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571. A framework for empirical galaxy phenomenology
ID:
ivo://CDS.VizieR/J/MNRAS/448/1430
Title:
A framework for empirical galaxy phenomenology
Short Name:
J/MNRAS/448/1430
Date:
21 Oct 2021
Publisher:
CDS
Description:
We develop a theoretical framework that extracts a deeper understanding of galaxy formation from empirically derived relations among galaxy properties by extending the main-sequence integration method for computing galaxy star formation histories. We properly account for scatter in the stellar mass-star formation rate relation and the evolving fraction of passive systems and find that the latter effect is almost solely responsible for the age distributions among z~0 galaxies with stellar masses above ~10^10^ M_{sun}_. However, while we qualitatively agree with the observed median stellar metallicity as a function of stellar mass, we attribute our inability to reproduce the distribution in detail largely to a combination of imperfect gas-phase metallicity and {alpha}/Fe ratio calibrations. Our formalism will benefit from new observational constraints and, in turn, improve interpretations of future data by providing self-consistent star formation histories for population synthesis modelling.
572. A frequency Comb calibrated solar atlas
ID:
ivo://CDS.VizieR/J/A+A/560/A61
Title:
A frequency Comb calibrated solar atlas
Short Name:
J/A+A/560/A61
Date:
21 Oct 2021
Publisher:
CDS
Description:
The solar spectrum is a primary reference for the study of physical processes in stars and their variation during activity cycles. High resolution spectra of the Sun are easily obtained from spatially selected regions of the solar disk, while those taken over the integrated disk are more problematic. However, a proxy can be obtained by using solar light reflected by small bodies of the solar system. We first apply the LFC solar spectrum to characterize the CCDs of the HARPS spectrograph. The comparison of the LFC and Th-Ar calibrated spectra reveals S-type distortions on each order along the whole spectral range with an amplitude of 40m/s. This confirms the pattern found by Wilken et al. (2010MNRAS.405L..16W) on a single order and extends the detection of the distortions to the whole analyzed region revealing that the precise shape varies with wavelength. A new data reduction is implemented to deal with CCD pixel inequalities to obtain a wavelength corrected solar spectrum. By using this spectrum we provide a new LFC calibrated solar atlas with 400 line positions in the range of 476-530, and 175 lines in the 534-585nm range corresponding to the LFC bandwidth. The new LFC atlas is consistent on average with that based on FTS solar spectra, but it improves the accuracy of individual lines by a significant factor reaching a mean value of 10m/s. The LFC-based solar line wavelengths are essentially free of major instrumental effects and provide a reference for absolute solar line positions at the date of Nov 2010, i.e. an epoch of low solar activity. We suggest that future LFC observations could be used to trace small radial velocity changes of the whole solar photospheric spectrum in connection with the solar cycle and for direct comparison with the predicted line positions of 3D radiative hydrodynamical models of the solar photosphere. The LFC calibrated solar atlas can be also used to verify the accuracy of ground or space spectrographs by means of the solar spectrum.
573. Afterglow light curve of GRB 090926A
ID:
ivo://CDS.VizieR/J/ApJ/720/862
Title:
Afterglow light curve of GRB 090926A
Short Name:
J/ApJ/720/862
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present VLT/FORS2 spectroscopy and Gamma-ray Optical/Near-Infrared Detector optical/near-IR photometry of the afterglow of the bright Fermi/LAT GRB 090926A. The spectrum shows prominent Lyman-{alpha} absorption with N_HI_=10^21.73+/-0.07^cm^-2^ and a multitude of metal lines at a common redshift of z=2.1062+/-0.0004, which we associate with the redshift of the gamma-ray burst (GRB). The metallicity derived from SII is log(Z/Z_{sun}_)~-1.9, one of the lowest values ever found in a GRB Damped Lyman-{alpha} (DLA) system. This confirms that the spread of metallicity in GRB-DLAs at z~2 is at least two orders of magnitude. We argue that this spread in metallicity does not require a similar range in abundances of the GRB progenitors, since the neutral interstellar medium probed by the DLA is expected to be at a significant distance from the explosion site. The hydrogen column density derived from the Swift/XRT afterglow spectrum (assuming log(Z/Z_{sun}_)~-1.9) is ~100 times higher than the N_HI_ obtained from the Lyman-{alpha} absorptions. This suggests either a large column density of ionized gas or a higher metallicity of the circum-burst medium compared to the gas traced by the DLA. We also discuss the afterglow light curve evolution and energetics. The absence of a clear jet-break like steeping until at least 21 days post-burst suggests a beaming-corrected energy release of E_{gamma}_>3.5x10^52^erg, indicating that GRB 090926A may have been one of the most energetic bursts ever detected.
574. Afterglows of short and long-duration GRBs
ID:
ivo://CDS.VizieR/J/ApJ/701/824
Title:
Afterglows of short and long-duration GRBs
Short Name:
J/ApJ/701/824
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a comparative study of the observed properties of the optical and X-ray afterglows of short- and long-duration {gamma}-ray bursts (GRBs). Using a large sample of 37 short and 421 long GRBs, we find a strong correlation between the afterglow brightness measured after 11hr and the observed fluence of the prompt emission. Both the optical (R band) and X-ray flux densities (F_R_ and F_X_) scale with the {gamma}-ray fluence, F_{gamma}_. For bursts with a known redshift, a tight correlation exists between the afterglow flux densities at 11hr (rest frame) and the total isotropic {gamma}-ray energy, E_{gamma},ISO_: F_R,X_{prop.to}E_{gamma},ISO_^{alpha}^, with {alpha}~1.
575. A-F type variable stars from Kepler
ID:
ivo://CDS.VizieR/J/AJ/149/68
Title:
A-F type variable stars from Kepler
Short Name:
J/AJ/149/68
Date:
03 Dec 2021 00:36:02
Publisher:
CDS
Description:
The light curves of 2768 stars with effective temperatures and surface gravities placing them near the gamma Doradus ({gamma} Dor)/delta Scuti ({delta} Sct) instability region were observed as part of the Kepler Guest Observer program from Cycles 1 through 5. The light curves were analyzed in a uniform manner to search for {gamma} Dor, {delta} Sct, and hybrid star pulsations. The {gamma} Dor, {delta} Sct, and hybrid star pulsations extend asteroseismology to stars slightly more massive (1.4-2.5M_{sun}_) than our Sun. We find 207 {gamma} Dor, 84 {delta} Sct, and 32 hybrid candidate stars. Many of these stars are cooler than the red edge of the {gamma} Dor instability strip as determined from ground-based observations made before Kepler. A few of our {gamma} Dor candidate stars lie on the hot side of the ground-based {gamma} Dor instability strip. The hybrid candidate stars cover the entire region between 6200K and the blue edge of the ground-based {delta} Sct instability strip. None of our candidate stars are hotter than the hot edge of the ground-based {delta} Sct instability strip. Our discoveries, coupled with the work of others, show that Kepler has discovered over 2000 {gamma} Dor, {delta} Sct, and hybrid star candidates in the 116 square degree Kepler field of view. We found relatively few variable stars fainter than magnitude 15, which may be because they are far enough away to lie between spiral arms in our Galaxy, where there would be fewer stars.
576. A Gaia DR2 mock stellar catalog
ID:
ivo://org.gavo.dc/gdr2mock/q/pub
Title:
A Gaia DR2 mock stellar catalog
Date:
06 Feb 2024 08:59:18
Publisher:
The GAVO DC team
Description:
This catalogue is a simulation of the Gaia DR2 stellar content using Galaxia (a tool to sample stars from a Besancon-like Milky Way model), 3d dust extinction maps and the latest PARSEC Isochrones. It is mimicking the Gaia DR2 data model and an apparent magnitude limit of g=20,7. Extinctions and photometry in different bands have also been included in a supplementary table as well as uncertainty estimates using a scaled nominal error model.
577. A3266 galaxies at 24um
ID:
ivo://CDS.VizieR/J/ApJ/693/1840
Title:
A3266 galaxies at 24um
Short Name:
J/ApJ/693/1840
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present Multiband Imaging Photometer observations of the cluster A3266. About 100 spectroscopic cluster members have been detected at 24um. The infrared (IR) luminosity function (LF) in A3266 is very similar to that in the Coma cluster down to the detection limit LIR~10^43^erg/s, suggesting a universal form of the bright-end IR LF for local rich clusters with M~10^15^M_{sun}_. The shape of the bright end of the A3266-Coma composite IR LF is not significantly different from that of nearby field galaxies, but the fraction of IR-bright galaxies (star formation rate (SFR)>0.2M_{sun}_/yr) in both clusters increases with cluster-centric radius. The decrease of the blue galaxy fraction toward the high-density cores only accounts for part of the trend; the fraction of red galaxies with moderate SFRs (0.2M_{sun}_/yr<SFR<1M_{sun}/yr) also decreases with increasing galaxy density. These results suggest that for the IR-bright galaxies nearby rich clusters are distinguished from the field by a lower star forming galaxy fraction, but not by a change in L*_IR_.
578. A3653 galaxies redshift catalogue
ID:
ivo://CDS.VizieR/J/MNRAS/368/651
Title:
A3653 galaxies redshift catalogue
Short Name:
J/MNRAS/368/651
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalogue of galaxies in Abell 3653 from observations made with the 2-degree field (2dF) spectrograph at the Anglo-Australian Telescope. Of the 391 objects observed, we find 111 are bona fide members of Abell 3653.
579. A2256 galaxies redshifts and 1.4GHz fluxes
ID:
ivo://CDS.VizieR/J/AJ/125/2393
Title:
A2256 galaxies redshifts and 1.4GHz fluxes
Short Name:
J/AJ/125/2393
Date:
21 Oct 2021
Publisher:
CDS
Description:
Abell 2256 is a nearby (z~0.06), rich cluster of galaxies with fascinating observed properties across a range of wavelengths. Long believed to represent a cluster merger, recent X-ray and optical results have suggested that in addition to the primary cluster and subcluster there is evidence for a third, poorer system. We present wide-field high-sensitivity 1.4GHz VLA radio observations of Abell 2256 in conjunction with optical imaging and additional spectroscopy. Over 40 cluster radio galaxies are identified, with optical spectroscopy indicating the emission source (star formation or active galactic nucleus) for most of them. While the overall fraction of galaxies exhibiting radio emission is consistent with a large sample of other nearby clusters, we find an increase in the activity level of galaxies belonging to the third system (hereafter "the Group"). Specifically, the Group has relatively more star formation than both the primary cluster and main subcluster. The position of the Group is also coincident with the observed cluster radio relic. We suggest that the Group recently (0.3Gyr) merged with the primary cluster and that this merger, not the ongoing merger of the primary and the main subcluster, might be responsible for many of the unusual radio properties of Abell 2256. Furthermore, the greater star formation activity of the Group suggests that the infall of groups is an important driver of galaxy evolution in clusters.
580. A959 galaxies r' magnitude and radial velocities
ID:
ivo://CDS.VizieR/J/A+A/495/15
Title:
A959 galaxies r' magnitude and radial velocities
Short Name:
J/A+A/495/15
Date:
21 Oct 2021
Publisher:
CDS
Description:
The connection of cluster mergers with the presence of extended, diffuse radio sources in galaxy clusters is still being debated. We aim to obtain new insights into the internal dynamics of Abell 959, showing evidence of a diffuse radio source, analyzing velocities and positions of member galaxies. Our analysis is based on redshift data for 107 galaxies in the cluster field acquired at the Telescopio Nazionale Galileo. We also use photometric data from the Sloan Digital Sky Survey (Data Release 6). We combine galaxy velocities and positions to select 81 galaxies recognized as cluster members and determine global dynamical properties. We analyze the cluster searching for substructures by using the weighted gap analysis, the KMM method and the Dressler-Shectman statistics. We also study the 2D galaxy distribution in the field of the cluster. We compare our results with those from X-ray and gravitational lensing analyses.

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