- ID:
- ivo://CDS.VizieR/J/ApJ/862/13
- Title:
- The Carnegie-Irvine Galaxy Survey. VI. Spirals
- Short Name:
- J/ApJ/862/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Carnegie-Irvine Galaxy Survey provides high-quality broadband optical images of a large sample of nearby galaxies for detailed study of their structure. To probe the physical nature and possible cosmological evolution of spiral arms, a common feature of many disk galaxies, it is important to quantify their main characteristics. We describe robust methods to measure the number of arms and their mean strength, length, and pitch angle. The arm strength depends only weakly on the adopted radii over which it is measured, and it is stronger in bluer bands than redder bands. The vast majority of clearly two-armed ("grand-design") spiral galaxies have a systematically higher relative amplitude of the m=2 Fourier mode in the main spiral region. We use both one-dimensional and two-dimensional Fourier decomposition to measure the pitch angle, finding reasonable agreement between these two techniques with a scatter of ~2{deg}. To understand the applicability and limitations of our methodology to imaging surveys of local and distant galaxies, we create mock images with properties resembling observations of local (z<~0.1) galaxies by the Sloan Digital Sky Survey and distant galaxies (0.1<~z<~1.1) observed with the Hubble Space Telescope. These simulations lay the foundation for forthcoming quantitative statistical studies of spiral structure to understand its formation mechanism, dependence on galaxy properties, and cosmological evolution.
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- ID:
- ivo://CDS.VizieR/II/365
- Title:
- The CatWISE2020 catalog (updated version 28-Jan-2021)
- Short Name:
- II/365
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CatWISE2020 Catalog consists of 1,890,715,640 sources over the entire sky selected from WISE and NEOWISE survey data at 3.4 and 4.6um (W1 and W2) collected from 2010 Jan 7 to 2018 Dec 13. This dataset adds two years to that used for the CatWISE Preliminary Catalog (Eisenhardt+ 2020ApJS..247...69E), bringing the total to six times as many exposures spanning over sixteen times as large a time baseline as the AllWISE catalog. The other major change from the CatWISE Preliminary Catalog is that the detection list for CatWISE2020 was generated using "crowdsource" software (Schlafly+ 2019ApJS..240...30S), while the Preliminary Catalog used the detection software used for AllWISE (II/328). These two factors result in roughly twice as many sources in CatWISE2020. The scatter with respect to Spitzer photometry at faint magnitudes in the COSMOS field, which is out of the Galactic plane and at low ecliptic latitude (corresponding to lower WISE coverage depth) is similar to that for the CatWISE Preliminary Catalog. The 90% completeness depth for CatWISE2020 is at roughly W1=17.7 and W2=17.5, about 1.7 mag deeper than in the Preliminary Catalog. From comparison to Gaia, CatWISE2020 motions are over a dozen times more accurate than those from AllWISE.
- ID:
- ivo://CDS.VizieR/J/A+AS/124/1
- Title:
- The Centaurus Cluster Catalogue
- Short Name:
- J/A+AS/124/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The central region of the Centaurus cluster was surveyed on a film copy of a high-resolution photographic Las Campanas duPont plate. A large number of cluster galaxy candidates were identified down to a limiting magnitude of 21.5 in B. Between cluster members and background objects were distinguished by applying morphological criteria. Following the morphological classification of each member, the images of all 296 cluster galaxies on a SERC deep-blue sky survey plate were digitized, processed and analysed with the image processing package MIDAS. We established total apparent B-magnitude and other structure parameters for each cluster galaxy which are listed in the Centaurus Cluster Catalogue.
- ID:
- ivo://CDS.VizieR/J/A+AS/134/59
- Title:
- The central Fornax Cluster. I. Galaxy photometry
- Short Name:
- J/A+AS/134/59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, a photometric catalog is presented of V and I photometry of galaxies in the central regions of the Fornax galaxy cluster. Our 11 CCD fields cover 0.17 square degrees in total. The limiting surface brightness is around 24mag/arcsec^2^, similar to that of Ferguson's (1989, Cat. <VII/180>) catalog, whereas our limiting total magnitude is around V=22mag, about two magnitudes fainter. The photometric properties of more than 870 objects are presented as a catalog (Appendix A). The properties and fit parameters of the surface brightness profiles for a sub-sample are presented in a second catalog (Appendix B). Four new dwarf galaxies are added to Ferguson's catalog. However, we confirm that the dwarf galaxies in Fornax follow a similar surface brightness -- magnitude relation as the Local Group dwarfs. They also follow the color (metallicity) -- magnitude relation seen in other galaxy clusters. A formerly suspected excess of dwarf galaxies surrounding the central giant cD galaxy NGC 1399 can be explained by the superposition of a background cluster at z=0.11 (Hilker et al. 1998, Cat. <J/A+AS/134/75>, Paper II in this series).
- ID:
- ivo://CDS.VizieR/J/ApJS/185/198
- Title:
- The Cepheus flare observed with IRAC and MIPS
- Short Name:
- J/ApJS/185/198
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Spitzer Infrared Array Camera (IRAC; ~2deg^2^) and Multiband Imaging Photometer for Spitzer (MIPS; ~8deg^2^) observations of the Cepheus Flare, which is associated with the Gould Belt, at an approximate distance of ~300pc. Around 6500 sources are detected in all four IRAC bands, of which ~900 have MIPS 24um detections. We identify 133 young stellar object (YSO) candidates using color-magnitude diagram techniques, and a large number of the YSO candidates are associated with the NGC 7023 reflection nebula. Cross-identifications were made with the Guide Star Catalog II and the IRAS Faint Source Catalog, and spectral energy distributions (SEDs) were constructed. SED modeling was conducted to estimate the degree of infrared excess. It was found that a large majority of disks were optically thick accreting disks, suggesting that there has been little disk evolution in these sources. Nearest-neighbor clustering analysis identified four small protostellar groups (L1228, L1228N, L1251A, and L1251B) with 5-15 members each and the larger NGC 7023 association with 32 YSO members. The star-formation efficiency for cores with clusters of protostars and for those without clusters was found to be ~8% and ~1%, respectively. The cores L1155, L1241, and L1247 are confirmed to be starless down to our luminosity limit of L_bol_=0.06L_{sun}_.
- ID:
- ivo://CDS.VizieR/II/317
- Title:
- The CFHTLS Survey (T0007 release)
- Short Name:
- II/317
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Canada and France joined a large fraction (~50%) of their dark and grey telescope time from mid-2003 to early 2009 for a large project, the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). The data acquisition and calibration has been a major undertaking for the Canadian and French communities: more than 2300 hours over 5 years (an equivalent of 450 nights) have been devoted to the survey using the wide field optical imaging camera MegaCam, a 1{deg}x1{deg} field of view 340 Megapixel camera. The CFHTLS comprises 2 components: "CFHTLS Deep", 4 independent 1deg^2^ MegaCam pointing, and "CFHT Wide" comprising 171 MegaCam pointings covering ~155deg^2^ in 4 contiguous independent patches. All areas are located far from the galactic plane, and their central positions are: -------------------------------------------------- Field RA (J2000) Dec Galactic position -------------------------------------------------- W1 02:18 -07:00 172.468 -61.242 W2 08:54 -04:15 232.067 +24.743 W3 14:17:54 +54:30:31 098.850 +58.390 W4 22:13:18 +01:19 063.243 -42.511 D1 02:25:59 -04:29:40 171.993 -58.054 D2 10:00:28 +02:23:30 236.616 +42.227 D3 14:19:27 +52:40:56 096.227 +59.642 D4 22:15:31 -17:43:56 039.271 -52.925 -------------------------------------------------- This final release of the CFHTLS benefits greatly from vastly improved flat-fielding and photometric calibration techniques developed by the Supernovae Legacy Survey (SNLS) team and CFHT which allows us to significantly improve the precision of our photometric calibration compared to previous releases. The astrometric accuracy reaches 0.02arcsec internal and 0.2arcsec external. The set of filters used for the survey are close to the SDSS filter set; their characteristics and a comparison to SDSS can be found at http://www3.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/megapipe/docs/filters.html Please ee the documentation file "T0007-doc.pdf" for details concerning this T0007 release.
- ID:
- ivo://CDS.VizieR/J/ApJ/821/114
- Title:
- The CGS. IV. Elliptical galaxies colors
- Short Name:
- J/ApJ/821/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Many recent observations and numerical simulations suggest that nearby massive, early-type galaxies (ETGs) were formed through a "two-phase" process. In the proposed second phase, the extended stellar envelope was accumulated through many dry mergers. However, details of the past merger history of present-day ellipticals, such as the typical merger mass ratio, are difficult to constrain observationally. Within the context and assumptions of the two-phase formation scenario, we propose a straightforward method, using photometric data alone, to estimate the average mass ratio of mergers that contributed to the build-up of massive elliptical galaxies. We study a sample of nearby massive elliptical galaxies selected from the Carnegie-Irvine Galaxy Survey, using two-dimensional analysis to decompose their light distribution into an inner, denser component plus an extended, outer envelope, each having a different optical color. The combination of these two substructures accurately recovers the negative color gradient exhibited by the galaxy as whole. The color difference between the two components (<{Delta}(B-V)>~0.10mag; <{Delta}(B-R)>~0.14mag), based on the slope of the M*-color relation for nearby ETGs, can be translated into an estimate of the average mass ratio of the mergers. The rough estimate, 1:5 to 1:10, is consistent with the expectation of the two-phase formation scenario, suggesting that minor mergers were largely responsible for building up the outer stellar envelopes of present-day massive ellipticals. With the help of accurate photometry, large sample sizes and more choices of colors promised by ongoing and future surveys, the approach proposed here can provide more insights into the growth of massive galaxies during the last few Gyr.
- ID:
- ivo://CDS.VizieR/J/ApJS/247/20
- Title:
- The CGS. IX. R-band single-Sersic fits to ellipticals
- Short Name:
- J/ApJS/247/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the statistical properties of 320 bulges of disk galaxies in the Carnegie-Irvine Galaxy Survey, using robust structural parameters of galaxies derived from image fitting. We apply the Kormendy relation to classify classical and pseudo bulges and characterize the bulge dichotomy with respect to the structural properties of the bulges and the physical properties of the host galaxies. We confirm previous findings that pseudo bulges on average have smaller Sersic indices, lower bulge-to-total ratios, and fainter surface brightnesses than classical bulges. Our sizable sample statistically shows that pseudo bulges are more intrinsically flattened than classical bulges. Pseudo bulges are most frequent (incidence >~80%) in late-type spirals (later than Sc). Our measurements support the picture in which pseudo bulges arose from star formation induced by inflowing gas, while classical bulges were born out of violent processes such as mergers and coalescence of clumps. We reveal differences with the literature that warrant attention: (1) the bimodal distribution of Sersic indices presented by previous studies is not reproduced in our study; (2) classical and pseudo bulges have similar relative bulge sizes; and (3) the pseudo bulge fraction is considerably smaller in early-type disks than reported in previous studies based on one-dimensional surface brightness profile fitting. We attribute these differences to our improved image quality, more robust bulge-to-disk decomposition technique, and to the different classification criteria that we applied. Moreover, we find that barred galaxies do not host more pseudo bulges or more prominent pseudo bulges than unbarred galaxies. Various implications of these findings are discussed.
- ID:
- ivo://CDS.VizieR/J/ApJS/244/34
- Title:
- The CGS. VIII. R-band images of disk galaxies
- Short Name:
- J/ApJS/244/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present multicomponent decomposition of high-quality R-band images of 320 disk galaxies from the Carnegie-Irvine Galaxy Survey. In addition to bulges and disks, we successfully model nuclei, bars, disk breaks, nuclear/inner lenses, and inner rings. Our modeling strategy treats nuclear rings and nuclear bars as part of the bulge component, while other features such as spiral arms, outer lenses, and outer rings are omitted from the fits because they are not crucial for accurate bulge measurements. The error budget of bulge parameters includes the uncertainties from sky-level measurements and model assumptions. Comparison with multicomponent decomposition from the Spitzer Survey of Stellar Structure in Galaxies reveals broad agreement for the majority of the overlapping galaxies, but for a considerable fraction of galaxies there are significant differences in bulge parameters caused by different strategies in model construction. We confirm that on average bulge prominence decreases from early- to late-type disk galaxies, although the large scatter of bulge-to-total ratios in each morphological bin limits the application of Hubble type as an accurate predictor of bulge-to-total ratio. In contrast with previous studies claiming that barred galaxies host weaker bulges, we find that barred and unbarred spiral galaxies have similar bulge prominence.
- ID:
- ivo://CDS.VizieR/J/ApJS/201/30
- Title:
- The Chandra COSMOS survey. III.
- Short Name:
- J/ApJS/201/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8Ms, Chandra program that has imaged the central 0.9deg^2^ of the COSMOS field down to limiting depths of 1.9x10^-16^erg/cm^2^/s in the soft (0.5-2keV) band, 7.3x10^-16^erg/cm^2^/s in the hard (2-10keV) band, and 5.7x10^-16^erg/cm^2^/s in the full (0.5-10keV) band. In this paper we report the i, K, and 3.6um identifications of the 1761 X-ray point sources. We use the likelihood ratio technique to derive the association of optical/infrared counterparts for 97% of the X-ray sources. For most of the remaining 3%, the presence of multiple counterparts or the faintness of the possible counterpart prevented a unique association. For only 10 X-ray sources we were not able to associate a counterpart, mostly due to the presence of a very bright field source close by. Only two sources are truly empty fields. The full catalog, including spectroscopic and photometric redshifts and classification described here in detail, is available online.