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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 559082.0, MPI für Astronomie / Publikationen_mpia
Tightly correlated H I and FUV emission in the outskirts of M83
Authors:Bigiel, F.; Leroy, A.; Seibert, M.; Walter, F.; Blitz, L.; Thilker, D.; Madore, B.
Date of Publication (YYYY-MM-DD):2010
Title of Journal:The Astrophysical Journal Letters
Journal Abbrev.:ApJL
Issue / Number:1
Start Page:L31
End Page:L35
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:We compare sensitive H I data from The H I Nearby Galaxy Survey and deep far-ultraviolet (FUV) data from the Galaxy Evolution Explorer in the outer disk of M83. The FUV and H I maps show a stunning spatial correlation out to almost 4 optical radii (r 25), roughly the extent of our maps. This underscores that H I traces the gas reservoir for outer-disk star formation (SF), and it implies that massive (at least low level) SF proceeds almost everywhere that H I is observed. Whereas the average FUV intensity steadily decreases with increasing radius before leveling off at ~1.7 r 25, the decline in H I surface density is more subtle. Low H I columns (lsim2 M sun pc–2) contribute most of the mass in the outer disk, which is not the case within r 25. The time for SF to consume the available H I, inferred from the ratio of H I to FUV intensity, rises with increasing radius before leveling off at ~100 Gyr, i.e., many Hubble times, near ~1.7 r 25. Assuming that the relatively short H2 depletion times observed in the inner parts of galaxies hold in outer disks, the conversion of H I into bound, molecular clouds seems to limit SF in outer galaxy disks. The long consumption times suggest that most of the extended H I observed in M83 will not be consumed by in situ SF. However, even these low SF rates are enough for moderate chemical enrichment in a closed outer disk to be expected.
Free Keywords:galaxies: evolution; galaxies: individual: M83; galaxies: ISM; radio lines: galaxies; stars: formation
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:URL:http://adsabs.harvard.edu/abs/2010ApJ...720L..31B [ID No:1]
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