- ID:
- ivo://CDS.VizieR/J/ApJS/235/36
- Title:
- SPLASH-SXDF multi-wavelength photometric catalog
- Short Name:
- J/ApJS/235/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multi-wavelength catalog in the Subaru/XMM-Newton Deep Field (SXDF) as part of the Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH). We include the newly acquired optical data from the Hyper-Suprime-Cam Subaru Strategic Program, accompanied by IRAC coverage from the SPLASH survey. All available optical and near-infrared data is homogenized and resampled on a common astrometric reference frame. Source detection is done using a multi-wavelength detection image including the u-band to recover the bluest objects. We measure multi-wavelength photometry and compute photometric redshifts as well as physical properties for ~1.17 million objects over ~4.2deg^2^, with ~800000 objects in the 2.4deg^2^ HSC-Ultra-Deep coverage. Using the available spectroscopic redshifts from various surveys over the range of 0<z<6, we verify the performance of the photometric redshifts and we find a normalized median absolute deviation of 0.023 and outlier fraction of 3.2%. The SPLASH-SXDF catalog is a valuable, publicly available resource, perfectly suited for studying galaxies in the early universe and tracing their evolution through cosmic time.
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- ID:
- ivo://CDS.VizieR/J/ApJS/224/38
- Title:
- SPOGS. I. SDSS Shocked POststarburst Galaxy cand.
- Short Name:
- J/ApJS/224/38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- There are many mechanisms by which galaxies can transform from blue, star-forming spirals, to red, quiescent early-type galaxies, but our current census of them does not form a complete picture. Recent observations of nearby case studies have identified a population of galaxies that quench "quietly". Traditional poststarburst searches seem to catch galaxies only after they have quenched and transformed, and thus miss any objects with additional ionization mechanisms exciting the remaining gas. The Shocked POststarburst Galaxy Survey (SPOGS) aims to identify transforming galaxies, in which the nebular lines are excited via shocks instead of through star formation processes. Utilizing the Oh-Sarzi-Schawinski-Yi (OSSY, 2011ApJS..195...13O) measurements on the Sloan Digital Sky Survey Data Release 7 catalog, we applied Balmer absorption and shock boundary criteria to identify 1067 SPOG candidates (SPOGs*) within z=0.2. SPOGs* represent 0.2% of the OSSY sample galaxies that exceed the continuum signal-to-noise cut (and 0.7% of the emission line galaxy sample). SPOGs* colors suggest that they are in an earlier phase of transition than OSSY galaxies that meet an "E+A" selection. SPOGs* have a 13% 1.4GHz detection rate from the Faint Images of the Radio Sky at Twenty Centimeters Survey, higher than most other subsamples, and comparable only to low-ionization nuclear emission line region hosts, suggestive of the presence of active galactic nuclei (AGNs). SPOGs* also have stronger Na i D absorption than predicted from the stellar population, suggestive of cool gas being driven out in galactic winds. It appears that SPOGs* represent an earlier phase in galaxy transformation than traditionally selected poststarburst galaxies, and that a large proportion of SPOGs* also have properties consistent with disruption of their interstellar media, a key component to galaxy transformation. It is likely that many of the known pathways to transformation undergo a SPOG phase. Studying this sample of SPOGs* further, including their morphologies, AGN properties, and environments, has the potential for us to build a more complete picture of the initial conditions that can lead to a galaxy evolving.
- ID:
- ivo://CDS.VizieR/J/ApJ/837/88
- Title:
- SPT-GMOS spectroscopy of gal. in massive clusters
- Short Name:
- J/ApJ/837/88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The velocity distribution of galaxies in clusters is not universal; rather, galaxies are segregated according to their spectral type and relative luminosity. We examine the velocity distributions of different populations of galaxies within 89 Sunyaev Zel'dovich (SZ) selected galaxy clusters spanning 0.28<z<1.08. Our sample is primarily draw from the SPT-GMOS spectroscopic survey, supplemented by additional published spectroscopy, resulting in a final spectroscopic sample of 4148 galaxy spectra -- 2868 cluster members. The velocity dispersion of star-forming cluster galaxies is 17+/-4% greater than that of passive cluster galaxies, and the velocity dispersion of bright (m<m^*^-0.5) cluster galaxies is 11+/-4% lower than the velocity dispersion of our total member population. We find good agreement with simulations regarding the shape of the relationship between the measured velocity dispersion and the fraction of passive versus star-forming galaxies used to measure it, but we find a small offset between this relationship as measured in data and simulations, which suggests that our dispersions are systematically low by as much as 3% relative to simulations. We argue that this offset could be interpreted as a measurement of the effective velocity bias that describes the ratio of our observed velocity dispersions and the intrinsic velocity dispersion of dark matter particles in a published simulation result. Measuring velocity bias in this way suggests that large spectroscopic surveys can improve dispersion-based mass-observable scaling relations for cosmology even in the face of velocity biases, by quantifying and ultimately calibrating them out.
- ID:
- ivo://CDS.VizieR/J/ApJ/878/55
- Title:
- SPT-SZ clusters with optical & X-ray data
- Short Name:
- J/ApJ/878/55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive cosmological constraints using a galaxy cluster sample selected from the 2500deg^2^ SPT-SZ survey. The sample spans the redshift range 0.25<z<1.75 and contains 343 clusters with SZ detection significance {xi}>5. The sample is supplemented with optical weak gravitational lensing measurements of 32 clusters with 0.29<z<1.13 (from Magellan and Hubble Space Telescope) and X-ray measurements of 89 clusters with 0.25<z<1.75 (from Chandra). We rely on minimal modeling assumptions: (i) weak lensing provides an accurate means of measuring halo masses, (ii) the mean SZ and X-ray observables are related to the true halo mass through power-law relations in mass and dimensionless Hubble parameter E(z) with a priori unknown parameters, and (iii) there is (correlated, lognormal) intrinsic scatter and measurement noise relating these observables to their mean relations. We simultaneously fit for these astrophysical modeling parameters and for cosmology. Assuming a flat {nu}{Lambda}CDM model, in which the sum of neutrino masses is a free parameter, we measure {Omega}_m_=0.276+/-0.047, {sigma}_8_=0.781+/-0.037, and {sigma}_8_({Omega}_m_/0.3)^0.2^=0.766+/-0.025. The redshift evolutions of the X-ray Y_X_-mass and M_gas_-mass relations are both consistent with self-similar evolution to within 1{sigma}. The mass slope of the Y_X_-mass relation shows a 2.3{sigma} deviation from self-similarity. Similarly, the mass slope of the M_gas_-mass relation is steeper than self-similarity at the 2.5{sigma} level. In a {nu}wCDM cosmology, we measure the dark energy equation-of-state parameter w=-1.55+/-0.41 from the cluster data. We perform a measurement of the growth of structure since redshift z~1.7 and find no evidence for tension with the prediction from general relativity. This is the first analysis of the SPT cluster sample that uses direct weak-lensing mass calibration and is a step toward using the much larger weak-lensing data set from DES. We provide updated redshift and mass estimates for the SPT sample.
- ID:
- ivo://CDS.VizieR/J/ApJ/792/45
- Title:
- SPT-SZ survey galaxy clusters optical spectroscopy
- Short Name:
- J/ApJ/792/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical spectroscopy of galaxies in clusters detected through the Sunyaev-Zel'dovich (SZ) effect with the South Pole Telescope (SPT). We report our own measurements of 61 spectroscopic cluster redshifts, and 48 velocity dispersions each calculated with more than 15 member galaxies. This catalog also includes 19 dispersions of SPT-observed clusters previously reported in the literature. The majority of the clusters in this paper are SPT-discovered; of these, most have been previously reported in other SPT cluster catalogs, and five are reported here as SPT discoveries for the first time. By performing a resampling analysis of galaxy velocities, we find that unbiased velocity dispersions can be obtained from a relatively small number of member galaxies (<~ 30), but with increased systematic scatter. We use this analysis to determine statistical confidence intervals that include the effect of membership selection. We fit scaling relations between the observed cluster velocity dispersions and mass estimates from SZ and X-ray observables. In both cases, the results are consistent with the scaling relation between velocity dispersion and mass expected from dark-matter simulations. We measure a ~30% log-normal scatter in dispersion at fixed mass, and a ~10% offset in the normalization of the dispersion-mass relation when compared to the expectation from simulations, which is within the expected level of systematic uncertainty.
- ID:
- ivo://CDS.VizieR/J/ApJ/594/154
- Title:
- 160 square degree ROSAT survey
- Short Name:
- J/ApJ/594/154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the revised catalog of galaxy clusters detected as extended X-ray sources in the 160 Square Degree ROSAT Survey, including spectroscopic redshifts and X-ray luminosities for 200 of the 201 members. The median redshift is z_median_=0.25, and the median X-ray luminosity is L_X,median_=4.2x10^43^h_50_^2^erg/s (0.5-2.0keV). This is the largest high-redshift sample of X-ray-selected clusters published to date. There are 73 objects at z>0.3 and 22 objects at z>0.5 drawn from a statistically complete flux-limited survey with a median object flux of 1.4x10^-13^erg/cm^2^/s. We describe the optical follow-up of these clusters with an emphasis on our spectroscopy, which has yielded 155 cluster redshifts, 110 of which are presented here for the first time. These measurements, combined with 45 from the literature and other sources, provide near-complete spectroscopic coverage for our survey. We discuss the final optical identifications for the extended X-ray sources in the survey region and compare our results to similar X-ray cluster searches.
- ID:
- ivo://CDS.VizieR/J/A+A/312/745
- Title:
- SSRS groups of galaxies redshift neighbourhood
- Short Name:
- J/A+A/312/745
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Southern Sky Redshift Survey (SSRS) includes 13 groups of 5 or more members with velocities >=2000km/s. By measuring redshifts and accumulating data from the literature, we increase the total number of known group members from 89 to 218. We also measured new redshifts for 59 foreground/background galaxies superimposed on the group neighborhoods. The velocity dispersions of the groups are remarkably stable.
- ID:
- ivo://CDS.VizieR/J/ApJ/686/127
- Title:
- Starbursts luminosities based on PAH
- Short Name:
- J/ApJ/686/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A summary of starburst luminosities based on polycyclic aromatic hydrocarbon (PAH) features is given for 243 starburst galaxies with 0<z<2.5, observed with the Spitzer Infrared Spectrograph. Luminosity {nu}L_{nu}_(7.7um) for the peak luminosity of the 7.7um PAH emission feature is found to scale as log[{nu}L_{nu}_(7.7{mu}m)]=44.63(+/-0.09)+2.48(+/-0.28)log(1+z) for the most luminous starbursts observed. Empirical calibrations of {nu}L_{nu}_(7.7um) are used to determine bolometric luminosity L_IR_ and the star formation rate (SFR) for these starbursts. The most luminous starbursts found in this sample have logL_IR_=45.4(+/-0.3)+2.5(+/-0.3)log(1+z), in ergs/s, and the maximum star formation rates for starbursts in units of M_{sun}_/yr are log(SFR)=2.1(+/-0.3)+2.5(+/-0.3)log(1+z), up to z=2.5. The exponent for pure luminosity evolution agrees with optical and radio studies of starbursts but is flatter than previous results based in infrared source counts. The maximum star formation rates are similar to the maxima determined for submillimeter galaxies; the most luminous individual starburst included within the sample has logL_IR_=46.9, which gives an SFR=3.4x10^3^M_{sun}/yr. Description: In this paper, we assemble data from 14 different Spitzer/IRS (InfraRed Spectrograph) programs (listed in "Ref" column of table1) to summarize a wide variety of sources having strong PAH spectral features, providing a total of 243 sources.
- ID:
- ivo://CDS.VizieR/J/ApJ/559/606
- Title:
- Star formation in spectroscopic survey
- Short Name:
- J/ApJ/559/606
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 15R-North galaxy redshift survey is a uniform spectroscopic survey (S/N~10) covering the range 3650-7400{AA} for 3149 galaxies with median redshift 0.05. The sample is 90% complete to R=15.4. The median slit covering fraction is 24% of the galaxy, apparently sufficient to minimize the effects of aperture bias on the EW(H{alpha}). Forty-nine percent of the galaxies in the survey have one or more emission lines detected at >=2{sigma}. In agreement with previous surveys, the fraction of absorption-line galaxies increases steeply with galaxy luminosity. We use H{beta}, [O III], H{alpha}, and [N II] to discriminate between star-forming galaxies and AGNs. At least 20% of the galaxies are star-forming, at least 17% have AGN-like emission, and 12% have unclassifiable emission. The data for the entire survey will appear in Geller et al. 2002, in preparation.
- ID:
- ivo://CDS.VizieR/J/ApJ/814/95
- Title:
- Star formation rate of 4<~z<~8 galaxies
- Short Name:
- J/ApJ/814/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent observations have shown that the characteristic luminosity of the rest-frame ultraviolet (UV) luminosity function does not significantly evolve at 4<z<7 and is approximately M_UV_^*^~21. We investigate this apparent non-evolution by examining a sample of 173 bright, M_UV_<-21 galaxies at z=4-7, analyzing their stellar populations and host halo masses. Including deep Spitzer/IRAC imaging to constrain the rest-frame optical light, we find that M_UV_^*^ galaxies at z=4-7 have similar stellar masses of log(M/M_{sun}_)=9.6-9.9 and are thus relatively massive for these high redshifts. However, bright galaxies at z=4-7 are less massive and have younger inferred ages than similarly bright galaxies at z=2-3, even though the two populations have similar star formation rates and levels of dust attenuation for a fixed dust-attenuation curve. Matching the abundances of these bright z=4-7 galaxies to halo mass functions from the Bolshoi {Lambda}CDM simulation implies that the typical halo masses in ~M_UV_^*^ galaxies decrease from log(M_h_/M_{sun}_)=11.9 at z=4 to log(M_h_/M_{sun}_)=11.4 at z=7. Thus, although we are studying galaxies at a similar stellar mass across multiple redshifts, these galaxies live in lower mass halos at higher redshift. The stellar baryon fraction in ~M_UV_^*^ galaxies in units of the cosmic mean {Omega}_b_/{Omega}_m_ rises from 5.1% at z=4 to 11.7% at z=7; this evolution is significant at the ~3{sigma} level. This rise does not agree with simple expectations of how galaxies grow, and implies that some effect, perhaps a diminishing efficiency of feedback, is allowing a higher fraction of available baryons to be converted into stars at high redshifts.