• DOI:10.1086/506196
• Corpus ID: 13901458

ULTRAVIOLET THROUGH FAR-INFRARED SPATIALLY RESOLVED ANALYSIS OF THE RECENT STAR FORMATION IN M81 (NGC 3031)

@article{PrezGonzlez2006ULTRAVIOLETTF,
  title={ULTRAVIOLET THROUGH FAR-INFRARED SPATIALLY RESOLVED ANALYSIS OF THE RECENT STAR FORMATION IN M81 (NGC 3031)},
  author={Pablo G. P{\'e}rez-Gonz{\'a}lez and Robert C. Kennicutt and Karl D. Gordon and Karl Anthony Misselt and Armando Gil de Paz and Charles William Engelbracht and George H. Rieke and George J Bendo and Luciana Bianchi and Samuel Boissier and Daniela Calzetti and Daniel A. Dale and Bruce T. Draine and Thomas H. Jarrett and David J. Hollenbach and Moire K. M. Prescott The University of Arizona and Universidad Complutense de Madrid and Observatories of the Carnegie Institution of Washington and Imperial College and Johns Hopkins University and Laboratoire d'Astrophysique de Marseille and Space Telescope Science Institute and University of Wyoming and Princeton University Observatory and Spitzer Science Center and Nasa Ames Research Center},
  journal={The Astrophysical Journal},
  year={2006},
  volume={648},
  pages={987-1006}
}

• P. Pérez-González, R. Kennicutt, +23 authors Nasa Ames Research Center
• Published 23 May 2006
• Physics
• The Astrophysical Journal

The recent star formation (SF) in the early-type spiral galaxy M81 is characterized using imaging observations from the far-ultraviolet to the far-infrared. We compare these data with models of the stellar, gas, and dust emission for subgalactic regions. Our results suggest the existence of a diffuse dust emission not directly linked to the recent star formation. We find a radial decrease of the dust temperature and dust mass density, and in the attenuation of the stellar light. The IR emission in M81 can be modeled with three components: (1) cold dust with a temperature = 18 ± 2 K, concentrated near the H II regions but also presenting a diffuse distribution; (2) warm dust with = 53 ± 7 K, directly linked with the H II regions; and (3) aromatic molecules, with diffuse morphology peaking around the H II regions. We derive several relationships to obtain total IR luminosities from IR monochromatic fluxes, and we compare five different star formation rate (SFR) estimators for H II regions in M81 and M51: the UV, H alpha, and three estimators based on Spitzer data. We find that the H alpha luminosity absorbed by dust correlates tightly with the 24 mu m emission. The correlation with the total IR luminosity is not as good. Important variations from galaxy to galaxy are found when estimating the total SFR with the 24 mu m or the total IR emission alone. The most reliable estimations of the total SFRs are obtained by combining the H alpha emission (or the UV) and an IR luminosity (especially the 24 mu m emission), which probe the unobscured and obscured SF, respectively. For the entire M81 galaxy, about 50% of the total SF is obscured by dust. The percentage of obscured SF ranges from 60% in the inner regions of the galaxy to 30% in the outer zones.