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Home Search Quick Search Advanced Fulltext Browse Collections Persons My eDoc Session History Login Name: Password: Documentation Help Support Wiki Direct access to document ID:	Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents ID: 709931.0, MPI für Astronomie / Publikationen_mpia A low H I column density filament in NGC 2403: signature of interaction or accretion Authors: de Blok, W. J. G.; Keating, K. M.; Pisano, D. J.; Fraternali, F.; Walter, F.; Oosterloo, T.; Brinks, E.; Bigiel, F.; Leroy, A. Date of Publication (YYYY-MM-DD): 2014 Title of Journal: Astronomy and Astrophysics Volume: 569 Start Page: id. A68 (11 pp) Audience: Not Specified Abstract / Description: Observed H i accretion around nearby galaxies can only account for a fraction of the gas supply needed to sustain the currently observed star formation rates. It is possible that additional accretion occurs in the form of low column density cold flows, as predicted by numerical simulations of galaxy formation. To constrain the presence and properties of such flows, we present deep H i observations obtained with the NRAO Green Bank Telescope of an area measuring 4° × 4° around NGC 2403. These observations, with a 5sigma detection limit of 2.4 × 1018 cm-2 over a 20 km s-1 linewidth, reveal a low column density, extended cloud outside the main H i disk, about 17' (~ 16 kpc or ~ 2 R25) to the NW of the center of the galaxy. The total H i mass of the cloud is 6.3 × 106 M&sun;, or 0.15 percent of the total H i mass of NGC 2403. The cloud is associated with an 8 kpc anomalous-velocity H i filament in the inner disk, that was previously observed in deep VLA observations. We discuss several scenarios for the origin of the cloud, and conclude that it is either accreting from the intergalactic medium, or is the result of a minor interaction with a neigboring dwarf galaxy. The reduced datacubes (FITS files) are only available at the CDS via anonymous ftp to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> (ftp://130.79.128.5) or via <A href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/569/A68">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/569/A68</A> Free Keywords: galaxies: ISM; galaxies: kinematics and dynamics; galaxies: halos; galaxies: individual: NGC 2403; galaxies: structure External Publication Status: published Document Type: Article Communicated by: N. N. Affiliations: MPI für Astronomie Identifiers: ISSN:0004-6361 %R 10.1051/0004-6361/201423880 URL:http://cdsads.u-strasbg.fr/abs/2014A%26A...569A..6... The scope and number of records on eDoc is subject to the collection policies defined by each institute - see "info" button in the collection browse view.