- ID:
- ivo://CDS.VizieR/J/MNRAS/413/3059
- Title:
- 4098 galaxy clusters in SDSS Stripe 82
- Short Name:
- J/MNRAS/413/3059
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of 4098 photometrically selected galaxy clusters with a median redshift <z>=0.32 in the 270deg^2^ "Stripe 82" region of the Sloan Digital Sky Survey (SDSS), covering the celestial equator in the Southern Galactic Cap (-50{deg}<RA<59{deg}, |DE|<=1.25). Owing to the multi-epoch SDSS coverage of this region, the ugriz photometry is ~2mag deeper than single scans within the main SDSS footprint. We exploit this to detect clusters of galaxies using an algorithm that searches for statistically significant overdensities of galaxies in a Voronoi tessellation of the projected sky.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/413/1145
- Title:
- Galaxy clusters in the COSMOS field
- Short Name:
- J/MNRAS/413/1145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxy clusters are usually detected in blind optical surveys via suitable filtering methods. We present an optimal matched filter which maximizes their signal-to-noise ratio by taking advantage of the knowledge we have of their intrinsic physical properties and of the data noise properties. In this paper we restrict our application to galaxy magnitudes, positions and photometric redshifts if available, and we also apply the filter separately to weak lensing data. The method is suitable to be naturally extended to a multi-band approach which could include not only additional optical bands but also observables with different nature such as X-rays. For each detection, the filter provides its significance, an estimate for the richness and for the redshift even if photo-z are not given. The provided analytical error estimate is tested against numerical simulations. We finally apply our method to the COSMOS field and compare the results with previous cluster detections obtained with different methods. Our catalogue contains 27 galaxy clusters with minimal threshold at 3{sigma} level including both optical and weak-lensing information.
- ID:
- ivo://CDS.VizieR/J/MNRAS/440/2810
- Title:
- Galaxy luminosity function at z =~ 7
- Short Name:
- J/MNRAS/440/2810
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a new search for bright star-forming galaxies at redshift z=~7 within the UltraVISTA second data release (DR2) and UKIDSS (UKIRT Infrared Deep Sky Survey) UDS (Ultra Deep Survey) DR10 data, which together provide 1.65deg^2^ of near-infrared imaging with overlapping optical and Spitzer data. Using a full photometric redshift analysis, to identify high-redshift galaxies and reject contaminants, we have selected a sample of 34 luminous (-22.7<M_UV_<-21.2) galaxies with 6.5<z<7.5. Crucially, the deeper imaging provided by UltraVISTA DR2 confirms all of the robust objects previously uncovered by Bowler et al., validating our selection technique. Our new expanded galaxy sample includes the most massive galaxies known at z=~7, with M*=~10^10^M_{sun}_, and the majority are resolved, consistent with larger sizes (r_1/2_=~1-1.5kpc) than displayed by less massive galaxies. From our final robust sample, we determine the form of the bright end of the rest-frame UV galaxy luminosity function (LF) at z=~7, providing strong evidence that it does not decline as steeply as predicted by the Schechter-function fit to fainter data. We exclude the possibility that this is due to either gravitational lensing, or significant contamination of our galaxy sample by active galactic nuclei (AGN). Rather, our results favour a double power-law form for the galaxy LF at high redshift, or, more interestingly, an LF which simply follows the form of the dark matter halo mass function at bright magnitudes. This suggests that the physical mechanism which inhibits star formation activity in massive galaxies (i.e. AGN feedback or some other form of 'mass quenching') has yet to impact on the observable galaxy LF at z=~7, a conclusion supported by the estimated masses of our brightest galaxies which have only just reached a mass comparable to the critical 'quenching mass' of M*=~10^10.2^M_{sun}_ derived from studies of the mass function of star-forming galaxies at lower redshift.
- ID:
- ivo://CDS.VizieR/J/MNRAS/432/2696
- Title:
- Galaxy luminosity function at z = 7-9
- Short Name:
- J/MNRAS/432/2696
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new determination of the ultraviolet (UV) galaxy luminosity function (LF) at redshift z=~7 and 8, and a first estimate at z=~9. An accurate determination of the form and evolution of the galaxy LF during this era is of key importance for improving our knowledge of the earliest phases of galaxy evolution and the process of cosmic reionization. Our analysis exploits to the full the new, deepest Wide Field Camera 3/infrared imaging from our Hubble Space Telescope (HST) Ultra-Deep Field 2012 (UDF12) campaign, with dynamic range provided by including a new and consistent analysis of all appropriate, shallower/wider area HST survey data. Our new measurement of the evolving LF at z=~7 to 8 is based on a final catalogue of =~600 galaxies, and involves a step-wise maximum-likelihood determination based on the photometric redshift probability distribution for each object; this approach makes full use of the 11-band imaging now available in the Hubble Ultra-Deep Field (HUDF), including the new UDF12 F140W data, and the latest Spitzer IRAC imaging. The final result is a determination of the z=~7 LF extending down to UV absolute magnitudes M_1500_=-16.75 (AB mag) and the z=~8 LF down to M_1500_=-17.00. Fitting a Schechter function, we find M_1500_^*^=-19.90^+0.23^_-0.28^, log{phi}^*^=-2.96^+0.18^_-0.23_ and a faint-end slope {alpha}=-1.90^+0.14^_-0.15_ at z=~7, and M_1500_^*^=-20.12^+0.37^_-0.48_, log{phi}^*^=-3.35^+0.28^_-0.47_ and {alpha}=-2.02^+0.22^_-0.23_ at z=~8. These results strengthen previous suggestions that the evolution at z>7 appears more akin to 'density evolution' than the apparent 'luminosity evolution' seen at z=~5-7. We also provide the first meaningful information on the LF at z=~9, explore alternative extrapolations to higher redshifts, and consider the implications for the early evolution of UV luminosity density. Finally, we provide catalogues (including derived z_phot_, M_1500_ and photometry) for the most robust z~6.5-11.9 galaxies used in this analysis. We briefly discuss our results in the context of earlier work and the results derived from an independent analysis of the UDF12 data based on colour-colour selection.
- ID:
- ivo://CDS.VizieR/J/MNRAS/388/1537
- Title:
- Galaxy pairs from SDSS-DR2
- Short Name:
- J/MNRAS/388/1537
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the incidence of major mergers creating massive (M_star_>10^11^M_{sun}_) galaxies in present-day (z<=0.12) groups and clusters. Using a volume-limited sample of 845 groups with dark matter halo masses above 2.5x10^13^M_{sun}_, we isolate 221 galaxy pairs with <=1.5 r-band magnitude differences, <=30kpc projected separations and combined masses above 10^11^M_{sun}_. We fit the r-band images of each pair as the line-of-sight projection of symmetric models and identify 38 mergers by the presence of residual asymmetric structure associated with both progenitors, such as non-concentric isophotes, broad and diffuse tidal tails and dynamical friction wakes.
- ID:
- ivo://CDS.VizieR/J/MNRAS/236/207
- Title:
- Galaxy redshift catalogue
- Short Name:
- J/MNRAS/236/207
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present redshifts and blue magnitudes for a sample of 264 'field' galaxies virtually complete to a limiting magnitude of bj~=16.80mag. The galaxies were selected by sampling one galaxy in every three in order of apparent magnitude on each of nine high-latitude UK Schmidt (UKST) fields. Photometric data were provided by COSMOS machine measures of UKST plates, zero-pointed with CCD photometry. The spectral data came from observations with the 1.9-m telescope at the South African Astronomical Observatory (SAAO), and the resulting radial velocities have a precision of ~+/-130km/s. This survey augments substantially the Durham/AAT redshift survey. In this paper we discuss the observational techniques and reduction procedures.
137. Galaxy Redshifts
- ID:
- ivo://CDS.VizieR/VII/36
- Title:
- Galaxy Redshifts
- Short Name:
- VII/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Catalog of Galaxy Redshifts was compiled by Dr. Rood to enter the most accurate redshift for each entry in the Uppsala General Catalog of Galaxies below 15000 km/s, plus some fainter galaxies in the fields of rich clusters, plus some southern galaxies. The catalog is 99 percent complete for declinations north of -2.5deg and blue magnitude (Pmag) brighter than 13. The present documentation is mostly adapted from the "Documentation of the Machine-Readable Version of the Catalog of Galaxy Redshifts" by Theresa A. Nagy and Robert S. Hill, May 1981, prepared for NASA GSFC, Greenbelt, No SSD-T-5069-0013-81.
- ID:
- ivo://CDS.VizieR/J/MNRAS/243/390
- Title:
- Galaxy redshift survey in a Coma strip
- Short Name:
- J/MNRAS/243/390
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/PASP/125/2
- Title:
- Galaxy Zoo: A catalog of overlapping galaxy pairs
- Short Name:
- J/PASP/125/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Analysis of galaxies with overlapping images offers a direct way to probe the distribution of dust extinction and its effects on the background light. We present a catalog of 1990 such galaxy pairs selected from the Sloan Digital Sky Survey (SDSS) by volunteers of the Galaxy Zoo project. We highlight subsamples which are particularly useful for retrieving such properties of the dust distribution as UV extinction, the extent perpendicular to the disk plane, and extinction in the inner parts of disks. The sample spans wide ranges of morphology and surface brightness, opening up the possibility of using this technique to address systematic changes in dust extinction or distribution with galaxy type. This sample will form the basis for forthcoming work on the ranges of dust distributions in local disk galaxies, both for their astrophysical implications and as the low-redshift part of a study of the evolution of dust properties. Separate lists and figures show deep overlaps, where the inner regions of the foreground galaxy are backlit, and the relatively small number of previously-known overlapping pairs outside the SDSS DR7 sky coverage.
- ID:
- ivo://CDS.VizieR/J/MNRAS/449/4277
- Title:
- GAMA blended spectra catalogue
- Short Name:
- J/MNRAS/449/4277
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalogue of blended galaxy spectra from the Galaxy And Mass Assembly (GAMA) survey. These are cases where light from two galaxies are significantly detected in a single GAMA fibre. Galaxy pairs identified from their blended spectrum fall into two principal classes: they are either strong lenses, a passive galaxy lensing an emission-line galaxy; or occulting galaxies, serendipitous overlaps of two galaxies, of any type. Blended spectra can thus be used to reliably identify strong lenses for follow-up observations (high-resolution imaging) and occulting pairs, especially those that are a late-type partly obscuring an early-type galaxy which are of interest for the study of dust content of spiral and irregular galaxies. The GAMA survey setup and its AUTOZ automated redshift determination were used to identify candidate blended galaxy spectra from the cross-correlation peaks. We identify 280 blended spectra with a minimum velocity separation of 600km/s, of which 104 are lens pair candidates, 71 emission-line-passive pairs, 78 are pairs of emission-line galaxies and 27 are pairs of galaxies with passive spectra. We have visually inspected the candidates in the Sloan Digital Sky Survey (SDSS) and Kilo Degree Survey (KiDS) images. Many blended objects are ellipticals with blue fuzz (Ef in our classification). These latter 'Ef' classifications are candidates for possible strong lenses, massive ellipticals with an emission-line galaxy in one or more lensed images. The GAMA lens and occulting galaxy candidate samples are similar in size to those identified in the entire SDSS. This blended spectrum sample stands as a testament of the power of this highly complete, second-largest spectroscopic survey in existence and offers the possibility to expand e.g. strong gravitational lens surveys.
