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711. Compact galaxies in the local universe
ID:
ivo://CDS.VizieR/J/ApJ/720/723
Title:
Compact galaxies in the local universe
Short Name:
J/ApJ/720/723
Date:
21 Oct 2021
Publisher:
CDS
Description:
We set out to test the claim that the recently identified population of compact, massive, and quiescent galaxies at z~2.3 must undergo significant size evolution to match the properties of galaxies found in the local universe. Using data from the Sloan Digital Sky Survey (SDSS; Data Release 7), we have conducted a search for local red sequence galaxies with sizes and masses comparable to those found at z~2.3. The SDSS spectroscopic target selection algorithm excludes high surface brightness objects; we show that this makes incompleteness a concern for such massive, compact galaxies, particularly for low redshifts (z<~0.05). We have identified 63 M_*_>10^10.7^M_{sun}_ (~5x10^10^M_{sun}_) red sequence galaxies at 0.066<z_spec_<0.12 which are smaller than the median size-mass relation by a factor of 2 or more. Consistent with expectations from the virial theorem, the median offset from the mass-velocity dispersion relation for these galaxies is 0.12 dex. We do not, however, find any galaxies with sizes and masses comparable to those observed at z~2.3, implying a decrease in the comoving number density of these galaxies, at fixed size and mass, by a factor of >~5000. This result cannot be explained by incompleteness: in the 0.066<z<0.12 interval, we estimate that the SDSS spectroscopic sample should typically be >~75% complete for galaxies with the sizes and masses seen at high redshift, although for the very smallest galaxies it may be as low as ~20%. In order to confirm that the absence of such compact massive galaxies in SDSS is not produced by spectroscopic selection effects, we have also looked for such galaxies in the basic SDSS photometric catalog, using photometric redshifts. While we do find signs of a slight bias against massive, compact galaxies, this analysis suggests that the SDSS spectroscopic sample is missing at most a few objects in the regime we consider.
712. Compact Groups in the UZC galaxy sample
ID:
ivo://CDS.VizieR/J/A+A/391/35
Title:
Compact Groups in the UZC galaxy sample
Short Name:
J/A+A/391/35
Date:
21 Oct 2021
Publisher:
CDS
Description:
Applying an automatic neighbour search algorithm to the 3D UZC galaxy catalogue (Falco et al., 1999, Cat. <J/PASP/111/438>) we have identified 291 compact groups (CGs) with radial velocity between 1000 and 10000km/s. The sample is analysed to investigate whether Triplets display kinematical and morphological characteristics similar to higher order CGs (Multiplets). It is found that Triplets constitute low velocity dispersion structures, have a gas-rich galaxy population and are typically retrieved in sparse environments. Conversely Multiplets show higher velocity dispersion, include few gas-rich members and are generally embedded structures. Evidence hence emerges indicating that Triplets and Multiplets, though sharing a common scale, correspond to different galaxy systems. Triplets are typically field structures whilst Multiplets are mainly subclumps (either temporarily projected or collapsing) within larger structures. Simulations show that selection effects can only partially account for differences, but significant contamination of Triplets by field galaxy interlopers could eventually induce the observed dependences on multiplicity.
713. Compact groups of compact galaxies
ID:
ivo://CDS.VizieR/VII/89B
Title:
Compact groups of compact galaxies
Short Name:
VII/89B
Date:
21 Oct 2021
Publisher:
CDS
Description:
The catalog is a compilation of ten published lists of compact groups of compact galaxies found on the Palomar Sky Survey red charts. The catalog contains 377 groups of compact galaxies and includes identifications, equatorial coordinates, numbers of constituent galaxies, magnitudes of the brightest member, sizes of the groups as a whole, and coefficients of relative compactness.
714. Compact Groups of galaxies from 2MASX
ID:
ivo://CDS.VizieR/J/MNRAS/426/296
Title:
Compact Groups of galaxies from 2MASX
Short Name:
J/MNRAS/426/296
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a photometric catalogue of compact groups of galaxies (p2MCGs) automatically extracted from the Two-Micron All Sky Survey (2MASS) extended source catalogue. A total of 262 p2MCGs are identified, following the criteria defined by Hickson, of which 230 survive visual inspection (given occasional galaxy fragmentation and blends in the 2MASS parent catalogue). Only one quarter of these 230 groups were previously known compact groups (CGs). Among the 144 p2MCGs that have all their galaxies with known redshifts, 85 (59%) have four or more accordant galaxies. This v2MCG sample of velocity-filtered p2MCGs constitutes the largest sample of CGs (with N>=4) catalogued to date, with both well-defined selection criteria and velocity filtering, and is the first CG sample selected by stellar mass. It is fairly complete up to K_group_~9 and radial velocity of ~6000km/s.
715. Compact groups of galaxies from SDSS-DR12 (MLCG)
ID:
ivo://CDS.VizieR/J/ApJS/225/23
Title:
Compact groups of galaxies from SDSS-DR12 (MLCG)
Short Name:
J/ApJS/225/23
Date:
21 Oct 2021
Publisher:
CDS
Description:
We apply a friends-of-friends algorithm to an enhanced SDSS DR12 spectroscopic catalog, including redshift from the literature to construct a catalog of 1588 N>=3 compact groups of galaxies containing 5178 member galaxies and covering the redshift range 0.01<z<0.19. This catalog contains 18 times as many systems and reaches 3 times the depth of the similar catalog of Barton et al. (1996AJ....112..871B). We construct catalogs from both magnitude-limited and volume-limited galaxy samples. Like Barton et al. we omit the frequently applied isolation criterion in the compact group selection algorithm. Thus the groups selected by fixed projected spatial and rest-frame line-of-sight velocity separation produce a catalog of groups with a redshift-independent median size. In contrast to previous catalogs, the enhanced SDSS DR12 catalog (including galaxies with r<14.5) includes many systems with z<~0.05. The volume-limited samples are unique to this study. The compact group candidates in these samples have a median stellar mass independent of redshift. Groups with velocity dispersion <~100km/s show abundant evidence for ongoing dynamical interactions among the members. The number density of the volume-limited catalogs agrees with previous catalogs at the lowest redshifts but decreases as the redshift increases. The SDSS fiber placement constraints limit the catalog's completeness. In spite of this issue, the volume-limited catalogs provide a promising basis for detailed spatially resolved probes of the impact of galaxy-galaxy interactions within similar dense systems over a broad redshift range.
716. Compact groups of galaxies in LCRS
ID:
ivo://CDS.VizieR/J/AN/321/101
Title:
Compact groups of galaxies in LCRS
Short Name:
J/AN/321/101
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have recently extracted a catalog of compact groups of galaxies (CGs) from the Las Campanas Redshift Survey. This catalog of Las Campanas Compact Groups (LCCGs) contains 76 CGs with a median redshift of z_med_~0.08. The physical properties of these CGs are similar to those form Hickson (1982, Cat. <VII/213>) and the Barton et al. (1996AJ....112..871B) catalogs. Here, we present an atlas of our catalog and briefly describe its general properties.
717. Compact groups of galaxies in SDSS & LAMOST. I.
ID:
ivo://CDS.VizieR/J/ApJS/246/12
Title:
Compact groups of galaxies in SDSS & LAMOST. I.
Short Name:
J/ApJS/246/12
Date:
21 Oct 2021
Publisher:
CDS
Description:
A compact group (CG) is a kind of special galaxy system where the galaxy members are separated at distances of the order of galaxy size. The strong interaction between the galaxy members makes CGs ideal labs for studying the environmental effects on galaxy evolution. The traditional photometric selection algorithm biases against the CG candidates at low redshifts, while the spectroscopic identification technique is affected by the spectroscopic incompleteness of sample galaxies and typically biases against the high redshift candidates. In this study, we combine these two methods and select CGs in the main galaxy sample of the Sloan Digital Sky Survey, where we also have taken the advantages of the complementary redshift measurements from the LAMOST spectral and GAMA surveys. We have obtained the largest and most complete CG samples to date. Our samples include 6144 CGs and 8022 CG candidates, which are unique in the studies of the nature of the CGs and the evolution of the galaxies inside.
718. Compact radio cores in radio galaxies.
ID:
ivo://CDS.VizieR/J/MNRAS/268/602
Title:
Compact radio cores in radio galaxies.
Short Name:
J/MNRAS/268/602
Date:
21 Oct 2021
Publisher:
CDS
Description:
This catalog contains compact core fluxes for a list of 175 southern radio galaxies, measured with the Parkes-Tidbinbilla Interferometer (PTI, Norris et al. 1988ApJS...67...85N) on a single 275 km baseline at 2.3 GHz and 8.4 GHz. The sample consists of large angular size ( > 0.5 arcmin) steep spectrum sources from Jones & McAdam (1992ApJS...80..137J) observed to determine the fraction of flux contained in compact (VLBI-scale) cores. Of the 172 sources observed at 2.3 GHz (100 milliarcsec fringe spacing), 63 had cores detected and upper limits were determined for the remaining 109. Of the 88 sources observed at 8.4 GHz (30 milliarcsec fringe spacing), 38 had cores detected and 50 have upper limits. A comparison of the detections and upper limits at the two frequencies shows that the cores have flat or inverted spectra. The core fluxes quoted here may vary by around 20 % if there is structure on the scale of the fringe spacing and the cores are probably intrinsically variable.
719. Compact radio sources in spiral galaxies. II.
ID:
ivo://CDS.VizieR/J/AJ/133/2559
Title:
Compact radio sources in spiral galaxies. II.
Short Name:
J/AJ/133/2559
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the analysis of deep radio observations of the interacting galaxy system M51 from the Very Large Array, with the goal of understanding the nature of the population of compact radio sources in nearby spiral galaxies. We detect 107 compact radio sources, 64% of which have optical counterparts in a deep H{alpha} Hubble Space Telescope image. Thirteen of the radio sources have X-ray counterparts from a Chandra observation of M51. We find that six of the associated H{alpha} sources are young supernova remnants (SNRs) with resolved shells. Most of the SNRs exhibit steep radio continuum spectral indices consistent with synchrotron emission. We detect emission from the Type Ic SN 1994I nearly a decade after explosion: the emission (160+/-22uJy/beam at 20cm, 46+/-11uJy/beam at 6cm, {alpha}=-1.02+/-0.28) is consistent with light-curve models for Type Ib/Ic supernovae. We detect X-ray emission from the supernova; however, no optical counterpart is present. We report on the analysis of the Seyfert 2 nucleus in this galaxy, including the evidence for bipolar outflows from the central black hole.
720. Compact star clusters in M81
ID:
ivo://CDS.VizieR/J/MNRAS/405/1293
Title:
Compact star clusters in M81
Short Name:
J/MNRAS/405/1293
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the population of compact star clusters (CSCs) in M81, using the Hubble Space Telescope/Advanced Camera for Surveys (ACS) images in the filters F435W, F606W and F814W covering, for the first time, the entire optical extent of the galaxy. Our sample contains 435 clusters of full width at half-maximum less than 10 ACS pixels (9pc). The sample shows the presence of two cluster populations, a blue group of 263 objects brighter than B=22mag, and a red group of 172 objects, brighter than B=24mag. On the basis of analysis of colour-magnitude diagrams and making use of simple stellar population models,

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