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Start Over Subject radio galaxies Validation Level 2
501. XDCP J0044.0-2033 J and Ks images
ID:
ivo://CDS.VizieR/J/A+A/568/A5
Title:
XDCP J0044.0-2033 J and Ks images
Short Name:
J/A+A/568/A5
Date:
21 Oct 2021
Publisher:
CDS
Description:
Recent observational progress has enabled the detection of galaxy clusters and groups out to very high redshifts and for the first time allows detailed studies of galaxy population properties in these densest environments in what was formerly known as the "redshift desert" at z>1.5. We aim to investigate various galaxy population properties of the massive X-ray luminous galaxy cluster XDCP J0044.0-2033 at z=1.58, which constitutes the most extreme currently known matter-density peak at this redshift. We analyzed deep VLT/HAWK-I near-infrared data with an image quality of 0.5" and limiting Vega magnitudes (50% completeness) of 24.2 in J- and 22.8 in the Ks band, complemented by similarly deep Subaru imaging in i and V, Spitzer observations at 4.5um, and new spectroscopic observations with VLT/FORS 2.
502. xGASS catalog
ID:
ivo://CDS.VizieR/J/MNRAS/476/875
Title:
xGASS catalog
Short Name:
J/MNRAS/476/875
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the extended GALEX Arecibo SDSS Survey (xGASS), a gas fraction-limited census of the atomic hydrogen (HI) gas content of 1179 galaxies selected only by stellar mass (M*=10^9^-10^11.5^M_{sun}_) and redshift (0.01<z<0.05). This includes new Arecibo observations of 208 galaxies, for which we release catalogues and HI spectra. In addition to extending the GASS HI scaling relations by one decade in stellar mass, we quantify total (atomic+molecular) cold gas fractions and molecular-to-atomic gas mass ratios, Rmol, for the subset of 477 galaxies observed with the IRAM 30m telescope. We find that atomic gas fractions keep increasing with decreasing stellar mass, with no sign of a plateau down to logM*/M_{sun}_=9. Total gas reservoirs remain HI-dominated across our full stellar mass range, hence total gas fraction scaling relations closely resemble atomic ones, but with a scatter that strongly correlates with Rmol, especially at fixed specific star formation rate. On average, Rmol weakly increases with stellar mass and stellar surface density {mu}*, but individual values vary by almost two orders of magnitude at fixed M* or {mu}*. We show that, for galaxies on the star-forming sequence, variations of Rmol are mostly driven by changes of the HI reservoirs, with a clear dependence on {mu}*. Establishing if galaxy mass or structure plays the most important role in regulating the cold gas content of galaxies requires an accurate separation of bulge and disc components for the study of gas scaling relations
503. 13+38 XMM-Newton/ROSAT 1.4GHz radio catalog
ID:
ivo://CDS.VizieR/J/MNRAS/352/131
Title:
13+38 XMM-Newton/ROSAT 1.4GHz radio catalog
Short Name:
J/MNRAS/352/131
Date:
21 Oct 2021
Publisher:
CDS
Description:
In order to determine the relationship between the faint X-ray and faint radio source populations, and hence to help understand the X-ray and radio emission mechanisms in those faint source populations, we have made a deep 1.4-GHz Very Large Array radio survey of the 13h+38{deg} XMMNewton/ROSAT X-ray Survey Area. From a combined data set of 10-h, B-configuration data and 14-h, A-configuration data, maps with 3.35-arcsec resolution and a noise limit of 7.5Jy were constructed. A complete sample of 449 sources was detected within a 30-arcmin diameter region above a 4 detection limit of 30Jy, at the map centre, making this one of the deepest radio surveys at this frequency. The differential source count shows a significant upturn at submilliJansky flux densities, similar to that seen in other deep surveys at 1.4GHz (e.g. the Phoenix survey, Cat. <J/MNRAS/296/839>), but larger than that seen in the Hubble Deep Field (HDF) which may have been selected to be underdense. This upturn is well modelled by the emergence of a population of medium-redshift star-forming galaxies which dominate at faint flux densities. The brighter source counts are well modelled by active galactic nuclei.
504. XMM observations of Fornax A (NGC 1316)
ID:
ivo://CDS.VizieR/J/ApJ/645/256
Title:
XMM observations of Fornax A (NGC 1316)
Short Name:
J/ApJ/645/256
Date:
21 Oct 2021
Publisher:
CDS
Description:
An XMM-Newton observation of the east radio lobe of the nearby radio galaxy Fornax A is reported. The diffuse hard X-ray emission associated with the east lobe, which was initially discovered by ASCA and ROSAT, is confirmed with significant signal statistics, after strictly removing 59 sources detected within the MOS field of view. Its X-ray spectrum is described by a single power-law model, which is absorbed by a medium with a column density consistent with that toward the object.
505. X-ray detection of radio-selected SF galaxies
ID:
ivo://CDS.VizieR/J/A+A/542/A16
Title:
X-ray detection of radio-selected SF galaxies
Short Name:
J/A+A/542/A16
Date:
21 Oct 2021
Publisher:
CDS
Description:
X-ray surveys contain sizable numbers of star forming galaxies, beyond the AGN which usually make the majority of detections. Many methods to separate the two populations are used in the literature, based on X-ray and multiwavelength properties. We aim at a detailed test of the classification schemes and to study the X-ray properties of the resulting samples. We build on a sample of galaxies selected at 1.4GHz in the VLA-COSMOS survey, classified by Smolcic et al. (2008ApJS..177...14S) according to their optical colours and observed with Chandra. A similarly selected control sample of AGN is also used for comparison. We review some X-ray based classification criteria and check how they affect the sample composition. The efficiency of the classification scheme devised by Smolcic et al. (2008ApJS..177...14S) is such that ~30% of composite/misclassified objects are expected because of the higher X-ray brightness of AGN with respect to galaxies. The latter fraction is actually 50% in the X-ray detected sources, while it is expected to be much lower among X-ray undetected sources. Indeed, the analysis of the stacked spectrum of undetected sources shows, consistently, strongly different properties between the AGN and galaxy samples. X-ray based selection criteria are then used to refine both samples. The radio/X-ray luminosity correlation for star forming (SF) galaxies is found to hold with the same X-ray/radio ratio valid for nearby galaxies. Some evolution of the ratio may be possible for sources at high redshift or high luminosity, tough it is likely explained by a bias arising from the radio selection. Finally, we discuss the X-ray number counts of star forming galaxies from the VLA- and C-COSMOS surveys according to different selection criteria, and compare them to the similar determination from the Chandra Deep Fields. The classification scheme proposed here may find application in future works and surveys.
506. X-ray, optical and radio monitoring of 3C 111
ID:
ivo://CDS.VizieR/J/ApJ/734/43
Title:
X-ray, optical and radio monitoring of 3C 111
Short Name:
J/ApJ/734/43
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of extensive multi-frequency monitoring of the radio galaxy 3C 111 between 2004 and 2010 at X-ray (2.4-10keV), optical (R band), and radio (14.5, 37, and 230GHz) wave bands, as well as multi-epoch imaging with the Very Long Baseline Array (VLBA) at 43GHz. Over the six years of observation, significant dips in the X-ray light curve are followed by ejections of bright superluminal knots in the VLBA images. This shows a clear connection between the radiative state near the black hole, where the X-rays are produced, and events in the jet. The X-ray continuum flux and Fe line intensity are strongly correlated, with a time lag shorter than 90 days and consistent with zero.
507. X-ray+Radio sources in XBootes
ID:
ivo://CDS.VizieR/J/MNRAS/396/2011
Title:
X-ray+Radio sources in XBootes
Short Name:
J/MNRAS/396/2011
Date:
21 Oct 2021
Publisher:
CDS
Description:
With the goal of investigating the nature and the environment of the faint radio sources (at mJy level), here are presented results of X-ray identifications of Faint Imaging Radio Survey at Twenty centimetres (FIRST) in the 9deg^2^ Bootes field of the National Optical Astronomy Observatory (NOAO) Deep Wide Field Survey (NDWFS), using data from the Chandra XBootes survey. A total of 92 (10 per cent) FIRST radio sources are identified above the X-ray flux limit f_X_)(0.5-7)keV=8x10^-15^erg/s/cm^2^, and 79 optical counterparts are common to both the radio and X-ray sources. Spectroscopic identifications [obtained from the Sloan Digital Sky Survey (SDSS) survey] were available for 22 sources (27 per cent).
508. X-ray survey of the 2Jy sample. I.
ID:
ivo://CDS.VizieR/J/MNRAS/440/269
Title:
X-ray survey of the 2Jy sample. I.
Short Name:
J/MNRAS/440/269
Date:
21 Oct 2021
Publisher:
CDS
Description:
We carry out a systematic study of the X-ray emission from the active nuclei of the 0.02<z<0.7 2Jy sample, using Chandra and XMM-Newton observations. We combine our results with those from mid-infrared, optical emission-line and radio observations, and add them to those of the 3CRR sources. We show that the low-excitation objects in our samples show signs of radiatively inefficient accretion. We study the effect of the jet-related emission on the various luminosities, confirming that it is the main source of soft X-ray emission for our sources. We also find strong correlations between the accretion-related luminosities, and identify several sources whose optical classification is incompatible with their accretion properties. We derive the bolometric and jet kinetic luminosities for the samples and find a difference in the total Eddington rate between the low- and high-excitation populations, with the former peaking at ~1% and the latter at ~20% Eddington. Our results are consistent with a simple Eddington switch when the effects of environment on radio luminosity and black hole mass calculations are considered. The apparent independence of jet kinetic power and radiative luminosity in the high-excitation population in our plots supports a model in which jet production and radiatively efficient accretion are not strongly correlated in high-excitation objects, though they have a common underlying mechanism.
509. X-shaped radio galaxies from FIRST
ID:
ivo://CDS.VizieR/J/ApJS/245/17
Title:
X-shaped radio galaxies from FIRST
Short Name:
J/ApJS/245/17
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a catalog of 290 "winged" or X-shaped radio galaxies (XRGs) extracted from the latest (2014 December 17) data release of the "Very Large Array Faint Images of the Radio Sky at Twenty centimeter". We have combined these radio images with their counterparts in the TIFR GMRT sky survey at 150MHz, in an attempt to identify any low surface brightness radio emission present in these sources. This has enabled us to assemble a sample of 106 "strong" XRG candidates and 184 "probable" XRG candidates whose XRG designation needs to be verified by further observations. The present sample of 290 XRG candidates is almost twice as large as the number of XRGs currently known. Twenty-five of our 290 XRG candidates (9 "strong" and 16 "probable") are identified as quasars. Double-peaked narrow emission lines are seen in the optical spectra of three of the XRG candidates (two "strong" and one "probable"). Nearly 90% of the sample is located in the FR II domain of the Owen-Ledlow diagram. A few of the strong XRG candidates have a rather flat radio spectrum (spectral index {alpha} flatter than -0.3) between 150MHz and 1.4GHz, or between 1.4 and 5GHz. Since this is not expected for lobe-dominated extragalactic radio sources (like nearly all known XRGs), these sources are particularly suited for follow-up radio imaging and near-simultaneous measurement of the radio spectrum.
510. X-shaped radio sources. II. New redshifts
ID:
ivo://CDS.VizieR/J/ApJS/181/548
Title:
X-shaped radio sources. II. New redshifts
Short Name:
J/ApJS/181/548
Date:
21 Oct 2021
Publisher:
CDS
Description:
We reported optical spectroscopic observations of X-shaped radio sources with the Hobby-Eberly Telescope and Multiple-Mirror Telescope, focused on the sample of candidates from the FIRST survey presented in Paper I (Cheung, 2007, Cat. <J/AJ/133/2097>). A total of 27 redshifts were successfully obtained, 21 of which are new, including a newly identified candidate source of this type which is presented here. With these observations, the sample of candidates from the previous paper is over 50% spectroscopically identified. Two new broad emission-lined X-shaped radio sources are revealed, while no emission lines were detected in about one-third of the observed sources; a detailed study of the line properties is deferred to a future paper. Finally, to explore their relation to the Fanaroff-Riley division, the radio luminosities and host galaxy absolute magnitudes of a spectroscopically identified sample of 50 X-shaped radio galaxies are calculated to determine their placement in the Owen-Ledlow plane.