- ID:
- ivo://CDS.VizieR/J/MNRAS/389/1924
- Title:
- Old stellar systems (globulars to ellipticals)
- Short Name:
- J/MNRAS/389/1924
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Elliptical galaxies and globular clusters (GCs) have traditionally been regarded as physically distinct entities due to their discontinuous distribution in key scaling diagrams involving size, luminosity and velocity dispersion. Recently this distinctness has been challenged by the discovery of stellar systems with mass intermediate between those of GCs and dwarf ellipticals (such as ultracompact dwarfs and dwarf galaxy transition objects). Here we examine the relationship between the virial and stellar mass for a range of old stellar systems, from GCs to giant ellipticals, and including such intermediate-mass objects (IMOs). Improvements on previous work in this area include the use of (i) near-infrared magnitudes from the Two Micron All Sky Survey (2MASS), (ii) aperture corrections to velocity dispersions, (iii) homogeneous half-light radii and (iv) accounting for the effects of non-homology in galaxies.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/2982
- Title:
- Optical and UV colors of Coma galaxies
- Short Name:
- J/MNRAS/421/2982
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and analyse optical and ultraviolet (UV) colours for passive and optically-red Coma cluster galaxies for which we have spectroscopic age and element abundance estimates. Our sample of 150 objects covers a wide range in mass, from giant ellipticals down to the bright end of the dwarf-galaxy regime. Galaxies with ongoing star formation have been removed using strict H{alpha} emission-line criteria. We focus on the colours FUV-i, NUV-i, FUV-NUV, u*-g and g-i. We find that all of these colours are correlated with both luminosity and velocity dispersion at the >5{sigma} level, with FUV-i and FUV-NUV becoming bluer with increasing 'mass' while the other colours become redder. We perform a purely empirical analysis to assess what fraction of the variation in each colour can be accounted for by variations in the average stellar populations, as traced by the optical spectra.
- ID:
- ivo://CDS.VizieR/J/MNRAS/454/3864
- Title:
- Orientation & QSO black hole mass estimation
- Short Name:
- J/MNRAS/454/3864
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have constructed a sample of 386 radio-loud quasars with z<0.75 from the Sloan Digital Sky Survey in order to investigate orientation effects on black hole mass estimates. Orientation is estimated using radio core dominance measurements based on FIRST survey maps. Black hole masses are estimated from virial-based scaling relationships using H{beta}, and compared to the stellar velocity dispersion ({sigma}*), predicted using the full width at half maximum (FWHM) of [OIII] {lambda}5007, which tracks mass via the M-{sigma}* relation. We find that the FWHM of H{beta} correlates significantly with radio core dominance and biases black hole mass determinations that use it, but that this is not the case for {sigma}* based on [OIII] {lambda}5007. The ratio of black hole masses predicted using orientation-biased and unbiased estimates, which can be determined for radio-quiet as well as radio-loud quasars, is significantly correlated with radio core dominance. Although there is significant scatter, this mass ratio calculated in this way may in fact serve as an orientation estimator. We additionally note the existence of a small population of radio core-dominated quasars with extremely broad H{beta} emission lines that we hypothesize may represent recent black hole mergers.
- ID:
- ivo://CDS.VizieR/J/A+A/572/A40
- Title:
- Outflow of H_2_ gas from NGC3256
- Short Name:
- J/A+A/572/A40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The nuclei of merging galaxies are often deeply buried in dense layers of gas and dust. In these regions, gas outflows driven by starburst and active galactic nuclear activity are believed to play a crucial role in the evolution of these galaxies. However, to fully understand this process it is essential to resolve the morphology and kinematics of such outflows. Using near-infrared integral-field spectroscopy obtained with SINFONI on the Very Large Telescope, we detect a kpc-scale structure of high-velocity molecular hydrogen (H_2_) gas associated with the deeply buried secondary nucleus of the infrared-luminous merger-galaxy NGC 3256. We show that this structure is most likely the hot component of a molecular outflow, which was recently also detected in the cold molecular gas through CO emission.
- ID:
- ivo://CDS.VizieR/J/MNRAS/446/2330
- Title:
- Overmassive black holes
- Short Name:
- J/MNRAS/446/2330
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Semi-analytical models in a {Lambda} cold dark matter cosmology have predicted the presence of outlying, 'overmassive' black holes at the high-mass end of the (black hole mass-galaxy velocity dispersion) M_BH_-{sigma} diagram (which we update here with a sample of 89 galaxies). They are a consequence of having experienced more dry mergers - thought not to increase a galaxy's velocity dispersion - than the 'main-sequence' population. Wet mergers and gas-rich processes, on the other hand, preserve the main correlation. Due to the scouring action of binary supermassive black holes, the extent of these dry mergers (since the last significant wet merger) can be traced by the ratio between the central stellar mass deficit and the black hole mass (M_def,*_/M_BH_). However, in a sample of 23 galaxies with partially depleted cores, including central cluster galaxies, we show that the 'overmassive' black holes are actually hosted by galaxies that appear to have undergone the lowest degree of such merging. In addition, the rotational kinematics of 37 galaxies in the M_BH_-{sigma} diagram reveals that fast and slow rotators are not significantly offset from each other, also contrary to what is expected if these two populations were the product of wet and dry mergers, respectively. The observations are thus not in accordance with model predictions and further investigation is required.
- ID:
- ivo://CDS.VizieR/J/ApJS/146/125
- Title:
- O VI in the galactic halo
- Short Name:
- J/ApJS/146/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Far-Ultraviolet Spectroscopic Explorer (FUSE) spectra of 100 extragalactic objects and two distant halo stars are analyzed to obtain measures of O VI {lambda}{lambda}1031.93, 1037.62 absorption along paths through the Milky Way thick disk/halo.
- ID:
- ivo://CDS.VizieR/J/ApJS/202/4
- Title:
- Planck cold clumps survey in the Orion complex
- Short Name:
- J/ApJS/202/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A mapping survey of 51 Planck cold clumps projected on the Orion complex was performed with J=1-0 lines of ^12^CO and ^13^CO with the 13.7m telescope at the Purple Mountain Observatory. The mean column densities of the Planck gas clumps range from 0.5 to 9.5x10^21^cm^-2^, with an average value of (2.9+/-1.9)x10^21^cm^-2^. The mean excitation temperatures of these clumps range from 7.4 to 21.1K, with an average value of 12.1+/-3.0K and the average three-dimensional velocity dispersion {sigma}_3D_ in these molecular clumps is 0.66+/-0.24km/s. The H2 column density of the molecular clumps calculated from molecular lines correlates with the aperture flux at 857GHz of the dust emission. By analyzing the distributions of the physical parameters, we suggest that turbulent flows can shape the clump structure and dominate their density distribution on large scales, but not function on small scales due to local fluctuations. Eighty-two dense cores are identified in the molecular clumps. The dense cores have an average radius and local thermal equilibrium (LTE) mass of 0.34+/-0.14pc and 38^+5^_-30_M_{sun}_, respectively. The structures of low column density cores are more affected by turbulence, while the structures of high column density cores are more affected by other factors, especially by gravity.
- ID:
- ivo://CDS.VizieR/J/AJ/147/46
- Title:
- Properties of clumps in the NAN complex
- Short Name:
- J/AJ/147/46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations of a 4.25deg^2^ area toward the North American and Pelican Nebulae in the J=1-0 transitions of ^12^CO, ^13^CO, and C^18^O. Three molecules show different emission areas with their own distinct structures. These different density tracers reveal several dense clouds with a surface density of over 500M_{sun}_pc^-2^ and a mean H_2_ column density of 5.8, 3.4, and 11.9x10^21^/cm2 for ^12^CO, ^13^CO, and C^18^O, respectively. We obtain a total mass of 5.4x10^4^M_{sun}_(^12^CO), 2.0x10^4^M_{sun}_(^13^CO), and 6.1x10^3^M_{sun}_(C^18^O) in the complex. The distribution of excitation temperature shows two phases of gas: cold gas (~10K) spreads across the whole cloud; warm gas (>20K) outlines the edge of the cloud heated by the W80 HII region. The kinetic structure of the cloud indicates an expanding shell surrounding the ionized gas produced by the HII region. There are six discernible regions in the cloud: the Gulf of Mexico, Caribbean Islands and Sea, and Pelican's Beak, Hat, and Neck. The areas of ^13^CO emission range within 2-10pc^2^ with mass of (1-5)x10^3^M_{sun}_ and line width of a few km/s. The different line properties and signs of star-forming activity indicate they are in different evolutionary stages. Four filamentary structures with complicated velocity features are detected along the dark lane in LDN 935. Furthermore, a total of 611 molecular clumps within the ^13^CO tracing cloud are identified using the ClumpFind algorithm. The properties of the clumps suggest that most of the clumps are gravitationally bound and at an early stage of evolution with cold and dense molecular gas.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A108
- Title:
- Properties of COMP2CAT sources
- Short Name:
- J/A+A/627/A108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of compact double radio galaxies (hereafter COMP2CAT) listing 43 edge-brightened radio sources whose projected linear size does not exceed 60 kpc, the typical size of their host galaxies. This is the fifth in a series of radio source catalogs recently created, namely: FRICAT, FRIICAT, FR0CAT, and WATCAT, each of which focuses on a different class of radio galaxies. The main aim of our analysis is to attain a better understanding of sources with intermediate morphologies between FR IIs and FR 0s. COMP2CAT sources were selected from an existing catalog of radio sources based on NVSS, FIRST and SDSS observations because they have i) edge-brightened morphologies typical of FR IIs, ii) redshifts z<0.15, and iii) projected linear sizes smaller than 60kpc. With radio luminosities at 1.4GHz 10^38^<L_1.4_<10^41^erg/s, COMP2CAT sources appear as the low radio luminosity tail of FR IIs. However, their host galaxies are indistinguishable from those of large-scale radio sources: they are luminous (-21>M_r_>-24), red, early-type galaxies with black hole masses in the range 10^7.5^<M_BH_<10^9.5^M_{sun}_. Moreover, all but one of the COMP2CAT sources are optically classifiable as low-excitation radio galaxies, in agreement with being the low radio luminosity tail of FR Is and FR IIs. This catalog of compact double sources, which is ~47% complete at z<0.15, can potentially be used to clarify the role of compact double sources in the general evolutionary scheme of radio galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/144/4
- Title:
- Properties of dwarf galaxies in the Local Group
- Short Name:
- J/AJ/144/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Positional, structural, and dynamical parameters for all dwarf galaxies in and around the Local Group are presented, and various aspects of our observational understanding of this volume-limited sample are discussed. Over 100 nearby galaxies that have distance estimates reliably placing them within 3Mpc of the Sun are identified. This distance threshold samples dwarfs in a large range of environments, from the satellite systems of the MW and M31, to the quasi-isolated dwarfs in the outer regions of the Local Group, to the numerous isolated galaxies that are found in its surroundings. It extends to, but does not include, the galaxies associated with the next nearest groups, such as Maffei, Sculptor, and IC 342. Our basic knowledge of this important galactic subset and their resolved stellar populations will continue to improve dramatically over the coming years with existing and future observational capabilities, and they will continue to provide the most detailed information available on numerous aspects of dwarf galaxy formation and evolution. Basic observational parameters, such as distances, velocities, magnitudes, mean metallicities, as well as structural and dynamical characteristics, are collated, homogenized (as far as possible), and presented in tables that will be continually updated to provide a convenient and current online resource. As well as discussing the provenance of the tabulated values and possible uncertainties affecting their usage, the membership and spatial extent of the MW sub-group, M31 sub-group, and the Local Group are explored. The morphological diversity of the entire sample and notable sub-groups is discussed, and timescales are derived for the Local Group members in the context of their orbital/interaction histories. The scaling relations and mean stellar metallicity trends defined by the dwarfs are presented, and the origin of a possible "floor" in central surface brightness (and, more speculatively, stellar mean metallicity) at faint magnitudes is considered.
