- 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.
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- ID:
- ivo://CDS.VizieR/J/ApJ/660/1151
- Title:
- Morphology of galaxies in 10 EDisCS clusters
- Short Name:
- J/ApJ/660/1151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe Hubble Space Telescope (HST) imaging of 10 of the 20 ESO Distant Cluster Survey (EDisCS) fields. Each ~40arcmin^2^ field was imaged in the F814W filter with the Advanced Camera for Surveys Wide Field Camera. Based on these data, we present visual morphological classifications for the ~920 sources per field that are brighter than Iauto=23mag. We use these classifications to quantify the morphological content of 10 intermediate-redshift (0.5<z<0.8) galaxy clusters within the HST survey region. The EDisCS results, combined with previously published data from seven higher redshift clusters, show no statistically significant evidence for evolution in the mean fractions of elliptical, S0, and late-type (Sp+Irr) galaxies in clusters over the redshift range 0.5<z<1.2.
- 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/MNRAS/419/687
- Title:
- Morphology of luminous radio-loud AGN
- Short Name:
- J/MNRAS/419/687
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a comparison between the optical morphologies of a complete sample of 46 southern 2Jy radio galaxies at intermediate redshifts (0.05<z<0.7) and those of two control samples of quiescent early-type galaxies: 55 ellipticals at redshifts z<=0.01 from the Observations of Bright Ellipticals at Yale (OBEY) survey, and 107 early-type galaxies at redshifts 0.2<z<0.7 in the Extended Groth Strip (EGS). Based on these comparisons, we discuss the role of galaxy interactions in the triggering of powerful radio galaxies (PRGs). We find that a significant fraction of quiescent ellipticals at low and intermediate redshifts show evidence for disturbed morphologies at relatively high surface brightness levels, which are likely the result of past or on-going galaxy interactions. However, the morphological features detected in the galaxy hosts of the PRGs (e.g. tidal tails, shells, bridges, etc.) are up to 2mag brighter than those present in their quiescent counterparts. Indeed, if we consider the same surface brightness limits, the fraction of disturbed morphologies is considerably smaller in the quiescent population (53% at z<0.2 and 48% at 0.2<=z<0.7) than in the PRGs (93% at z<0.2 and 95% at 0.2<=z<0.7 considering strong-line radio galaxies only). This supports a scenario in which PRGs represent a fleeting active phase of a subset of the elliptical galaxies that have recently undergone mergers/interactions. However, we demonstrate that only a small proportion (<~20%) of disturbed early-type galaxies are capable of hosting powerful radio sources.
- 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/AJ/111/645
- Title:
- Morphology of Quasars
- Short Name:
- J/AJ/111/645
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The optical morphology of bright extragalactic objects listed by Green et al. (1986ApJS...61..305G) is determined on Palomar Observatory Sky Survey prints. Morphological types are assigned according to whether objects appear resolved or unresolved. These are plotted in the Hubble Diagram. When combined with previous results from the Medium-Bright Quasar Survey (MBQS), objects of redshift z are found to be unresolved on 1.2m Schmidt telescopes at apparent magnitudes brighter than B=21-3/4z over a large magnitude range 12.5<B<18.5. A luminosity cutoff for unresolved objects in this range is found to be M_B=-24, (H0=50), in agreement with an earlier estimate. Relevance to the search for large, bright, host galaxies, and for "naked quasar" candidates, is noted.
- 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.
