- ID:
- ivo://CDS.VizieR/J/ApJ/826/L32
- Title:
- Black hole masses in megamaser disk galaxies
- Short Name:
- J/ApJ/826/L32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use new precision measurements of black hole (BH) masses from water megamaser disks to investigate scaling relations between macroscopic galaxy properties and supermassive BH mass. The megamaser-derived BH masses span 10^6^-10^8^M_{sun}_, while all the galaxy properties that we examine (including total stellar mass, central mass density, and central velocity dispersion) lie within a narrower range. Thus, no galaxy property correlates tightly with M_BH_ in ~L* spiral galaxies as traced by megamaser disks. Of them all, stellar velocity dispersion provides the tightest relation, but at fixed {sigma}_*_ the mean megamaser M_BH_ are offset by -0.6+/-0.1dex relative to early-type galaxies. Spiral galaxies with non-maser dynamical BH masses do not appear to show this offset. At low mass, we do not yet know the full distribution of BH mass at fixed galaxy property; the non-maser dynamical measurements may miss the low-mass end of the BH distribution due to an inability to resolve their spheres of influence and/or megamasers may preferentially occur in lower-mass BHs.
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- ID:
- ivo://CDS.VizieR/J/ApJ/797/82
- Title:
- Brightest cluster galaxies in Abell clusters
- Short Name:
- J/ApJ/797/82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained photometry and spectroscopy of 433 z<=0.08 brightest cluster galaxies (BCGs) in a full-sky survey of Abell clusters to construct a BCG sample suitable for probing deviations from the local Hubble flow. This sample allows us to explore the structural and photometric properties of BCGs at the present epoch, their location in their hosting galaxy clusters, and the effects of the cluster environment on their structure and evolution. We revisit the L_m_-{alpha} relation for BCGs, which uses {alpha}, the log-slope of the BCG photometric curve of growth, to predict the metric luminosity in an aperture with 14.3kpc radius, L_m_, for use as a distance indicator. We measure central stellar velocity dispersions, {sigma}, of the BCGs.
- ID:
- ivo://CDS.VizieR/J/ApJ/862/100
- Title:
- Carnegie-Irvine Galaxy Survey VII. S0 galaxies
- Short Name:
- J/ApJ/862/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using high-quality optical images from the Carnegie-Irvine Galaxy Survey, we perform multicomponent decompositions of S0 galaxies (S0s) to derive accurate structural parameters to constrain their physical origin. Many S0s do not host prominent bulges. S0s have a broad distribution of bulge-to-total ratios (B/T) and Sersic indices (n), with average values of B/T=0.34+/-0.15 and n=2.62+/-1.02, qualitatively consistent with the notion that S0s define a parallel sequence with and may have evolved from spiral galaxies. This is further reinforced by the incidence of bars and lenses in S0s, which, when compared with the statistics in spirals, supports the idea that lenses are demised bars. However, despite their wide range of prominence, the bulges of S0s form a surprisingly uniform sequence on both the Kormendy and fundamental plane relations. There is no evidence for population dichotomy or other indications of differentiation into classical and pseudo bulges. Most of the S0s reside in the field and in groups; cluster environment is not a necessary condition for S0 production. The properties of S0 bulges show little correlation with environmental indicators, after the dependence of galaxy stellar mass on environment is taken into account. As the bulges of late-type spirals and S0s are intrinsically different, and environmental effects that may account for such evolution appear to be minimal, we conclude that late- type spirals are not plausible progenitors of S0s. The bulges of S0s likely formed at an early epoch, after which secular processes contributed little to their subsequent evolution.
- ID:
- ivo://CDS.VizieR/J/ApJS/183/1
- Title:
- Catalog of central stellar velocity dispersions
- Short Name:
- J/ApJS/183/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new central stellar velocity dispersion measurements for 428 galaxies in the Palomar spectroscopic survey of bright, northern galaxies. Of these, 142 have no previously published measurements, most being relatively late-type systems with low velocity dispersions (<~100km/s). We provide updates to a number of literature dispersions with large uncertainties. Our measurements are based on a direct pixel-fitting technique that can accommodate composite stellar populations by calculating an optimal linear combination of input stellar templates. The original Palomar survey data were taken under conditions that are not ideally suited for deriving stellar velocity dispersions for galaxies with a wide range of Hubble types. We describe an effective strategy to circumvent this complication and demonstrate that we can still obtain reliable velocity dispersions for this sample of well-studied nearby galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/751/50
- Title:
- Catalog of galaxy groups from DEEP2 Redshift Survey
- Short Name:
- J/ApJ/751/50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a public catalog of galaxy groups constructed from the spectroscopic sample of galaxies in the fourth data release from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Galaxy Redshift Survey, including the Extended Groth Strip (EGS). The catalog contains 1165 groups with two or more members in the EGS over the redshift range 0<z<1.5 and 1295 groups at z>0.6 in the rest of DEEP2. 25% of EGS galaxies and 14% of high-z DEEP2 galaxies are assigned to galaxy groups. The groups were detected using the Voronoi-Delaunay method (VDM) after it has been optimized on mock DEEP2 catalogs following similar methods to those employed in Gerke et al (2005, J/ApJ/625/6). In the optimization effort, we have taken particular care to ensure that the mock catalogs resemble the data as closely as possible, and we have fine-tuned our methods separately on mocks constructed for the EGS and the rest of DEEP2. We have also probed the effect of the assumed cosmology on our inferred group-finding efficiency by performing our optimization on three different mock catalogs with different background cosmologies, finding large differences in the group-finding success we can achieve for these different mocks. Using the mock catalog whose background cosmology is most consistent with current data, we estimate that the DEEP2 group catalog is 72% complete and 61% pure (74% and 67% for the EGS) and that the group finder correctly classifies 70% of galaxies that truly belong to groups, with an additional 46% of interloper galaxies contaminating the catalog (66% and 43% for the EGS). We also confirm that the VDM catalog reconstructs the abundance of galaxy groups with velocity dispersions above ~300 km/s to an accuracy better than the sample variance, and this successful reconstruction is not strongly dependent on cosmology.
- ID:
- ivo://CDS.VizieR/VII/72
- Title:
- Catalog of Stellar Velocity Dispersions
- Short Name:
- VII/72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalog of central stellar velocity dispersion measurements is presented, current through 1984. The catalog includes 1096 measurements of 725 galaxies. A set of 51 standard galaxies is defined which consists of galaxies with at least three reliable, concordant measurements.
- ID:
- ivo://CDS.VizieR/J/AJ/129/2138
- Title:
- Centers of early-type galaxies with HST
- Short Name:
- J/AJ/129/2138
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations of 77 early-type galaxies imaged with the PC1 CCD of the Hubble Space Telescope (HST) WFPC2. "Nuker-law" parametric fits to the surface brightness profiles are used to classify the central structure into "core" or "power-law" forms.
- ID:
- ivo://CDS.VizieR/J/AJ/132/1275
- Title:
- CIRS (Cluster Infall Regions in the SDSS). I.
- Short Name:
- J/AJ/132/1275
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the Fourth Data Release of the Sloan Digital Sky Survey (SDSS) to test the ubiquity of infall patterns around galaxy clusters and measure cluster mass profiles to large radii. The Cluster and Infall Region Nearby Survey (CAIRNS) found infall patterns in nine clusters, but the cluster sample was incomplete. Here we match X-ray cluster catalogs with SDSS, search for infall patterns, and compute mass profiles for a complete sample of X-ray-selected clusters. Very clean infall patterns are apparent in most of the clusters, with the fraction decreasing with increasing redshift due to shallower sampling. All 72 clusters in a well-defined sample limited by redshift (ensuring good sampling) and X-ray flux (excluding superpositions) show infall patterns sufficient to apply the caustic technique. This sample is by far the largest sample of cluster mass profiles extending to large radii to date. Similar to CAIRNS, cluster infall patterns are better defined in observations than in simulations. Further work is needed to determine the source of this difference. We use the infall patterns to compute mass profiles for 72 clusters and compare them to model profiles. Cluster scaling relations using caustic masses agree well with those using X-ray or virial mass estimates, confirming the reliability of the caustic technique. We confirm the conclusion of CAIRNS that cluster infall regions are well fitted by Navarro-Frenk-White (NFW) and Hernquist profiles and poorly fitted by singular isothermal spheres. This much larger sample enables new comparisons of cluster properties with those in simulations. The shapes (specifically NFW concentrations) of the mass profiles agree well with the predictions of simulations. The mass in the infall region is typically comparable to or larger than that in the virial region. Specifically, the mass inside the turnaround radius is on average 2.19+/-0.18 times that within the virial radius. This ratio agrees well with recent predictions from simulations of the final masses of dark matter halos.
- ID:
- ivo://CDS.VizieR/J/ApJ/830/127
- Title:
- CLASSy: CARMA obs. in L1451 region of Perseus
- Short Name:
- J/ApJ/830/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a 3mm spectral line and continuum survey of L1451 in the Perseus Molecular Cloud. These observations are from the CARMA Large Area Star Formation Survey (CLASSy), which also imaged Barnard 1, NGC1333, Serpens Main, and Serpens South. L1451 is the survey region with the lowest level of star formation activity-it contains no confirmed protostars. HCO^+^, HCN, and N_2_H^+^ (J=1->0) are all detected throughout the region, with HCO^+^ being the most spatially widespread, and molecular emission seen toward 90% of the area above N(H_2_) column densities of 1.9x10^21^cm^-2^. HCO^+^ has the broadest velocity dispersion, near 0.3km/s on average, compared with ~0.15km/s for the other molecules, thus representing a range of subsonic to supersonic gas motions. Our non-binary dendrogram analysis reveals that the dense gas traced by each molecule has a similar hierarchical structure, and that gas surrounding the candidate first hydrostatic core (FHSC), L1451-mm, and other previously detected single-dish continuum clumps has similar hierarchical structure; this suggests that different subregions of L1451 are fragmenting on the pathway to forming young stars. We determined that the three-dimensional morphology of the largest detectable dense-gas structures was relatively ellipsoidal compared with other CLASSy regions, which appeared more flattened at the largest scales. A virial analysis shows that the most centrally condensed dust structures are likely unstable against collapse. Additionally, we identify a new spherical, centrally condensed N_2_H^+^ feature that could be a new FHSC candidate. The overall results suggest that L1451 is a young region starting to form its generation of stars within turbulent, hierarchical structures.
- ID:
- ivo://CDS.VizieR/J/ApJ/860/172
- Title:
- Cloud-scale molecular gas properties in 15 galaxies
- Short Name:
- J/ApJ/860/172
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure the velocity dispersion, {sigma}, and surface density, {Sigma}, of the molecular gas in nearby galaxies from CO spectral line cubes with spatial resolution 45-120pc, matched to the size of individual giant molecular clouds. Combining 11 galaxies from the PHANGS-ALMA survey with four targets from the literature, we characterize ~30000 independent sightlines where CO is detected at good significance. {Sigma} and {sigma} show a strong positive correlation, with the best-fit power-law slope close to the expected value for resolved, self-gravitating clouds. This indicates only a weak variation in the virial parameter {alpha}_vir_{propto}{sigma}^2^/{Sigma}, which is ~1.5-3.0 for most galaxies. We do, however, observe enormous variation in the internal turbulent pressure P_turb_{propto}{Sigma}{sigma}^2^, which spans ~5dex across our sample. We find {Sigma}, {sigma}, and P_turb_ to be systematically larger in more massive galaxies. The same quantities appear enhanced in the central kiloparsec of strongly barred galaxies relative to their disks. Based on sensitive maps of M31 and M33, the slope of the {sigma}-{Sigma} relation flattens at {Sigma}<~10M_{sun}_/pc^2^, leading to high {sigma} for a given {Sigma} and high apparent {alpha}_vir_. This echoes results found in the Milky Way and likely originates from a combination of lower beam-filling factors and a stronger influence of local environment on the dynamical state of molecular gas in the low-density regime.
