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1341. ETGs sample for the Coma cluster
ID:
ivo://CDS.VizieR/J/ApJ/810/138
Title:
ETGs sample for the Coma cluster
Short Name:
J/ApJ/810/138
Date:
21 Oct 2021
Publisher:
CDS
Description:
We explore the properties of early-type galaxies (ETGs), including ellipticals (E) and lenticulars (S0), in rich environments, such as clusters of galaxies (Virgo and Coma). The L_24_/L_K_ distribution of ETGs in both Virgo and Coma clusters shows that some S0s have a much larger L_24_/L_K_ ratio (0.5 to ~2 dex) than the bulk of the ETG population. This could be interpreted as an enhanced star formation rate in these lenticulars. We compare the optical colors of galaxies in these two clusters and investigate the nature of these sources with a large L_24_/L_K_ ratio by looking at their spatial distribution within the cluster, analyzing their optical spectra, and looking at their optical colors compared to late-types. We obtain 10 Coma and 3 Virgo early-type sources with larger L_24_/L_K_ ratios than the bulk of their population. We call these sources mid-infrared enhanced galaxies (MIEGs). In Coma, they are mostly located in the southwest part of the cluster where a substructure is falling onto the main cluster. MIEGs present a lower g-r color than the rest of the ETG sample because of a blue continuum. We interpret the excess L_24_/L_K_ ratio as evidence for enhanced star formation induced as a consequence of their infall into the main cluster.
1342. Euclid preparation. XIV. C3R2 survey DR3
ID:
ivo://CDS.VizieR/J/ApJS/256/9
Title:
Euclid preparation. XIV. C3R2 survey DR3
Short Name:
J/ApJS/256/9
Date:
18 Jan 2022 14:01:22
Publisher:
CDS
Description:
The Complete Calibration of the Color-Redshift Relation (C3R2) survey is obtaining spectroscopic redshifts in order to map the relation between galaxy color and redshift to a depth of i~24.5 (AB). The primary goal is to enable sufficiently accurate photometric redshifts for Stage IV dark energy projects, particularly Euclid and the Nancy Grace Roman Space Telescope (Roman), which are designed to constrain cosmological parameters through weak lensing. We present 676 new high-confidence spectroscopic redshifts obtained by the C3R2 survey in the 2017B-2019B semesters using the DEIMOS, LRIS, and MOSFIRE multiobject spectrographs on the Keck telescopes. Combined with the 4454 redshifts previously published by this project, the C3R2 survey has now obtained and published 5130 high-quality galaxy spectra and redshifts. If we restrict consideration to only the 0.2<z_p_<2.6 range of interest for the Euclid cosmological goals, then with the current data release, C3R2 has increased the spectroscopic redshift coverage of the Euclid color space from 51% (as reported by Masters+ 2017, J/ApJ/841/111) to the current 91%. Once completed and combined with extensive data collected by other spectroscopic surveys, C3R2 should provide the spectroscopic calibration set needed to enable photometric redshifts to meet the cosmology requirements for Euclid, and make significant headway toward solving the problem for Roman.
1343. Evolu. star mass-metallicity relation. II.
ID:
ivo://CDS.VizieR/J/ApJ/885/100
Title:
Evolu. star mass-metallicity relation. II.
Short Name:
J/ApJ/885/100
Date:
16 Mar 2022 11:50:55
Publisher:
CDS
Description:
We present the stellar mass-[Fe/H] and mass-[Mg/H] relation of quiescent galaxies in two galaxy clusters at z~0.39 and z~0.54. We derive the age, [Fe/H], and [Mg/Fe] for each individual galaxy using a full-spectrum fitting technique. By comparing with the relations for z~0 Sloan Digital Sky Survey galaxies, we confirm our previous finding that the mass-[Fe/H] relation evolves with redshift. The mass-[Fe/H] relation at higher redshift has lower normalization and possibly steeper slope. However, based on our sample, the mass-[Mg/H] relation does not evolve over the observed redshift range. We use a simple analytic chemical evolution model to constrain the average outflow that these galaxies experience over their lifetime, via the calculation of mass-loading factor. We find that the average mass-loading factor {eta} is a power-law function of galaxy stellar mass, {eta}{prop}M*^-0.21{+/-}0.09^. The measured mass-loading factors are consistent with the results of other observational methods for outflow measurements and with the predictions where outflow is caused by star formation feedback in turbulent disks.
1344. Evolved Galactic open clusters dynamical properties
ID:
ivo://CDS.VizieR/J/A+A/624/A8
Title:
Evolved Galactic open clusters dynamical properties
Short Name:
J/A+A/624/A8
Date:
21 Oct 2021
Publisher:
CDS
Description:
The stellar content of Galactic open clusters (OCs) is gradually depleted during their evolution as a result of internal relaxation and external interactions. The final residues of the long-term evolution of OCs are called open cluster remnants (OCRs).These are sparsely populated structures that can barely be distinguished from the field. We aimed to characterise and compare the dynamical states of a set of 16 objects catalogued as OCRs or OCR candidates. The sample also includes 7 objects that are catalogued as dynamically evolved OCs for comparison purposes. We used photometric data from the 2MASS catalogue, proper motions and parallaxes from the GAIA DR2 catalogue, and a decontamination algorithm that was applied to the three-dimensional astrometric space of proper motions and parallaxes ({mu}_{alpha}, {mu}_{delta}, {varpi}) for stars in the objects' areas. The investigated OCRs present masses (M) and velocity dispersions ({sigma}_v_) within well-defined ranges: M between ~10-40M_{sun} and {sigma}_v_ between ~1-7km/s. Some objects in the remnant sample have a limiting radius R_lim_<~2pc, which means that they are more compact than the investigated OCs; other remnants have R_lim_ between ~2-7pc, which is comparable to the OCs. In general, our clusters show signals of depletion of low-mass stars. This confirms their dynamically evolved states. Using results from N-body simulations, we conclude that the OCRs we studied are in fact remnants of initially very populous OCs (N_0_~10^3^-10^4^stars). The outcome of the long-term evolution is to bring the final residues of the OCs to dynamical states that are similar to each other, thus masking out the memory of the initial formation conditions of star clusters.
1345. Evolved massive stars with TESS. II.
ID:
ivo://CDS.VizieR/J/ApJ/902/24
Title:
Evolved massive stars with TESS. II.
Short Name:
J/ApJ/902/24
Date:
14 Mar 2022 07:45:17
Publisher:
CDS
Description:
Massive stars briefly pass through the yellow supergiant (YSG) phase as they evolve redward across the H-R diagram and expand into red supergiants (RSGs). Higher-mass stars pass through the YSG phase again as they evolve blueward after experiencing significant RSG mass loss. These post-RSG objects offer us a tantalizing glimpse into which stars end their lives as RSGs and why. One telltale sign of a post-RSG object may be an instability to pulsations, depending on the star's interior structure. Here we report the discovery of five YSGs with pulsation periods faster than 1 day, found in a sample of 76 cool supergiants observed by the Transiting Exoplanet Survey Satellite (TESS) at a two-minute cadence. These pulsating YSGs are concentrated in an H-R diagram region not previously associated with pulsations; we conclude that this is a genuine new class of pulsating star, fast yellow pulsating supergiants (FYPSs). For each FYPS, we extract frequencies via iterative prewhitening and conduct a time-frequency analysis. One FYPS has an extracted frequency that is split into a triplet, and the amplitude of that peak is modulated on the same timescale as the frequency spacing of the triplet; neither rotation nor binary effects are likely culprits. We discuss the evolutionary status of FYPS and conclude that they are candidate post-RSGs. All stars in our sample also show the same stochastic low-frequency variability found in hot OB stars and attributed to internal gravity waves. Finally, we find four {alpha} Cygni variables in our sample, of which three are newly discovered.
1346. Evolved stars in M13
ID:
ivo://CDS.VizieR/J/AJ/139/2374
Title:
Evolved stars in M13
Short Name:
J/AJ/139/2374
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have analyzed photometry from space- and ground-based cameras to identify all bright red giant branch (RGB), horizontal branch (HB), and asymptotic giant branch (AGB) stars within 10' of the center of the globular cluster M13.
1347. EW measurements of 6 Segue 1 red giants
ID:
ivo://CDS.VizieR/J/ApJ/786/74
Title:
EW measurements of 6 Segue 1 red giants
Short Name:
J/ApJ/786/74
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present Magellan/MIKE and Keck/HIRES high-resolution spectra of six red giant stars in the dwarf galaxy Segue 1. Including one additional Segue 1 star observed by Norris et al. (2010ApJ...722L.104N), high-resolution spectra have now been obtained for every red giant in Segue 1. Remarkably, three of these seven stars have metallicities below [Fe/H]=-3.5, suggesting that Segue 1 is the least chemically evolved galaxy known. We confirm previous medium-resolution analyses demonstrating that Segue 1 stars span a metallicity range of more than 2 dex, from [Fe/H]=-1.4 to [Fe/H]=-3.8. All of the Segue 1 stars are {alpha}-enhanced, with [{alpha}/Fe]~0.5. High {alpha}-element abundances are typical for metal-poor stars, but in every previously studied galaxy [{alpha}/Fe] declines for more metal-rich stars, which is typically interpreted as iron enrichment from supernova Ia. The absence of this signature in Segue 1 indicates that it was enriched exclusively by massive stars. Other light element abundance ratios in Segue 1, including carbon enhancement in the three most metal-poor stars, closely resemble those of metal-poor halo stars. Finally, we classify the most metal-rich star as a CH star given its large overabundances of carbon and s-process elements. The other six stars show remarkably low neutron-capture element abundances of [Sr/H]<-4.9 and [Ba/H]<-4.2, which are comparable to the lowest levels ever detected in halo stars. This suggests minimal neutron-capture enrichment, perhaps limited to a single r-process or weak s-process synthesizing event. Altogether, the chemical abundances of Segue 1 indicate no substantial chemical evolution, supporting the idea that it may be a surviving first galaxy that experienced only one burst of star formation.
1348. Exoplanet candidates from TESS first 2yr obs
ID:
ivo://CDS.VizieR/J/ApJS/254/39
Title:
Exoplanet candidates from TESS first 2yr obs
Short Name:
J/ApJS/254/39
Date:
03 Dec 2021 00:47:43
Publisher:
CDS
Description:
We present 2241 exoplanet candidates identified with data from the Transiting Exoplanet Survey Satellite (TESS) during its 2yr Prime Mission. We list these candidates in the TESS Objects of Interest (TOI) Catalog, which includes both new planet candidates found by TESS and previously known planets recovered by TESS observations. We describe the process used to identify TOIs, investigate the characteristics of the new planet candidates, and discuss some notable TESS planet discoveries. The TOI catalog includes an unprecedented number of small planet candidates around nearby bright stars, which are well suited for detailed follow-up observations. The TESS data products for the Prime Mission (sectors 1-26), including the TOI catalog, light curves, full-frame images, and target pixel files, are publicly available at the Mikulski Archive for Space Telescopes.
1349. Exoplanet candidates in Campaign 5 of the K2 mission
ID:
ivo://CDS.VizieR/J/AJ/159/154
Title:
Exoplanet candidates in Campaign 5 of the K2 mission
Short Name:
J/AJ/159/154
Date:
08 Dec 2021
Publisher:
CDS
Description:
We present a uniform transiting exoplanet candidate list for Campaign 5 of the K2 mission. This catalog contains 75 planets with seven multi-planet systems (five double, one triple, and one quadruple planet system). Within the range of our search, we find eight previously undetected candidates, with the remaining 67 candidates overlapping 51% of the study of Kruse+, (2019, J/ApJS/244/11) that manually vets candidates from Campaign 5. In order to vet our potential transit signals, we introduce the Exoplanet Detection Identification Vetter (EDI-Vetter), which is a fully automated program able to determine whether a transit signal should be labeled as a false positive or a planet candidate. This automation allows us to create a statistically uniform catalog, ideal for measurements of planet occurrence rate. When tested, the vetting software is able to ensure that our sample is 94.2% reliable against systematic false positives. Additionally, we inject artificial transits at the light-curve level of the raw K2 data and find that the maximum completeness of our pipeline is 70% before vetting and 60% after vetting. For convenience of future studies of occurrence rate, we include measurements of stellar noise (CDPP; combined differential photometric precision --Christiansen+ 2012, J/PASP/124/1279) and the three-transit window function for each target.
1350. Exoplanet candidates in Praesepe (M 44)
ID:
ivo://CDS.VizieR/J/MNRAS/463/1780
Title:
Exoplanet candidates in Praesepe (M 44)
Short Name:
J/MNRAS/463/1780
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this work we keep pushing K2 data to a high photometric precision, close to that of the Kepler main mission, using a PSF-based, neighbour-subtraction technique, which also overcome the dilution effects in crowded environments. We analyse the open cluster M 44 (NGC 2632), observed during the K2 Campaign 5, and extract light curves of stars imaged on module 14, where most of the cluster lies. We present two candidate exoplanets hosted by cluster members and five by field stars. As a by-product of our investigation, we find 1680 eclipsing binaries and variable stars, 1071 of which are new discoveries. Among them, we report the presence of a heartbeat binary star. Together with this work, we release to the community a catalogue with the variable stars and the candidate exoplanets found, as well as all our raw and detrended light curves.