratio ($k$), orbital
inclination ($i$), surface brightness ratio ($J$), and combinations of the
longitude of the periastron and orbital eccentricity ($e\,\sin\,\omega$ and
$e\,\cos\,\omega$). Geometric light curve fitting is performed using version 43
of the {\sc jktebop} code, serving as the primary tool for determining orbital
elements and physical ratios. Careful uncertainty estimates for these findings
are derived through bootstrap simulations. This work introduces unprecedented
photometric solutions for 172 well-detached eclipsing systems, while the
results for the remaining nine systems exhibit excellent agreement with those
previously reported in the literature. Additionally, a critical primary radius
fraction ($R_{\rm a}/a$) of 0.266 is identified for our sample of radiative
envelope stars, consistent with observational and theoretical findings in the
literature. Finally, we determine a circularization period of 5.762 days based
on a function from the literature, revealing a discrepancy with Zahn's theory
for hot stars.
Title: Age analysis of extrasolar planets: Insight from stellar isochrone
models
Authors: C. Swastik, Ravinder K. Banyal, Mayank Narang, Athira Unni, and T.
Sivarani
https://arxiv.org/pdf/2404.13398
.pdf
Abstract:
There is growing evidence from stellar kinematics and galactic chemical
evolution (GCE) suggesting that giant planets (M$_{P}\geq$0.3$M_{J}$) are
relatively young compared to the most commonly occurring population of small
planets (M$_{P} <$0.3$M_{J}$). To further test the validity of these results,
we analyzed the ages for a large number of 2336 exoplanet hosting stars
determined using three different but well-established isochrone fitting models,
namely, PARSEC, MIST, and Yonsei Yale (YY). As input parameters, we used Gaia
DR3 parallaxes, magnitudes, and photometric temperature, as well as
spectroscopically determined more accurate temperatures and metallicities from
the Sweet Catalog. Our analysis suggests that $\sim$~50$\%$ to 70$\%$ of stars
with planets are younger than the sun. We also find that, among the confirmed
exoplanetary systems, stars hosting giant planets are even younger compared to
small planet hosts. The median age of $\sim$~2.61 to 3.48~Gyr estimated for the
giant planet-hosting stars (depending on the model input parameters) suggests
that the later chemical enrichment of the galaxy by the iron-peak elements,
largely produced from Type Ia supernovae, may have paved the way for the
formation of gas giants. Furthermore, within the giant planet population
itself, stars hosting hot Jupiters (orbital period $\le$10 days) are found to
be younger compared to the stellar hosts of cool and warm Jupiters (orbital
period $>$10 days), implying that hot Jupiters could be the youngest systems to
emerge in the progression of planet formation.
Title: The Impact of Tidal Migration of Hot Jupiters on the Rotation of
Sun-like Main-sequence Stars
Authors: Shuai-Shuai Guo
https://arxiv.org/pdf/2404.13548
.pdf
Abstract:
The tidal interactions of planets affect the stellar evolutionary status and
the constraint of their physical parameters by gyrochronology. In this work, we
incorporate the tidal interaction and magnetic braking of the stellar wind into
MESA and calculate a large grid of 25000 models, covering planets with masses
of 0.1-13.0$\,$$M_{\mathrm{J}}$ with different orbital distances that orbit
late-type stars of different metallicities. We also explore the effect of
different stellar initial rotations on the tidal interactions. Our results show
that in the case of tidal inward migration, the stellar rotation periods are
always lower than that of the star without planet before the planet is engulfed
and the difference in the rotation period of its host star always increases
with time. After the planet is engulfed, the stellar rotation periods are still
lower than that of star without planet, but the difference of periods can be
quickly eliminated if the star has a thick convective envelope(smaller mass and
larger metallicity), regardless of the mass of the planet and the initial
rotation period of the star. In the case of stars with thinner convective
envelopes(larger mass and smaller metallicity), the stars will be spined up and
remain the faster rotation in a long time. Meanwhile, the planet is easily
swallowed and the period differences are large if the initial rotation period
of its host star is higher. Final, we also study the evolution of WASP-19 and
estimate the range of tidal quality parameter $Q'_{*} = (4.6 \pm 0.9) \times
10^{6}$ and initial semi-major axis as $(0.035 \pm 0.004)$$\,$au.
Title: The effect of local photoionization on the galaxy properties and the
circumgalactic medium in simulations of Milky Way-sized galaxies
Authors: Bocheng Zhu and Volker Springel
https://arxiv.org/pdf/2404.13837
.pdf
Abstract:
In this study, we investigate the impact of local stellar radiation in
cosmological zoom simulations of the formation of Milky Way-sized galaxies. We
include the radiation field as an additional feedback component that is
computed alongside gravity with a tree code in an optically thin approximation.
We resimulate the initial conditions of five Milk Way-like systems taken from
the Auriga project with and without stellar radiation, and study the effects of
local stellar radiation on several properties of the galaxies and the
circumgalactic medium (CGM). Similar to previous findings, we observe that
local stellar radiation can modify gas cooling in the circumgalactic medium and
thus suppress star formation and the surface densities of young stars and HI
gas, while having little impact on the total gas content. Even though the
magnitude of the effect we find is smaller than reported in earlier work, the
radiation field is thus clearly an important component in simulations of late
time galaxies. In particular, it also suppresses the peak of the rotation curve
and reduces the mass of the stellar bulge. In the CGM region, the young stellar
radiation exceeds the external UVB and dominates the radiation field within the
virial halo at all redshifts. Nevertheless, we find that the local stellar
radiation has overall little impact on the radial density and temperature
profile of the CGM gas. The metallicity profile is slightly reduced, however,
as well as the HI and MgII column densities within $\sim 0.3\,R_{\rm vir}$. In
contrast, we find that the OVI column density is hardly impacted by the
radiation field. Additional effects can be expected from the radiation of the
central AGN during phases of quasar activity, which has not yet been included
in the simulations of the present study.
Title: X-shooter spectroscopy of Liller1 giant stars
Authors: D. A. Alvarez Garay, C. Fanelli, L. Origlia, C. Pallanca, A.
Mucciarelli, L. Chiappino, C. Crociati, B. Lanzoni, F. R. Ferraro, R. M.
Rich, and E. Dalessandro
https://arxiv.org/pdf/2404.14130
.pdf
Abstract:
We present the first comprehensive chemical study of a representative sample
of 27 luminous red giant branch (RGB) stars belonging to Liller 1, a complex
stellar system in the Galactic bulge. This study is based on medium-resolution
near-infrared spectra acquired with X-shooter at the Very Large Telescope. We
found a subpopulation counting 22 stars with subsolar metallicity
($<$[Fe/H]$>=-0.31\pm0.02$ and 1$\sigma$ dispersion of 0.08 dex) and with
enhanced [$\alpha$/Fe], [Al/Fe], and [K/Fe] that likely formed early and
quickly from gas that was mainly enriched by type II supernovae, and a
metal-rich population counting 5 stars with supersolar metallicity
($<$[Fe/H]$>$=+0.22$\pm$0.03 and 1$\sigma$ dispersion of 0.06 dex) and roughly
solar-scaled [$\alpha$/Fe], [Al/Fe], and [K/Fe] that formed at later epochs
from gas that was also enriched by type Ia supernovae. Moreover, both
subpopulations show enhanced [Na/Fe], as in the bulge field, about solar-scaled
[V/Fe], and depletion of [C/Fe] and $^{12}$C/$^{13}$C with respect to the solar
values. This indicates that mixing and extra-mixing processes during the RGB
evolution also occur at very high metallicities. Notably, no evidence of a Na-O
anticorrelation, which is considered the fingerprint of genuine globular
clusters, has been found. This challenges any formation scenarios that invoke
the accretion of a molecular cloud or an additional stellar system onto a
genuine globular cluster. The results of this study underline the strong
chemical similarity between Liller 1 and Terzan 5 and support the hypothesis
that these complex stellar systems might be fossil fragments of the epoch of
Galactic bulge formation.
Title: The impact of a top-heavy IMF on the formation and evolution of dark
star clusters
Authors: Ali Rostami Shirazi, Hosein Haghi, Akram Hasani Zonoozi, Ahmad
Farahani Asl, Pavel Kroupa
https://arxiv.org/pdf/2404.14259
.pdf
Abstract:
The Spitzer instability leads to the formation of a black hole sub-system
(BHSub) at the center of a star cluster providing energy to luminous stars
(LSs) and increasing their rate of evaporation. When the self-depletion time of
the BHSub exceeds the evaporation time of the LSs, a dark star cluster (DSC)
will appear. Using the NBODY7 code, we performed a comprehensive set of direct
\Nbody simulations over a wide range of initial conditions to study the pure
effect of the top-heaviness of the IMF on the formation of the DSC phase. In
the Galactic tidal field, top-heavy IMFs lead to the fast evaporation of LSs
and the formation of DSCs. Therefore, DSCs can be present even in the outer
region of the Milky Way (MW). To successfully transition to the DSC phase, the
MW Globular Clusters (GCs) must possess an initial BH mass fraction of
$\widetilde{\mathit{M}}_\mathrm{BH}(0)>0.05$. For star clusters with
$\widetilde{\mathit{M}}_\mathrm{BH}(0)>0.08$, the DSC phase will be created for
any given initial density of the cluster and Galactocentric distance. The
duration of the cluster's lifetime spent in the DSC phase shows a negative
(positive) correlation with the initial density, and Galactocentric distance of
the star cluster if $\widetilde{\mathit{M}}_\mathrm{BH}(0)\leq 0.12$
($\widetilde{\mathit{M}}_\mathrm{BH}(0)\geq 0.15$). Considering the canonical
IMF, it is unlikely for any MW GCs to enter the DSC phase. We discuss the BH
retention fraction in view of the observed properties of the GCs of the MW.
Title: Investigation of [KSF2015] 1381-19L, a WC9-type star in the high
extinction Galactic region
Authors: Subhajit Kar, Ramkrishna Das and Tapas Baug
https://arxiv.org/pdf/2404.14260
.pdf
Abstract:
We report a multi-wavelength study of the Wolf Rayet (WR) star: [KSF2015]
1381-19L, which is located in the solar metallicity region (Z=0.014) of the
Milky Way Galaxy, strongly obscured by the interstellar dust. We perform a
detailed characterization of the stellar atmosphere by fitting the spectral
emission lines observed in the Optical and Near-InfraRed (NIR) bands, using
CMFGEN. The best-fitted spectroscopic model indicates a highly luminous
($10^{5.89}L_{\odot}$) star with a larger radius ($15\,R_{\odot}$) and
effective temperature, wind terminal velocity, and chemical composition similar
to that of Galactic WC9-dusty (WC9d)-type stars. The atmospheric ionization
structure shows coexisting ionization states of different elements,
simultaneously affecting the opacity and thermal electron balance. Fitting of
the spectral energy data (SED) reveals high interstellar optical extinction
($A_{V}=$ 8.87) while the IR extinction is found to be comparatively lower
($A_{K_{s}}=$ 0.98). We do not detect any excess emission at near-IR
wavelengths due to dust. Upon comparison of our results with the GENEVA single
star evolutionary models (Z=0.014), we identify the best possible progenitors (
a rotating star of $67\,M_{\odot}$ and a non-rotating star of $90\,M_{\odot}$).
Title: On the incidence rate of RR Lyrae stars with non-radial modes
Authors: H. Netzel, V. Varga, R. Szabo, R. Smolec, E. Plachy
https://arxiv.org/pdf/2404.14373
.pdf
Abstract:
Over the recent years, additional low-amplitude non-radial modes were
detected in many of the first-overtone RR Lyrae stars. These non-radial modes
form a characteristic period ratio with the dominant first-overtone mode of
around 0.61. The incidence rate of this phenomenon changes from population to
population. It is also strongly dependent on the quality of the analyzed data.
Current models explaining these additional signals involve non-radial modes of
degrees 8 and 9. Using synthetic horizontal branch populations, we investigate
the incidence rate of first-overtone RR Lyrae stars with non-radial modes
depending on the population properties, i.e., ages and metallicities. We
compare our results with the observed results for globular clusters and the
numerous collection of field first-overtone RR Lyrae stars to test the
predictions of the models. We used synthetic horizontal branches combined with
pulsation models to predict how the incidence rate would depend on the age and
metallicity of the population. To test whether the results based on synthetic
horizontal branches are realistic, we compared them to incidence rates observed
by TESS in first-overtone field RR Lyrae stars, using photometric metallicity
values from a newly established calibration for TESS. The analysis of synthetic
horizontal branches showed that the incidence rate decreases with decreasing
metallicity. We inferred photometric metallicity for RR Lyrae stars observed by
TESS and showed that the theoretical predictions are in agreement with the
observations. Using the same method, we also conclude that the metallicity
distribution of RR Lyrae stars showing an additional mode with a period-ratio
around $0.68$ appears to be different from that of both all first-overtone
stars and those showing additional non-radial modes.
18 Apr24
Title: OGLE-2015-BLG-0845L: A low-mass M dwarf from the microlensing parallax and xallarap effects
Authors: Zhecheng Hu, Wei Zhu, Andrew Gould, Andrzej Udalski, Takahiro Sumi,
Ping Chen, Sebastiano Calchi Novati, Jennifer C. Yee, Charles A. Beichman,
Geoffery Bryden, Sean Carey, Michael Fausnaugh, B. Scott Gaudi, Calen B.
Henderson, Yossi Shvartzvald, Benjamin Wibking, Przemek Mr\'oz, Jan Skowron,
Radoslaw Poleski, Michae{\l} K. Szyma\'nski, Igor Soszyn\'ski, Pawe{\l}
Pietrukowicz, Szymon Koz{\l}owski, Krzysztof Ulaczyk, Krzysztof A. Rybicki,
Patryk Iwanek, Marcin Wrona, Mariusz Gromadzki, Fumio Abe, Richard Barry,
David P. Bennett, Aparna Bhattacharya, Ian A. Bond, Hirosane Fujii, Akihiko
Fukui, Ryusei Hamada, Yuki Hirao, Stela Ishitani Silva, Yoshitaka Itow,
Rintaro Kirikawa, Naoki Koshimoto, Yutaka Matsubara, Shota Miyazaki, Yasushi
Muraki, Greg Olmschenk, Cl\'ement Ranc, Nicholas J. Rattenbury, Yuki Satoh,
Daisuke Suzuki, Mio Tomoyoshi, Paul. J. Tristram, Aikaterini Vandorou, Hibiki
Yama, Kansuke Yamashita
https://arxiv.org/pdf/2404.13031
.pdf
Abstract:
We present the analysis of the microlensing event OGLE-2015-BLG-0845, which
was affected by both the microlensing parallax and xallarap effects. The former
was detected via the simultaneous observations from the ground and Spitzer, and
the latter was caused by the orbital motion of the source star in a relatively
close binary. The combination of these two effects led to a direct mass
measurement of the lens object, revealing a low-mass ($0.14 \pm 0.05
M_{\odot}$) M-dwarf at the bulge distance ($7.6 \pm 1.0$ kpc). The source
binary consists of a late F-type subgiant and a K-type dwarf of $\sim1.2
M_{\odot}$ and $\sim 0.9 M_{\odot}$, respectively, and the orbital period is
$70 \pm 10$ days. OGLE-2015-BLG-0845 is the first single-lens event in which
the lens mass is measured via the binarity of the source. Given the abundance
of binary systems as potential microlensing sources, the xallarap effect may
not be a rare phenomenon. Our work thus highlights the application of the
xallarap effect in the mass determination of microlenses, and the same method
can be used to identify isolated dark lenses.
Title: Dynamical formation of Gaia BH3 in the progenitor globular cluster of
the ED-2 stream
Authors: Daniel Mar\'in Pina, Sara Rastello, Mark Gieles, Kyle Kremer, Laura
Fitzgerald, Bruno Rando
https://arxiv.org/pdf/2404.13036
.pdf
Abstract:
Context. The star-black hole (S-BH) binary discovered by the Gaia
Collaboration - Gaia BH3 - is chemically and kinematically associated with the
metal-poor ED-2 stream in the Milky Way halo.
Aims. We explore the possibility that Gaia BH3 was assembled dynamically in
the progenitor globular cluster (GC) of the ED-2 stream.
Methods. We use a public suite of star-by-star dynamical Monte Carlo models
by Kremer et al. (2020) to identify S-BH binaries in GCs with different initial
masses and (half-mass) radii.
Results. We show that a likely progenitor of the ED-2 stream was a relatively
low-mass ($\lesssim10^5M_\odot$) GC with an initial half-mass radius of 2 - 4
pc. Such a GC can dynamically retain a large fraction of its BH population and
dissolve on the orbit of ED-2. From the suite of models we find that GCs
produce ~ 3 - 30 S-BH binaries, approximately independent of initial GC mass
and inversely correlated with initial cluster radius. Scaling the results to
the Milky Way GC population, we find that ~$75\%$ of the S-BH binaries formed
in GCs are ejected from their host GC in the early phases of evolution
($\lesssim1$ Gyr)
Title: Formation of a $33\,M_{\odot}$ black hole in a low-metallicity binary
Authors: Kareem El-Badry
https://arxiv.org/pdf/2404.13047
.pdf
Abstract:
A $33\,M_\odot$ black hole (BH) was recently discovered in an 11.6-year
binary only 590 pc from the Sun. The system, Gaia BH3, contains a
$0.8\,M_\odot$ low-metallicity giant ($\rm [M/H]=-2.2$) and is kinematically
part of the Galactic halo, suggesting that the BH formed from a low-metallicity
massive star. I show that orbits similar to that of Gaia BH3 are naturally
produced through isolated binary evolution. The system's period and
eccentricity can result from a broad range of initial orbits with a modest
natal kick ($v_{\rm kick}\lesssim 75\,\rm km\,s^{-1}$) to the BH. I construct
MESA models for metal-poor massive stars with initial masses ranging from
$35-55\,M_{\odot}$, which reach maximum radii of $1150-1800\,R_{\odot}$ as red
supergiants. Stars of this size would fit inside most plausible pre-supernova
orbits for the system without overflowing their Roche lobes. In addition,
models with moderately rapid initial rotation ($\Omega/\Omega_{\rm crit}
\gtrsim 0.45$) undergo chemically homogeneous evolution and never expand to
radii larger than $10\,R_{\odot}$. There are thus multiple channels through
which a low-metallicity, extreme-mass ratio binary could produce a system like
Gaia BH3. Dynamical formation scenarios are also viable, and there is little
doubt that both isolated and dynamically-formed BH binaries with orbits similar
to Gaia BH3 will be discovered in Gaia DR4. Only about 1 in 10,000 stars in the
solar neighborhood have metallicities as low as Gaia BH3. This suggests that BH
companions are dramatically over-represented at low-metallicity, though caveats
related to small number statistics apply. The fact that the luminous star in
Gaia BH3 has been a giant - greatly boosting its detectability - only for
$\sim$1% of the time since the system's formation implies that additional
massive BHs remain to be discovered with only moderately fainter companions.
17 Apr24
Title: Joint r-Process Enrichment by Supernovae with a Metallicity Threshold and Neutron Star Mergers
Authors: Takuji Tsujimoto
https://arxiv.org/pdf/2404.11668
.pdf
Abstract:
The enrichment history of $r$-process elements has been imprinted on the
stellar abundances that change in accordance with increasing metallicity in
galaxies. Close examination of the [Eu/Fe] feature caused by stars in nearby
galaxies, including the Large Magellanic Cloud (LMC), shows its perplexity. The
decreasing trend of the [Eu/Fe] feature is followed by a nearly constant value
Title: VELOcities of CEpheids (VELOCE) I. High-precision radial velocities of
Cepheids
Authors: Richard I. Anderson, Giordano Viviani, S. Shreeya Shetye, Nami
Mowlavi, Laurent Eyer, Lovro Palaversa, Berry Holl, Sergi Blanco-Cuaresma,
Kateryna Kravchenko, Micha{\l} Pawlak, Mauricio Cruz Reyes, Saniya Khan,
Henryka E. Netzel, Lisa L\"obling, P\'eter I. P\'apics, Andreas Postel,
Maroussia Roelens, Zoi T. Spetsieri, Anne Thoul, Ji\v{r}\'i Z\'ak, Vivien
Bonvin, David V. Martin, Martin Millon, Sophie Saesen, Aur\'elien Wyttenbach,
Pedro Figueira, Maxime Marmier, Saskia Prins, Gert Raskin, Hans van Winckel
https://arxiv.org/pdf/2404.12280
.pdf
Abstract:
This first VELOCE data release comprises 18,225 high-precision RV
measurements of 258 bona fide classical Cepheids on both hemispheres collected
mainly between 2010 and 2022, alongside 1161 additional observations of 164
other stars. The median per-observation RV uncertainty is 0.037 km/s, and some
reach 0.002 km/s. Non-variable standard stars characterize RV zero-point
stability and provide a base for future cross-calibrations. We determined
zero-point differences between VELOCE and 31 literature data sets using
template fitting and measured linear period changes of 146 Cepheids. Seventy
six spectroscopic binary Cepheids and 14 candidates are identified using VELOCE
data alone and are investigated in detail in a companion paper (VELOCE II).
Several new insights into Cepheid pulsations were obtained, including: a) the
most detailed description of the Hertzsprung progression by RVs
16 Apr24
Title: Assessment of SDSS-Derived Galaxy Morphologies Using HST Imaging
Authors: Chandler Osborne and Samir Salim
https://arxiv.org/pdf/2404.11485
.pdf
Abstract:
The Sloan Digital Sky Survey (SDSS) was foundational to the study of galaxy
evolution, having revealed the bimodality of galaxies and the relationship
between their structure and star-forming activity. However, ground-based
optical surveys like SDSS are limited in resolution and depth which may lead to
biases or poor quality in the derived morphological properties, potentially
impacting our understanding of how and why galaxies cease their star formation
(quench). We use archival HST imaging of ~2,000 SDSS objects to assess the
reliability of SDSS-derived morphologies, taking advantage of both SDSS
statistical samples and of HST's superior resolution and sensitivity. Single
Sersic fitting and bulge-disk decomposition is performed on HST images for
direct comparison with SDSS results. Of the three catalogs of SDSS-derived
morphologies considered, none are significantly more accurate than the others.
For disk-dominated galaxies (n<2.5), global Sersic indices (n) from Meert et
al. 2015 (M15) are preferred. For bulge-dominated galaxies (n>2.5), Simard et
al. 2011 (S11) and M15 overestimate n by ~20%, and NYU-derived global n are
preferred. Global R_eff from S11 are preferred, but overestimate R_eff for the
largest galaxies by 0.1 dex. SDSS-derived single-component parameters are
generally significantly more robust than SDSS-derived two-component parameters.
The bulge Sersic index (n_bulge) cannot be reliably constrained from SDSS
imaging. The bulge-to-total (B/T) ratio can be reliably inferred from SDSS for
galaxies with SDSS B/T<0.6 provided that n_bulge=4 is enforced. The difference
in global n between HST and SDSS depends strongly on B/T
Title: Sky localization of Massive Black Hole Binaries in the foreground of
Galactic white dwarf binaries
Authors: Pan Guo, Hong-Bo Jin, Cong-Feng Qiao, and Yue-Liang Wu
https://arxiv.org/pdf/2404.11505
.pdf
Abstract:
Quickly sky localizing of massive black hole binaries (MBHBs) from the
foreground of double white dwarf (DWD) is essential for space-based
gravitational wave (GW) detection. In an orbit period of the space crafts,
there is an optimal orbital position of the GW detectors to observe GW sources,
where the signal intensity is at its peak. From the model Q3-d, five MBHB
sources are selected based on the optimal observation orbital positions of the
GW detectors, which are associated with the orientation of the MBHB
perpendicular to the detection arms. For two MBHB sources of lower intensity,
luminosity distance uncertainties, $\Delta D_L$/$D_L$ at the 95$\%$ confidence
level from the overlapping GW signals of MBHB and DWD sources, when employing
wavelet decomposition and reconstruction methods, are improved by $\sim$ 2
times and $\sim$ 10 times. Besides, the angular resolutions $\Delta \Omega_s$
are also improved by a factor of $\sim$ 35 and $\sim$ 8. These results imply
that we can obtain relatively high accuracy of quickly localizing MBHB from the
overlapped GW signals with DWDs at the best observation orbit position. The
luminosity distance uncertainties at the 95$\%$ confidence level for MBHB
sources with the higher sign-noise ratio, have constraints on the precision of
the Hubble constant.
15 Apr24
Title: Membership determination in open clusters using the DBSCAN Clustering Algorithm
Authors: Mudasir Raja, Priya Hasan, Md Mahmudunnobe, Md Saifuddin, S N Hasan
https://arxiv.org/pdf/2404.10477
.pdf
Abstract:
In this paper, we apply the machine learning clustering algorithm Density
Based Spatial Clustering of Applications with Noise (DBSCAN) to study the
membership of stars in twelve open clusters (NGC~2264, NGC~2682, NGC~2244,
NGC~3293, NGC~6913, NGC~7142, IC~1805, NGC~6231, NGC~2243, NGC 6451, NGC 6005
and NGC 6583) based on Gaia DR3 Data. This sample of clusters spans a variety
of parameters like age, metallicity, distance, extinction and a wide parameter
space in proper motions and parallaxes. We obtain reliable cluster members
using DBSCAN as faint as $G \sim 20$ mag and also in the outer regions of
clusters. With our revised membership list, we plot color-magnitude diagrams
and we obtain cluster parameters for our sample using ASteCA and compare it
with the catalog values. We also validate our membership sample by
spectroscopic data from APOGEE and GALAH for the available data. This paper
demonstrates the effectiveness of DBSCAN in membership determination of
clusters.
Title: Discovery of a dormant 33 solar-mass black hole in pre-release Gaia
astrometry
Authors: Gaia Collaboration: P. Panuzzo, T. Mazeh, F. Arenou, B. Holl, E.
Caffau, A. Jorissen, C. Babusiaux, P. Gavras, J. Sahlmann, U. Bastian, {\L}.
Wyrzykowski, L. Eyer, N. Leclerc, N. Bauchet, A. Bombrun, N. Mowlavi, G.M.
Seabroke, D. Teyssier, E. Balbinot, A. Helmi, A.G.A. Brown, A. Vallenari, T.
Prusti, J.H.J. de Bruijne, A. Barbier, M. Biermann, O.L. Creevey, C.
Ducourant, D.W. Evans, R. Guerra, A. Hutton, C. Jordi, S.A. Klioner, U.
Lammers, L. Lindegren, X. Luri, F. Mignard, C. Nicolas, S. Randich, P.
Sartoretti, R. Smiljanic, P. Tanga, N.A. Walton, C. Aerts, C.A.L.
Bailer-Jones, M. Cropper, R. Drimmel, F. Jansen, D. Katz, M.G. Lattanzi, C.
Soubiran, F. Th\'evenin, F. van Leeuwen, R. Andrae, M. Audard, J. Bakker, R.
Blomme, J. Casta\~neda, F. De Angeli, C. Fabricius, M. Fouesneau, Y.
Fr\'emat, et al. (352 additional authors not shown)
https://arxiv.org/pdf/2404.10486
.pdf
Abstract:
Gravitational waves from black-hole merging events have revealed a population
of extra-galactic BHs residing in short-period binaries with masses that are
higher than expected based on most stellar evolution models - and also higher
than known stellar-origin black holes in our Galaxy. It has been proposed that
those high-mass BHs are the remnants of massive metal-poor stars. Gaia
astrometry is expected to uncover many Galactic wide-binary systems containing
dormant BHs, which may not have been detected before. The study of this
population will provide new information on the BH-mass distribution in binaries
and shed light on their formation mechanisms and progenitors. As part of the
validation efforts in preparation for the fourth Gaia data release (DR4), we
analysed the preliminary astrometric binary solutions, obtained by the Gaia
Non-Single Star pipeline, to verify their significance and to minimise
false-detection rates in high-mass-function orbital solutions. The astrometric
binary solution of one source, Gaia BH3, implies the presence of a 32.70 \pm
0.82 M\odot BH in a binary system with a period of 11.6 yr. Gaia radial
velocities independently validate the astrometric orbit. Broad-band photometric
and spectroscopic data show that the visible component is an old, very
metal-poor giant of the Galactic halo, at a distance of 590 pc. The BH in the
Gaia BH3 system is more massive than any other Galactic stellar-origin BH known
thus far. The low metallicity of the star companion supports the scenario that
metal-poor massive stars are progenitors of the high-mass BHs detected by
gravitational-wave telescopes. The Galactic orbit of the system and its
metallicity indicate that it might belong to the Sequoia halo substructure.
Alternatively, and more plausibly, it could belong to the ED-2 stream, which
likely originated from a globular cluster that had been disrupted by the Milky
Way.
Title: Photometric and Spectroscopic Analysis of V583 Lyrae, an Algol with a
g-mode Pulsating Primary and Accretion Disk
Authors: Hui-Ting Zhang, Sheng-Bang Qian, Wen-Ping Liao, B. Soonthornthum, N.
Sarotsakulchai
https://arxiv.org/pdf/2404.10711
.pdf
Abstract:
V583 Lyr is an extremely low mass ratio Algol-type binary with an orbital
period of 11.2580 days. We determined an effective temperature of T_{eff1} =
9000 \pm 350 K from newly observed spectra, which might be an underestimate due
to binary mass transfer. The binary mass ratio q = 0.1 \pm 0.004 and the
orbital inclination i = 85.5{\deg} are determined based on the assumption that
the secondary fills its Roche lobe and rotates synchronously. The radial
velocity curve is obtained from time series spectra, allowing for improved
estimation of stellar masses and radii: M1 = 3.56 \pm 0.5 Msun, R1 = 2.4 \pm
0.2 Rsun
Title: Deep Learning and LLM-based Methods Applied to Stellar Lightcurve
Classification
Authors: Yu-Yang Li, Yu Bai, Cunshi Wang, Mengwei Qu, Ziteng Lu, Roberto Soria,
Jifeng Liu
https://arxiv.org/pdf/2404.10757
.pdf
Abstract:
Light curves serve as a valuable source of information on stellar formation
and evolution. With the rapid advancement of machine learning techniques, it
can be effectively processed to extract astronomical patterns and information.
In this study, we present a comprehensive evaluation of deep-learning and large
language model (LLM) based models for the automatic classification of variable
star light curves, based on large datasets from the Kepler and K2 missions.
Special emphasis is placed on Cepheids, RR Lyrae, and eclipsing binaries,
examining the influence of observational cadence and phase distribution on
classification precision. Employing AutoDL optimization, we achieve striking
performance with the 1D-Convolution+BiLSTM architecture and the Swin
Transformer, hitting accuracies of 94\% and 99\% correspondingly, with the
latter demonstrating a notable 83\% accuracy in discerning the elusive Type II
Cepheids-comprising merely 0.02\% of the total dataset.We unveil StarWhisper
LightCurve (LC), an innovative Series comprising three LLM-based models: LLM,
multimodal large language model (MLLM), and Large Audio Language Model (LALM).
Each model is fine-tuned with strategic prompt engineering and customized
training methods to explore the emergent abilities of these models for
astronomical data. Remarkably, StarWhisper LC Series exhibit high accuracies
around 90\%, significantly reducing the need for explicit feature engineering,
thereby paving the way for streamlined parallel data processing and the
progression of multifaceted multimodal models in astronomical applications. The
study furnishes two detailed catalogs illustrating the impacts of phase and
sampling intervals on deep learning classification accuracy, showing that a
substantial decrease of up to 14\% in observation duration and 21\% in sampling
points can be realized without compromising accuracy by more than 10\%.