8 research outputs found
Powerful Radio Sources in the Southern Sky. II. A SWIFT X-Ray Perspective
We recently constructed the G4Jy-3CRE, a catalog of extragalactic radio
sources based on the GLEAM 4-Jy (G4Jy) sample, with the aim of increasing the
number of powerful radio galaxies and quasars with similar selection criteria
to those of the revised release of the Third Cambridge catalog (3CR). The
G4Jy-3CRE consists of a total of 264 radio sources mainly visible from the
Southern Hemisphere. Here, we present an initial X-ray analysis of 89 G4Jy-3CRE
radio sources with archival X- ray observations from the Neil Gehrels Swift
Observatory. We reduced a total of 615 Swift observations, for about 0.89 Msec
of integrated exposure time, we found X-ray counterparts for 61 radio sources
belonging to the G4Jy-3CRE, 11 of them showing extended X-ray emission. The
remaining 28 sources do not show any X-ray emission associated with their radio
cores. Our analysis demonstrates that X-ray snapshot observations, even if
lacking uniform exposure times, as those carried out with Swift, allow us to
(i) verify and/or re ne the host galaxy identi cation; (ii) discover the
extended X-ray emission around radio galaxies of the intracluster medium when
harbored in galaxy clusters, as the case of G4Jy 1518 and G4Jy 1664, and (iii)
detect X-ray radiation arising from their radio lobes, as for G4Jy 1863.Comment: 35 pages, 17 figures, 2 tables; second paper of a series, pre-proof
versio
Powerful Radio Sources in the Southern Sky. I. Optical Identifications
Since the early sixties, our view of radio galaxies and quasars has been
drastically shaped by discoveries made thanks to observations of radio sources
listed in the Third Cambridge catalog and its revised version (3CR). However,
the largest fraction of data collected to date on 3CR sources was performed
with relatively old instruments, rarely repeated and/or updated. Importantly,
the 3CR contains only objects located in the Northern Hemisphere thus having
limited access to new and innovative astronomical facilities. To mitigate these
limitations we present a new catalog of powerful radio sources visible from the
Southern Hemisphere, extracted from the GLEAM 4-Jy (G4Jy) catalog and based on
equivalent selection criteria as the 3CR. This new catalog, named G4Jy- 3CRE,
where the E stands for "equivalent", lists a total of 264 sources at
declination below -5 degrees and with 9 Jy limiting sensitivity at ~178 MHz. We
explored archival radio maps obtained with different surveys and compared then
with optical images available in the Pan-STARRS, DES and DSS databases to
search for optical counterparts of their radio cores. We compared mid-infrared
counterparts, originally associated in the G4Jy, with the optical ones
identified here and we present results of a vast literature search carried out
to collect redshift estimates for all G4Jy-3CRE sources resulting in a total of
145 reliable z measurements.Comment: 72 pages, 35 figures, 5 Table
Probing multiphase gas in local massive elliptical galaxies via multiwavelength observations
We investigate the cold and warm gas content, kinematics, and spatial
distribution of six local massive elliptical galaxies to probe the origin of
the multiphase gas in their atmospheres. We report new observations, including
SOFIA [CII], ALMA CO, MUSE H+[NII] and VLA radio observations. These
are complemented by a large suite of multiwavelength archival datasets,
including thermodynamical properties of the hot gas and radio jets, which are
leveraged to investigate the role of AGN feeding/feedback in regulating the
multiphase gas content. Our galaxy sample shows a significant diversity in cool
gas content, spanning filamentary and rotating structures. In our non-central
galaxies, the distribution of such gas is often concentrated, at variance with
the more extended features observed in central galaxies. Misalignment between
the multiphase gas and stars suggest that stellar mass loss is not the primary
driver. A fraction of the cool gas might be acquired via galaxy interactions,
but we do not find quantitative evidence of mergers in most of our systems.
Instead, key evidence supports the origin via condensation out of the diffuse
halo. Comparing with Chaotic Cold Accretion (CCA) simulations, we find that our
cool gas-free galaxies are likely in the overheated phase of the self-regulated
AGN cycle, while for our galaxies with cool gas the k-plot and AGN power
correlation corroborate the phase of CCA feeding in which the condensation rain
is triggering more vigorous AGN heating. The related C-ratio further shows that
central/non-central galaxies are expected to generate an extended/inner rain,
consistent with our sample.Comment: 26 pages, 18 figures, 8 tables, accepted for publication in ApJ;
typos corrected, reference adde
COMP2CAT: hunting compact double radio sources in the local Universe
We present a catalog of compact double radio galaxies (hereafter COMP2CAT) listing 43 edge-brightened radio sources whose projected linear size does not exceed 60 kpc, the typical size of their host galaxies. This is the fifth in a series of radio source catalogs recently created, namely: FRICAT, FRIICAT, FR0CAT, and WATCAT, each of which focuses on a different class of radio galaxies. The main aim of our analysis is to attain a better understanding of sources with intermediate morphologies between FR IIs and FR 0s. COMP2CAT sources were selected from an existing catalog of radio sources based on NVSS, FIRST and SDSS observations because they have (i) edge-brightened morphologies typical of FR IIs, (ii) redshifts z <  0.15, and (iii) projected linear sizes smaller than 60 kpc. With radio luminosities at 1.4 GHz 1038 ≲ L1.4 ≲ 1041 erg s−1, COMP2CAT sources appear as the low radio luminosity tail of FR IIs. However, their host galaxies are indistinguishable from those of large-scale radio sources: they are luminous (−21 ≳ Mr ≳ −24), red, early-type galaxies with black hole masses in the range 107.5 ≲ MBH ≲ 109.5 M⊙. Moreover, all but one of the COMP2CAT sources are optically classifiable as low-excitation radio galaxies, in agreement with being the low radio luminosity tail of FR Is and FR IIs. This catalog of compact double sources, which is ∼47% complete at z <  0.15, can potentially be used to clarify the role of compact double sources in the general evolutionary scheme of radio galaxies
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