- ID:
- ivo://CDS.VizieR/J/ApJ/793/39
- Title:
- Spectroscopic properties of BOSS compact galaxies
- Short Name:
- J/ApJ/793/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Massive compact systems at 0.2<z<0.6 are the missing link between the predominantly compact population of massive quiescent galaxies at high redshift and their analogs and relics in the local volume. The evolution in number density of these extreme objects over cosmic time is the crucial constraining factor for the models of massive galaxy assembly. We select a large sample of ~200 intermediate-redshift massive compacts from the Baryon Oscillation Spectroscopic Survey (BOSS) spectroscopy by identifying point-like Sloan Digital Sky Survey photometric sources with spectroscopic signatures of evolved redshifted galaxies. A subset of our targets have publicly available high-resolution ground-based images that we use to augment the dynamical and stellar population properties of these systems by their structural parameters. We confirm that all BOSS compact candidates are as compact as their high-redshift massive counterparts and less than half the size of similarly massive systems at z~0. We use the completeness-corrected numbers of BOSS compacts to compute lower limits on their number densities in narrow redshift bins spanning the range of our sample. The abundance of extremely dense quiescent galaxies at 0.2<z<0.6 is in excellent agreement with the number densities of these systems at high redshift. Our lower limits support the models of massive galaxy assembly through a series of minor mergers over the redshift range 0<z<2.
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Search Results
- 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/A+A/395/753
- Title:
- Spectroscopy of Coma early-type galaxies. II.
- Short Name:
- J/A+A/395/753
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present minor axis, offset major axis and one diagonal long slit spectra for 10 E and S0 galaxies of the Coma cluster drawn from a magnitude-limited sample studied before. We derive rotation curves, velocity dispersion profiles and the H_3_ and H_4_ coefficients of the Hermite decomposition of the line of sight velocity distribution. Moreover, we derive the line index profiles of Mg, Fe and Hbeta line indices and assess their errors. The data will be used to construct dynamical models of the galaxies and study their stellar populations.
- ID:
- ivo://CDS.VizieR/J/AJ/146/45
- Title:
- Spectroscopy of 6 early-type galaxies
- Short Name:
- J/AJ/146/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Adaptive optics assisted SINFONI observations of the central regions of 10 early-type galaxies are presented. Based primarily on the SINFONI kinematics, 10 black hole (BH) masses occupying the high-mass regime of the M_BH_-{sigma} relation are derived using three-integral Schwarzschild models. The effect of dark matter (DM) inclusion on the BH mass is explored. The omission of a DM halo in the model results in a higher stellar mass-to-light ratio, especially when extensive kinematic data are used in the model. However, when the diameter of the sphere of influence--computed using the BH mass derived without a dark halo--is at least 10 times the point-spread function FWHM during the observations, it is safe to exclude a DM component in the dynamical modeling, i.e., the change in BH mass is negligible. When the spatial resolution is marginal, restricting the mass-to-light ratio to the right value returns the correct M_BH_ although a dark halo is not present in the model. Compared to the M_BH_-{sigma} and M_BH_-L relations of McConnell et al., the 10 BHs are all more massive than expected from the luminosities and 7 BH masses are higher than expected from the stellar velocity dispersions of the host bulges. Using new fitted relations, which include the 10 galaxies, we find that the space density of the most massive BHs (M_BH_>~10^9^M_{sun}_) estimated from the M_BH_-L relation is higher than the estimate based on the M_BH_-{sigma} relation and the latter is higher than model predictions based on quasar counts, each by about an order of magnitude.
- ID:
- ivo://CDS.VizieR/J/AJ/116/2738
- Title:
- Spectroscopy of early-type galaxies
- Short Name:
- J/AJ/116/2738
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present central velocity dispersion measurements for 325 early-type galaxies in eight clusters and groups of galaxies, including new observations for 212 galaxies. The clusters and groups are the A262, A1367, Coma (A1656), A2634, Cancer, and Pegasus Clusters and the NGC 383 and NGC 507 Groups. The new measurements were derived from medium-dispersion spectra that cover 600{AA} centered on the Mg I b triplet at {lambda}~5175{AA}. Velocity dispersions were measured using the Tonry & Davis (1979AJ.....84.1511T) cross-correlation method, with a typical accuracy of 6%. A detailed comparison with other data sources is made.
- ID:
- ivo://CDS.VizieR/J/AJ/144/78
- Title:
- Spectroscopy of early-type galaxies in A262
- Short Name:
- J/AJ/144/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new radially resolved spectroscopy of eight early-type galaxies in the A262 cluster. The measurements include stellar rotation, velocity dispersion, H_3_ and H_4_coefficients of the line-of-sight velocity distribution along the major and minor axes and an intermediate axis as well as line-strength index profiles of Mg, Fe, and H{beta}. The ionized-gas velocity and velocity dispersion is measured for six sample galaxies along different axes. We derive dynamical mass-to-light ratios and dark matter densities from orbit-based dynamical models, complemented by the galaxies' ages, metallicities, and {alpha}-element abundances from single stellar-population models. The ionized-gas kinematics give a valuable consistency check for the model assumptions about orientation and intrinsic shape of the galaxies. Four galaxies have a significant detection of dark matter and their halos are about 10 times denser than in spirals of the same stellar mass. By calibrating dark matter densities to cosmological simulations we find assembly redshifts of z_DM_{approx}1-3, as previously reported for the Coma Cluster. The dynamical mass that follows the light is larger than expected for a Kroupa stellar initial mass function (IMF), especially in galaxies with high velocity dispersion {sigma}_eff_ inside the effective radius r_eff_. This could indicate a "massive" IMF in massive galaxies. Alternatively, some of the dark matter in massive galaxies could follow the light very closely. In combination with our comparison sample of Coma early-type galaxies, we now have 5 of 24 galaxies where (1) mass follows light to 1-3r_eff_, (2) the dynamical mass-to-light ratio of all the mass that follows the light is large ({approx}8-10 in the Kron-Cousins R band), and (3) the dark matter fraction is negligible to 1-3r_eff_. Unless the IMF in these galaxies is particularly "massive" and somehow coupled to the dark matter content, there seems to be a significant degeneracy between luminous and dark matter in at least some early-type galaxies. The role of violent relaxation is briefly discussed.
- ID:
- ivo://CDS.VizieR/J/AJ/154/251
- Title:
- Spectroscopy of galaxies in z=0.2-0.9 clusters
- Short Name:
- J/AJ/154/251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of stellar populations in passive galaxies in seven massive X-ray clusters at z=0.19-0.89. Based on absorption-line strengths measured from our high signal-to-noise spectra, the data support primarily passive evolution of the galaxies. We use the scaling relations between velocity dispersions and the absorption-line strengths to determine representative mean line strengths for the clusters. From the age determinations based on the line strengths (and stellar population models), we find a formation redshift of z_form_=1.96_-0.19_^+0.24^. Based on line strength measurements from high signal-to-noise composite spectra of our data, we establish the relations between velocity dispersions, ages, metallicities [M/H], and abundance ratios [{alpha}/Fe] as a function of redshift. The [M/H]-velocity dispersion and [{alpha}/Fe]-velocity dispersion relations are steep and tight. The age-velocity dispersion relation is flat, with zero-point changes reflecting passive evolution. The scatter in all three parameters is within 0.08-0.15 dex at fixed velocity dispersions, indicating a large degree of synchronization in the evolution of the galaxies. We find an indication of cluster-to-cluster differences in metallicities and abundance ratios. However, variations in stellar populations with the cluster environment can only account for a very small fraction of the intrinsic scatter in the scaling relations. Thus, within these very massive clusters, the main driver of the properties of the stellar populations in passive galaxies appears to be the galaxy velocity dispersion.
- ID:
- ivo://CDS.VizieR/J/ApJS/203/3
- Title:
- Spectroscopy of 39 IRAS 1Jy sample ULIRG
- Short Name:
- J/ApJS/203/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Emission-line spectra extracted at multiple locations across 39 ultraluminous infrared galaxies have been compiled into a spectrophotometric atlas. Line profiles of H{alpha}, [NII], [SII], [OI], H{beta}, and [OIII] are resolved and fit jointly with common velocity components. Diagnostic ratios of these line fluxes are presented in a series of plots, showing how the Doppler shift, line width, gas excitation, and surface brightness change with velocity at fixed position and also with distance from the nucleus. One general characteristic of these spectra is the presence of shocked gas extending many kiloparsecs from the nucleus. In some systems, the rotation curves of the emitting gas indicate motions that suggest gas disks, which are most frequent at early merger stages. At these early merger stages, the emission line ratios indicate the presence of shocked gas, which may be triggered by the merger event. We also report the general characteristics of the integrated spectra.
- ID:
- ivo://CDS.VizieR/J/ApJS/193/8
- Title:
- Spectroscopy of 26 lensing cluster cores
- Short Name:
- J/ApJS/193/8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a spectroscopic program targeting 26 strong-lensing cluster cores that were visually identified in the Sloan Digital Sky Survey (SDSS; Gladders et al. 2011, in prep) and the Second Red-Sequence Cluster Survey (RCS-2; Bayliss et al. 2011, in prep). The 26 galaxy cluster lenses span a redshift range of 0.2<z<0.65, and our spectroscopy reveals 69 unique background sources with redshifts as high as z=5.200. We also identify redshifts for 262 cluster member galaxies and measure the velocity dispersions and dynamical masses for 18 clusters where we have redshifts for N>=10 cluster member galaxies. We account for the expected biases in dynamical masses of strong-lensing-selected clusters as predicted by results from numerical simulations and discuss possible sources of bias in our observations.
- ID:
- ivo://CDS.VizieR/J/ApJ/902/17
- Title:
- Spectroscopy of quiescent gal. in 9 lensing clusters
- Short Name:
- J/ApJ/902/17
- Date:
- 03 Mar 2022 11:35:20
- Publisher:
- CDS
- Description:
- We measure the central stellar velocity dispersion function for quiescent galaxies in a set of nine northern clusters in the redshift range 0.18<z<0.29 and with strong lensing arcs in Hubble Space Telescope images. The velocity dispersion function links galaxies directly to their dark matter halos. From dense SDSS and MMT/Hectospec spectroscopy, we identify 222-463 spectroscopic members in each cluster. We derive physical properties of cluster members including redshift, D_n_4000, and central stellar velocity dispersion and we include a table of these measurements for 3419 cluster members. We construct the velocity dispersion functions for quiescent galaxies with D_n_4000>1.5 and within R200. The cluster velocity dispersion functions all show excesses at {sigma}>~250km/s compared to the field velocity dispersion function. The velocity dispersion function slope at large velocity dispersion ({sigma}>160km/s) is steeper for more massive clusters, consistent with the trend observed for cluster luminosity functions. The spatial distribution of galaxies with large velocity dispersion at radii larger than R200 further underscores the probable major role of dry mergers in the growth of massive cluster galaxies during cluster assembly.
