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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 731822.0, MPI für Astronomie / Publikationen_mpia
Satellite accretion in action: a tidally disrupting dwarf spheroidal around the nearby spiral galaxy NGC 253
Authors:Romanowsky, A. J.; Martínez-Delgado, D.; Martin, N. F.; Morales, G.; Jennings, Z. G.; GaBany, R. J.; Brodie, J. P.; Grebel, E. K.; Schedler, J.; Sidonio, M.
Date of Publication (YYYY-MM-DD):2016
Title of Journal:Monthly Notices of the Royal Astronomical Society
Issue / Number:1
Start Page:L103
End Page:L107
Audience:Not Specified
Abstract / Description:We report the discovery of NGC 253-dw2, a dwarf spheroidal (dSph) galaxy candidate undergoing tidal disruption around a nearby spiral galaxy, NGC 253 in the Sculptor group: the first such event identified beyond the Local Group. The dwarf was found using small-aperture amateur telescopes, and followed up with Suprime-Cam on the 8 m Subaru Telescope in order to resolve its brightest stars. Using g- and Rc-band photometry, we detect a red giant branch consistent with an old, metal-poor stellar population at a distance of ˜3.5 Mpc. From the distribution of likely member stars, we infer a highly elongated shape with a semimajor axis half-light radius of (2 ± 0.4) kpc. Star counts also yield a luminosity estimate of ˜2 × 106 L⊙,V (MV ˜ -10.7). The morphological properties of NGC 253-dw2 mark it as distinct from normal dSphs and imply ongoing disruption at a projected distance of ˜50 kpc from the main galaxy. Our observations support the hierarchical paradigm wherein massive galaxies continuously accrete less massive ones, and provide a new case study for dSph infall and dissolution dynamics. We also note the continued efficacy of small telescopes for making big discoveries.
Free Keywords:galaxies: dwarf; galaxies: individual: NGC 253; galaxies: interactions
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0035-8711 %R 10.1093/mnrasl/slv207
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