- ID:
- ivo://CDS.VizieR/J/ApJ/659/84
- Title:
- Spectroscopy and photometry of z~=5 galaxies
- Short Name:
- J/ApJ/659/84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new measurement of the integrated stellar mass per comoving volume at redshift 5 determined via spectral energy fitting drawn from a sample of 214 photometrically selected galaxies with z'_850LP_<26.5 in the southern GOODS field. Following recent procedures introduced by Eyles et al. (2007MNRAS.374..910E), we estimate stellar masses for various subsamples for which reliable and unconfused Spitzer IRAC detections are available. A spectroscopic sample of 14 of the most luminous sources with z{bar}=4.92 provides a firm lower limit to the stellar mass density of 1x10^6^M_{sun}_/Mpc^3^. We then consider a larger sample whose photometric redshifts in the publicly available GOODS-MUSIC catalog lie in the range 4.4<z<5.6.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/135/1837
- Title:
- Spectroscopy in A2199 and Virgo clusters
- Short Name:
- J/AJ/135/1837
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a new determination of the faint end of the galaxy luminosity function (LF) in the nearby clusters Abell 2199 and Virgo using data from the Sloan Digital Sky Survey (SDSS) and the Hectospec multifiber spectrograph on the MMT. The luminosity function of A2199 is consistent with a single Schechter function to M_r_=-15.6+5log(h_70_) with a faint-end slope of alpha=-1.13+/-0.07 (statistical). The LF in Virgo extends to M_r_~-13.5~M*+8 and has a slope of alpha=-1.28+/-0.06 (statistical).
- ID:
- ivo://CDS.VizieR/J/A+A/557/A62
- Title:
- Spectroscopy in Abell 3921
- Short Name:
- J/A+A/557/A62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectrophotometric analysis of the galaxy population in the area of the merging cluster Abell 3921 at z=0.093. We investigate the impact of the complex cluster environment on galaxy properties such as morphology or star formation rate. We combine multi-object spectroscopy from the Two Degree Field (2dF) spectrograph with optical imaging taken with the ESO Wide Field Imager. We carry out a redshift analysis and determine cluster velocity dispersions using biweight statistics. Applying a Dressler-Shectman test we seek evidence for cluster substructure. Cluster and field galaxies are investigated with respect to [OII] and H{alpha} equivalent width, star formation rate and morphological descriptors such as concentration index and Gini coefficient. We study these cluster galaxy properties as a function of clustercentric distance and investigate the spatial distribution of various galaxy types. Applying the Dressler-Shectman test we find a third component (A3921-C) in addition to the two main subclusters (A3921-A and A3921-B) already known. The re-determined mass ratio between the main components A and B is ~2:1. Similar to previous studies of galaxy clusters, we find that a large fraction of the disk galaxies close to the cluster core show no detectable star formation. These are likely systems that are quenched due to ram pressure stripping. Interestingly, we also find quenched spirals at rather large distances of 3-4Mpc from the cluster core.
- ID:
- ivo://CDS.VizieR/J/A+A/507/671
- Title:
- Spectroscopy in cluster RDCS J1252.9-2927 (z=1.2)
- Short Name:
- J/A+A/507/671
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent wide-field imaging observations of the X-ray luminous cluster RDCS J1252.9-2927 at z=1.24 uncovered several galaxy groups that appear to be embedded in filamentary structure extending from the cluster core. We make a spectroscopic study of the galaxies in these groups using GMOS on Gemini-South and FORS2 on VLT with the aim of determining if these galaxies are physically associated to the cluster. We find that three groups contain galaxies at the cluster redshift and that they are probably bound to the cluster. This is the first confirmation of filamentary structure as traced by galaxy groups at z>1. We then use several spectral features in the FORS2 spectra to determine the star formation histories of group galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/641/169
- Title:
- Spectroscopy in lens fields
- Short Name:
- J/ApJ/641/169
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results from our spectroscopic survey of strong gravitational lens environments. Six of the eight lens galaxies in our sample belong to a poor group of galaxies, three of which are newly discovered here (those associated with BRI 0952-0115, MG 1654+1346, and B2114+022).
- ID:
- ivo://CDS.VizieR/J/ApJ/853/36
- Title:
- Spectroscopy obs. of 20 Planck gal. cluster cand.
- Short Name:
- J/ApJ/853/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Gemini and Keck spectroscopic redshifts and velocity dispersions for 20 clusters detected via the Sunyaev-Zel'dovich (SZ) effect by the Planck space mission, with estimated masses in the range 2.3x10^14^M_{sun}_<M_500_^Pl^<9.4x10^14^M_{sun}_. Cluster members were selected for spectroscopic follow-up with Palomar, Gemini, and Keck optical and (in some cases) infrared imaging. Seven cluster redshifts were measured for the first time with this observing campaign, including one of the most distant Planck clusters confirmed to date, at z=0.782+/-0.010, PSZ2 G085.95+25.23. The spectroscopic redshift catalogs of members of each confirmed cluster are included as online tables. We show the galaxy redshift distributions and measure the cluster velocity dispersions. The cluster velocity dispersions obtained in this paper were used in a companion paper to measure the Planck mass bias and to constrain the cluster velocity bias.
- ID:
- ivo://CDS.VizieR/J/ApJ/769/54
- Title:
- Spectroscopy of Damped Ly{alpha} (DLA) systems
- Short Name:
- J/ApJ/769/54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a sample of 100 H I-selected damped Ly{alpha} (DLA) systems, observed with the High Resolution Echelle Spectrometer on the Keck I telescope, we present evidence that the scatter in the well-studied correlation between the redshift and metallicity of a DLA is largely due to the existence of a mass-metallicity relationship at each redshift. To describe the fundamental relations that exist between redshift, metallicity, and mass, we use a fundamental plane description, which is described by the following equation: [M/H]=(-1.9+/-0.5)+(0.74+/-0.21)*log{Delta}v_90_-(0.32+/-0.06)*z. Here, we assert that the velocity width, {Delta}v_90_, which is defined as the velocity interval containing 90% of the integrated optical depth, traces the mass of the underlying dark matter halo. This description provides two significant improvements over the individual descriptions of the mass-metallicity correlation and metallicity-redshift correlation. Firstly, the fundamental equation reduces the scatter around both relationships by about 20%, providing a more stringent constraint on numerical simulations modeling DLAs. Secondly, it confirms that the dark matter halos that host DLAs satisfy a mass-metallicity relationship at each redshift between redshifts 2 through 5.
- ID:
- ivo://CDS.VizieR/J/AJ/146/10
- Title:
- Spectroscopy of 120 emission-line ICRF2 candidates
- Short Name:
- J/AJ/146/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Continuing our program of spectroscopic observations of International Celestial Reference Frame (ICRF) sources, we present redshifts for 120 quasars and radio galaxies. Data were obtained with five telescopes: the 3.58m European Southern Observatory New Technology Telescope, the two 8.2m Gemini telescopes, the 2.5m Nordic Optical Telescope (NOT), and the 6.0m Big Azimuthal Telescope of the Special Astrophysical Observatory in Russia. The targets were selected from the International VLBI Service for Geodesy & Astrometry candidate International Celestial Reference Catalog which forms part of an observational very long baseline interferometry (VLBI) program to strengthen the celestial reference frame. We obtained spectra of the potential optical counterparts of more than 150 compact flat-spectrum radio sources, and measured redshifts of 120 emission-line objects, together with 19 BL Lac objects. These identifications add significantly to the precise radio-optical frame tie to be undertaken by Gaia, due to be launched in 2013, and to the existing data available for analyzing source proper motions over the celestial sphere. We show that the distribution of redshifts for ICRF sources is consistent with the much larger sample drawn from Faint Images of the Radio Sky at Twenty cm (FIRST) and Sloan Digital Sky Survey, implying that the ultra-compact VLBI sources are not distinguished from the overall radio-loud quasar population. In addition, we obtained NOT spectra for five radio sources from the FIRST and NRAO VLA Sky Survey catalogs, selected on the basis of their red colors, which yielded three quasars with z>4.
- ID:
- ivo://CDS.VizieR/J/ApJ/714/1521
- Title:
- Spectroscopy of galaxies around distant QSOs
- Short Name:
- J/ApJ/714/1521
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report results from a survey of MgII absorbers in the spectra of background quasi-stellar objects (QSOs) that are within close angular distances to a foreground galaxy at z<0.5, using the Magellan Echellette Spectrograph. We have established a spectroscopic sample of 94 galaxies at a median redshift of <z>=0.24 in fields around 70 distant background QSOs (z_QSO_>0.6), 71 of which are in an "isolated" environment with no known companions and located at {rho}<~120h^-1^kpc from the line of sight of a background QSO. The rest-frame absolute B-band magnitudes span a range from M_B_-5logh=-16.4 to M_B_-5logh=-21.4 and rest-frame B_AB_-R_AB_ colors range from B_AB_-R_AB_~0 to B_AB_-R_AB_~1.5. Of these "isolated" galaxies, we find that 47 have corresponding MgII absorbers in the spectra of background QSOs and rest-frame absorption equivalent width W_r_(2796)=0.1-2.34{AA}, and 24 do not give rise to MgII absorption to sensitive upper limits.
- ID:
- ivo://CDS.VizieR/J/AJ/149/79
- Title:
- Spectroscopy of 299 galaxies from NewHa survey
- Short Name:
- J/AJ/149/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a sample of 299 H{alpha}-selected galaxies at z~~0.8, we study the relationship between galaxy stellar mass, gas-phase metallicity, and star formation rate (SFR), and compare to previous results. We use deep optical spectra obtained with the IMACS spectrograph at the Magellan telescope to measure strong oxygen lines. We combine these spectra and metallicities with (1) rest-frame UV-to-optical imaging, which allows us to determine stellar masses and dust attenuation corrections, and (2) H{alpha} narrowband imaging, which provides a robust measurement of the instantaneous SFR. Our sample spans stellar masses of ~10^9^-6x10^11^M_{sun}_, SFRs of 0.4-270M_{sun}_/yr, and metal abundances of 12+log(O/H)~~8.3-9.1(~~0.4-2.6Z_{sun}_). The correlations that we find between the H{alpha}-based SFR and stellar mass (i.e., the star-forming "main sequence") and between the stellar mass and metallicity are both consistent with previous z~1 studies of star-forming galaxies. We then study the relationship between the three properties using various plane-fitting techniques and a curve-fitting projection. In all cases, we exclude strong dependence of the M_{star}_-Z relation on SFR, but are unable to distinguish between moderate and no dependence. Our results are consistent with previous mass-metallicity-SFR studies. We check whether data set limitations may obscure a strong dependence on the SFR by using mock samples drawn from the Sloan Digital Sky Survey. These experiments reveal that the adopted signal-to-noise ratio cuts may have a significant effect on the measured dependence. Further work is needed to investigate these results, and to test whether a "fundamental metallicity relation" or a "fundamental plane" describes star-forming galaxies across cosmic time.
