Cannibalization and Rebirth in the NGC 5387 System. I. The Stellar Stream and Star-forming Region

Type Journal Article
Names Rachael L. Beaton, David Martínez-Delgado, Steven R. Majewski, Elena D'Onghia, Stefano Zibetti, R. Jay Gabany, Kelsey E. Johnson, Michael Blanton, Anne Verbiscer
Publication The Astrophysical Journal
Volume 790
Issue 2
Pages 117
Journal Abbreviation The Astrophysical Journal
Date August 1, 2014
DOI 10.1088/0004-637X/790/2/117
ISSN 0004-637X
Library Catalog
Abstract We have identified a low surface brightness stellar stream from visual inspection of Sloan Digital Sky Survey (SDSS) imaging for the edge-on, spiral galaxy NGC 5387. An optically blue overdensity coincident with the stream intersection with the NGC 5387 disk was also identified in SDSS and in the Galaxy Evolution Explorer Deep Imaging Survey contributing 38% of the total far-UV integrated flux from NGC 5387. Deeper optical imaging was acquired with the Vatican Advanced Technology Telescope that confirmed the presence of both features. The stellar stream is red in color, (B - V) = 0.7, has a stellar mass of 6 × 108 M ⊙, which implies a 1:50 merger ratio, has a circular radius, R circ ~ 11.7 kpc, formed in ~240 Myr, and the progenitor had a total mass of ~4 × 1010 M ⊙. Spectroscopy from LBT+MODS1 was used to determine that the blue overdensity is at the same redshift as NGC 5387, consists of young stellar populations (~10 Myr), is metal-poor (12 + log (O/H) = 8.03), and is forming stars at an enhanced rate (~1-3 M ⊙ yr-1). The most likely interpretations are that the blue overdensity is (1) a region of enhanced star formation in the outer disk of NGC 5387 induced by the minor accretion event or (2) the progenitor of the stellar stream experiencing enhanced star formation. Additional exploration of these scenarios is presented in a companion paper. Based on observations with the VATT: the Alice P. Lennon Telescope and the Thomas J. Bannan Astrophysics Facility.
Tags GALAXIES: EVOLUTION, Galaxies: Dwarf, Galaxies: General, galaxies: individual: NGC 5387, galaxies: star formation
UW-Madison Astronomy Home