2006/09/06 by Ekta, Ekta Ekta, Jayaram N. Chengalur +2 · 2 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Bar (unit) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gamma-ray bursts and supernovae #Giant Metrewave Radio Telescope #Irregular galaxy #Lenticular galaxy #Physics #Radio galaxy #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2006.10904.x
published as Mon.Not.Roy.Astron.Soc.372:853-861,2006 · 10 pages, 8 figures; accepted in MNRAS
arxiv created 2006/09/06 · openalex publication_date 2006/09/27 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present Giant Metrewave Radio Telescope H i observations of an extremely metal-deficient galaxy SBS 1129+576. SBS 1129+576 has a weighted mean oxygen abundance of 12 + log (O/H) = 7.41 ± 0.07, or 1/18 of the solar value. Our H i observations show that the galaxy is strongly interacting with a companion (projected separation ∼27 kpc) galaxy, SBS 1129+577. H i emission from a third, smaller galaxy, SDSS J113227.68+572142.3, is also present in the data cube. We study the H i morphology and kinematics of this small group at angular resolutions ranging from ∼40 to 8 arcsec. The low-resolution map shows a bridge of emission connecting the two larger galaxies and a large one-armed spiral distortion of the disc of SBS 1129+577. We measure H i masses of ∼4.2 × 108, ∼2.7 × 109 and ∼2.1 × 108 M⊙ for SBS 1129+576, SBS 1129+577 and the gas in the bridge, respectively. Assuming that most of the bridge gas originally came from SBS 1129+576, approximately one-third of its original gas mass has been stripped off. The third smaller galaxy has an H i mass of (MH I∼ 1.1 × 107 M⊙) and does not show any sign of interaction with the other two galaxies. The higher-resolution maps show that SBS 1129+577 has a central bar and a ring surrounding the bar; there is also a hint of an integral-shaped warp in SBS 1129+576. All these features are very likely to have been induced by the tidal interaction. In both SBS 1129+576 and SBS 1129+577, there is, in general, a good correspondence between regions with high H i column density and those with ongoing star formation. The two brightest H ii regions in SBS 1129+576 have (inclination-corrected) gas column densities of ∼1.6 × 1021 and ∼1.8 × 1021 atoms cm−2, respectively. The inclination-corrected H i column density near the H ii regions in SBS 1129+577 is generally above ∼2.0 × 1021 atoms cm−2. These values are close to the threshold density for star formation observed in other blue compact galaxies. In contrast to SBS 1129+576 and SBS 1129+577 which are very gas-rich, the third member of this group, SDSS J113227.68+572142.3, is gas-poor.