- ID:
- ivo://CDS.VizieR/J/AJ/116/2081
- Title:
- Hubble Deep Field catalog of color-based redshift
- Short Name:
- J/AJ/116/2081
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive simple empirical color-redshift relations for z<~4 galaxies in the Hubble Deep Field (HDF) using a linear function of three photometric colors (U-B, B-V, V-I). The dispersion between the estimated redshifts and the spectroscopically observed ones is small for relations derived in several separate color regimes; the dispersions range from {sigma}_z_~=0.03 to 0.1 for z<~2 galaxies, and from {sigma}_z_~=0.14 to 0.25 for z>~2 galaxies. We apply the color-redshift relations to the HDF photometric catalog and obtain estimated redshifts that are consistent with those derived from spectral template fitting methods. The advantage of these color-redshift relations is that they are simple and easy to use and do not depend on the assumption of any particular spectral templates; they provide model independent redshift estimates for z<~4 galaxies using only multiband photometry, and they apply to about 90% of all galaxies. We provide a color-based estimated redshift catalog of HDF galaxies to z<~4. We use the estimated redshifts to investigate the redshift distribution of galaxies in the HDF; we find peaks in the redshift distribution that suggest large-scale clustering of galaxies to at least z~1 and that are consistent with those identified in spectroscopic probes of the HDF.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/548/127
- Title:
- Hubble Deep Field-South region
- Short Name:
- J/ApJ/548/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the galaxy-galaxy angular correlations as a function of photometric redshift in a deep, wide galaxy survey centered on the Hubble Deep Field-South (HDF-S). Images were obtained with the Big Throughput Camera on the Blanco 4-m telescope at CTIO, of 1/2 square degree in broadband uBVRI, reaching ~24mag. Approximately 40,000 galaxies are detected in the survey. We determine photometric redshifts using galaxy template fitting to the photometry.
- ID:
- ivo://CDS.VizieR/J/ApJ/613/200
- Title:
- Hubble Higher z Supernova Search, HHZSS
- Short Name:
- J/ApJ/613/200
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from the Hubble Higher z Supernova Search, the first space-based open field survey for supernovae (SNe). In cooperation with the Great Observatories Origins Deep Survey, we have used the Hubble Space Telescope with the Advanced Camera for Surveys to cover ~300arcmin^2^ in the area of the Chandra Deep Field South and the Hubble Deep Field North on five separate search epochs (separated by ~45day intervals) to a limiting magnitude of F850LP~26. These deep observations have allowed us to discover 42 SNe in the redshift range 0.2<z<1.6. As these data span a large range in redshift, they are ideal for testing the validity of Type Ia supernova progenitor models with the distribution of expected "delay times" from progenitor star formation to Type Ia SN explosion, and the SN rates these models predict. Through a Bayesian maximum likelihood test, we determine which delay-time models best reproduce the redshift distribution of SNe Ia discovered in this survey. We find that models that require a large fraction of "prompt" (less than 2Gyr) SNe Ia poorly reproduce the observed redshift distribution and are rejected at greater than 95% confidence. We find that Gaussian models best fit the observed data for mean delay times in the range of 2-4Gyr.
- 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/A+A/297/617
- Title:
- Hydra/Antlia extension redshifts
- Short Name:
- J/A+A/297/617
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectroscopic observations have been carried out for galaxies in the Milky Way with the 1.9m telescope of the South African Astronomical Observatory (SAAO). The galaxies were selected from a deep optical galaxy search covering 266deg<~l<~296deg, |b|<~10deg (Kraan-Korteweg 1994). This is in the extension of the Hydra and Antlia clusters and in the approximate direction of the dipole anisotropy in the Cosmic Microwave Background radiation.
- ID:
- ivo://CDS.VizieR/J/ApJS/182/12
- Title:
- ICM entropy profiles (ACCEPT)
- Short Name:
- J/ApJS/182/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radial entropy profiles of the intracluster medium (ICM) for a collection of 239 clusters taken from the Chandra X-ray Observatory's Data Archive. We find that most ICM entropy profiles are well fitted by a model which is a power law at large radii and approaches a constant value at small radii: K(r)=K_0_+K_100_(r/100kpc)^{alpha}^, where K_0_ quantifies the typical excess of core entropy above the best-fitting power law found at larger radii. For completeness, we include previously unpublished optical spectroscopy of H{alpha} and [NII] emission lines discussed in Cavagnolo et al. (2008ApJ...683L.107C). All data and results associated with this work are publicly available via the project Web site (ACCEPT: Archive of Chandra Cluster Entropy Profile Tables).
- ID:
- ivo://CDS.VizieR/J/ApJ/873/132
- Title:
- ICRF3 radio-loud quasars with Gaia DR2 data
- Short Name:
- J/ApJ/873/132
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate a sample of 3413 International Celestial Reference Frame (ICRF3) extragalactic radio-loud sources with accurate positions determined by very long baseline interferometry in the S/X band, mostly active galactic nuclei and quasars, which are cross-matched with optical sources in the second Gaia data release (Gaia DR2). The main goal of this study is to determine a core sample of astrometric objects that define the mutual orientation of the two fundamental reference frames, the Gaia (optical) and the ICRF3 (radio) frames. The distribution of normalized offsets between the VLBI sources and their optical counterparts is non-Rayleigh, with a deficit around the modal value and a tail extending beyond the 3{sigma} confidence level. A few filters are applied to the sample in order to discard double cross-matches, confusion sources, and Gaia astrometric solutions of doubtful quality. Panoramic Survey Telescope and Rapid Response System and Dark Energy Survey stacked multicolor images are used to further deselect objects that are less suitable for precision astrometry, such as extended galaxies, double and multiple sources, and obvious misidentifications. After this cleaning, 2643 quasars remain, of which 20% still have normalized offset magnitudes exceeding 3, or a 99% confidence level. We publish a list of 2119 radio-loud quasars of prime astrometric quality. The observed dependence of binned median offset on redshift shows the expected decline at small redshifts, but also an unexpected rise at z~1.6, which may be attributed to the emergence of the CIV emission line in the Gaia's G band. The Gaia DR2 parallax zero-point is found to be color-dependent, suggesting an uncorrected instrumental calibration effect.
608. IfA Deep SN rates
- ID:
- ivo://CDS.VizieR/J/ApJ/723/47
- Title:
- IfA Deep SN rates
- Short Name:
- J/ApJ/723/47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The IfA Deep Survey uncovered ~130 thermonuclear supernova (TN SN, i.e., Type Ia) candidates at redshifts from z=0.1 out to beyond z=1. The TN SN explosion rates derived from these data have been controversial, conflicting with evidence emerging from other surveys. This work revisits the IfA Deep Survey to re-evaluate the photometric evidence. Applying the SOFT (Supernova Ontology with Fuzzy Templates) program to the light curves of all SN candidates, we derive new classification grades and redshift estimates. We find a volumetric rate for z~0.5 that is substantially smaller than the originally published values, bringing the revised IfA Deep rate into good agreement with other surveys. With our improved photometric analysis techniques, we are able to confidently extend the rate measurements to higher redshifts and we find a steadily increasing TN SN rate, with no indication of a peak out to z=1.05.
- ID:
- ivo://CDS.VizieR/J/ApJ/588/218
- Title:
- i*g* photometry of SDSS EDR galaxies
- Short Name:
- J/ApJ/588/218
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present a new statistic for quantifying galaxy morphology based on measurements of the Gini coefficient of galaxy light distributions. This statistic is easy to measure and is commonly used in econometrics to measure how wealth is distributed in human populations. When applied to galaxy images, the Gini coefficient provides a quantitative measure of the inequality with which a galaxy's light is distributed among its constituent pixels. We measure the Gini coefficient of local galaxies in the Early Data Release of the Sloan Digital Sky Survey and demonstrate that this quantity is closely correlated with measurements of central concentration, but with significant scatter.
- 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.
