- ID:
- ivo://CDS.VizieR/J/MNRAS/476/1765
- Title:
- MaNGA E and S galaxies properties
- Short Name:
- J/MNRAS/476/1765
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform full spectrum fitting stellar population analysis and Jeans Anisotropic modelling of the stellar kinematics for about 2000 early-type galaxies (ETGs) and spiral galaxies from the MaNGA DR14 sample. Galaxies with different morphologies are found to be located on a remarkably tight mass plane which is close to the prediction of the virial theorem, extending previous results for ETGs. By examining an inclined projection ('the mass-size' plane), we find that spiral and early-type galaxies occupy different regions on the plane, and their stellar population properties (i.e. age, metallicity, and stellar mass-to-light ratio) vary systematically along roughly the direction of velocity dispersion, which is a proxy for the bulge fraction. Galaxies with higher velocity dispersions have typically older ages, larger stellar mass-to-light ratios and are more metal rich, which indicates that galaxies increase their bulge fractions as their stellar populations age and become enriched chemically. The age and stellar mass-to-light ratio gradients for low-mass galaxies in our sample tend to be positive (centre<outer), while the gradients for most massive galaxies are negative. The metallicity gradients show a clear peak around velocity dispersion log_10_{sigma}_e_~=2.0, which corresponds to the critical mass ~3x10^10^M_{sun}_ of the break in the mass-size relation. Spiral galaxies with large mass and size have the steepest gradients, while the most massive ETGs, especially above the critical mass M_crit_>=2x 10^11^M_{sun}_, where slow rotator ETGs start dominating, have much flatter gradients. This may be due to differences in their evolution histories, e.g. mergers.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/780/173
- Title:
- Masses of giant molecular clouds in Milky Way
- Short Name:
- J/ApJ/780/173
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The mass fraction of dense gas within giant molecular clouds (GMCs) of the Milky Way is investigated using ^13^CO data from the Five College Radio Astronomy Observatory Galactic Plane Surveys and the Bolocam Galactic Plane Survey (BGPS) of 1.1mm dust continuum emission. A sample of 860 compact dust sources are selected from the BGPS catalog and kinematically linked to 344 clouds of extended (>3') ^13^CO J=1-0 emission. Gas masses are tabulated for the full dust source and subregions within the dust sources with mass surface densities greater than 200M_{sun}_/pc^2^, which are assumed to be regions of enhanced volume density. Masses of the parent GMCs are calculated assuming optically thin ^13^CO J=1-0 emission and local thermodynamic equilibrium conditions. The mean fractional mass of dust sources to host GMC mass is 0.11^+0.12^_-0.06__. The high column density subregions comprise 0.07^+0.13^_-0.05_ of the mass of the cloud. Owing to our assumptions, these values are upper limits to the true mass fractions. The fractional mass of dense gas is independent of GMC mass and gas surface density. The low dense gas mass fraction suggests that the formation of dense structures within GMCs is the primary bottleneck for star formation. The distribution of velocity differences between the dense gas and the low density material along the line of sight is also examined. We find a strong, centrally peaked distribution centered on zero velocity displacement. This distribution of velocity differences is modeled with radially converging flows toward the dense gas position that are randomly oriented with respect to the observed line of sight. These models constrain the infall velocities to be 2-4km/s for various flow configurations.
- ID:
- ivo://CDS.VizieR/J/AJ/149/171
- Title:
- 2MASS galaxy group catalog
- Short Name:
- J/AJ/149/171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A galaxy group catalog is built from the sample of the 2MASS Redshift Survey almost complete to K_s_=11.75 over 91% of the sky. Constraints in the construction of the groups were provided by scaling relations determined by close examination of well defined groups with masses between 10^11^ and 10^15^M_{sun}_. Group masses inferred from K_s_ luminosities are statistically in agreement with masses calculated from application of the virial theorem. While groups have been identified over the full redshift range of the sample, the properties of the nearest and farthest groups are uncertain and subsequent analysis has only considered groups with velocities between 3000 and 10000km/s. The 24044 galaxies in this range are identified with 13607 entities, 3461 of them with two or more members. A group mass function is constructed. The Sheth-Tormen formalism provides a good fit to the shape of the mass function for group masses above 6h^-1^x10^12^M_{sun}_ but the count normalization is poor. Summing all the mass associated with the galaxy groups between 3000 and 10000km/s gives a density of collapsed matter as a fraction of the critical density of {Omega}_collapsed_=0.16.
- ID:
- ivo://CDS.VizieR/J/ApJ/874/66
- Title:
- MASSIVE survey. XII. Early-type galaxy gradients
- Short Name:
- J/ApJ/874/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measure the stellar populations as a function of the radius for 90 early-type galaxies (ETGs) in the MASSIVE survey, a volume-limited integral-field spectroscopic (IFS) galaxy survey targeting all northern-sky ETGs with an absolute K-band magnitude of M_K_{<}-25.3mag or a stellar mass of M_*_>~4x10^11^M_{sun}_, within 108Mpc. We are able to measure reliable stellar population parameters for individual galaxies out to 10-20kpc (1-3R_e_) depending on the galaxy. Focusing on ~R_e_ (~10kpc), we find significant correlations between the abundance ratios, {sigma}, and M^*^ at a large radius, but we also find that the abundance ratios saturate in the highest-mass bin. We see a strong correlation between the kurtosis of the line-of-sight velocity distribution (h4) and the stellar population parameters beyond R_e_. Galaxies with higher radial anisotropy appear to be older, with metal-poorer stars and enhanced [{alpha}/Fe]. We suggest that the higher radial anisotropy may derive from more accretion of small satellites. Finally, we see some evidence for correlations between environmental metrics (measured locally and on >5Mpc scales) and the stellar populations, as expected if satellites are quenched earlier in denser environments.
- ID:
- ivo://CDS.VizieR/J/ApJ/569/720
- Title:
- Mass-to-light ratio of galaxy systems
- Short Name:
- J/ApJ/569/720
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the mass-to-light ratio of galaxy systems from poor groups to rich clusters and present for the first time a large database for useful comparisons with theoretical predictions. We extend a previous work, where B_j_ band luminosities and optical virial masses were analyzed for a sample of 89 clusters. Here we also consider a sample of 52 more clusters, 36 poor clusters, seven rich groups, and two catalogs, of ~500 groups each, recently identified in the Nearby Optical Galaxy sample by using two different algorithms. We obtain the blue luminosity and virial mass for all systems considered. We devote a large effort to establishing the homogeneity of the resulting values, as well as to considering comparable physical regions, i.e., those included within the virial radius.
- ID:
- ivo://CDS.VizieR/J/ApJ/850/15
- Title:
- Mass-to-light ratios in low-mass early-type gal.
- Short Name:
- J/ApJ/850/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present dynamical measurements of the central mass-to-light ratio (M/L) of a sample of 27 low-mass early-type ATLAS^3D^ galaxies. We consider all ATLAS^3D^ galaxies with 9.7<log(M*/M_{sun}_)<10.5 in our analysis, selecting out galaxies with available high-resolution Hubble Space Telescope (HST) data, and eliminating galaxies with significant central color gradients or obvious dust features. We use the HST images to derive mass models for these galaxies and combine these with the central velocity dispersion values from ATLAS^3D^ data to obtain a central dynamical M/L estimate. These central dynamical M/Ls are higher than dynamical M/Ls derived at larger radii and stellar population estimates of the galaxy centers in ~80% of galaxies, with a median enhancement of ~14% and a statistical significance of 3.3{sigma}. We show that the enhancement in the central M/L is best described either by the presence of black holes in these galaxies or by radial initial mass function variations. Assuming a black hole model, we derive black hole masses for the sample of galaxies. In two galaxies, NGC 4458 and NGC 4660, the data suggest significantly overmassive black holes, while in most others only upper limits are obtained. We also show that the level of M/L enhancements we see in these early-type galaxy nuclei are consistent with the larger enhancements seen in ultracompact dwarf galaxies (UCDs), supporting the scenario where massive UCDs are created by stripping galaxies of these masses.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/1520
- Title:
- Milky Way globular clusters data
- Short Name:
- J/MNRAS/478/1520
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have determined masses, stellar mass functions, and structural parameters of 112 Milky Way globular clusters by fitting a large set of N-body simulations to their velocity dispersion and surface density profiles. The velocity dispersion profiles were calculated based on a combination of more than 15000 high-precision radial velocities which we derived from archival ESO/VLT and Keck spectra together with ~20000 published radial velocities from the literature. Our fits also include the stellar mass functions of the globular clusters, which are available for 47 clusters in our sample, allowing us to self-consistently take the effects of mass segregation and ongoing cluster dissolution into account. We confirm the strong correlation between the global mass functions of globular clusters and their relaxation times recently found by Sollima & Baumgardt (2017). We also find a correlation of the escape velocity from the centre of a globular cluster and the fraction of first generation stars (FG) in the cluster recently derived for 57 globular clusters by Milone et al. (2017), but no correlation between the FG star fraction and the global mass function of a globular cluster. This could indicate that the ability of a globular cluster to keep the wind ejecta from the polluting star(s) is the crucial parameter determining the presence and fraction of second-generation stars and not its later dynamical mass loss.
- ID:
- ivo://CDS.VizieR/J/ApJS/252/32
- Title:
- MIR outbursts in nearby SDSS gal. (MIRONG). I.
- Short Name:
- J/ApJS/252/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Optical time-domain astronomy has grown rapidly in the past decade, but the dynamic infrared sky is rarely explored. Aiming to construct a sample of mid-infrared outbursts in nearby galaxies (MIRONG), we have conducted a systematical search of low-redshift (z<0.35) Sloan Digital Sky Survey spectroscopic galaxies that have experienced recent mid-infrared (MIR) flares using their Wide-field Infrared Survey Explorer (WISE) light curves. A total of 137 galaxies have been selected by requiring a brightening amplitude of 0.5mag in at least one WISE band with respect to their quiescent phases. Only a small fraction (10.9%) has corresponding optical flares. Except for the four supernovae (SNe) in our sample, the MIR luminosities of the remaining sources (L_4.6{mu}m_>10^42^erg/s) are markedly brighter than known SNe, and their physical locations are very close to the galactic center (median <0.1"). Only four galaxies are radio-loud, indicating that synchrotron radiation from relativistic jets could contribute to MIR variability. We propose that these MIR outbursts are dominated by the dust echoes of transient accretion onto supermassive black holes, such as tidal disruption events (TDEs) and turn-on (changing-look) active galactic nuclei. Moreover, the inferred peak MIR luminosity function is generally consistent with the X-ray and optical TDEs at the high end, albeit with large uncertainties. Our results suggest that a large population of transients has been overlooked by optical surveys, probably due to dust obscuration or intrinsically optical weakness. Thus, a search in the infrared band is crucial for us to obtain a panoramic picture of nuclear outburst. The multiwavelength follow-up observations of the MIRONG sample are in progress and will be presented in a series of subsequent papers.
- ID:
- ivo://CDS.VizieR/J/ApJS/229/20
- Title:
- MMT/Hectospec redshift survey for Abell 2029
- Short Name:
- J/ApJS/229/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on an extensive redshift survey for galaxy clusters Abell 2029 and Coma, we measure the luminosity functions (LFs) and stellar mass functions (SMFs) for the entire cluster member galaxies. Most importantly, we measure the velocity dispersion functions (VDFs) for quiescent members. The MMT/Hectospec redshift survey for galaxies in A2029 identifies 982 spectroscopic members; for 838 members, we derive the central velocity dispersion from the spectroscopy. Coma is the only other cluster surveyed as densely. The LFs, SMFs, and VDFs for A2029 and Coma are essentially identical. The SMFs of the clusters are consistent with simulations. The A2029 and Coma VDFs for quiescent galaxies have a significantly steeper slope than those of field galaxies for velocity dispersion 100km/s. The cluster VDFs also exceed the field at velocity dispersion 250km/s. The differences between cluster and field VDFs are potentially important tests of simulations and of the formation of structure in the universe.
- ID:
- ivo://CDS.VizieR/J/ApJ/750/136
- Title:
- Molecular clouds in the Antennae from CO(2-1)
- Short Name:
- J/ApJ/750/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Super star clusters--extremely massive clusters found predominately in starburst environments--are essential building blocks in the formation of galaxies and thought to dominate star formation in the high-redshift universe. However, the transformation from molecular gas into these ultracompact star clusters is not well understood. To study this process, we used the Submillimeter Array and the Plateau de Bure Interferometer to obtain high angular resolution (~1.5" or 160pc) images of the Antennae overlap region in CO(2-1) to search for the molecular progenitors of the super star clusters. We resolve the molecular gas distribution into a large number of clouds, extending the differential cloud mass function down to a 5{sigma} completeness limit of 3.8x10^5^M_{sun}_. We identify a distinct break in the mass function around log M_mol_/M_{sun}_{approx}6.5, which separates the molecular clouds into two distinct populations. The smaller, less massive clouds reside in more quiescent areas in the region, while the larger, more massive clouds cluster around regions of intense star formation. A broken power-law fit to the mass function yields slopes of {alpha}=-1.39+/-0.10 and {alpha}=-1.44+/-0.14 for the low- and high-mass cloud population, well matched to the mass function found for super star clusters in the Antennae galaxies. We find large velocity gradients and velocity dispersions at the locations of intense star formation, suggestive of compressive shocks. It is likely that these environmental factors contribute to the formation of the observed massive molecular clouds and super star clusters in the Antennae galaxies.
