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- ID:
- ivo://CDS.VizieR/J/ApJ/854/73
- Title:
- Full-data results of HFF: galaxies z~6-9
- Short Name:
- J/ApJ/854/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UV luminosity functions of dropout galaxies at z~6-10 with the complete Hubble Frontier Fields data. We obtain a catalog of ~450 dropout-galaxy candidates (350, 66, and 40 at z~6-7, 8, and 9, respectively), with UV absolute magnitudes that reach ~-14mag, ~2 mag deeper than the Hubble Ultra Deep Field detection limits. We carefully evaluate number densities of the dropout galaxies by Monte Carlo simulations, including all lensing effects such as magnification, distortion, and multiplication of images as well as detection completeness and contamination effects in a self-consistent manner. We find that UV luminosity functions at z~6-8 have steep faint-end slopes, {alpha}~-2, and likely steeper slopes, {alpha}<~-2 at z~9-10. We also find that the evolution of UV luminosity densities shows a non-accelerated decline beyond z~8 in the case of M_trunc_=-15, but an accelerated one in the case of M_trunc_=-17. We examine whether our results are consistent with the Thomson scattering optical depth from the Planck satellite and the ionized hydrogen fraction Q_HII_ at z<~7 based on the standard analytic reionization model. We find that reionization scenarios exist that consistently explain all of the observational measurements with the allowed parameters of f_esc_=0.17_-0.03_^+0.07^ and M_trunc_>-14.0 for log{xi}_ion_/[erg^-1^Hz]=25.34, where f_esc_ is the escape fraction, Mtrunc is the faint limit of the UV luminosity function, and {xi}_ion_ is the conversion factor of the UV luminosity to the ionizing photon emission rate. The length of the reionization period is estimated to be {Delta}z=3.9_-1.6_^+2.0^ (for 0.1<Q_HII_<0.99), consistent with the recent estimate from Planck.
- ID:
- ivo://CDS.VizieR/J/ApJ/625/156
- Title:
- FUV-NUV observations of NGC 2808
- Short Name:
- J/ApJ/625/156
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a reanalysis of far-ultraviolet (FUV) observations of the globular cluster NGC 2808 obtained with the Hubble Space Telescope. These data were first analyzed by Brown and coworkers (2001, Cat. <J/ApJ/562/368>), with an emphasis on the bright, blue horizontal-branch (HB) stars in this cluster. Here, our focus is on the population of fainter FUV sources, which include white dwarfs (WDs), blue stragglers (BSs), and cataclysmic variables (CVs).
- ID:
- ivo://CDS.VizieR/J/AJ/135/2141
- Title:
- F814W+F606W photometry of NGC 6397 faint stars
- Short Name:
- J/AJ/135/2141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the color-magnitude diagram (CMD) from deep Hubble Space Telescope imaging in the globular cluster NGC 6397. The Advanced Camera for Surveys (ACS) was used for 126 orbits to image a single field in two colors (F814W, F606W) 5' SE of the cluster center. The field observed overlaps that of archival WFPC2 data from 1994 and 1997 which were used to proper motion (PM) clean the data. Applying the PM corrections produces a remarkably clean CMD which reveals a number of features never seen before in a globular cluster CMD. In our field, the main-sequence stars appeared to terminate close to the location in the CMD of the hydrogen-burning limit predicted by two independent sets of stellar evolution models.
- ID:
- ivo://CDS.VizieR/J/AJ/133/504
- Title:
- Galaxies around CenA/M83 galaxy complex
- Short Name:
- J/AJ/133/504
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Hubble Space Telescope ACS images and color-magnitude diagrams for 24 nearby galaxies in and near the constellation of Centaurus with radial velocities V_LG_<550km/s. Distances are determined based on the luminosities of stars at the tip of the red giant branch that range from 3.0 to 6.5Mpc. The galaxies are concentrated in two spatially separated groups around Cen A (NGC 5128) and M83 (NGC 5236).
- ID:
- ivo://CDS.VizieR/J/MNRAS/404/749
- Title:
- Galaxies in the field of B2108+213
- Short Name:
- J/MNRAS/404/749
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The gravitational lens system CLASS B2108+213 has two radio-loud lensed images separated by 4.56 arcsec. The relatively large image separation implies that the lensing is caused by a group of galaxies. In this paper, new optical imaging and spectroscopic data for the lensing galaxies of B2108+213 and the surrounding field galaxies are presented. These data are used to investigate the mass and composition of the lensing structure.
- ID:
- ivo://CDS.VizieR/J/ApJ/820/98
- Title:
- Galaxy candidates in the Hubble Frontier Fields
- Short Name:
- J/ApJ/820/98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present the results of our search for and study of z>~6 galaxy candidates behind the third Frontier Fields (FFs) cluster, MACS J0717.5+3745, and its parallel field, combining data from Hubble and Spitzer. We select 39 candidates using the Lyman break technique, for which the clear non-detection in optical make the extreme mid-z interlopers hypothesis unlikely. We also take benefit from z>~6 samples selected using the previous FF data sets of Abell 2744 and MACS 0416 to improve the constraints on the properties of very high redshift objects. We compute the redshift and the physical properties such emission lines properties, star formation rate, reddening, and stellar mass for all FF objects from their spectral energy distribution using templates including nebular emission lines. We study the relationship between several physical properties and confirm the trend already observed in previous surveys for evolution of star formation rate with galaxy mass and between the size and the UV luminosity of our candidates. The analysis of the evolution of the UV luminosity function with redshift seems more compatible with an evolution of density. Moreover, no robust z>=8.5 object is selected behind the cluster field and few z~9 candidates have been selected in the two previous data sets from this legacy survey, suggesting a strong evolution in the number density of galaxies between z~8 and 9. Thanks to the use of the lensing cluster, we study the evolution of the star formation rate density produced by galaxies with L>0.03 L_{star}_, and confirm the strong decrease observed between z~8 and 9.
- ID:
- ivo://CDS.VizieR/J/ApJ/631/85
- Title:
- Galaxy morphologies in the Hubble UDF
- Short Name:
- J/ApJ/631/85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxies in the Hubble Ultra Deep Field (UDF) larger than 10 pixels (0.3") have been classified according to morphology, and their photometric properties are presented. There are 269 spiral, 100 elliptical, 114 chain, 126 double-clump, 97 tadpole, and 178 clump-cluster galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/811/29
- Title:
- GLASS. IV. Lensing cluster Abell 2744
- Short Name:
- J/ApJ/811/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a strong and weak lensing reconstruction of the massive cluster Abell 2744, the first cluster for which deep Hubble Frontier Fields (HFF) images and spectroscopy from the Grism Lens-Amplified Survey from Space (GLASS) are available. By performing a targeted search for emission lines in multiply imaged sources using the GLASS spectra, we obtain five high-confidence spectroscopic redshifts and two tentative ones. We confirm one strongly lensed system by detecting the same emission lines in all three multiple images. We also search for additional line emitters blindly and use the full GLASS spectroscopic catalog to test reliability of photometric redshifts for faint line emitters. We see a reasonable agreement between our photometric and spectroscopic redshift measurements, when including nebular emission in photometric redshift estimations. We introduce a stringent procedure to identify only secure multiple image sets based on colors, morphology, and spectroscopy. By combining 7 multiple image systems with secure spectroscopic redshifts (at 5 distinct redshift planes) with 18 multiple image systems with secure photometric redshifts, we reconstruct the gravitational potential of the cluster pixellated on an adaptive grid, using a total of 72 images. The resulting mass map is compared with a stellar mass map obtained from the deep Spitzer Frontier Fields data to study the relative distribution of stars and dark matter in the cluster. We find that the stellar to total mass ratio varies substantially across the cluster field, suggesting that stars do not trace exactly the total mass in this interacting system. The maps of convergence, shear, and magnification are made available in the standard HFF format.
- ID:
- ivo://CDS.VizieR/J/ApJ/835/254
- Title:
- GLASS. IX. Structural param. from HFF & GLASS
- Short Name:
- J/ApJ/835/254
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using deep Hubble Frontier Fields imaging and slitless spectroscopy from the Grism Survey from Space, we study 2200 cluster and 1748 field galaxies at 0.2<=z<=0.7 to determine the impact of environment on galaxy size and structure at stellar masses logM_*_/M_{sun}_>7.8, an unprecedented limit at these redshifts. Based on simple assumptions-r_e_=f(M_*_)-we find no significant differences in half-light radii (r_e_) between equal-mass cluster or field systems. More complex analyses --r_e_=f(M_*_,U-V,n,z,{Sigma})-- reveal local density ({Sigma}) to induce only a 7%+/-3% (95% confidence) reduction in r_e_ beyond what can be accounted for by U-V color, Sersic index (n), and redshift (z) effects. Almost any size difference between galaxies in high- and low-density regions is thus attributable to their different distributions in properties other than environment. Indeed, we find a clear color-r_e_ correlation in low-mass passive cluster galaxies (logM_*_/M_{sun}_<9.8) such that bluer systems have larger radii, with the bluest having sizes consistent with equal-mass star-forming galaxies. We take this as evidence that large-r_e_ low-mass passive cluster galaxies are recently acquired systems that have been environmentally quenched without significant structural transformation (e.g., by ram pressure stripping or starvation). Conversely, ~20% of small-r_e_ low-mass passive cluster galaxies appear to have been in place since z>~3. Given the consistency of the small-r_e_ galaxies' stellar surface densities (and even colors) with those of systems more than ten times as massive, our findings suggest that clusters mark places where galaxy evolution is accelerated for an ancient base population spanning most masses, with late-time additions quenched by environment-specific mechanisms mainly restricted to the lowest masses.
