Radio continuum emission and H i gas accretion in the NGC 5903/5898 compact group of early-type galaxies

Gopal-Krishna, . .; Mhaskey, Mukul; Wiita, Paul J.; Sirothia, S. K.; Kantharia, N. G.; Ishwara‐Chandra, C. H.

doi:10.1111/j.1365-2966.2012.20933.x

Cited by 8 publications

(9 citation statements)

References 32 publications

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“…The only diffuse radio source in the low-richness sample, appears in the galaxy group NGC 5903 (see Figure B23). It has also been examined by several earlier studies at many different frequencies (e.g., Gopal-Krishna 1978;Gopal-Krishna et al 2012;. It hosts a ∼75 kpc wide diffuse, steepspectrum (α 612 150 ∼ 1.03; O'Sullivan et al 2018) radio source whose origin may be through a combination of AGN activity and violent galaxy interactions (see A23).…”

Section: Radio Morphologymentioning

confidence: 98%

The complete local volume groups sample – III. Characteristics of group central radio galaxies in the Local Universe

Kolokythas

O’Sullivan

Intema

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Using new 610 MHz and 235 MHz observations from the Giant Metrewave Radio Telescope (GMRT) in combination with archival GMRT and Very Large Array (VLA) survey data we present the radio properties of the dominant early-type galaxies in the low-richness sub-sample of the Complete Local-volume Groups Sample (CLoGS; 27 galaxy groups) and provide results for the radio properties of the full CLoGS sample for the first time. We find a high radio detection rate in the dominant galaxies of the low-richness sub-sample of 82% (22/27); for the full CLoGS sample the detection rate is 87% (46/53). The group-dominant galaxies exhibit a wide range of radio power, 10 20 − 10 25 W Hz −1 in the 235 and 610 MHz bands, with the majority (53%) presenting point-like radio emission, 19% hosting currently active radio jets, 6% having remnant jets, 9% being diffuse and 13% having no detected radio emission. The mean spectral index of the detected radio sources in the 235−610 MHz frequency range is found to be α 610 235 ∼0.68, and α 1400 235 ∼0.59 in the 235−1400 MHz one. In agreement with earlier studies, we find that the fraction of ultra-steep spectrum sources (α >1.3) is ∼4%, mostly dependent on the detection limit at 235 MHz. The majority of pointlike systems are found to reside in dynamically young groups, whereas jet systems show no preference between spiral-rich and spiral-poor group environments. The mechanical power of the jet sources in the low-richness sample groups is estimated to be ∼10 42 − 10 44 erg s −1 with their black hole masses ranging between 2×10 8 − 5×10 9 M . We confirm previous findings that, while radio jet sources tend to be associated with more massive black holes, black hole mass is not the decisive factor in determining jet activity or power.

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Section: Radio Morphologymentioning

confidence: 98%

The complete local volume groups sample – III. Characteristics of group central radio galaxies in the Local Universe

Kolokythas

O’Sullivan

Intema

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…As of this writing, there have been five data releases, with only about ten percent of the survey images having been processed and released through the TGSS project website 1 . A small number of publications have been published using data from this initial release including Bagchi et al (2011), Gopal-Krishna et al (2012), Sirothia et al (2014), and Krishna et al (2014).…”

Section: Introductionmentioning

confidence: 99%

The GMRT 150 MHz all-sky radio survey

Intema

Jagannathan

Mooley

et al. 2017

A&A

831

767

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We present the first full release of a survey of the 150 MHz radio sky, observed with the Giant Metrewave Radio Telescope (GMRT) between April 2010 and March 2012 as part of the TIFR GMRT Sky Survey (TGSS) project. Aimed at producing a reliable compact source survey, our automated data reduction pipeline efficiently processed more than 2000 h of observations with minimal human interaction. Through application of innovative techniques such as image-based flagging, direction-dependent calibration of ionospheric phase errors, correcting for systematic offsets in antenna pointing, and improving the primary beam model, we created good quality images for over 95 percent of the 5336 pointings. Our data release covers 36 900 deg 2 (or 3.6 π steradians) of the sky between −53• and +90• declination (Dec), which is 90 percent of the total sky. The majority of pointing images have a noise level below 5 mJy beamwith an approximate resolution of 25 × 25 (or 25 × 25 /cos (Dec − 19 • ) for pointings south of 19 • declination). We have produced a catalog of 0.62 Million radio sources derived from an initial, high reliability source extraction at the seven sigma level. For the bulk of the survey, the measured overall astrometric accuracy is better than two arcseconds in right ascension and declination, while the flux density accuracy is estimated at approximately ten percent. Within the scope of the TGSS alternative data release (TGSS ADR) project, the source catalog, as well as 5336 mosaic images (5• × 5 • ) and an image cutout service, are made publicly available at the CDS as a service to the astronomical community. Next to enabling a wide range of different scientific investigations, we anticipate that these survey products will provide a solid reference for various new low-frequency radio aperture array telescopes (LOFAR, LWA, MWA, SKA-low), and can play an important role in characterizing the epoch-of-reionisation (EoR) foreground. The TGSS ADR project aims at continuously improving the quality of the survey data products. Near-future improvements include replacement of bright source snapshot images with archival targeted observations, using new observations to fill the holes in sky coverage and replace very poor quality observational data, and an improved flux calibration strategy for less severely affected observational data.

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“…Some examples include the detection of hot gas through X-rays (Forman et al 1979;O'Sullivan, Forbes & Ponman 2001;Macchetto et al 1996), H I gas (e.g. VerdesMontenegro et al 2001;Gopal-Krishna et al 2012), warm ionized gas (Demoulin-Ulrich, Butcher & Boksenberg 1984;Kim 1989;Trinchieri & di Serego Alighieri 1991;Kehrig et al 2012), and dust (Rowlands et al 2012;di Serego Alighieri et al 2013). In this context, Trager et al (2000) proposed a 'frosting' model in which the apparently young ages inferred for some ellipticals by single stellar population models, is due to a 'frosting' of younger stars in a primarily old stellar population (but see Maraston & Thomas 2000).…”

Section: Introductionmentioning

confidence: 99%

Ionized gas discs in elliptical and S0 galaxies at z < 1

Jaffé

Aragón-Salamanca

Ziegler

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We analyse the extended, ionized-gas emission of 24 early-type galaxies (ETGs) at 0 < z < 1 from the ESO Distant Cluster Survey (EDisCS). We discuss different possible sources of ionization and favour star formation as the main cause of the observed emission. 10 galaxies have disturbed gas kinematics, while 14 have rotating gas discs. In addition, 15 galaxies are in the field, while 9 are in the infall regions of clusters. This implies that, if the gas has an internal origin, this is likely stripped as the galaxies get closer to the cluster centre. If the gas instead comes from an external source, then our results suggest that this is more likely acquired outside the cluster environment, where galaxy-galaxy interactions more commonly take place. We analyse the Tully-Fisher relation of the ETGs with gas discs, and compare them to EDisCS spirals. Taking a matched range of redshifts, M B < −20, and excluding galaxies with large velocity uncertainties, we find that, at fixed rotational velocity, ETGs are 1.7 mag fainter in M B than spirals. At fixed stellar mass, we also find that ETGs have systematically lower specific star formation rates than spirals. This study constitutes an important step forward towards the understanding of the evolution of the complex ISM in ETGs by significantly extending the look-back-time baseline explored so far.

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Radio continuum emission and H i gas accretion in the NGC 5903/5898 compact group of early-type galaxies

Cited by 8 publications

References 32 publications

The complete local volume groups sample – III. Characteristics of group central radio galaxies in the Local Universe

The complete local volume groups sample – III. Characteristics of group central radio galaxies in the Local Universe

The GMRT 150 MHz all-sky radio survey

Ionized gas discs in elliptical and S0 galaxies at z < 1

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