- 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.
Number of results to display per page
Search Results
- 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.
- ID:
- ivo://CDS.VizieR/J/MNRAS/444/3015
- Title:
- Morphologies of S4G galaxies
- Short Name:
- J/MNRAS/444/3015
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue and images of visually detected features, such as asymmetries, extensions, warps, shells, tidal tails, polar rings, and obvious signs of mergers or interactions, in the faint outer regions (at and outside of R_25_) of nearby galaxies. This catalogue can be used in future quantitative studies that examine galaxy evolution due to internal and external factors. We are able to reliably detect outer region features down to a brightness level of 0.03MJy/sr/pixel at 3.6{mu}m in the Spitzer Survey of Stellar Structure in Galaxies (S4G). We also tabulate companion galaxies. We find asymmetries in the outer isophotes in 22+/-1% of the sample. The asymmetry fraction does not correlate with galaxy classification as an interacting galaxy or merger remnant, or with the presence of companions. We also compare the detected features to similar features in galaxies taken from cosmological zoom re-simulations. The simulated images have a higher fraction (33%) of outer disc asymmetries, which may be due to selection effects and an uncertain star formation threshold in the models. The asymmetries may have either an internal (e.g. lopsidedness due to dark halo asymmetry) or external origin.
- ID:
- ivo://CDS.VizieR/J/ApJS/219/15
- Title:
- Morphologies of z=0-10 galaxies with HST data
- Short Name:
- J/ApJS/219/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the redshift evolution of the galaxy effective radius r_e_ obtained from the Hubble Space Telescope (HST) samples of ~190000 galaxies at z=0-10. Our HST samples consist of 176152 photo-z galaxies at z=0-6 from the 3D-HST+CANDELS catalog (Skelton+, 2014, J/ApJS/214/24) and 10454 Lyman break galaxies (LBGs) at z=4-10 identified in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), HUDF 09/12, and HFF parallel fields, (Harikane+, 2015, in prep) providing the largest data set to date for galaxy size evolution studies. We derive r_e_ with the same technique over the wide redshift range of z=0-10, evaluating the optical-to-UV morphological K correction and the selection bias of photo-z galaxies+LBGs as well as the cosmological surface-brightness dimming effect.
- ID:
- ivo://CDS.VizieR/J/ApJS/217/27
- Title:
- Morphologies of z<0.01 SDSS-DR7 galaxies
- Short Name:
- J/ApJS/217/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The morphological types of 5836 galaxies were classified by a visual inspection of color images using the Sloan Digital Sky Survey Data Release 7 to produce a morphology catalog of a representative sample of local galaxies with z<0.01. The sample galaxies are almost complete for galaxies brighter than r_pet_=17.77. Our classification system is basically the same as that of the Third Reference Catalog of Bright Galaxies with some simplifications for giant galaxies. On the other hand, we distinguish the fine features of dwarf elliptical (dE)-like galaxies to classify five subtypes: dE, blue-cored dwarf ellipticals, dwarf spheroidals (dSph), blue dwarf ellipticals (dE_blue_), and dwarf lenticulars (dS0). In addition, we note the presence of nucleation in dE, dSph, and dS0. Elliptical galaxies and lenticular galaxies contribute only ~1.5 and 4.9% of local galaxies, respectively, whereas spirals and irregulars contribute ~32.1 and ~42.8%, respectively. The dE_blue_ galaxies, which are a recently discovered population of galaxies, contribute a significant fraction of dwarf galaxies. There seem to be structural differences between dSph and dE galaxies. The dSph galaxies are fainter and bluer with a shallower surface brightness gradient than dE galaxies. They also have a lower fraction of galaxies with small axis ratios (b/a<~0.4) than dE galaxies. The mean projected distance to the nearest neighbor galaxy is ~260 kpc. About 1% of local galaxies have no neighbors with comparable luminosity within a projected distance of 2Mpc.
- ID:
- ivo://CDS.VizieR/J/MNRAS/448/2530
- Title:
- Morphology and structure of BCG
- Short Name:
- J/MNRAS/448/2530
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study a large sample of 625 low-redshift brightest cluster galaxies (BCGs) and link their morphologies to their structural properties. We derive visual morphologies and find that ~57% of the BCGs are cD galaxies, ~13% are ellipticals, and ~21% belong to the intermediate classes mostly between E and cD. There is a continuous distribution in the properties of the BCG's envelopes, ranging from undetected (E class) to clearly detected (cD class), with intermediate classes (E/cD and cD/E) showing the increasing degrees of the envelope presence. A minority (~7%) of BCGs have disc morphologies, with spirals and S0s in similar proportions, and the rest (~2%) are mergers. After carefully fitting the galaxies light distributions by using one-component (Sersic) and two-component (Sersic+Exponential) models, we find a clear link between the BCGs morphologies and their structures and conclude that a combination of the best-fitting parameters derived from the fits can be used to separate cD galaxies from non-cD BCGs. In particular, cDs and non-cDs show very different distributions in the R_e_-RFF plane, where R_e_ is the effective radius and RFF (the residual flux fraction) measures the proportion of the galaxy flux present in the residual images after subtracting the models. In general, cDs have larger R_e_ and RFF values than ellipticals. Therefore we find, in a statistically robust way, a boundary separating cD and non-cD BCGs in this parameter space. BCGs with cD morphology can be selected with reasonably high completeness (~75%) and low contamination (~20%). This automatic and objective technique can be applied to any current or future BCG sample with good-quality images.
- ID:
- ivo://CDS.VizieR/J/AJ/146/151
- Title:
- Morphology catalog of nearby galaxies from SDSS DR7
- Short Name:
- J/AJ/146/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the statistical properties of a volume-limited sample of 7429 nearby (z=0.033-0.044) galaxies from the Sloan Digital Sky Survey Data Release 7. Our database includes morphology distribution as well as the structural and spectroscopic properties of each morphology type based on the recent remeasurements of spectral line strengths by Oh and collaborators. Our database does not include galaxies that are apparently smaller and flatter because morphology classification of them turned out to be difficult. Our statistics confirmed the up-to-date knowledge of galaxy populations, e.g., correlations between morphology and line strengths as well as the derived ages. We hope that this database will be useful as a reference.
- ID:
- ivo://CDS.VizieR/J/ApJS/194/31
- Title:
- Morphology for groups in the FIRST database
- Short Name:
- J/ApJS/194/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The morphology of selected groups of sources in the Faint Images of the Radio Sky at Twenty Centimeters (FIRST) survey and catalog is examined. Sources in the FIRST catalog (2003 April release, 811117 entries) were sorted into singles, doubles, triples, and groups of higher-count membership based on a proximity criteria. The 7106 groups with four or more components were examined individually for bent types including, but not limited to, wide-angle tail and narrow-angle tail types. In the process of this examination, ring, double-double, X-shaped, hybrid morphology, giant radio sources, and the herein described W-shaped and tri-axial morphology systems were also identified. For the convenience of the reader separate tables for distinctive types were generated. A few curiosities were found. For the 16950 three-component groups and 74788 two-component groups, catalogs with probability estimates for bent classification, as determined by pattern recognition techniques, are presented.
- ID:
- ivo://CDS.VizieR/J/ApJ/784/111
- Title:
- Morphology of candidate intermediate-mass SFRs
- Short Name:
- J/ApJ/784/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an all-sky sample of 984 candidate intermediate-mass Galactic star-forming regions that are color selected from the Infrared Astronomical Satellite (IRAS) Point Source Catalog and morphologically classify each object using mid-infrared Wide-field Infrared Survey Explorer (WISE) images. Of the 984 candidates, 616 are probable star-forming regions (62.6%), 128 are filamentary structures (13.0%), 39 are point-like objects of unknown nature (4.0%), and 201 are galaxies (20.4%). We conduct a study of four of these regions, IRAS 00259+5625, IRAS 00420+5530, IRAS 01080+5717, and IRAS 05380+2020, at Galactic latitudes|b|>5{deg} using optical spectroscopy from the Wyoming Infrared Observatory, along with near-infrared photometry from the Two-Micron All Sky Survey, to investigate their stellar content. New optical spectra, color-magnitude diagrams, and color-color diagrams reveal their extinctions, spectrophotometric distances, and the presence of small stellar clusters containing 20-78M_{sun}_ of stars. These low-mass diffuse star clusters contain ~65-250 stars for a typical initial mass function, including one or more mid-B stars as their most massive constituents. Using infrared spectral energy distributions we identify young stellar objects near each region and assign probable masses and evolutionary stages to the protostars. The total infrared luminosity lies in the range 190-960L_{sun}_, consistent with the sum of the luminosities of the individually identified young stellar objects.
- ID:
- ivo://CDS.VizieR/J/ApJ/652/1068
- Title:
- Morphology of cool and warm infrared galaxies
- Short Name:
- J/ApJ/652/1068
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have analyzed a sample of nearby cool and warm infrared (IR) galaxies using photometric and structural parameters. The set of measures include far-infrared color [C=log(S_60um_/S_100um_)], total IR luminosity (L_FIR_), radio surface brightness, and radio, near-infrared, and optical sizes.
