- 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).
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- 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.
- ID:
- ivo://CDS.VizieR/J/ApJS/143/73
- Title:
- Morphology of spiral galaxies
- Short Name:
- J/ApJS/143/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We announce the initial release of data from the Ohio State University (OSU) Bright Spiral Galaxy Survey (OSUBSGS), a BVRJHK imaging survey of a well-defined sample of 205 bright, nearby spiral galaxies. We present H-band morphological classification on the Hubble sequence for the OSU Survey sample. We compare the H-band classification to B-band classification from our own images and from standard galaxy catalogs. Our B-band classifications match well with those of the standard catalogs. On average, galaxies with optical classifications from Sa through Scd appear about one T type earlier in the H band than in the B band, but with large scatter. This result does not support recent claims made in the literature that the optical and near-IR morphologies of spiral galaxies are uncorrelated. We present detailed descriptions of the H-band morphologies of our entire sample, as well as B- and H-band images for a set of 17 galaxies chosen as type examples and BRH color-composite images of six galaxies chosen to demonstrate the range in morphological variation as a function of wavelength.
- ID:
- ivo://CDS.VizieR/J/MNRAS/424/2841
- Title:
- Morphology of supernova host galaxies
- Short Name:
- J/MNRAS/424/2841
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents an analysis of core-collapse supernova distributions in isolated and interacting host galaxies, paying close attention to the selection effects involved in conducting host galaxy supernova studies. When taking into account all of the selection effects within our host galaxy sample, we draw the following conclusions. 1. Within interacting, or 'disturbed', systems there is a real, and statistically significant, increase in the fraction of stripped-envelope supernovae in the central regions. A discussion into what may cause this increased fraction, compared to the more common Type IIP supernovae and Type II supernovae without subclassifications, is presented. Selection effects are shown not to drive this result, and so we propose that this study provides direct evidence for a high-mass weighted initial mass function within the central regions of disturbed galaxies. 2. Within 'undisturbed' spiral galaxies the radial distribution of Type Ib and Type Ic supernovae is statistically very different, with the latter showing a more centrally concentrated distribution. This could be driven by metallicity gradients in these undisturbed galaxies, or radial variations in other properties (binarity or stellar rotation) driving envelope loss in progenitor stars. This result is not found in 'disturbed' systems, where the distributions of Type Ib and Ic supernovae are consistent.
- ID:
- ivo://CDS.VizieR/J/ApJ/721/98
- Title:
- Morphology of 70um COSMOS galaxies
- Short Name:
- J/ApJ/721/98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze the morphological properties of a large sample of 1503 70um selected galaxies in the COSMOS field spanning the redshift range 0.01<z<3.5 with a median redshift of 0.5 and an infrared luminosity range of 10^8^<L_IR_(8-1000um)<10^14^L_{sun}_ with a median luminosity of 10^11.4^L_{sun}_. In general, these galaxies are massive, with a stellar mass range of 10^10^-10^12^M_{sun}_, and luminous, with -25<M_K_<-20. The precise fraction of mergers in any given L_IR_ bin varies by redshift due to sources at z>1 being difficult to classify and subject to the effects of bandpass shifting; therefore, these numbers can only be considered lower limits. At z<1, where the morphological classifications are most robust, major mergers clearly dominate the ULIRG population (~50%-80%) and are important for the LIRG population (~25%-40%). At z>1, the fraction of major mergers is lower, but is at least 30%-40% for ULIRGs. In a comparison of our visual classifications with several automated classification techniques we find general agreement; however, the fraction of identified mergers is underestimated due to automated classification methods being sensitive to only certain timescales of a major merger. The distribution of the U-V color of the galaxies in our sample peaks in the green valley (<U-V>=1.1) with a large spread at bluer and redder colors and with the major mergers peaking more strongly in the green valley than the rest of the morphological classes.
- ID:
- ivo://CDS.VizieR/J/ApJ/743/123
- Title:
- Motions of galaxies in Coma I cloud
- Short Name:
- J/ApJ/743/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We note that nearby galaxies having high negative peculiar velocities are distributed over the sky very inhomogeneously. A part of this anisotropy is caused by the "Local Velocity Anomaly," i.e., by the bulk motion of nearby galaxies away from the Local Void. However, half of the fast-flying objects reside within a small region [RA=11.5h-13.0h, DE=+20{deg}-40{deg}] known as the Coma I cloud. According to Makarov & Karachentsev, this complex contains 8 groups, 5 triplets, 10 pairs, and 83 single galaxies with a total mass of 4.7x10^13^M_{sun}_. We use 122 galaxies in the Coma I region with known distances and radial velocities V_LG_<3000km/s to draw the Hubble relation for them. The Hubble diagram shows a Z-shaped effect of infall with an amplitude of +200km/s on the nearby side and -700km/s on the back side. This phenomenon can be understood as the galaxy infall toward a dark attractor with a mass of ~2x10^14^M_{sun}_ situated at a distance of 15 Mpc from us. The existence of a large void between the Coma and Virgo clusters also probably affects the Hubble flow around the Coma I.