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2372. Morphology of galaxies
- ID:
- ivo://CDS.VizieR/J/AJ/131/143
- Title:
- Morphology of galaxies
- Short Name:
- J/AJ/131/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comparison of late-type galaxies (Sa and later) in intermediate-redshift clusters and in the field using images from the Advanced Camera for Surveys aboard the Hubble Space Telescope. Cluster and field galaxies are selected by matching photometric and spectroscopic catalogs of four cluster fields: Cl 0152-1357, Cl 1056-0337 (MS 1054), Cl 1604+4304, and Cl 1604+4321. Concentration, asymmetry, and clumpiness parameters are calculated for each galaxy in blue (F606W or F625W) and red (F775W or F814W) filters. Galaxy half-light radii, disk scale lengths, color gradients, and overall color are compared.
- ID:
- ivo://CDS.VizieR/J/ApJ/602/664
- Title:
- Morphology of galaxies in Coma cluster core
- Short Name:
- J/ApJ/602/664
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a quantitative morphological analysis of 187 galaxies in a region covering the central 0.28deg^2^ of the Coma Cluster. Structural parameters from the best-fitting Sersic r^1/n^ bulge plus, where appropriate, exponential disk model, are tabulated here. This sample is complete down to a magnitude of R=17mag. By examining the recent compilation by Edwards et al. (2002ApJ...567..178E) of galaxy redshifts in the direction of Coma, we find that 163 of the 187 galaxies are Coma Cluster members and that the rest are foreground and background objects. For the Coma Cluster members, we have studied differences in the structural and kinematic properties between early- and late-type galaxies and between the dwarf and giant galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/490/923
- Title:
- Morphology of galaxies in Coma cluster direction
- Short Name:
- J/A+A/490/923
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents morphological type, membership and U-V colour for a sample of galaxies in the Coma cluster direction, complete down to M_B_=-15.00mag and extending down to M_B_=-14.25mag. We have examined 1155 objects from the GMP 1983 catalogue on B and V images of the CFH12K camera, and obtained the Hubble type in most cases. Coma cluster membership for 473 galaxies has been derived using morphology, apparent size and surface brightness, and, afterward, redshift. The comparison between morphology- and redshift- memberships and of luminosity functions derived from this morphologically-selected sample, or using statistical members or spectroscopic members, both show that the morphological membership provided here can be trusted. For the first time the morphological classification of Coma galaxies reaches faint enough magnitudes to observe the whole magnitude range of the giant types, E, S0 and spiral stages. The data presented in this paper makes our sample the richest environment where membership and morphology for complete samples down to faint magnitudes (M_B_~-15mag) are available, hence enlarging the baseline of environmental studies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/420/926
- Title:
- Morphology of galaxies in WINGS clusters
- Short Name:
- J/MNRAS/420/926
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the morphological catalog of galaxies in nearby clusters of the WINGS survey (Fasano et al., 2006A&A...445..805F). The catalog contains a total number of 39923 galaxies, for which we provide the automatic estimates of the morphological type applying the purposely devised tool MORPHOT to the V-band WINGS imaging. For ~3000 galaxies we also provide visual estimates of the morphological types. A substantial part of the paper is devoted to the description of the MORPHOT tool, whose application is limited, at least for the moment, to the WINGS imaging only. The approach of the tool to the automation of morphological classification is a non parametric and fully empirical one. In particular, MORPHOT exploits 21 morphological diagnostics, directly and easily computable from the galaxy image, to provide two independent classifications: one based on a Maximum Likelihood (ML), semi-analytical technique, the other one on a Neural Network (NN) machine. A suitably selected sample of ~1000 visually classified WINGS galaxies is used to calibrate the diagnostics for the ML estimator and as a training set in the NN machine. The final morphological estimator combines the two techniques and proves to be effective both when applied to an additional test sample of ~1000 visually classified WINGS galaxies and when compared with small samples of SDSS galaxies visually classified by Fukugita et al. (2007, Cat. J/AJ/134/579) and Nair et al. (2010, Cat. J/ApJS/186/427). Finally, besides the galaxy morphology distribution (corrected for field contamination) in the WINGS clusters, we present the ellipticity, color (B-V) and Sersic index (n) distributions for different morphological types, as well as the morphological fractions as a function of the clustercentric distance (in units of R200).
- ID:
- ivo://CDS.VizieR/J/ApJS/125/349
- Title:
- Morphology of 12micron Seyfert Galaxies
- Short Name:
- J/ApJS/125/349
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 263 optical and near-infrared (NIR) images for 42 1s and 48 Seyfert 2s, selected from the Extended 12{mu}m Galaxy Sample. Elliptically averaged profiles are derived from the images, and isophotal radii and magnitudes are calculated from these. We also report virtual aperture photometry that, judging from comparison with previous work, is accurate to roughly 0.05 mag in the optical, and 0.07 mag in the NIR. Our B-band isophotal magnitude and radii, obtained from ellipse fitting, are in good agreement with those of Third Reference Catalogue of Bright Galaxies. When compared with the B band, V, I, J, and K isophotal diameters show that the colors in the outer regions of Seyfert galaxies are consistent with the colors of normal spirals. Differences in the integrated isophotal colors and comparison with a simple model show that the active nucleus+bulge are stronger and redder in the NIR than in the optical. Finally, roughly estimated Seyfert disk surface brightnesses are significantly brighter in B and K than those in normal spirals of similar morphological type.
- ID:
- ivo://CDS.VizieR/J/AJ/132/321
- Title:
- Morphology of narrow-line Seyfert 1 galaxies
- Short Name:
- J/AJ/132/321
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the nuclear morphology of a sample of narrow- and broad-line Seyfert 1 galaxies (NLS1s and BLS1s, respectively) based on broadband images in the Hubble Space Telescope archives. In our previous study we found that large-scale stellar bars at >1kpc from the nucleus are more common in NLS1s than BLS1s. In this paper we find that NLS1s preferentially have grand-design dust spirals within ~1kpc of their centers. We also find that NLS1s have a higher fraction of nuclear star-forming rings than BLS1s. We find that many of the morphological differences are due to the presence or absence of a large-scale stellar bar within the spiral host galaxy. In general, barred Seyfert 1 galaxies tend to have grand-design dust spirals at their centers, confirming the results of other researchers. The high fraction of grand-design nuclear dust spirals and stellar nuclear rings observed in NLS1s' host galaxies suggests a means for efficient fueling of their nuclei to support their high Eddington ratios.
- ID:
- ivo://CDS.VizieR/J/A+AS/129/357
- Title:
- Morphology of peculiar ring galaxies
- Short Name:
- J/A+AS/129/357
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It is proposed that Peculiar Ring Galaxies can be divided into five principal types according to the morphology of the ring and bulge, based on the visual inspection of 489 selected object. Those objects have been named "peculiar" following the "Catalogue of Southern Peculiar Galaxies and Associations" by Arp & Madore (1986, Cat. <VII/170>).
- ID:
- ivo://CDS.VizieR/J/ApJS/141/61
- Title:
- Morphology of satellite galaxies
- Short Name:
- J/ApJS/141/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results of an ongoing project to study the morphological, kinematical, dynamical, and chemical properties of satellite galaxies of external giant spiral galaxies. The sample of objects has been selected from the catalog by Zaritsky et al. (1993ApJ...405..464Z). The paper analyzes the morphology and structural parameters of a subsample of 60 such objects. The satellites span a great variety of morphologies and surface brightness profiles. About two-thirds of the sample are spirals and irregulars, the remaining third being early-types. Some cases showing interaction between pairs of satellites are presented and briefly discussed.
- ID:
- ivo://CDS.VizieR/J/MNRAS/476/3661
- Title:
- Morphology of SDSS galaxies
- Short Name:
- J/MNRAS/476/3661
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a morphological catalogue for ~670000 galaxies in the Sloan Digital Sky Survey in two flavours: T-type, related to the Hubble sequence, and Galaxy Zoo 2 (GZ2 hereafter) classification scheme. By combining accurate existing visual classification catalogues with machine learning, we provide the largest and most accurate morphological catalogue up to date. The classifications are obtained with Deep Learning algorithms using Convolutional Neural Networks (CNNs). We use two visual classification catalogues, GZ2 and Nair & Abraham (2010ApJS..186..427N, Cat. J/ApJS/186/427), for training CNNs with colour images in order to obtain T-types and a series of GZ2 type questions (disc/features, edge-on galaxies, bar signature, bulge prominence, roundness, and mergers). We also provide an additional probability enabling a separation between pure elliptical (E) from S0, where the T-type model is not so efficient. For the T-type, our results show smaller offset and scatter than previous models trained with support vector machines. For the GZ2 type questions, our models have large accuracy (>97 per cent), precision and recall values (>90 per cent), when applied to a test sample with the same characteristics as the one used for training. The catalogue is publicly released with the paper.
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