- ID:
- ivo://CDS.VizieR/J/other/PASA/16.113
- Title:
- New structure in Shapley supercluster
- Short Name:
- J/other/PASA/16.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new radial velocities for 306 bright (R<16) galaxies in a 77{deg}^2^ region of the Shapley supercluster, measured with the FLAIR-II spectrograph on the UK Schmidt Telescope. The galaxies we measured were uniformly distributed over the survey area, in contrast to previous samples which were concentrated in several rich Abell clusters. Most of the galaxies (230) were members of the Shapley supercluster: they trace out two previously unknown sheets of galaxies linking the Abell clusters of the supercluster. In a 44{deg}^2^ area of the supercluster excluding the Abell clusters, these sheets alone represent an overdensity of a factor of 2.0+/-0.2 compared to a uniform galaxy distribution. The supercluster is not flattened in the Declination direction as has been suggested in previous papers. Within our survey area the new galaxies contribute an additional 50% to the known contents of the Shapley supercluster, with a corresponding increase in its contribution to the motion of the Local Group.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/855/142
- Title:
- Next Generation Fornax Survey (NGFS) II.
- Short Name:
- J/ApJ/855/142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a photometric study of the dwarf galaxy population in the core region (<~r_vir_/4) of the Fornax galaxy cluster based on deep u'g'i' photometry from the Next Generation Fornax Cluster Survey. All imaging data were obtained with the Dark Energy Camera mounted on the 4m Blanco telescope at the Cerro Tololo Interamerican Observatory. We identify 258 dwarf galaxy candidates with luminosities -17<~Mg'<~-8mag, corresponding to typical stellar masses of 9.5>~logM*/M_{sun}_>~5.5, reaching ~3mag deeper in point-source luminosity and ~4mag deeper in surface brightness sensitivity compared to the classic Fornax Cluster Catalog. Morphological analysis shows that the dwarf galaxy surface-brightness profiles are well represented by single-component Sersic models with average Sersic indices of <n>_u',g',i'_=(0.78-0.83)+/-0.02 and average effective radii of <r_e_>_u',g',i'_=(0.67-0.70+/-0.02kpc. Color-magnitude relations indicate a flattening of the galaxy red sequence at faint galaxy luminosities, similar to the one recently discovered in the Virgo cluster. A comparison with population synthesis models and the galaxy mass-metallicity relation reveals that the average faint dwarf galaxy is likely older than ~5Gyr. We study galaxy scaling relations between stellar mass, effective radius, and stellar mass surface density over a stellar mass range covering six orders of magnitude. We find that over the sampled stellar mass range several distinct mechanisms of galaxy mass assembly can be identified: (1) dwarf galaxies assemble mass inside the half-mass radius up to logM*~8.0, (2) isometric mass assembly occurs in the range 8.0<~logM*/M_{sun}_<~10.5, and (3) massive galaxies assemble stellar mass predominantly in their halos at logM*~10.5 and above.
- ID:
- ivo://CDS.VizieR/J/AJ/140/1093
- Title:
- NGC7332/7339 and NGC 1156 HI sources from AGES
- Short Name:
- J/AJ/140/1093
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Two 5deg^2^ regions around the NGC 7332/9 galaxy pair and the isolated galaxy NGC 1156 have been mapped in the 21cm line of neutral hydrogen (HI) with the Arecibo L-band Feed Array out to a redshift of ~0.065 (~20000km/s) as part of the Arecibo Galaxy Environment Survey. One of the aims of this survey is to investigate the environment of galaxies by identifying dwarf companions and interaction remnants; both of these areas provide the potential for such discoveries. The neutral hydrogen observations were complemented by optical and radio follow-up observations with a number of telescopes. A total of 87 galaxies were found, of which 39 (45%) were previously catalogued and 15 (17%) have prior redshifts. Two dwarf galaxies have been discovered in the NGC 7332 group and a single dwarf galaxy in the vicinity of NGC 1156. A parallel optical search of the area revealed one further possible dwarf galaxy near NGC 7332.
- ID:
- ivo://CDS.VizieR/J/AJ/130/1502
- Title:
- NGC 5846 group: photometry and spectroscopy
- Short Name:
- J/AJ/130/1502
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We conduct a photometric and spectroscopic survey of a 10{deg}^2^ region surrounding the nearby NGC 5846 group of galaxies, using the Canada-France-Hawaii and Keck I telescopes to study the population of dwarf galaxies as faint as M_R_=-10. Candidates are identified on the basis of quantitative surface brightness and qualitative morphological criteria. Spectroscopic follow up and a spatial correlation analysis provide the basis for affirming group memberships. Altogether, 324 candidates are identified, and 83 have spectroscopic membership confirmation.
- ID:
- ivo://CDS.VizieR/J/A+A/611/A93
- Title:
- NGC3115 & NGC1399 VEGAS-SSS globular clusters
- Short Name:
- J/A+A/611/A93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze the globular cluster (GC) systems in two very different galaxies, NGC 3115 and NGC 1399. With the papers of this series, we aim at highlighting common and different properties in the GC systems in galaxies covering a wide range of parameter space. We compare the GCs in NGC 3115 and NGC 1399 as derived from the analysis of one square degree u-, g-, and i-band images taken with the VST telescope as part of the VST early-type galaxy survey (VEGAS) and Fornax deep survey (FDS). We selected GC candidates using as reference the morpho-photometric and color properties of confirmed GCs. The surface density maps of GCs in NGC 3115 reveal a morphology similar to the light profile of field stars; the same is true when blue and red GCs are taken separately. The GC maps for NGC 1399 are richer in structure and confirm the existence of an intra-cluster GC component. We confirm the presence of a spatial offset in the NGC 1399 GC centroid and find that the centroid of the GCs for NGC 3115 coincides well with the galaxy center. Both GC systems show unambiguous color bimodality in (g-i) and (u-i); the color-color relations of the two GC systems are slightly different with NGC 3115 appearing more linear than NGC 1399. The azimuthal average of the radial density profiles in both galaxies reveals a larger spatial extent for the total GCs population with respect to the galaxy surface brightness profile. For both galaxies, the red GCs have radial density profiles compatible with the galaxy light profile, while the radial profiles for blue GCs are shallower. As for the specific frequency of GCs, SN, we find it is a factor of two higher in NGC 1399 than for NGC 3115; this is mainly the result of extra blue GCs. By inspecting the radial behavior of the specific frequency, S_N_(<r), for the total, blue, and red GCs, we find notable similarities between the trends for red GCs in the two targets. In spite of extremely different host environments, the red GCs in both cases appear closely linked to the light distribution of field stars. Blue GCs extend to larger galactocentric scales than red GCs, marking a significant difference between the two galaxies: the blue/red GCs and field stellar components of NGC 3115 appear well thermalized with each other and the blue GCs in NGC 1399 appear to fade into an unrelaxed intra-cluster GC population.
- ID:
- ivo://CDS.VizieR/J/A+A/518/A44
- Title:
- NGC 1399 planetary nebula velocities
- Short Name:
- J/A+A/518/A44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a counter-dispersed slitless spectroscopy technique, we detect and measure the line-of-sight velocities of 187 planetary nebulae (PNe) around one of the nearest cD galaxies, NGC 1399, with FORS1 on the VLT. We describe the method for identifying and classifying the emission-line sources and the procedure for computing their J2000 coordinates and velocities. The number of PN detections and the errors in the velocity measurements (37km/s) indicate that this technique is comparable to other methods. **************************************************************************** * * * The PN line-of-sight velocities will be published with a * * subsequent paper that also includes dynamical models of the system. * * * ****************************************************************************
- ID:
- ivo://CDS.VizieR/J/ApJ/859/52
- Title:
- NGFS. III. Dwarf galaxies in outer regions
- Short Name:
- J/ApJ/859/52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of 271 previously undetected dwarf galaxies in the outer Fornax cluster regions at radii r_vir_/4<r<r_vir_/2 using data from the Next Generation Fornax Survey (NGFS) with deep coadded u', g', and i' images obtained with Blanco/DECam at Cerro Tololo Interamerican Observatory. From the 271 dwarf candidates, we find 39 to be nucleated. Together with our previous study of the central Fornax region, the new dwarfs detected with NGFS data number 392, of which 56 are nucleated. The total Fornax dwarf galaxy population from NGFS and other catalogs rises, therefore, to a total of 643 with 181 being nucleated, yielding an overall nucleation fraction of 28%. The absolute i'-band magnitudes for the outer NGFS dwarfs are in the range -18.80<=M_i'_<=-8.78 with effective radii r_eff,i'_=0.18-2.22kpc and an average Sersic index <n>_i'_=0.81. Nonnucleated dwarfs are found to be fainter and smaller by {Delta}<M_i'_>=2.25mag and {Delta}<r_eff,i'_>=0.4kpc than the nucleated dwarfs. We demonstrate a significant clustering of dwarf galaxies on scales <~100kpc, and projected surface number density profile estimates, {Sigma}_N_(r), show a concentration of dwarfs in the Fornax core region within r<~350kpc. {Sigma}_N_(r) has a flat distribution up to ~350kpc, beyond which it declines for the nonnucleated dwarfs. The nucleated dwarfs have a steeper {Sigma}N(r) distribution, are more concentrated toward NGC 1399, and are decreasing rapidly outwards. This is the first time the transition from cluster to field environment has been established for the very faint dwarf galaxy population with robust sample statistics.
- ID:
- ivo://CDS.VizieR/J/A+A/650/A99
- Title:
- NGVS 3543 images at 8 wavelengths
- Short Name:
- J/A+A/650/A99
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The interaction of galaxies with their environment plays an important role in their evolution. Ultra-diffuse galaxies (UDGs) have been found in large numbers in clusters. We detected a few star forming blobs in the VESTIGE survey, located at ~5kpc from a UDG, namely NGVS 3543, in association with an HI gas cloud AGC 226178, suggesting a recent interaction of this low surface brightness system with the surrounding cluster environment. We use a complete set of multi-frequency data including deep optical, UV, and narrow- band H{alpha} imaging and HI data to understand the formation process which gave birth to this peculiar system. For this purpose, we measured: i) multi-wavelength radial surface brightness profiles of NGVS 3543 and compared them to the predictions of spectro-photometric models of galaxy evolution in rich clusters, ii) aperture photometry of the blue regions in the vicinity of NGVS 3543 in order to determine their age and stellar mass. The comparison of the observations with the evolutionary models indicate that the NGVS 3543 has undergone a ram-pressure stripping (RPS) that peaked ~100Myr ago, transforming a blue gas-rich UDG into a red gas-poor UDG. Star formation has taken place in the ram pressure stripped gas, whose mass is ~10^8^M_{sun}_, forming star complexes of typical age ~20Myr and stellar mass ~10^4^M_{sun}_. These results suggest that we are observing for the first time the ongoing transformation of a gas-rich UDG into a red and quiescent UDG under the effect of a ram-pressure stripping event. The same process could thus explain the lack of star forming UDGs in rich environments observed in several nearby clusters.
- ID:
- ivo://CDS.VizieR/J/ApJ/890/128
- Title:
- NGVS. XIV. Bona fide Virgo cluster members
- Short Name:
- J/ApJ/890/128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Next Generation Virgo Cluster Survey (NGVS) was designed to provide a deep census of baryonic structures in the Virgo cluster. The survey covers the 104deg^2^ area from the core of Virgo out to one virial radius, in the u*griz bandpasses, to a point-source depth of g~25.9mag (10{sigma}) and a single pixel surface brightness limit of {mu}_g_~29mag/arcsec^2^ (2{sigma} above the sky). Here we present the final catalog of 404 Virgo galaxies located within a 3.71deg^2^ (0.3Mpc^2^) region centered on M87, Virgo's dominant galaxy. Of these, 154 were previously uncataloged and span the range 17.8mag<g<23.7mag (-13.4mag<M_g_{<}-7.4mag at the 16.5Mpc distance of Virgo). Extensive simulations show that the NGVS catalog is complete down to g=18.6mag (M_g_=-12.5mag, corresponding to a stellar mass M~1.6x10^7^M_{sun}_ for an old stellar population), and 50% complete at g=22.0mag (M_g_=-9.1mag, M~6.2x10^5^M_{sun}_). The NGVS 50% completeness limit is 3mag deeper than that of the Virgo Cluster Catalog (VCC), which has served as Virgo's reference standard for over a quarter century, and 2mag deeper than the VCC detection limit. We discuss the procedure adopted for the identification of objects and the criteria used to assess cluster membership. For each of the 404 galaxies in the NGVS Virgo Cluster core catalog, we present photometric and structural parameters based on a nonparametric curve-of-growth and isophotal analysis, as well as parametric (Sersic, double-Sersic, and/or core-Sersic) fits to the one-dimensional surface brightness profiles and two-dimensional light distributions.
- ID:
- ivo://CDS.VizieR/J/ApJ/878/18
- Title:
- NGVS. XXIII. Nuclear star clusters
- Short Name:
- J/ApJ/878/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using deep, high-resolution optical imaging from the Next Generation Virgo Cluster Survey, we study the properties of nuclear star clusters (NSCs) in a sample of nearly 400 quiescent galaxies in the core of Virgo with stellar masses 10^5^<~M*/M_{sun}_<~10^12^. The nucleation fraction reaches a peak value f_n_~90% for M*~10^9^M_{sun}_ galaxies and declines for both higher and lower masses, but nuclei populate galaxies as small as M*~5x10^5^M_{sun}_. Comparison with literature data for nearby groups and clusters shows that at the low-mass end nucleation is more frequent in denser environments. The NSC mass function peaks at M_NSC_~7x10^5^M_{sun}_, a factor 3-4 times larger than the turnover mass for globular clusters (GCs). We find a nonlinear relation between the stellar masses of NSCs and those of their host galaxies, with a mean nucleus-to-galaxy mass ratio that drops to M_NSC_/M*~3.6x10^-3^ for M*~5x10^9^M_{sun}_ galaxies. Nuclei in both more and less massive galaxies are much more prominent: M_NSC_{propto}M_*_^0.46^ at the low-mass end, where nuclei are nearly 50% as massive as their hosts. We measure an intrinsic scatter in NSC masses at a fixed galaxy stellar mass of 0.4dex, which we interpret as evidence that the process of NSC growth is significantly stochastic. At low galaxy masses we find a close connection between NSCs and GC systems, including very similar occupation distributions and comparable total masses. We discuss these results in the context of current dissipative and dissipationless models of NSC formation.
