- ID:
- ivo://CDS.VizieR/J/ApJS/222/11
- Title:
- Hubble Tarantula Treasury Project (HTTP). III.
- Short Name:
- J/ApJS/222/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and describe the astro-photometric catalog of more than 800000 sources found in the Hubble Tarantula Treasury Project (HTTP). HTTP is a Hubble Space Telescope Treasury program designed to image the entire 30 Doradus region down to the sub-solar (~0.5M_{sun}_) mass regime using the Wide Field Camera 3 and the Advanced Camera for Surveys. We observed 30 Doradus in the near-ultraviolet (F275W, F336W), optical (F555W, F658N, F775W), and near-infrared (F110W, F160W) wavelengths. The stellar photometry was measured using point-spread function fitting across all bands simultaneously. The relative astrometric accuracy of the catalog is 0.4mas. The astro-photometric catalog, results from artificial star experiments, and the mosaics for all the filters are available for download. Color-magnitude diagrams are presented showing the spatial distributions and ages of stars within 30 Dor as well as in the surrounding fields. HTTP provides the first rich and statistically significant sample of intermediate- and low-mass pre-main sequence candidates and allows us to trace how star formation has been developing through the region. The depth and high spatial resolution of our analysis highlight the dual role of stellar feedback in quenching and triggering star formation on the giant HII region scale. Our results are consistent with stellar sub-clustering in a partially filled gaseous nebula that is offset toward our side of the Large Magellanic Cloud.
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- ID:
- ivo://CDS.VizieR/J/AJ/132/1729
- Title:
- Hubble Ultra Deep Field BVI-dropout sources
- Short Name:
- J/AJ/132/1729
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents the Hubble Ultra Deep Field (HUDF), a 1 million secs exposure of an 11arcmin^2^ region in the southern sky with the Advanced Camera for Surveys on the Hubble Space Telescope using Director's Discretionary Time. The exposure time was divided among four filters, F435W (B435), F606W (V606), F775W (i775), and F850LP (z850), to give approximately uniform limiting magnitudes m_AB_~29 for point sources. The image contains at least 10000 objects, presented here as a catalog, the vast majority of which are galaxies. Visual inspection of the images shows few if any galaxies at redshifts greater than ~4 that resemble present-day spiral or elliptical galaxies. The image reinforces the conclusion from the original Hubble Deep Field that galaxies evolved strongly during the first few billion years in the infancy of the universe. Using the Lyman break dropout method to derive samples of galaxies at redshifts between 4 and 7, it is possible to study the apparent evolution of the galaxy luminosity function and number density.
- ID:
- ivo://CDS.VizieR/II/258
- Title:
- Hubble Ultra Deep Field Catalog (UDF)
- Short Name:
- II/258
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Hubble Ultra Deep Field (PI: Steven V. W. Beckwith) is a 400-orbit Cycle 12 program to image a single field of the Wide Field Camera (WFC) of the Advanced Camera for Surveys (ACS) in four filters: F435W (B), F606W (V), F775W (i), and F850LP (z). The observations took place over 4 months from September 2003 to January 2004 under two program IDs: 9978 and 10086. The observations consist of half-orbit exposures, cycling through each of the filters in a 4-point dither pattern to provide sub-pixel sampling, as well as a larger-scale 3-point line pattern to cover the 2 second of arc gap between the two ACS/WFC chips. The total exposure times are summarized below, with typical exposure times of 1200s for individual images. The AB magnitude zero-points for ACS are current as of March 2004. --------------------------------------------------------------- Number of Number of Total Exp. AB mag. Orbits Exposures Time (s) zero-point --------------------------------------------------------------- B (F435W): 56 112 134880 25.673 V (F606W): 56 112 135320 26.486 i (F775W): 144 288 347110 25.654 z (F850LP): 144 288 346620 24.862 --------------------------------------------------------------- More details are found in the "intro.txt" file, or from the UDF home page.
- ID:
- ivo://CDS.VizieR/J/ApJ/735/L22
- Title:
- HUDF galaxy properties at z~2
- Short Name:
- J/ApJ/735/L22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use ultra-deep Hubble Space Telescope Wide Field Camera 3/infrared imaging of the Hubble Ultra Deep Field to investigate the rest-frame optical morphologies of a mass-selected sample of galaxies at z~2. We find a large variety of galaxy morphologies, ranging from large, blue, disk-like galaxies to compact, red, early-type galaxies. We derive rest-frame u-g color profiles for these galaxies and show that most z~2 galaxies in our sample have negative color gradients such that their cores are red.
- ID:
- ivo://CDS.VizieR/J/ApJ/768/102
- Title:
- I-band GALFIT analysis of luminous infrared galaxies
- Short Name:
- J/ApJ/768/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A Hubble Space Telescope/Advanced Camera for Surveys study of the structural properties of 85 luminous and ultraluminous (L_IR_>10^11.4^ L_{sun}_) infrared galaxies (LIRGs and ULIRGs) in the Great Observatories All-sky LIRG Survey (GOALS) sample is presented. Two-dimensional GALFIT analysis has been performed on F814W "I-band" images to decompose each galaxy, as appropriate, into bulge, disk, central point-spread function (PSF) and stellar bar components. The fraction of bulge-less disk systems is observed to be higher in LIRGs (35%) than in ULIRGs (20%), with the disk+bulge systems making up the dominant fraction of both LIRGs (55%) and ULIRGs (45%). Further, bulge+disk systems are the dominant late-stage merger galaxy type and are the dominant type for LIRGs and ULIRGs at almost every stage of galaxy-galaxy nuclear separation. The mean I-band host absolute magnitude of the GOALS galaxies is -22.64+/-0.62 mag (1.8_-0.4_^+1.4^ L_1_^*^), and the mean bulge absolute magnitude in GOALS galaxies is about 1.1 mag fainter than the mean host magnitude. Almost all ULIRGs have bulge magnitudes at the high end (-20.6 to -23.5 mag) of the GOALS bulge magnitude range. Mass ratios in the GOALS binary systems are consistent with most of the galaxies being the result of major mergers, and an examination of the residual-to-host intensity ratios in GOALS binary systems suggests that smaller companions suffer more tidal distortion than the larger companions. We find approximately twice as many bars in GOALS disk+bulge systems (32.8%) than in pure-disk mergers (15.9%) but most of the disk+bulge systems that contain bars are disk-dominated with small bulges. The bar-to-host intensity ratio, bar half-light radius, and bar ellipticity in GOALS galaxies are similar to those found in nearby spiral galaxies. The fraction of stellar bars decreases toward later merger stages and smaller nuclear separations, indicating that bars are destroyed as the merger advances. In contrast, the fraction of nuclear PSFs increases toward later merger stages and is highest in late-stage systems with a single nucleus. Thus, light from an active galactic nucleus or compact nuclear star cluster is more visible at I band as ULIRGs enter their latter stages of evolution. Finally, both GOALS elliptical hosts and nearby Sloan Digital Sky Survey (SDSS) ellipticals occupy the same part of the surface brightness versus half-light radius plot (i.e., the "Kormendy Relation") and have similar slopes, consistent with the possibility that the GOALS galaxies belong to the same parent population as the SDSS ellipticals.
- ID:
- ivo://CDS.VizieR/J/AJ/148/117
- Title:
- Imaging and spectroscopy in Lynx W
- Short Name:
- J/AJ/148/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- RX J0848.6+4453 (Lynx W) at redshift 1.27 is part of the Lynx Supercluster of galaxies. We present an analysis of the stellar populations and star formation history for a sample of 24 members of the cluster. Our study is based on deep optical spectroscopy obtained with Gemini North combined with imaging data from Hubble Space Telescope. Focusing on the 13 bulge-dominated galaxies for which we can determine central velocity dispersions, we find that these show a smaller evolution with redshift of sizes and velocity dispersions than reported for field galaxies and galaxies in poorer clusters. Our data show that the galaxies in RX J0848.6+4453 populate the fundamental plane (FP) similar to that found for lower-redshift clusters. The zero-point offset for the FP is smaller than expected if the cluster's galaxies are to evolve passively through the location of the FP we established in our previous work for z=0.8-0.9 cluster galaxies and then to the present-day FP. The FP zero point for RXJ0848.6+4453 corresponds to an epoch of last star formation at z_form_=1.95_-0.15_^+0.22^. Further, we find that the spectra of the galaxies in RXJ0848.6+4453 are dominated by young stellar populations at all galaxy masses and in many cases show emission indicating low-level ongoing star formation. The average age of the young stellar populations as estimated from the strength of the high-order Balmer line H{zeta} is consistent with a major star formation episode 1-2Gyr prior, which in turn agrees with z_form_=1.95. These galaxies dominated by young stellar populations are distributed throughout the cluster. We speculate that low-level star formation has not yet been fully quenched in the center of this cluster, possibly because the cluster is significantly poorer than other clusters previously studied at similar redshifts, which appear to have very little ongoing star formation in their centers. The mixture in RXJ0848.6+4453 of passive galaxies with young stellar populations and massive galaxies still experiencing some star formation appears similar to the galaxy populations recently identified in two z{approx}2 clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/145/77
- Title:
- Imaging and spectroscopy in three galaxy clusters
- Short Name:
- J/AJ/145/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of stellar populations and evolutionary history of galaxies in three similarly rich galaxy clusters MS0451.6-0305 (z=0.54), RXJ0152.7-1357 (z=0.83), and RXJ1226.9+3332 (z=0.89). Our analysis is based on high signal-to-noise ground-based optical spectroscopy and Hubble Space Telescope imaging for a total of 17-34 members in each cluster. Using the dynamical masses together with the effective radii and the velocity dispersions, we find no indication of evolution of sizes or velocity dispersions with redshift at a given galaxy mass. We establish the Fundamental Plane (FP) and scaling relations between absorption line indices and velocity dispersions. We confirm that the FP is steeper at z~0.86 compared to the low-redshift FP, indicating that under the assumption of passive evolution the formation redshift, z_form_, depends on the galaxy velocity dispersion (or alternatively mass). At a velocity dispersion of {sigma}=125km/s (Mass=10^10.55^M_{sun}_) we find z_form_=1.24+/-0.05, while at {sigma}=225km/s (Mass=10^11.36^M_{sun}_) the formation redshift is z_form_=1.95^+0.3^_-0.2_, for a Salpeter initial mass function. The three clusters follow similar scaling relations between absorption line indices and velocity dispersions as those found for low-redshift galaxies. The zero point offsets for the Balmer lines depend on cluster redshifts. However, the offsets indicate a slower evolution, and therefore higher formation redshift, than the zero point differences found from the FP, if interpreting the data using a passive evolution model. Specifically, the strength of the higher order Balmer lines H{delta} and H{gamma} implies z_form_>2.8. The scaling relations for the metal indices in general show small and in some cases insignificant zero point offsets, favoring high formation redshifts for a passive evolution model.
- ID:
- ivo://CDS.VizieR/J/A+A/649/A138
- Title:
- Intensity profiles for GC1 of M81
- Short Name:
- J/A+A/649/A138
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Researching the properties of the brightest globular cluster (referred to as GC1) in M 81 can provide a fossil record of the earliest stages of galaxy formation and evolution. The Beijing-Arizona-Taiwan-Connecticut (BATC) Multicolour Sky Survey has carried out deep exposures of M 81. We derive the magnitudes in intermediate-band filters of the BATC system for GC1 and determine its age, mass, and structural parameters. GC1 was observed by BATC using 14 intermediate-band filters covering a wavelength range of 4000-10000{AA}. Based on photometric data in BATC and Two Micron All Sky Survey near-infrared JHKs filters, we constructed an extensive spectral energy distribution of GC1, spanning the wavelength range from 4000 to 20000{AA}. By comparing multicolour photometry with theoretical single stellar population synthesis models, we derived the age and mass of GC1. In addition, we obtained ellipticities, position angles, and surface brightness profiles for GC1 based on the images of deep observations with the Advanced Camera for Surveys on the Hubble Space Telescope. GC1 is better fitted by the Wilson model than by the King and Sersic models in the F606W filter, and it is better fitted by the Sersic model than by the King and Wilson models in the F814W filter. The 'best-fit' half-light radius of GC1 obtained here is 5.59pc, which is larger than the majority of normal globular clusters (GCs) of the same luminosity. The age and mass of GC1 estimated here are 13.0+/-2.90Gyr and 1.06-1.48x10^7^M_{sun}_, respectively. The Rh versus MV diagram shows that GC1 occupies the same area as extended star clusters. Therefore, we suggest that GC1 is more likely an accreted former nuclear star cluster than a classical GC similar to most of those in the Milky Way.
- ID:
- ivo://CDS.VizieR/J/ApJ/624/L5
- Title:
- IR photometry of z~10 galaxies in NICMOS fields
- Short Name:
- J/ApJ/624/L5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use all available fields with deep NICMOS imaging to search for J_110_-dropouts (H_160,AB_<~28) at z~10. Our primary data set for this search is the two J_110_+H_160_ NICMOS fields taken in parallel with the Advanced Camera for Surveys (ACS) Hubble Ultra Deep Field (UDF). The 5{sigma} limiting magnitudes were ~28.6 in J_110_ and ~28.5 in H_160_ (0.6" apertures).
- ID:
- ivo://CDS.VizieR/J/ApJ/850/137
- Title:
- ISLAndS project. III. Variable stars
- Short Name:
- J/ApJ/850/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a census of variable stars in six M31 dwarf spheroidal satellites observed with the Hubble Space Telescope. We detect 870 RR Lyrae (RRL) stars in the fields of And I (296), II (251), III (111), XV (117), XVI (8), and XXVIII (87). We also detect a total of 15 Anomalous Cepheids, three eclipsing binaries, and seven field RRL stars compatible with being members of the M31 halo or the Giant Stellar Stream. We derive robust and homogeneous distances to the six galaxies using different methods based on the properties of the RRL stars. Working with the up-to-date set of Period-Wesenheit (I, B-I) relations published by Marconi et al., we obtain distance moduli of {mu}0=[24.49, 24.16, 24.36, 24.42, 23.70, 24.43]mag (respectively), with systematic uncertainties of 0.08mag and statistical uncertainties <0.11mag. We have considered an enlarged sample of 16 M31 satellites with published variability studies, and compared their pulsational observables (e.g., periods and amplitudes) with those of 15 Milky Way satellites for which similar data are available. The properties of the (strictly old) RRL in both satellite systems do not show any significant difference. In particular, we found a strikingly similar correlation between the mean period distribution of the fundamental RRL pulsators (RRab) and the mean metallicities of the galaxies. This indicates that the old RRL progenitors were similar at the early stage in the two environments, suggesting very similar characteristics for the earliest stages of evolution of both satellite systems.
