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441. Cl 1103.7-1245 at z=0.96: spectroscopic catalog
ID:
ivo://CDS.VizieR/J/A+A/544/A104
Title:
Cl 1103.7-1245 at z=0.96: spectroscopic catalog
Short Name:
J/A+A/544/A104
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new spectroscopic observations in a field containing the highest redshift cluster of the ESO Distant Cluster Survey (EDisCS). We measure galaxy redshifts and determine the velocity dispersions of the galaxy structures located in this field. Together with the main cluster Cl 1103.7-1245 (z=0.9580; {sigma}_clus_=522+/-111km/s) we find a secondary structure at z=0.9830, Cl 1103.7-1245c. We then characterize the galaxy properties in both systems. These new spectroscopic observations for Cl 1103.7-1245 complement the previous analysis of Milvang-Jensen et al. (2008, Cat. J/A+A/482/419), whose observations targetted z=0.70.
442. CLEAR. II. SFRs of quiescent galaxies
ID:
ivo://CDS.VizieR/J/ApJ/898/171
Title:
CLEAR. II. SFRs of quiescent galaxies
Short Name:
J/ApJ/898/171
Date:
16 Mar 2022 00:57:30
Publisher:
CDS
Description:
The origin of the correlations between mass, morphology, quenched fraction, and formation history in galaxies is difficult to define, primarily due to the uncertainties in galaxy star formation histories (SFHs). SFHs are better constrained for higher redshift galaxies, observed closer to their formation and quenching epochs. Here we use "nonparametric" SFHs and a nested sampling method to derive constraints on the formation and quenching timescales of quiescent galaxies at 0.7<z<2.5. We model deep HST grism spectroscopy and photometry from the CLEAR (CANDELS Ly{alpha} Emission at Reionization) survey. The galaxy formation redshifts, z50 (defined as the point where they had formed 50% of their stellar mass) range from z_50_~2 (shortly prior to the observed epoch) up to z_50_~5-8. We find that early formation redshifts are correlated with high stellar-mass surface densities, log{Sigma}_1_/(M_{sun}_kpc^-2^)>10.25, where {Sigma}_1_ is the stellar mass within 1pkpc (proper kpc). Quiescent galaxies with the highest stellar-mass surface density, log{Sigma}_1_/(M_{sun}_kpc^-2^)>10.25, show a minimum formation redshift: all such objects in our sample have z_50_>2.9. Quiescent galaxies with lower surface density, log{Sigma}_1_/(M_{sun}_kpc^-2^)=9.5-10.25, show a range of formation epochs (z_50_~1.5-8), implying these galaxies experienced a range of formation and assembly histories. We argue that the surface density threshold log{Sigma}_1_/(M_{sun}_kpc^-2^)>10.25 uniquely identifies galaxies that formed in the first few Gyr after the big bang, and we discuss the implications this has for galaxy formation models.
443. Cl0939+4713 H{alpha} z~0.4 star-forming galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/458/3443
Title:
Cl0939+4713 H{alpha} z~0.4 star-forming galaxies
Short Name:
J/MNRAS/458/3443
Date:
21 Oct 2021
Publisher:
CDS
Description:
Cluster star-forming galaxies are found to have an excess of far-infrared emission relative to H{alpha}, when compared to those in the field, which could be caused by intense active galactic nuclei (AGN) activity, dust and/or declining star formation histories. Here we present spectroscopic observations of H{alpha} emitters in the Cl 0939+4713 (Abell 851) super-cluster at z=0.41, using AF2+ WYFFOS on the William Herschel Telescope. We measure [OII], H{beta}, [OIII], H{alpha} and [NII] for a sample of 119 H{alpha} emitters in and around the cluster. We find that 17+/-5 per cent of the H{alpha} emitters are AGN, irrespective of environment. For star-forming galaxies, we obtain Balmer decrements, metallicities and ionization parameters with different methods, individually and by stacking. We find a strong mass-metallicity relation at all environments, with no significant dependence on environment. The ionization parameter declines with increasing stellar mass for low-mass galaxies. H{alpha} emitters residing in intermediate environments show the highest ionization parameters (along with high [OIII]/H{alpha} and high [OIII]/[OII] line ratios, typically twice as large as in the highest and lowest densities), which decline with increasing environmental density. Dust extinction (A_H{alpha}_) correlates strongly with stellar mass, but also with environmental density. Star-forming galaxies in the densest environments are found to be significantly dustier (A_H{alpha}_~=1.5-1.6) than those residing in the lowest density environments (A_H{alpha}_~=0.6), deviating significantly from what would be predicted given their stellar masses.
444. Cl J0023+0423 and Cl J1604+4304 spectroscopy
ID:
ivo://CDS.VizieR/J/AJ/116/560
Title:
Cl J0023+0423 and Cl J1604+4304 spectroscopy
Short Name:
J/AJ/116/560
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an extensive photometric and spectroscopic study of two high-redshift clusters of galaxies based on data obtained from the Keck 10m telescopes and the Hubble Space Telescope. The clusters Cl 0023+0423 (z=0.84) and Cl 1604+4304 (z=0.90) are part of a multiwavelength program of Oke, Postman & Lubin (1998AJ....116..549O, Paper I) to study nine candidate clusters at z>~0.6. Based on these observations, we study in detail both the field and cluster populations. From the confirmed cluster members, we find that Cl 0023+0423 actually consists of two components separated by ~2900km/s. A kinematic analysis indicates that the two components are a poor cluster with ~3x10^14^M_{sun}_ and a less massive group with ~10^13^M_{sun}_. Cl 1604+4304 is a centrally concentrated, rich cluster at z=0.8967 with a velocity dispersion of 1226km/s and a mass of ~3x10^15^M_{sun}_.
445. Close companions to young stars. I. ChaI & Tau
ID:
ivo://CDS.VizieR/J/ApJ/745/119
Title:
Close companions to young stars. I. ChaI & Tau
Short Name:
J/ApJ/745/119
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a multiplicity survey of 212 T Tauri stars in the Chamaeleon I and Taurus-Auriga star-forming regions, based on high-resolution spectra from the Magellan Clay 6.5m telescope. From these data, we achieved a typical radial velocity (RV) precision of ~80m/s with slower rotators yielding better precision, in general. For 174 of these stars, we obtained multi-epoch data with sufficient time baselines to identify binaries based on RV variations. We identified eight close binaries and four close triples, of which three and two, respectively, are new discoveries. The spectroscopic multiplicity fractions we find for Chamaeleon I (7%) and Taurus-Auriga (6%) are similar to each other, and to the results of field star surveys in the same mass and period regime. However, unlike the results from imaging surveys, the frequency of systems with close companions in our sample is not seen to depend on primary mass. Additionally, we do not find a strong correlation between accretion and close multiplicity. This implies that close companions are not likely the main source of the accretion shut down observed in weak-lined T Tauri stars. Our results also suggest that sufficient RV precision can be achieved for at least a subset of slowly rotating young stars to search for hot Jupiter planets.
446. Close pairs of galaxies in MUSE Deep Fields
ID:
ivo://CDS.VizieR/J/A+A/631/A87
Title:
Close pairs of galaxies in MUSE Deep Fields
Short Name:
J/A+A/631/A87
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using the ILLUSTRIS cosmological simulation project, we investigate the relation between the separation of galaxies in a pair, both in velocity and projected spatial separation space, and the probability that these interacting galaxies will merge in the future. From this analysis, we propose a new set of criteria to select close pairs of galaxies along with a new corrective term to be applied to the computation of the galaxy merger fraction. We then probe the evolution of the major and minor merger fraction using the latest MUSE deep observations over the Hubble Ultra Deep Field, Hubble Deep Field South, COSMOS-Gr30 and Abell 2744 regions. From a parent sample of 2483 galaxies with spectroscopic redshifts, we identify 366 close pairs spread over a large range of redshifts (0.2<z<6) and stellar masses (10^7^-10^11^M_{sun}_). Using the stellar mass ratio between the secondary and primary galaxy as a proxy to split the sample into major, minor and very minor mergers, we found a total of 183 major, 142 minor and 47 very minor close pairs corresponding to a mass ratio range of 1:1-1:6, 1:6-1:100 and lower than 1:100, respectively. Due to completeness issues, we do not consider the very minor pairs in the analysis. Overall, the major merger fraction increases up to z~2-3 reaching 25% for pairs with the most massive galaxy with a stellar mass M*>10^9.5^M_{sun}_. Beyond this redshift, the fraction decreases down to ~5% at z~6. The major merger fraction for lower mass primary galaxies M*<10^9.5^M_{sun}_, seems to follow a more constant evolutionary trend with redshift. Thanks to the addition of new MUSE fields and new selection criteria, the increased statistics of the pair samples allow to narrow significantly the error bars compared to our previous analysis (Ventou et al., 2017A&A...608A...9V). The evolution of the minor merger fraction is roughly constant with cosmic time, with a fraction of 20% at z<3 and a slow decrease between 3<z<6 to 8-13%.
447. Cloud Atlas: HST/WFC3 NIR spectral library
ID:
ivo://CDS.VizieR/J/AJ/157/101
Title:
Cloud Atlas: HST/WFC3 NIR spectral library
Short Name:
J/AJ/157/101
Date:
21 Oct 2021
Publisher:
CDS
Description:
Bayesian atmospheric retrieval tools can place constraints on the properties of brown dwarfs' and hot Jupiters' atmospheres. To fully exploit these methods, high signal-to-noise spectral libraries with well-understood uncertainties are essential. We present a high signal-to-noise spectral library (1.10-1.69 {mu}m) of the thermal emission of 76 brown dwarfs and hot Jupiters. All our spectra have been acquired with the Hubble Space Telescope's Wide Field Camera 3 instrument and its G141 grism. The near-infrared spectral types of these objects range from L4 to Y1. Eight of our targets have estimated masses below the deuterium-burning limit. We analyze the database to identify peculiar objects and/or multiple systems, concluding that this sample includes two very-low-surface-gravity objects and five intermediate-surface-gravity objects. In addition, spectral indices designed to search for composite-atmosphere brown dwarfs indicate that eight objects in our sample are strong candidates to have such atmospheres. None of these objects are overluminous, so their composite atmospheres are unlikely to be companion-induced artifacts. Five of the eight confirmed candidates have been reported as photometrically variable, suggesting that composite atmospheric indices are useful in identifying brown dwarfs with strongly heterogeneous cloud covers. We compare hot Jupiters and brown dwarfs in a near-infrared color-magnitude diagram. We confirm that the coldest hot Jupiters in our sample have spectra similar to mid-L dwarfs, and the hottest hot Jupiters have spectra similar to those of M-dwarfs. Our sample provides a uniform data set of a broad range of ultracool atmospheres, allowing large-scale comparative studies and providing an HST legacy spectral library.
448. Cluster difference imaging photometric survey. II.
ID:
ivo://CDS.VizieR/J/AJ/160/239
Title:
Cluster difference imaging photometric survey. II.
Short Name:
J/AJ/160/239
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of TOI837b and its validation as a transiting planet. We characterize the system using data from the NASA Transiting Exoplanet Survey Satellite mission, the ESA Gaia mission, ground-based photometry from El Sauce and ASTEP400, and spectroscopy from CHIRON, FEROS, and Veloce. We find that TOI837 is a T=9.9mag G0/F9 dwarf in the southern open cluster IC2602. The star and planet are therefore 35_-5_^+11^ million years old. Combining the transit photometry with a prior on the stellar parameters derived from the cluster color-magnitude diagram, we find that the planet has an orbital period of 8.3days and is slightly smaller than Jupiter (R_p_=0.77_-0.07_^+0.09^R_Jup_). From radial velocity monitoring, we limit M_p_sin(i) to less than 1.20M_Jup_(3{sigma}). The transits either graze or nearly graze the stellar limb. Grazing transits are a cause for concern, as they are often indicative of astrophysical false-positive scenarios. Our follow-up data show that such scenarios are unlikely. Our combined multicolor photometry, high-resolution imaging, and radial velocities rule out hierarchical eclipsing binary scenarios. Background eclipsing binary scenarios, though limited by speckle imaging, remain a 0.2% possibility. TOI837b is therefore a validated adolescent exoplanet. The planetary nature of the system can be confirmed or refuted through observations of the stellar obliquity and the planetary mass. Such observations may also improve our understanding of how the physical and orbital properties of exoplanets change in time.
449. Cluster SC2008-57(A3667)
ID:
ivo://CDS.VizieR/J/MNRAS/259/233
Title:
Cluster SC2008-57(A3667)
Short Name:
J/MNRAS/259/233
Date:
21 Oct 2021
Publisher:
CDS
Description:
(Abstract of the paper) We present the results of photometric and spectroscopic observations of the cluster of galaxies SC2008-57 (A3667). The observations have resulted in a catalogue with positions and magnitudes for 203 galaxies, complete at b_25 = 18.0, and radial velocities for 128 galaxies, 91 per cent complete at b_25 = 17.5. The cluster can be classified as type L because its galaxy distribution is highly flattened. It shows two strong concentrations: a main concentration, centred on the cluster brightest galaxy (a D galaxy) and coincident with the peak of X-ray emission, and a substructure around the second brightest galaxy (also a D galaxy). Most of the galaxies in this substructure seem to be bound to the second-brightest galaxy, forming a dynamical subunit inside the cluster. The extreme flattening of the cluster may at least partially be due to the presence of the substructure. The cluster also shows evidence for luminosity segregation, with the brightest galaxies being preferentially found in high galaxy density regions. Most of the luminosity segregation, however, is produced by galaxies associated with the two clumps around the D galaxies, suggesting that dynamical friction is effective in subclusters with low velocity dispersions and may be associated with the formation of D galaxies. The velocity dispersion of SC2008-57 is high, about 1200 km/s, but consistent with the observed X-ray luminosity. The cluster mass, derived using several estimators, is about 2.6 x 10^15 M_solar. Both the cluster mass and velocity dispersion may be overestimates due to the presence of the substructure.
450. 1.3cm line survey toward Orion KL
ID:
ivo://CDS.VizieR/J/A+A/581/A48
Title:
1.3cm line survey toward Orion KL
Short Name:
J/A+A/581/A48
Date:
18 Nov 2021 11:23:37
Publisher:
CDS
Description:
Orion KL has served as a benchmark for spectral line searches throughout the (sub)millimeter regime. The main goal is to systematically study spectral characteristics of Orion KL in the 1.3cm band. We carried out a spectral line survey (17.9GHz to 26.2GHz) with the Effelsberg-100m telescope towards Orion KL. We find 261 spectral lines, yielding an average line density of about 32 spectral features per GHz above 3 sigma. The identified lines include 164 radio recombination lines (RRLs) and 97 molecular lines. A total of 23 molecular transitions from species known to exist in Orion KL are detected for the first time in the interstellar medium. Non-metastable ^15^NH_3_ transitions are detected in Orion KL for the first time. Based on the velocity information of detected lines and the ALMA images, the spatial origins of molecular emission are constrained and discussed. A narrow feature is found in SO_2_ (8_1,7_-7_2,6_), possibly suggesting the presence of a maser line. Column densities and fractional abundances relative to H_2_ are estimated for 12 molecules with LTE methods. Rotational diagrams of non-metastable ^14^NH_3_ transitions with J=K+1 to J=K+4 yield different results; metastable ^15^NH_3_ is found to have a higher excitation temperature than non-metastable ^15^NH_3_, indicating that they may trace different regions. Elemental and isotopic abundance ratios are estimated: ^12^C/^13^C=63+/-17, ^14^N/^15^N=100+/-51, D/H=0.0083+/-0.0045. The dispersion of the He/H ratios derived from H_alpha/He_alpha_ pairs to H_delta_/He_delta_ pairs is very small, which is consistent with theoretical predictions that the departure coefficients bn factors for hydrogen and helium are nearly identical. Based on a non-LTE code neglecting excitation by the infrared radiation field and a likelihood analysis, we find that the denser regions have lower kinetic temperature, which favors an external heating of the Hot Core.

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