- ID:
- ivo://CDS.VizieR/J/MNRAS/357/819
- Title:
- Colours and HI line observations in Virgo
- Short Name:
- J/MNRAS/357/819
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to investigate the nature of dwarf low surface brightness (LSB) galaxies we have undertaken a deep B- and I-band CCD survey of a 14-deg^2^ strip in the Virgo Cluster and applied a Fourier convolution technique to explore its dwarf galaxy population down to a central surface brightness of ~26Bmag/arcsec^2^ and a total absolute B magnitude of ~-10. In this paper we carry out an analysis of their morphology, (B-I) colours and atomic hydrogen content.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/600/L99
- Title:
- Colours of z~6 galaxies in GOODS
- Short Name:
- J/ApJ/600/L99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report early results on galaxies at z~6 selected from Hubble Space Telescope imaging for the Great Observatories Origins Deep Survey. Spectroscopy of one object with the Advanced Camera for Surveys grism and from the Keck and Very Large Telescope observatories shows a strong continuum break and asymmetric line emission, identified as Ly{alpha} at z=5.83. We find only five spatially extended candidates with signal-to-noise ratios greater than 10, two of which have spectroscopic confirmation. This is much fewer than would be expected if galaxies at z=6 had the same luminosity function as those at z=3. There are many fainter candidates, but we expect substantial contamination from foreground interlopers and spurious detections. Our best estimates favor a z=6 galaxy population with fainter luminosities, higher space density, and similar comoving ultraviolet emissivity to that at z=3, but this depends critically on counts at fluxes fainter than those reliably probed by the current data.
- ID:
- ivo://CDS.VizieR/J/ApJ/883/78
- Title:
- Column densities of CGM absorption lines
- Short Name:
- J/ApJ/883/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the geometric distribution of gas metallicities in the circumgalactic medium (CGM) around 47, z<0.7 galaxies from the "Multiphase Galaxy Halos" Survey. Using a combination of quasar spectra from Hubble Space Telescope (HST)/COS and from Keck/HIRES or Very Large Telescope/UVES, we measure column densities of, or determine limits on, CGM absorption lines. We then use a Markov Chain Monte Carlo approach with Cloudy to estimate the metallicity of cool (T~10^4^K) CGM gas. We also use HST images to determine host-galaxy inclination and quasar-galaxy azimuthal angles. Our sample spans a HI column density range of 13.8cm^-2^<logN_HI_<19.9cm^-2^. We find (1) while the metallicity distribution appears bimodal, a Hartigan dip test cannot rule out a unimodal distribution (0.4{sigma}). (2) CGM metallicities are independent of halo mass, spanning three orders of magnitude at a fixed halo mass. (3) The CGM metallicity does not depend on the galaxy azimuthal and inclination angles regardless of HI column density, impact parameter, and galaxy color. (4) The ionization parameter does not depend on azimuthal angle. We suggest that the partial Lyman limit metallicity bimodality is not driven by a spatial azimuthal bimodality. Our results are consistent with simulations where the CGM is complex and outflowing, accreting, and recycled gas are well-homogenized at z<0.7. The presence of low-metallicity gas at all orientations suggests that cold streams of accreting filaments are not necessarily aligned with the galaxy plane at low redshifts or intergalactic transfer may dominate. Finally, our results support simulations showing that strong metal absorption can mask the presence of low-metallicity gas in integrated line-of-sight CGM metallicities.
- ID:
- ivo://CDS.VizieR/J/A+AS/126/67
- Title:
- Coma and Perseus clusters galaxies
- Short Name:
- J/A+AS/126/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an isophotal shape analysis of galaxies in the Coma and Perseus clusters. These data, together with those of two previous papers, provide two complete samples of galaxies with reliable Hubble types in rich clusters: 1) all galaxies brighter than m_b_=16.5 falling within one degree (=2.3Mpc) from the center of the Coma cluster (187 galaxies), 2) all galaxies brighter than m_(Zwicky)=15.7 in a region of 5 deg 3' times 5 deg 27' around the center of the Perseus cluster (139 galaxies). These two complete samples cover 5 orders of magnitude in galaxy density and span areas of 91 and 17Mpc^2^, clustercentric radii up to 2.3 and 6.4Mpc, for Perseus and Coma respectively. They will be used in subsequent papers to study the dependence of galaxy types on cluster environment and as reference samples in comparisons with distant clusters.
- ID:
- ivo://CDS.VizieR/J/MNRAS/458/582
- Title:
- Coma clusters and filaments galaxies FIR survey
- Short Name:
- J/MNRAS/458/582
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a far-infrared survey of the Coma cluster and the galaxy filament it resides within. Our survey covers an area of ~150 deg^2^ observed by Herschel H-ATLAS (Herschel Astrophysical Terahertz Large Area Survey) in five bands at 100, 160, 250, 350 and 500{mu}m. The SDSS spectroscopic survey (m_r_<=17.8) is used to define an area (within the virial radius) and redshift selected (4268<v<9700km/s) sample of 744 Coma cluster galaxies - the Coma Cluster Catalogue. For comparison, we also define a sample of 951 galaxies in the connecting filament - the Coma Filament Catalogue. The optical positions and parameters are used to define appropriate apertures to measure each galaxy's far-infrared emission. We have detected 99 of 744 (13 per cent) and 422 of 951 (44 per cent) of the cluster and filament galaxies in the SPIRE 250um band. We consider the relative detection rates of galaxies of different morphological types finding that it is only the S0/Sa population that shows clear differences between the cluster and filament. We find no differences between the dust masses and temperatures of cluster and filament galaxies with the exception of early-type galaxy dust temperatures, which are significantly hotter in the cluster than in the filament (X-ray heating?). From a chemical evolution model, we find no evidence for different evolutionary processes (gas loss or infall) between galaxies in the cluster and filament.
1376. Coma cluster VLA survey
- ID:
- ivo://CDS.VizieR/J/AJ/137/4436
- Title:
- Coma cluster VLA survey
- Short Name:
- J/AJ/137/4436
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep 1.4GHz Very Large Array radio continuum observations of two ~0.5{deg}^2^ fields in the Coma cluster of galaxies. The two fields, "Coma 1" and "Coma 3", correspond to the cluster core and southwest infall region and were selected on account of abundant preexisting multiwavelength data. In their most sensitive regions the radio data reach 22uJy rms per 4.4" beam, sufficient to detect (at 5{sigma}) Coma member galaxies with L_1.4GHz_=1.3x10^20^W/Hz. The full catalog of radio detections is presented herein and consists of 1030 sources detected at >=5{sigma}, 628 of which are within the combined Coma 1 and Coma 3 area. We also provide optical identifications of the radio sources using data from the Sloan Digital Sky Survey. The depth of the radio observations allows us to detect active galactic nucleus in cluster elliptical galaxies with M_r_<-20.5 (AB magnitudes), including radio detections for all cluster ellipticals with M_r_<-21.8. At fainter optical magnitudes (-20.5<M_r_~<-19), the radio sources are associated with star-forming galaxies with star formation rates as low as 0.1M_{sun}_/yr.
- ID:
- ivo://CDS.VizieR/J/A+AS/141/113
- Title:
- Coma extensive H photometry
- Short Name:
- J/A+AS/141/113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present extensive and accurate photometry in the near-infrared H band (about 1.62{mu}m) of a complete sample of objects in an area of about 400arcmin^2^ toward the Coma cluster of galaxies. The sample, including about 300 objects, is complete down to H~17mag, the exact value depending on the type of magnitude (isophotal, aperture, Kron) and the particular region studied. This is six magnitudes below the characteristic magnitude of galaxies, well into the dwarfs' regime at the distance of the Coma cluster. For each object (star or galaxy) we provide aperture magnitudes computed within five different apertures, the magnitude within the 22mag/arcsec^2^ isophote, the Kron magnitude and radius, magnitude errors, as well as the coordinates, the isophotal area, and a stellarity index. Photometric errors are 0.2mag at the completness limit. This sample is meant to be the zero-redshift reference for evolutionary studies of galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/4336
- Title:
- Coma galaxies UV and opt. view
- Short Name:
- J/MNRAS/478/4336
- Date:
- 10 Dec 2021 00:56:54
- Publisher:
- CDS
- Description:
- The Coma supercluster (100h^-1^Mpc) offers an unprecedented contiguous range of environments in the nearby Universe. In this paper, we present a catalogue of spectroscopically confirmed galaxies in the Coma supercluster detected in the ultraviolet (UV) wavebands. We use the arsenal of UV and optical data for galaxies in the Coma supercluster covering ~500deg^2^ on the sky to study their photometric and spectroscopic properties as a function of environment at various scales. We identify the different components of the cosmic-web: large-scale filaments and voids using Discrete Persistent Structures Extractor, and groups and clusters using Hierarchical Density-based spatial clustering of applications with noise, respectively. We find that in the Coma supercluster the median emission in H{alpha} inclines, while the g-r and FUV-NUV colours of galaxies become bluer moving further away from the spine of the filaments out to a radius of ~1Mpc. On the other hand, an opposite trend is observed as the distance between the galaxy and centre of the nearest cluster or group decreases. Our analysis supports the hypothesis that properties of galaxies are not just defined by its stellar mass and large-scale density, but also by the environmental processes resulting due to the intrafilament medium whose role in accelerating galaxy transformations needs to be investigated thoroughly using multiwavelength data.
- ID:
- ivo://CDS.VizieR/J/MNRAS/411/2439
- Title:
- Coma Treasury Survey. Structural parameters
- Short Name:
- J/MNRAS/411/2439
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of structural parameters for 8814 galaxies in the 25 fields of the Hubble Space Telescope/ACS Coma Treasury Survey. Parameters from Sersic fits to the two-dimensional surface brightness distributions are given for all galaxies from our published Coma photometric catalogue with mean effective surface brightness brighter than 26.0mag/arcsec^2^ and brighter than 24.5mag (equivalent to absolute magnitude -10.5), as given by the fits, all in F814W(AB). The sample comprises a mixture of Coma members and background objects; 424 galaxies have redshifts and of these 163 are confirmed members. The fits were carried out using both the GIM2D and GALFIT codes.
- ID:
- ivo://CDS.VizieR/J/ApJ/835/75
- Title:
- Common proper motion stars in the Kepler field
- Short Name:
- J/ApJ/835/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a search of proper motion catalogs for common proper motion stars in the field of the Kepler spacecraft I identified 93 likely binary systems. A comparison of their rotation periods is a test of the gyrochronology concept. To find their periods I calculated the autocorrelation function (ACF) of the Kepler mission photometry for each star. In most systems for which good periods can be found, the cooler star has a longer period than the hotter component, in general agreement with models. However, there is a wide range in the gradients of lines connecting binary pairs in a period-color diagram. Furthermore, near the solar color, only a few stars have longer periods than the Sun, suggesting that they, and their cooler companions, are not much older than the Sun. In addition, there is an apparent gap at intermediate periods in the period distribution of the late K and early M stars. Either star formation in this direction has been variable, or stars evolve in period at a non-uniform rate, or some stars evolve more rapidly than others at the same mass. Finally, using the ACF as a measure of the activity level, I found that while the F, G, and early K stars become less active as their periods increase, there is no correlation between period and activity for the mid K to early M stars.
