Query : 2008A&A...488..519E

2008A&A...488..519E - Astronomy and Astrophysics, volume 488, 519-522 (2008/9-3)

From major merger to radio galaxy: low surface-brightness stellar counterpart to the giant H I ring around B2 0648+27.


Abstract (from CDS):

We present the detection of a low surface-brightness stellar counterpart to an enormous (190kpc) ring of neutral hydrogen (HI) gas that surrounds the nearby radio galaxy B2 0648+27. This system is currently in an evolutionary stage between major merger and (radio-loud) early-type galaxy. In a previous paper we investigated in detail the timescales between merger, starburst and AGN activity in B2 0648+27, based on its unusual multi-wavelength properties (large-scale HI ring, dominating post-starburst stellar population and infra-red luminosity). In this Research Note we present deep optical B- and V-band imaging that provides further evidence for the merger origin of B2 0648+27. The host galaxy shows a distorted optical morphology and a broad tidal arm is clearly present. A low surface-brightness stellar tail or partial ring curls around more than half the host galaxy at a distance of up to 55 kpc from the centre of the galaxy, following the large-scale, ring-like HI structure that we detected previously around this system. The gas and stars in this ring are most likely tidally expelled material that slowly fell back onto the host galaxy after the merger event. There also appear to be sites of star formation within the HI ring that may have formed within the gaseous tidal debris after the merger. We argue that the observed properties of the gas and stars in B2 0648+27, as well as the apparent time-delay between the merger and the starburst event, may be the logical result of a merger between two gas-rich disk galaxies with a prominent bulge, or of a merger between an elliptical and a gas-rich spiral galaxy. There also appears to be a significant time-delay between the merger/starburst event and the current episode of radio-AGN activity.

Abstract Copyright:

Journal keyword(s): galaxies: individual: B2 0648+27 - galaxies: interactions - galaxies: starburst - galaxies: active - galaxies: evolution - ISM: kinematics and dynamics

Simbad objects: 2

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Number of rows : 2
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 MCG+05-16-010 AGN 06 52 02.5060831464 +27 27 39.387328884   14.9       ~ 81 1
2 NGC 5266 GiG 13 43 02.0849196792 -48 10 10.000751592   11.89 11.14 11.9 11.3 ~ 161 0

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