Title:	Arp 65 interaction debris: massive H I displacement and star formation
Authors:	Sengupta, C. Scott, T.C. Paudel, S. Saikia, D.J. Dwarakanath, K.S. Sohn, B. W.
Keywords:	galaxies star formation galaxies: interactions radio lines: ISM galaxies: ISM
Issue Date:	2-Dec-2015
Publisher:	EDP Sciences
Citation:	Astronomy and Astrophysics, 2015, Vol.584, Article No.A114
Abstract:	Context: Pre-merger interactions between galaxies can induce significant changes in the morphologies and kinematics of the stellar and ISM components. Large amounts of gas and stars are often found to be disturbed or displaced as tidal debris. This debris then evolves, sometimes forming stars and occasionally tidal dwarf galaxies. Here we present results from our HI study of Arp 65, an interacting pair hosting extended HI tidal debris. Aims: In an effort to understand the evolution of tidal debris produced by interacting pairs of galaxies, including in situ star and tidal dwarf galaxy formation, we are mapping HI in a sample of interacting galaxy pairs. The Arp 65 pair is one of them. Methods: Our resolved HI 21 cm line survey is being carried out using the Giant Metrewave Radio Telescope (GMRT). We used our HI survey data as well as available SDSS optical, Spitzer infra-red and GALEX UV data to study the evolution of the tidal debris and the correlation of HI with the star-forming regions within it. Results: In Arp 65 we see a high impact pre-merger interaction involving a pair of massive galaxies (NGC 90 and NGC 93) that have a stellar mass ratio of ~ 1:3. The interaction, which probably occurred ~ 1.0 -- 2.5 × 108 yr ago, appears to have displaced a large fraction of the HI in NGC 90 (including the highest column density HI) beyond its optical disk. We also find extended ongoing star formation in the outer disk of NGC 90. In the major star-forming regions, we find the HI column densities to be ~ 4.7 × 1020 cm−2 or lower. But no signature of star formation was found in the highest column density HI debris, SE of NGC 90. This indicates conditions within the highest column density HI debris remain hostile to star formation and it reaffirms that high HI column densities may be a necessary but not sufficient criterion for star formation.
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/7915
ISSN:	0004-6361 1432-0746
Alternative Location:	https://ui.adsabs.harvard.edu/abs/2015A%26A...584A.114S/abstract https://arxiv.org/abs/1509.02614 https://doi.org/10.1051/0004-6361/201425149
Copyright:	2015 ESO
Appears in Collections:	Research Papers (A&A)

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