- ID:
- ivo://CDS.VizieR/J/AZh/87/739
- Title:
- Steep and ultra-steep spectra RC sources
- Short Name:
- J/AZh/87/739
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of spectroscopy of 71 objects with steep and ultra-steep spectra (alpha<-0.9, S{prop.to}nu^alpha^) from the "Big Trio" (RATAN-600-VLA-BTA) project, performed with the "Scorpio" spectrograph on the 6-m telescope of the Special Astrophysical Observatory (Russian Academy of Sciences). Redshifts were determined for these objects. We also present several other parameters of the sources, such as their R magnitudes, maximum radio sizes in seconds of arc, flux densities at 500, 1425, and 3940MHz, radio luminosities at 500 and 3940MHz, and morphology. Of the total number of radio galaxies studied, four have redshifts 1<=z<2, three have 2<=z<3, one has 3<=z<4, and one has z=4.51. Thirteen sources have redshifts 0.7<z<1 and 15 have 0.2<z<0.7. Of all the quasars studied, five have redshifts 0.7<z<1, seven have 1<=z<2, four have 2<=z<3, and one has z=3.57. We did not detect any spectral lines for 17 objects.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/477/4711
- Title:
- Stellar angular momentum for ManGa galaxies
- Short Name:
- J/MNRAS/477/4711
- Date:
- 17 Jan 2022 00:26:35
- Publisher:
- CDS
- Description:
- We measure {lambda}_Re_, a proxy for galaxy specific stellar angular momentum within one effective radius, and the ellipticity, {epsilon}, for about 2300 galaxies of all morphological types observed with integral field spectroscopy as part of the Mapping Nearby Galaxies at Apache Point Observatory survey, the largest such sample to date. We use the ({lambda}_Re_, {epsilon}) diagram to separate early-type galaxies into fast and slow rotators. We also visually classify each galaxy according to its optical morphology and two-dimensional stellar velocity field. Comparing these classifications to quantitative {lambda}_Re_ measurements reveals tight relationships between angular momentum and galaxy structure. In order to account for atmospheric seeing, we use realistic models of galaxy kinematics to derive a general approximate analytic correction for {lambda}_Re_. Thanks to the size of the sample and the large number of massive galaxies, we unambiguously detect a clear bimodality in the ({lambda}_Re_, {epsilon}) diagram which may result from fundamental differences in galaxy assembly history. There is a sharp secondary density peak inside the region of the diagram with low {lambda}_Re_ and {epsilon}<0.4, previously suggested as the definition for slow rotators. Most of these galaxies are visually classified as non-regular rotators and have high velocity dispersion. The intrinsic bimodality must be stronger, as it tends to be smoothed by noise and inclination. The large sample of slow rotators allows us for the first time to unveil a secondary peak at +/-90{deg} in their distribution of the misalignments between the photometric and kinematic position angles. We confirm that genuine slow rotators start appearing above M>=2x10^11^M_{sun}_ where a significant number of high-mass fast rotators also exist.
- ID:
- ivo://CDS.VizieR/J/A+A/597/A48
- Title:
- Stellar kinematics in CALIFA survey
- Short Name:
- J/A+A/597/A48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the stellar kinematic maps of a large sample of galaxies from the integral-field spectroscopic survey CALIFA. The sample comprises 300 galaxies displaying a wide range of morphologies across the Hubble sequence, from ellipticals to late-type spirals. This dataset allows us to homogeneously extract stellar kinematics up to several effective radii. In this paper, we describe the level of completeness of this subset of galaxies with respect to the full CALIFA sample, as well as the virtues and limitations of the kinematic extraction compared to other well-known integral-field surveys. In addition, we provide averaged integrated velocity dispersion radial profiles for different galaxy types, which are particularly useful to apply aperture corrections for single aperture measurements or poorly resolved stellar kinematics of high-redshift sources. The work presented in this paper sets the basis for the study of more general properties of galaxies that will be explored in subsequent papers of the survey.
- ID:
- ivo://CDS.VizieR/J/ApJ/819/L27
- Title:
- Stellar masses of optical & IR QSO hosts
- Short Name:
- J/ApJ/819/L27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The relation between star formation rates (SFRs) and stellar masses, i.e., the galaxy main sequence, is a useful diagnostic of galaxy evolution. We present the distributions relative to the main sequence of 55 optically selected PG and 12 near-IR-selected Two Micron All Sky Survey (2MASS) quasars at z<=0.5. We estimate the quasar host stellar masses from Hubble Space Telescope or ground-based AO photometry, and the SFRs through the mid-infrared aromatic features and far-IR photometry. We find that PG quasar hosts more or less follow the main sequence defined by normal star-forming galaxies while 2MASS quasar hosts lie systematically above the main sequence. PG and 2MASS quasars with higher nuclear luminosities seem to have higher specific SFRs (sSFRs), although there is a large scatter. No trends are seen between sSFRs and SMBH masses, Eddington ratios, or even morphology types (ellipticals, spirals, and mergers). Our results could be placed in an evolutionary scenario with quasars emerging during the transition from ULIRGs/mergers to ellipticals. However, combined with results at higher redshift, they suggest that quasars can be widely triggered in normal galaxies as long as they contain abundant gas and have ongoing star formation.
- ID:
- ivo://CDS.VizieR/J/MNRAS/506/928
- Title:
- Stellar mass-size relation for low M* galaxies
- Short Name:
- J/MNRAS/506/928
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We reliably extend the stellar mass-size relation over 0.2<=z<=2 to low stellar mass galaxies by combining the depth of Hubble Frontier Fields (HFF) with the large volume covered by CANDELS. Galaxies are simultaneously modelled in multiple bands using the tools developed by the MegaMorph project, allowing robust size (i.e., half-light radius) estimates even for small, faint, and high redshift galaxies. We show that above 10^7^M_{sun}_, star-forming galaxies are well represented by a single power law on the mass-size plane over our entire redshift range. Conversely, the stellar mass - size relation is steep for quiescent galaxies with stellar masses >=10^10.3^M_{sun}_ and flattens at lower masses, regardless of whether quiescence is selected based on star-formation activity, rest-frame colours, or structural characteristics. This flattening occurs at sizes of ~1kpc at z<=1. As a result, a double power law is preferred for the stellar mass-size relation of quiescent galaxies, at least above 10^7^M_{sun}_. We find no strong redshift dependence in the slope of the relation of star-forming galaxies as well as of high mass quiescent galaxies. We also show that star-forming galaxies with stellar masses >=10^9.5^M_{sun}_ and quiescent galaxies with stellar masses>=10^10.3^M_{sun}_ have undergone significant size growth since z~2, as expected; however, low mass galaxies have not. Finally, we supplement our data with predominantly quiescent dwarf galaxies from the core of the Fornax cluster, showing that the stellar mass-size relation is continuous below 10^7^M_{sun}_, but a more complicated functional form is necessary to describe the relation.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A172
- Title:
- Stellar populations of fossil galaxy groups
- Short Name:
- J/A+A/618/A172
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Fossil groups (FGs) are galaxy aggregates with an extended and luminous X-ray halo, which are dominated by a very massive early-type galaxy and lack of L* objects. FGs are indeed characterized by a large magnitude gap between their central and surrounding galaxies. This is explained by either speculating that FGs are failed groups which formed without bright satellite galaxies and did not suffer any major merger, or suggesting that FGs are very old systems which had enough time to exhaust their bright satellite galaxies through multiple major mergers. Since major mergers leave signatures in the stellar populations of the resulting galaxy, we study the stellar population parameters of the brightest central galaxies (BCGs) of FGs as a benchmark against which the formation and evolution scenarios of FGs can be compared. We present long-slit spectroscopic observations along the major, minor, and diagonal axis of NGC 6482 and NGC 7556, which are the BCGs of two nearby FGs. The measurements include spatially resolved stellar kinematics and radial profiles of line-strength indices, which we converted into stellar population parameters using single stellar-population models. NGC 6482 and NGC 7556 are very massive (M*~1*10^11.5^M_{sun}_) and large (D_25_~50kpc) galaxies. They host a centrally-concentrated stellar population, which is significantly younger and more metal rich than the rest of the galaxy. The age gradients of both galaxies are somewhat larger than those of the other FG BCGs studied so far, whereas their metallicity gradients are similarly negative and shallow. Moreover, they have negligible gradients of alpha-element abundance ratio. The measured metallicity gradients are less steep than those predicted for massive galaxies which formed monolithically and evolved without experiencing any major merger. We conclude that the observed FGs formed through major mergers rather than being failed groups missing bright satellite galaxies since the beginning.
- ID:
- ivo://CDS.VizieR/J/MNRAS/412/423
- Title:
- Stellar population trends in S0 galaxies
- Short Name:
- J/MNRAS/412/423
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present stellar population age and metallicity trends for a sample of 59 S0 galaxies based on optical Sloan Digital Sky Survey (SDSS) and near-infrared (NIR) J and H photometry. When combined with optical g and r passband imaging data from the SDSS archive and stellar population models, we obtain radial age and metallicity trends out to at least five effective radii for most of the galaxies in our sample. The sample covers a range in stellar mass and light concentration.
- ID:
- ivo://CDS.VizieR/J/ApJ/860/37
- Title:
- Stellar specific angular momentum & mass relation
- Short Name:
- J/ApJ/860/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the relation between stellar specific angular momentum j*, stellar mass M*, and bulge-to-total light ratio {beta} for The HI Nearby Galaxy Survey, the Calar Alto Legacy Integral Field Area Survey, and Romanowsky & Fall (2012ApJS..203...17R) data sets, exploring the existence of a fundamental plane between these parameters, as first suggested by Obreschkow & Glazebrook (2014ApJ...784...26O). Our best-fit M*-j* relation yields a slope of {alpha}=1.03+/-0.11 with a trivariate fit including {beta}. When ignoring the effect of {beta}, the exponent {alpha}=0.56+/-0.06 is consistent with {alpha}=2/3 that is predicted for dark matter halos. There is a linear {beta}-j*/M* relation for {beta}<~0.4, exhibiting a general trend of increasing {beta} with decreasing j*/M*. Galaxies with {beta}>~0.4 have higher j* than predicted by the relation. Pseudobulge galaxies have preferentially lower {beta} for a given j*/M* than galaxies that contain classical bulges. Pseudobulge galaxies follow a well- defined track in {beta}-j*/M* space, consistent with Obreschkow & Glazebrook, while galaxies with classical bulges do not. These results are consistent with the hypothesis that while growth in either bulge type is linked to a decrease in j*/M*, the mechanisms that build pseudobulges seem to be less efficient at increasing bulge mass per decrease in specific angular momentum than those that build classical bulges.
- ID:
- ivo://CDS.VizieR/J/AJ/146/20
- Title:
- Structural parameters for 79 globular clusters in M31
- Short Name:
- J/AJ/146/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present surface brightness profiles for 79 globular clusters in M31, using images observed with the Hubble Space Telescope, some of which are from new observations. The structural and dynamical parameters are derived from fitting the profiles to several different models for the first time. The results show that in the majority of cases, King models fit the M31 clusters just as well as Wilson models and better than S\'ersic models. However, there are 11 clusters best fitted by Sersic models with the Sersic index n>2, meaning that they have cuspy central density profiles. These clusters may be the well-known core-collapsed candidates. There is a bimodality in the size distribution of M31 clusters at large radii, which is different from their Galactic counterparts. In general, the properties of clusters in M31 and the Milky Way fall in the same regions of parameter spaces. The tight correlations of cluster properties indicate a "fundamental plane" for clusters, which reflects some universal physical conditions and processes operating at the epoch of cluster formation.
- ID:
- ivo://CDS.VizieR/J/A+A/626/A61
- Title:
- Structural parameters of galaxies
- Short Name:
- J/A+A/626/A61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-resolution multi-wavelength photometry is crucial to explore the spatial distribution of star formation in galaxies and understand how these evolve. To this aim, in this paper we exploit the deep, multi-wavelength Hubble Space Telescope (HST) data available in the central parts of the GOODS fields and study the distribution of star formation activity and mass in galaxies located at different positions with respect to the Main Sequence (MS) of star-forming galaxies. Our sample consists of galaxies with stellar mass >=10^9.5^M_{sun}_ in the redshift range 0.2<=z<=1.2. Exploiting 10-band photometry from the UV to the near-infrared at HST resolution, we derive spatially resolved maps of galaxies properties, such as stellar mass and star formation rate and specific star formation rate, with a resolution of 0.16arcsec. We find that the star formation activity is centrally enhanced in galaxies above the MS and centrally suppressed below the MS, with quiescent galaxies (1dex below the MS) characterised by the highest suppression. The sSFR in the outer region does not show systematic trends of enhancement or suppression above or below the MS. The distribution of mass in MS galaxies indicates that bulges are growing when galaxies are still on the MS relation. Galaxies below the MS are more bulge-dominated with respect to MS counterparts at fixed stellar mass, while galaxies in the upper envelope are more extended and have Sersic indexes that are always smaller than or comparable to their MS counterparts. The suppression of star formation activity in the central region of galaxies below the MS hints at inside-out quenching, as star formation is still ongoing in the outer regions.
