- ID:
- ivo://CDS.VizieR/J/MNRAS/427/3159
- Title:
- Quantified HI morphology. VI. NUV/FUV
- Short Name:
- J/MNRAS/427/3159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extended ultraviolet (XUV) discs have been found in a substantial fraction of late-type - S0, spiral and irregular - galaxies. Similarly, most late-type spirals have an extended gas disc, observable in the 21-cm radio line (HI). The morphology of galaxies can be quantified well using a series of scale-invariant parameters; concentration-asymmetry-smoothness (CAS), Gini, M_20_, and G_M_ parameters. In this series of papers, we apply these to HI column density maps to identify mergers and interactions, lopsidedness and now XUV discs. In this paper, we compare the quantified morphology and effective radius (R_50_) of the Westerbork observations of neutral Hydrogen in Irregular and SPiral galaxies Project (WHISP) HI maps to those of far- and near-ultraviolet images obtained with GALEX, to explore how close the morphology and scales of HI and UV in these discs correlate. We find that XUV discs do not stand out by their effective radii in UV or HI. However, the concentration index in far-ultraviolet (FUV) appears to select some XUV discs. And known XUV discs can be identified via a criterion using asymmetry and M_20_; 80 per cent of XUV discs are included but with 55 per cent contamination. This translates into 61 candidate XUV disc out of our 266 galaxies, 23 per cent consistent with previous findings. Otherwise, the UV and HI morphology parameters do not appear closely related.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/703/1569
- Title:
- Radial distribution in SINGS galaxies. I.
- Short Name:
- J/ApJ/703/1569
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present ultraviolet through far-infrared (FIR) surface brightness profiles for the 75 galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS). The imagery used to measure the profiles includes Galaxy Evolution Explorer UV data, optical images from Kitt Peak National Observatory, Cerro Tololo Inter-American Observatory, and Sloan Digital Sky Survey, near-IR data from Two Micron All Sky Survey, and mid- and FIR images from Spitzer. Along with the radial profiles, we also provide multi-wavelength asymptotic magnitudes and several nonparametric indicators of galaxy morphology: the concentration index (C42), the asymmetry (A), the Gini coefficient (G), and the normalized second-order moment of the brightest 20% of the galaxy's flux ({overline}M_20_). In this paper, the first of a series, we describe the technical aspects regarding the surface photometry, and present a basic analysis of the global and structural properties of the SINGS galaxies at different wavelengths.
- ID:
- ivo://CDS.VizieR/J/A+A/515/A57
- Title:
- Radial velocities in clusters of galaxies. V.
- Short Name:
- J/A+A/515/A57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As a part of our galaxy-cluster redshift survey, we present a set of 79 new velocities in the 4 clusters Abell 376, Abell 970, Abell 1356, and Abell 2244, obtained at Haute-Provence observatory. This set now completes our previous analyses, especially for the first two clusters. Data on individual galaxies are presented, and we discuss some cluster properties.
- ID:
- ivo://CDS.VizieR/J/AJ/141/182
- Title:
- Radio and optical properties of QSOs
- Short Name:
- J/AJ/141/182
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the largest homogeneous quasar sample with high-quality optical spectra and robust radio morphology classifications assembled to date, we investigate relationships between radio and optical properties with unprecedented statistical power. The sample consists of 4714 radio quasars from FIRST with S_20_>=2mJy and with spectra from the Sloan Digital Sky Survey (SDSS). Radio morphology classes include core-only (core), core-lobe (lobe), core-jet (jet), lobe-core-lobe (triple), and double-lobe.
- ID:
- ivo://CDS.VizieR/J/A+A/482/247
- Title:
- Radio detections of 3G sources
- Short Name:
- J/A+A/482/247
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A considerable fraction of the gamma-ray sources discovered with the Energetic Gamma-Ray Experiment Telescope (EGRET) remain unidentified. The EGRET sources that have been properly identified are either pulsars or variable sources at both radio and gamma-ray wavelengths. Most of the variable sources are strong radio blazars. However, some low galactic-latitude EGRET sources, with highly variable gamma-ray emission, lack any evident counterpart according to the radio data available until now. The primary goal of this paper is to identify and characterise the potential radio counterparts of four highly variable gamma-ray sources in the galactic plane through mapping the radio surroundings of the EGRET confidence contours and determining the variable radio sources in the field whenever possible. We have carried out a radio exploration of the fields of the selected EGRET sources using the Giant Metrewave Radio Telescope (GMRT) interferometer at 21 cm wavelength, with pointings being separated by months.
- ID:
- ivo://CDS.VizieR/J/A+A/544/A18
- Title:
- Radio galaxies of the local universe
- Short Name:
- J/A+A/544/A18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first catalog of radio-emitting galaxies that covers the entire sky. Our catalog allows the selection of volume-limited subsamples containing all low-power radio galaxies, similar to the prototypical low-power radio galaxies Cen A or M87, within some hundred Mpc. Over 30% of the galaxies in our catalog are not contained in existing large-area extra-galactic radio samples. We find that the local galaxy density in a sphere of 2Mpc centered on the radio galaxies is 1.7 times higher than around non-radio galaxies of the same luminosity and morphology. This significant enhancement suggests a causal relation between external galaxy properties, such as environment or merger history, and the formation of powerful jets in the present universe. Since the enhancement is observed with respect to galaxies of the same luminosity and Hubble type, it is not primarily driven by black hole mass. Our automated matching procedure is found to select radio-emitting galaxies with high efficiency (99%) and purity (91%).
- ID:
- ivo://CDS.VizieR/J/ApJS/179/306
- Title:
- Radio galaxy morphologies
- Short Name:
- J/ApJS/179/306
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a statistical study of 51 radio galaxies at the millijansky flux level selected from the Faint Images of the Radio Sky at Twenty cm survey, including their optical morphologies and structure obtained with the Hubble Space Telescope (HST). Our optical imaging is significantly deeper (~2mag) than previous studies with the superior angular resolution of space-based imaging. We that find 8/51 (16%) of the radio sources have no optically identifiable counterpart to AB~24mag. For the remaining 43 sources, only 25 are sufficiently resolved in the HST images to reliably assign a visual classification: 15 (60%) are elliptical galaxies, two (8%) are late-type spiral galaxies, one (4%) is an S0, three (12%) are pointlike objects (quasars), and four (16%) are merger systems. We find a similar distribution of optical types with measurements of the Sersic index.
- ID:
- ivo://CDS.VizieR/J/MNRAS/397/281
- Title:
- Radio imaging in Lockman Hole
- Short Name:
- J/MNRAS/397/281
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the run up to routine observations with the upcoming generation of radio facilities, the nature of sub-mJy radio population has been hotly debated. Here, we describe multi-frequency data designed to probe the emission mechanism that dominates in these faint radio sources. Our analysis is based on observations of the Lockman Hole using the Giant Metrewave Radio Telescope (GMRT) - the deepest 610-MHz imaging yet reported - together with 1.4-GHz imaging from the Very Large Array (VLA), well matched in resolution and sensitivity to the GMRT data: {sigma}_610_MHz~15uJy/beam, {sigma}_1.4GHz_~6uJy/beam, full width at half-maximum (FWHM) ~5arcsec. The GMRT and VLA data are cross-matched to obtain the radio spectral indices for the faint radio emitters.
- ID:
- ivo://CDS.VizieR/J/AJ/130/1358
- Title:
- Radio observations of the HDFS region. I
- Short Name:
- J/AJ/130/1358
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is the first of a series describing the results of the Australia Telescope Hubble Deep Field-South radio survey. The survey was conducted at four wavelengths, 20, 11, 6, and 3cm, over a 4 year period and achieves an rms sensitivity of about 10{mu}Jy at each wavelength. We describe the observations and data reduction processes and present data on radio sources close to the center of the Hubble Deep Field-South. We discuss in detail the properties of a subset of these sources. The sources include both starburst galaxies and galaxies powered by an active galactic nucleus and range in redshift from 0.1 to 2.2. Some of them are characterized by unusually high radio-to-optical luminosities, presumably caused by dust extinction.
- ID:
- ivo://CDS.VizieR/J/AJ/130/1373
- Title:
- Radio observations of the HDFS region. II
- Short Name:
- J/AJ/130/1373
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is part of a series describing the results from the Australia Telescope Hubble Deep Field-South (ATHDFS) survey obtained with the Australia Telescope Compact Array. This survey consists of observations at 1.4, 2.5, 5.2, and 8.7GHz, all centered on the Hubble Deep Field-South. Here we present the first results from the extended observing campaign at 1.4GHz. A total of 466 sources have been cataloged to a local sensitivity of 5{sigma} (11{mu}Jy rms). A source extraction technique is developed that (1) successfully excludes spurious sources from the final source catalogs and (2) accounts for the nonuniform noise in our image. A source catalog is presented, and the general properties of the 1.4GHz image are discussed. We also present source counts derived from our ATHDFS 1.4GHz catalog.
