- ID:
- ivo://CDS.VizieR/J/other/RAA/19.127
- Title:
- C- and S-shaped radio galaxies
- Short Name:
- J/other/RAA/19.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the environment of radio galaxies with different morphological types using the Proctor sample, which was built from the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey archive. Among the 15 radio galaxy types classified by Proctor, 199 C-shaped (i.e., wide- or narrow-angle tail) and 203 S-shaped (i.e., S- or Z-shaped) sources are selected in this work, which are located in the redshift range of 0.02<z<1, because these two subsamples are relatively larger than the other subsamples in the Proctor sample. By cross-matching these radio galaxies with the optical sources drawn from the Sloan Digital Sky Survey (SDSS) database and counting the SDSS sources with an r-band absolute magnitude brighter than -19 located within a 0.5Mpc distance around each source (i.e., the richness), we find that the fraction of C-shaped sources with a richness above 10 is larger than that of S-shaped sources. We have also correlated the radio galaxies in our sample with the brightest cluster galaxies (BCGs) defined in the NASA/IPAC Extragalactic Database (NED), and infer that the C-shaped sources are more likely to be BCGs than the S-shaped sources. These results support the idea that C-shaped radio galaxies often reside in a richer environment than radio galaxies with other morphological types.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/862/100
- Title:
- Carnegie-Irvine Galaxy Survey VII. S0 galaxies
- Short Name:
- J/ApJ/862/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using high-quality optical images from the Carnegie-Irvine Galaxy Survey, we perform multicomponent decompositions of S0 galaxies (S0s) to derive accurate structural parameters to constrain their physical origin. Many S0s do not host prominent bulges. S0s have a broad distribution of bulge-to-total ratios (B/T) and Sersic indices (n), with average values of B/T=0.34+/-0.15 and n=2.62+/-1.02, qualitatively consistent with the notion that S0s define a parallel sequence with and may have evolved from spiral galaxies. This is further reinforced by the incidence of bars and lenses in S0s, which, when compared with the statistics in spirals, supports the idea that lenses are demised bars. However, despite their wide range of prominence, the bulges of S0s form a surprisingly uniform sequence on both the Kormendy and fundamental plane relations. There is no evidence for population dichotomy or other indications of differentiation into classical and pseudo bulges. Most of the S0s reside in the field and in groups; cluster environment is not a necessary condition for S0 production. The properties of S0 bulges show little correlation with environmental indicators, after the dependence of galaxy stellar mass on environment is taken into account. As the bulges of late-type spirals and S0s are intrinsically different, and environmental effects that may account for such evolution appear to be minimal, we conclude that late- type spirals are not plausible progenitors of S0s. The bulges of S0s likely formed at an early epoch, after which secular processes contributed little to their subsequent evolution.
- ID:
- ivo://CDS.VizieR/J/ApJ/659/162
- Title:
- CAS parameters of 199 nearby galaxies
- Short Name:
- J/ApJ/659/162
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a quantitative analysis of the morphologies for 199 nearby galaxies as parameterized with measurements of the concentration, asymmetry, and clumpiness (CAS) parameters at wavelengths from 0.15 to 0.85um. We find that these CAS parameters depend on both galaxy type and the wavelength of observation. As such, we use them to obtain a quantitative measure of the "morphological k-correction", i.e., the change in appearance of a galaxy with rest-frame wavelength.
- ID:
- ivo://CDS.VizieR/J/ApJ/744/82
- Title:
- Catalog of cosmic voids from the SDSS-DR7
- Short Name:
- J/ApJ/744/82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a large sample of galaxies from the the seventh data release of the Sloan Digital Sky Survey (SDSS-DR7), we have analyzed the alignment of disk galaxies around cosmic voids. We have constructed a complete sample of cosmic voids (devoid of galaxies brighter than M_r_-5log h=-20.17) with radii larger than 10h^-1^Mpc up to redshift 0.12. Disk galaxies in shells around these voids have been used to look for particular alignments between the angular momentum of the galaxies and the radial direction of the voids. We find that disk galaxies around voids larger than >~15h^-1^Mpc within distances not much larger than 5h^-1^Mpc from the surface of the voids present a significant tendency to have their angular momenta aligned with the void's radial direction with a significance >~98.8% against the null hypothesis. The strength of this alignment is dependent on the void's radius and for voids with a radius >~15h^-1^Mpc the distribution of the orientation of the galaxies is compatible with a random distribution. Finally, we find that this trend observed in the alignment of galaxies is similar to the one observed for the minor axis of dark matter halos around cosmic voids found in cosmological simulations, suggesting a possible link in the evolution of both components.
- ID:
- ivo://CDS.VizieR/J/AJ/128/62
- Title:
- Catalog of double nucleus disk galaxies
- Short Name:
- J/AJ/128/62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled a catalog of disk galaxies that have a double nucleus, through systematic examination of existing catalogs and publications. The Catalog of Double Nucleus Disk Galaxies includes 107 objects, together with their basic data. The aim of the catalog is to provide a more systematic and homogeneous basis for the study of the relevance of galaxy interactions and minor mergers in the formation of these double nuclei. We have also investigated possible correlations between geometric and photometric parameters of the double nuclei and their host galaxies. The preliminary results indicate the presence of several significant correlations that should be considered in any theoretical scenario describing minor mergers and disk galaxy evolution
- ID:
- ivo://CDS.VizieR/J/ApJS/157/228
- Title:
- Catalog of galaxy morphology in four clusters
- Short Name:
- J/ApJS/157/228
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Hubble Space Telescope (HST) imaging of four rich, X-ray-luminous, galaxy clusters (0.33<z<0.83) is used to produce quantitative morphological measurements for galaxies in their fields. Catalogs of these measurements are presented for 1642 galaxies brighter than F814W(AB)=23.0. Galaxy luminosity profiles are fitted with three models: exponential disk, de Vaucouleurs bulge, and a disk-plus-bulge hybrid model. The best fit is selected and produces a quantitative assessment of the morphology of each galaxy: the principal parameters derived being B/T, the ratio of bulge to total luminosity, the scale lengths and half-light radii, axial ratios, position angles, and surface brightnesses of each component. Cluster membership is determined using a statistical correction for field galaxy contamination, and a mass normalization factor (mass within boundaries of the observed fields) is derived for each cluster. Morphological classes are defined using B/T: disk galaxies have 0<=B/T<=0.4, intermediate galaxies 0.4<B/T<0.8, and bulge-dominated galaxies have 0.8<=B/T<=1.
- ID:
- ivo://CDS.VizieR/J/other/JAD/12.1
- Title:
- Catalog of galaxy structures based on the MRSS
- Short Name:
- J/other/JAD/12.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of galaxy structures (groups and clusters) found in an area of 5000 square degrees in the southern hemisphere. The catalogue, which we call the PF Catalogue, was created by making use of galaxy positions and magnitudes given in the Muenster Red Sky Survey (MRSS, 2003JAD.....9....1U). We applied an automated procedure for structure finding, involving the Voronoi tessellation. The completeness limit for galaxies in the MRSS is r_F_=18.3m. Therefore, the present version of the PF Catalogue is based on galaxies brighter than this limit. In order to be included in the PF Catalogue, a structure must have at least 10 members in a magnitude range m_3_, m_3_+3^m^. We found 6188 structures which are listed in the present catalogue. The PF Catalogue contains positions, radii, areas, number of galaxies within the magnitude limit m_3_, m_3_+3^m^, a number estimation of background galaxies; ellipticity and position angle for each structure, as well as the magnitudes of the first, the third and the tenth galaxies in a structure, taken from the MRSS.
- ID:
- ivo://CDS.VizieR/J/PASP/132/E4301
- Title:
- Catalog of Infrared Dark Clouds
- Short Name:
- J/PASP/132/E4301
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The field of computer vision has greatly matured in the past decade, and many of the methods and techniques can be useful for astronomical applications. One example is in searching large imaging surveys for objects of interest, especially when it is difficult to specify the characteristics of the objects being searched for. We have developed a method using contour finding and convolution neural networks (CNNs) to search for Infrared Dark Clouds (IRDCs) in the Spitzer Galactic plane survey data. IRDCs can vary in size, shape, orientation, and optical depth, and are often located near regions with complex emission from molecular clouds and star formation, which can make the IRDCs difficult to reliably identify. False positives can occur in regions where emission is absent, rather than from a foreground IRDC. The contour finding algorithm we implemented found most closed figures in the mosaic and we developed rules to filter out some of the false positive before allowing the CNNs to analyze them. The method was applied to the Spitzer data in the Galactic plane surveys, and we have constructed a catalog of IRDCs which includes additional parts of the Galactic plane that were not included in earlier surveys.
- ID:
- ivo://CDS.VizieR/J/AJ/147/106
- Title:
- Catalog of member galaxies in A2319
- Short Name:
- J/AJ/147/106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Asymmetric X-ray emission and a powerful cluster-scale radio halo indicate that A2319 is a merging cluster of galaxies. This paper presents our multicolor photometry for A2319 with 15 optical intermediate filters in the Beijing-Arizona-Taiwan-Connecticut (BATC) system. There are 142 galaxies with known spectroscopic redshifts within the viewing field of 58'x58' centered on this rich cluster, including 128 member galaxies (called sample I). A large velocity dispersion in the rest frame, 1622_-70_^+91^km/s, suggests merger dynamics in A2319. The contour map of projected density and localized velocity structure confirm the so-called A2319B substructure, at ~10' northwest to the main concentration A2319A. The spectral energy distributions (SEDs) of more than 30000 sources are obtained in our BATC photometry down to V~20mag. A u-band (~3551{AA}) image with better seeing and spatial resolution, obtained with the Bok 2.3m telescope at Kitt Peak, is taken to make star-galaxy separation and distinguish the overlapping contamination in the BATC aperture photometry. With color-color diagrams and photometric redshift technique, 233 galaxies brighter than h_BATC_=19.0 are newly selected as member candidates after an exclusion of false candidates with contaminated BATC SEDs by eyeball-checking the u-band Bok image. The early-type galaxies are found to follow a tight color-magnitude correlation. Based on sample I and the enlarged sample of member galaxies (called sample II), subcluster A2319B is confirmed. The star formation properties of cluster galaxies are derived with the evolutionary synthesis model, PEGASE, assuming a Salpeter initial mass function and an exponentially decreasing star formation rate (SFR). A strong environmental effect on star formation histories is found in the manner that galaxies in the sparse regions have various star formation histories, while galaxies in the dense regions are found to have shorter SFR time scales, older stellar ages, and higher interstellar medium metallicities. For the merging cluster A2319, local surface density is a better environmental indicator rather than the cluster-centric distance. Compared with the well-relaxed cluster A2589, a higher fraction of star-forming galaxies is found in A2319, indicating that the galaxy-scale turbulence stimulated by the subcluster merger might have played a role in triggering the star formation activity.
- ID:
- ivo://CDS.VizieR/J/ApJS/181/233
- Title:
- Catalog of merging galaxies
- Short Name:
- J/ApJS/181/233
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new catalog and images of interacting and merging galaxies obtained with morphological identification from Canada-France-Hawaii Telescope observations. We first used a morphological pattern recognition searching routine to select possible candidates, and then visually inspected the images of these candidates to identify true merging/interacting sources. We discover 15147 new pairs of merging galaxies within 422deg^2^ of Red Sequence Cluster Survey 2. Furthermore, we also find nine new candidates of galaxy clusters by searching for regions with significant density enhancements of merging galaxies. This catalog has the largest number of morphologically identified interacting and merging galaxies based on consistent searching criteria. These sources provide a uniform sample of merging galaxies for further photometric and spectroscopic studies of galaxy evolution.
