Please use this identifier to cite or link to this item: http://hdl.handle.net/2248/7241
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dc.contributor.authorKharb, P-
dc.contributor.authorSrivastava, S-
dc.contributor.authorSingh, V-
dc.contributor.authorGallimore, J. F-
dc.contributor.authorIshwara-Chandra, C. H-
dc.contributor.authorAnanda, H-
dc.date.accessioned2020-11-19T13:36:53Z-
dc.date.available2020-11-19T13:36:53Z-
dc.date.issued2016-06-
dc.identifier.citationMonthly Notices of the Royal Astronomical Society, Vol. 459, No. 2, pp. 1310-1326en_US
dc.identifier.issn1365-2966-
dc.identifier.urihttp://prints.iiap.res.in/handle/2248/7241-
dc.descriptionRestricted Access © Royal Astronomical Society http://dx.doi.org/10.1093/mnras/stw699en_US
dc.description.abstractLow-frequency observations at 325 and 610 MHz have been carried out for two ‘radio-loud’ Seyfert galaxies, NGC 4235 and NGC 4594 (Sombrero galaxy), using the Giant Meterwave Radio Telescope (GMRT). The 610 MHz total intensity and 325–610 MHz spectral index images of NGC 4235 tentatively suggest the presence of a ‘relic’ radio lobe, most likely from a previous episode of active galactic nucleus (AGN) activity. This makes NGC 4235 only the second known Seyfert galaxy after Mrk 6 to show signatures of episodic activity. Spitzer and Herschel infrared spectral energy distribution (SED) modelling using the CLUMPYDREAM code predicts star formation rates (SFRs) that are an order of magnitude lower than those required to power the radio lobes in these Seyferts ( ∼ 0.13–0.23 M yr − 1 compared to the required SFR of ∼ 2.0–2.7 M yr − 1 in NGC 4594 and NGC 4235, respectively). This finding along with the detection of parsec and sub-kpc radio jets in both Seyfert galaxies, that are roughly along the same position angles as the radio lobes, strongly support the suggestion that Seyfert lobes are AGN powered. SED modelling supports the ‘true’ type 2 classification of NGC 4594: this galaxy lacks significant dust obscuration as well as a prominent broad-line region. Between the two Seyfert galaxies, there is an inverse relation between their radio-loudness and Eddington ratio and a direct relation between their Eddington-scaled jet power and bolometric power.en_US
dc.language.isoenen_US
dc.publisherOxford University Press on behalf of the Royal Astronomical Societyen_US
dc.subjecttechniques: interferometricen_US
dc.subjectgalaxies: individual: NGC 4235, NGC 4594en_US
dc.subjectgalaxies: Seyfert – infrared: galaxiesen_US
dc.subjectradio continuum: galaxiesen_US
dc.titleA GMRT study of Seyfert galaxies NGC 4235 and NGC 4594: evidence of episodic activity?en_US
dc.typeArticleen_US
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