- ID:
- ivo://CDS.VizieR/J/ApJ/864/123
- Title:
- Morphological parameters of galaxies with GALEX
- Short Name:
- J/ApJ/864/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Evolutionary studies that compare galaxy structure as a function of redshift are complicated by the fact that any particular galaxy's appearance depends in part on the rest-frame wavelength of the observation. This leads to the necessity for a "morphological k-correction" between different passbands, especially when comparing the rest-frame optical or infrared (IR) to the ultraviolet (UV). This is of particular concern for high-redshift studies that are conducted in the rest-frame UV. We investigate the effects of this "bandpass shifting" out of the UV by quantifying nearby galaxy structure via concentration, asymmetry, and clumpiness (CAS) parameters. For this study we combine panchromatic data from the UV through the near-IR with Galaxy Evolution Explorer (GALEX) data of 2073 nearby galaxies in the "near-UV" (NUV; ~230nm) and 1127 in the "far-UV" (FUV; ~150nm), providing the largest study of this kind in the mid- to far-UV. We find a relationship between the CAS parameters and observed rest-frame wavelength that make galaxies appear more late-type at shorter wavelengths, particularly in the UV. The effect is strongest for E/S0 galaxies in the far-UV, which have concentrations and asymmetries that more closely resemble those of spiral and peculiar/merging galaxies in the optical. This may be explained by extended disks containing recent star formation. Here, we also release the CAS values of the galaxies imaged in GALEX NUV and FUV for use in comparisons with deep Hubble Space Telescope imaging and the James Webb Space Telescope in the future.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/416/2415
- Title:
- Morphological parameters of WHISP galaxies
- Short Name:
- J/MNRAS/416/2415
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Lopsidedness of the gaseous disc of spiral galaxies is a common phenomenon in disc morphology, profile and kinematics. Simultaneously, the asymmetry of a galaxy's stellar disc, in combination with other morphological parameters, has seen extensive use as an indication of recent merger or interaction in galaxy samples. Quantified morphology of stellar spiral discs is one avenue to determine the merger rate over much of the age of the Universe. In this paper, we measure the quantitative morphology parameters for the HI column density maps from the Westerbork observations of neutral Hydrogen in Irregular and SPiral galaxies (WHISP). These are Concentration, Asymmetry, Smoothness, Gini, M20 and one addition of our own, the Gini parameter of the second-order moment (GM). Our aim is to determine if lopsided or interacting discs can be identified with these parameters. Our sample of 141 HI maps have all previous classifications on their lopsidedness and interaction.
- ID:
- ivo://CDS.VizieR/VII/174
- Title:
- Morphological type catalog in 55 rich galaxy clusters
- Short Name:
- VII/174
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Data are presented from a study of 55 rich clusters of galaxies. The data include positions, morphological types, estimated total magnitudes, bulge sizes, and ellipticities for ~6000 galaxies, as determined from high scale photographic plates. data reduction procedures are described, and a brief analysis of cluster richness, which indicates that Abell richness classes are only rough indicators of total cluster membership, is included.
- ID:
- ivo://CDS.VizieR/J/MNRAS/435/2835
- Title:
- Morphological types from Galaxy Zoo 2
- Short Name:
- J/MNRAS/435/2835
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the data release for Galaxy Zoo 2 (GZ2), a citizen science project with more than 16 million morphological classifications of 304122 galaxies drawn from the Sloan Digital Sky Survey (SDSS). Morphology is a powerful probe for quantifying a galaxy's dynamical history; however, automatic classifications of morphology (either by computer analysis of images or by using other physical parameters as proxies) still have drawbacks when compared to visual inspection. The large number of images available in current surveys makes visual inspection of each galaxy impractical for individual astronomers. GZ2 uses classifications from volunteer citizen scientists to measure morphologies for all galaxies in the DR7 Legacy survey with m_r_>17, in addition to deeper images from SDSS Stripe 82. While the original GZ2 project identified galaxies as early-types, late-types or mergers, GZ2 measures finer morphological features. These include bars, bulges and the shapes of edge-on discs, as well as quantifying the relative strengths of galactic bulges and spiral arms. This paper presents the full public data release for the project, including measures of accuracy and bias. The majority (>90 per cent) of GZ2 classifications agree with those made by professional astronomers, especially for morphological T-types, strong bars and arm curvature. Both the raw and reduced data products can be obtained in electronic format at http://data.galaxyzoo.org .
- ID:
- ivo://CDS.VizieR/J/MNRAS/410/166
- Title:
- Morphological types from Galaxy Zoo 1
- Short Name:
- J/MNRAS/410/166
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Morphology is a powerful indicator of a galaxy's dynamical and merger history. It is strongly correlated with many physical parameters, including mass, star formation history and the distribution of mass. The Galaxy Zoo project collected simple morphological classifications of nearly 900000 galaxies drawn from the Sloan Digital Sky Survey, contributed by hundreds of thousands of volunteers. This large number of classifications allows us to exclude classifier error, and measure the influence of subtle biases inherent in morphological classification. This paper presents the data collected by the project, alongside measures of classification accuracy and bias. The data are now publicly available and full catalogues can be downloaded in electronic format from http://data.galaxyzoo.org .
- ID:
- ivo://CDS.VizieR/J/ApJ/542/673
- Title:
- Morphological types of galaxies in clusters
- Short Name:
- J/ApJ/542/673
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The morphological types of galaxies in nine clusters in the redshift range 0.1<~z<~0.25 are derived from very good seeing images taken at the North Optical Telescope (NOT) and the La Silla-Danish telescopes, with all galaxies at M_V_<-20 and within the central ~1Mpc^2^ area being classified. With the purpose of investigating the evolution of the fraction of different morphological types with redshift, we compare our results with the morphological content of nine distant clusters studied by the MORPHS group, five clusters observed with HST/WFPC2 at redshift z=0.2-0.3, and Dressler's large sample of nearby clusters.
- ID:
- ivo://CDS.VizieR/J/MNRAS/376/125
- Title:
- Morphologies and photometry in A2218
- Short Name:
- J/MNRAS/376/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the stellar populations and morphologies of galaxies in the core of the galaxy cluster Abell 2218. Integral field spectroscopy (IFS) observations were performed using PMAS in the PPAK mode covering a field of view of ~74x64arcsec^2^ centred on the core of the cluster, in order to obtain spectroscopy of an unbiased flux-limited sample of cluster galaxies. 43 objects were detected in the IFS data, 31 of them with enough signal-to-noise ratio to derive the redshift, all of them brighter than I<21.5mag. 28 are at the redshift of the cluster (17 with previously unknown redshift). Individual spectra of the cluster members were extracted and compared with single stellar population models to derive the luminosity-weighted ages and metallicities. In addition, deep Hubble Space Telescope (HST)/ACS F475W-, F555W-, F625W- and F850LP-band images centred on the cluster core were obtained from the HST archive (zlim~28mag). A detailed morphological analysis of all the galaxies within the field of view of these images down to zlim<22.5mag was performed classifying them as late-type, intermediate and early-type, on the basis of their Sersic indices. The literature was scanned to look for spectroscopically confirmed cluster members located within the field of view of the ACS image. The final sample of 59 galaxies comprises our reported sample of 28 galaxies in the core, and 31 additional galaxies in the outer regions. In addition, multiband broad-band photometry was extracted from the literature for all objects.
- ID:
- ivo://CDS.VizieR/J/A+A/453/923
- Title:
- Morphologies in the Cepheus Flare region
- Short Name:
- J/A+A/453/923
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- These tables contain the data of the cloud sample on which the study of the relationships between cloud morphology, optical and IR properties, and star formation is based. The sample was defined using the extinction map of the Cepheus Flare region covering ~256 square degrees created from the B band star counts of the USNO-A2.0 catalogue (Cat. <I/252>) with a typical resolution of 3 arcminutes on a 1.5 arcminute grid. Cloud definition and description was carried out using automatized methods. The main table lists the positions, peak extinctions, sizes, morphological parameters and classes, distances, mass estimations, parent cloud complexes, and the number of YSO candidates associated. An additional table with the names of the previously catalogued associated clouds and their references is also available.
- ID:
- ivo://CDS.VizieR/J/ApJS/107/1
- Title:
- Morphologies of distant galaxies II
- Short Name:
- J/ApJS/107/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The morphological properties of high-redshift galaxies are investigated using a sample of 507 objects (I<22.0mag) from the Hubble Space Telescope (HST) Medium Deep Survey. Independent visual morphological classifications for each galaxy are used to quantify the statistical uncertainties in the galaxy classifications. Visual classifications are found to agree well for I<21mag. Fainter than I=21mag significant disagreements are seen in the independent visual classifications of late-type systems with T>7, merging systems, and peculiar galaxies. The classifications of these systems are shown to be somewhat subjective. Objective classifications based upon measurements of central concentration and asymmetry for the Medium Deep Survey sample are presented. These classifications are calibrated using measurements of structural parameters for an artificially redshifted sample of local objects. Morphologically segregated number counts using both sets of visual classifications and objective classifications support the conclusion that the observed galaxy counts agree with no-evolution predictions for the elliptical and spiral populations, as reported in Glazebrook et al. (1995MNRAS.275L..19G). A major conclusion is that the large overdensity of merging/ peculiar/ irregular galaxies relative to the predictions of no-evolution models (reported by Glazebrook et al. 1995MNRAS.275L..19G) is confirmed. However, the shape of the faint-end (I>21.0mag) number count relation for peculiar objects is sensitive to the large systematic uncertainties inherent in the visual classification of these objects. Despite this caveat, the frequency of objects showing clear evidence for tidal interactions (e.g., tidal tails) in the HST sample is at least 50% larger than it is among nearby galaxies, at the 2{sigma} level. Relatively few "chain galaxies" are seen among the sample of peculiar objects, suggesting that these systems do not form a large component of the peculiar galaxy population at I<22mag.
- ID:
- ivo://CDS.VizieR/J/AJ/140/533
- Title:
- Morphologies of selected AGN
- Short Name:
- J/AJ/140/533
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the optical morphologies of candidate active galaxies identified at radio, X-ray, and mid-infrared wavelengths. We use the Advanced Camera for Surveys General Catalog (ACS-GC) to identify 372, 1360, and 1238 active galactic nucleus (AGN) host galaxies from Very Large Array, XMM-Newton, and Spitzer Space Telescope observations of the COSMOS field, respectively. We investigate both quantitative (GALFIT) and qualitative (visual) morphologies of these AGN host galaxies, split by brightness in their selection band.
