GMRT observations of IC 711 – the longest head-tail radio galaxy known (original) (raw)
Related papers
Monthly Notices of the Royal Astronomical Society, 2021
We present original Giant Metrewave Radio Telescope (GMRT) radio observations of the galaxy cluster Abell 725, at a redshift (z) of 0.09, along with other archival observations. Our GMRT maps reveal two steep-spectrum diffuse filaments in the cluster, along with a previously reported arc-like structure, and a wide-angle-tail (WAT) radio source associated with the brightest cluster galaxy (BCG) at the periphery of the cluster. The bent morphology of the WAT indicates that its jets have been swept back by the dynamic pressure resulting from the motion of the BCG through the surrounding intracluster medium. The BCG associated with the WAT hosts a black hole whose mass we estimate to be 1.4 pm0.4times109,rmModot\ \pm\ 0.4 \times 10^{9}\,\rm M_{\odot }pm0.4times109,rmModot. We observe a 2 arcmin (195 kpc in projection) offset between the BCG and the X-ray centroid of the galaxy cluster, which, along with other dynamic features, indicates the cluster’s early stage of evolution. The WAT radio galaxy, the arc, and the filaments h...
Tailed radio galaxies from the TIFR GMRT sky survey
Monthly Notices of the Royal Astronomical Society
We present a list of tailed radio galaxies using the Tata Institute of Fundamental Research (TIFR) Giant Metrewave Radio Telescope (GMRT) Sky Survey Alternative Data Release 1 (TGSS ADR1) at 150 MHz. We visually examined 5336 image fields and found 264 tailed radio galaxies. Tailed radio galaxies are classified as wide-angle tailed (WAT) galaxies or narrow-angle tailed (NAT) galaxies, based on the angle between the two jets of the galaxy. Our sample of tailed radio galaxies included 203 WAT- and 61 NAT-type sources. These newly identified tailed sources are significant additions to the list of known tailed radio galaxies. The source morphology and luminosity features of the various galaxies and their optical identifications are presented. Other radio properties and general features of the sources are also discussed.
A new catalogue of head-tail radio galaxies from LoTSS DR1
2021
The peculiar morphology of Head-Tail (HT) radio galaxies indicates strong interactions between the radio jets and their intra-cluster medium. We systematically search for HT radio galaxies from LOFAR Two-metre Sky Survey first data release (LoTSS DR1) at 144 MHz frequency. We present here a catalogue of fifty new HT radio sources, among them, five are Narrow-Angle Tailed sources (NATs) and forty-five are Wide Angle Tailed sources (WATs). NATs are characterized by tails bent in a narrow ‘V’ like shape with less than a ninety-degree opening angle. For WAT radio galaxies, the opening angle between jets is more than ninety degrees which exhibit wide ‘C’ like morphologies. We found that thirty-one out of fifty HT sources are associated with known galaxy clusters. The various physical properties and statistical studies of these HT sources are also presented in this paper. Subject headings: galaxies: active – galaxies: jets – quasars: general – radio continuum: galaxies
Discovery of X-shaped morphology of the giant radio galaxy 0503-286
Astronomy & Astrophysics
The high surface-brightness sensitivity of the galactic and extragalactic all-sky mwa survey (GLEAM) image of the giant radio galaxy (GRG) 0503-28 at 70–230 MHz has revealed an inversion-symmetric bending of its two lobes, while maintaining a ∼200 kpc wide strip-like radio emission gap between their bent portions. This lends the source the appearance of a mega-sized X-shaped radio galaxy. Identifying the emission gap with the presence of a gaseous layer, probably a WHIM-filled sheet in the cosmic web, we suggest that the layer is the most likely cause of the inversion-symmetric bending of the two radio lobes. Multiple observational manifestations of such gaseous layers are noted. The two lobes of this GRG, known to extend very asymmetrically from the host galaxy, are remarkably symmetric about the emission gap, confirming a curious trend noted earlier for double radio sources of normal dimensions. The anomalous radio spectral gradient reported for the northern lobe of this GRG is no...
Substructure in Clusters Containing Wide-Angle–Tailed Radio Galaxies. I. New Redshifts
The Astronomical Journal, 2000
We present new redshifts and positions for 635 galaxies in nine rich clusters containing Wide-Angle Tailed (WAT) radio galaxies. Combined with existing data, we now have a sample of 18 WAT-containing clusters with more than 10 redshifts. This sample contains a substantial portion of the WAT clusters in the VLA 20 cm survey of Abell clusters, including 75% of WAT clusters in the complete survey (z≤0.09), and 20% of WAT clusters with z>0.09. It is a representative sample which should not contain biases other than selection by radio morphology. We graphically present the new data using histograms and sky maps. A semi-automated procedure is used to -2search for emission lines in the spectra in order to add and verify galaxy redshifts. We find that the average apparent fraction of emission line galaxies is about 9% in both the clusters and the field. We investigate the magnitude completeness of our redshift surveys with CCD data for a test case, Abell 690. This case indicates that our galaxy target lists are deeper than the detection limit of a typical MX exposure, and they are 82% complete down to R=19.0. The importance of the uniformity of the placement of fibers on targets is posited, and we evaluate this in our datasets. We find some cases of non-uniformities which may influence dynamical analyses. A second paper will use this database to look for correlations between the WAT radio morphology and the cluster's dynamical state.
Radio Galaxy Zoo: discovery of a poor cluster through a giant wide-angle tail radio galaxy
Monthly Notices of the Royal Astronomical Society, 2016
We have discovered a previously unreported poor cluster of galaxies (RGZ-CL J0823.2+0333) through an unusual giant wide-angle tail radio galaxy found in the Radio Galaxy Zoo project. We obtained a spectroscopic redshift of z = 0.0897 for the E0-type host galaxy, 2MASX J08231289+0333016, leading to M r = −22.6 and a 1.4 GHz radio luminosity density of L 1.4 = 5.5 × 10 24 W Hz −1. These radio and optical luminosities are typical for wide-angle tailed radio galaxies near the borderline between Fanaroff-Riley classes I and II. The projected largest angular size of ≈8 arcmin corresponds to 800 kpc and the full length of the source along the curved jets/trails is 1.1 Mpc in projection. X-ray data from the XMM-Newton archive yield an upper limit on the X-ray luminosity of the thermal emission surrounding RGZ J082312.9+033301 at 1.2-2.6 × 10 43 erg s −1 for assumed intracluster medium temperatures of 1.0-5.0 keV. Our analysis of the environment surrounding RGZ J082312.9+033301 indicates that RGZ J082312.9+033301 lies within a poor cluster. The observed radio morphology suggests that (a) the host galaxy is moving at a significant velocity with respect to an ambient medium like that of at least a poor cluster, and that (b) the source may have had two ignition events of the active galactic nucleus with 10 7 yr in between. This reinforces the idea that an association between RGZ J082312.9+033301 and the newly discovered poor cluster exists.
A new sample of large angular size radio galaxies
Astronomy and Astrophysics, 2004
We present in this paper a detailed study of a new sample of large angular size FR I and FR II radio galaxies and compare the properties of the two classes. As expected, a pure morphology based distinction of FR Is and FR IIs corresponds to a break in total radio power. The radio cores in FR Is are also weaker than in FR IIs, although there is not a well defined break power. We find that asymmetry in the structure of the sample members must be the consequence of anisotropies in the medium where the lobes expand, with orientation playing a minor role. Moreover, literature data and our observations at kiloparsec scales suggest that the large differences between the structures of FR I and FR II radio galaxies must arise from the poorly known central kiloparsec region of their host galaxies. We analyze the sub-sample of giant radio galaxies, and do not find evidence that these large objects require higher core powers. Our results are consistent with giant radio galaxies being the older population of normal FR I and FR II objects evolving in low density environments. Comparing results from our sample with predictions from the radio luminosity function we find no evidence of a possible FR II to FR I evolution. Moreover, we conclude that at z ∼ 0.1, one out of four FR II radio sources has a linear size above 500 kpc, thus being in an advanced stage of evolution (for example, older than ∼ 10 Myr assuming a jet-head velocity of 0.1c). Radio activity seems to be a short-lived process in active galaxies, although in some cases recurrent: five objects in our sample present signs of reactivation in their radio structures.
3C40 in Abell194: can tail radio galaxies exist in a quiescent cluster
Monthly Notices of The Royal Astronomical Society, 2008
The nearby cluster Abell194 hosts two luminous, distorted radio galaxies. Both reside within the cluster's core region, being separated in projection by only 100 kpc. It is often suggested that tailed radio galaxies such as these reside in clusters that are under formation and are accreting new material from their outskirts. In this paper, we study the intriguing appearance of Abell 194, and test whether the cluster and radio source dynamics are consistent with the cluster formation/merger model. We analyse data from the XMM-Newton satellite and previously unpublished observations with the Very Large Array as well as present new data from the Giant Metre-Wave Radio Telescope (GMRT). The shape of the jets, and the lack of significant stripping of the galaxies' interstellar media, indicates that the radio galaxies are not moving at the large velocities they would have had if they were falling into the cluster from its outskirts; galaxy velocities of <=300kms-1 are adequate instead. A plausible scenario that could explain the observations is that the dynamics of the cluster centre are relatively quiescent, with the dominant system of massive galaxies being bound and orbiting the cluster centre of mass. For plausible jet/plume speeds and densities and the galaxy dynamics implied by this picture of the cluster, we show that the observed jet structures can be explained without invoking a major cluster merger event.
Linear radio structures in selected Seyfert and LINER galaxies
AIP Conference Proceedings, 2006
High resolution MERLIN 5 GHz observations (0 ′′. 04) of 7 Seyfert galaxies, selected as the ones previously showing evidence of collimated ejection, have been compared with high resolution archive HST data. The radio maps reveal rich structures in all the galaxies. NGC 2639 and TXFS 2226-184 have multiple knot parsec-scale extended structures, Mrk 1034, Mrk 1210, NGC 4922C and NGC 5506 reveal one-sided jets, while IC 1481 exhibits a jet-like extension. The close correlation between the radio-emitting relativistic plasma and the ionized gas in the inner regions of these galaxies allows us to study in detail the physics close to the center of low luminosity AGN.