Arp 65 interaction debris: massive HI displacement and star formation

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 $\times$ 10${}^8$ 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 $\times$ 10${}^{20}$ 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.

Accepted in A&A

References in corpus (6)

• The Spitzer Spirals, Bridges, and Tails Interacting Galaxy Survey: Interaction-Induced Star Formation in the Mid-Infrared
• Physical Properties of Tidal Features in Interacting Disk Galaxies
• HI content in galaxies in loose groups
• An HI Threshold for Star Cluster Formation in Tidal Debris
• Multi-object Spectroscopy of Young Star Clusters in NGC 4676
• HI in the Arp 202 system and its tidal dwarf candidate

Cited by in corpus (13)

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• Mapping kiloparsec-scale structures in the extended HI disc of the galaxy UGC 00439 by HI 21-cm absorption
• Young tidal dwarf galaxies cannot be used to probe dark matter in galaxies
• HI debris in the IC 1459 galaxy group
• HI, star formation and tidal dwarf candidate in the Arp 305 system
• Optical spectroscopy of young tidal objects around two interacting galaxy pairs
• NGC 90: a hidden jelly-fish galaxy?
• Detection and characterization of detached tidal dwarf galaxies
• Star formation in low density HI gas around the Elliptical Galaxy NGC2865
• Interacting system NGC 7805/6 (Arp 112) and its tidal dwarf galaxy candidate