Issue |
A&A
Volume 489, Number 3, October III 2008
|
|
---|---|---|
Page(s) | 1189 - 1200 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:200810341 | |
Published online | 25 August 2008 |
A mid-infrared study of H II regions in the Magellanic Clouds: N88 A and N160 A
1
Instituto de Astrofisíca de Canarias, Vía Láctea s/n, 38205 La Laguna, Spain e-mail: leticia@iac.es
2
NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035, USA
3
SETI Institute, 515 N. Whisman Road, Mountain View, CA 94043, USA
4
Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7, Canada
5
NASA Ames Research Center, MS 245-3, Moffett Field, CA 94035, USA
Received:
6
June
2008
Accepted:
6
August
2008
Aims. To show the importance of high-spatial resolution observations of H II regions when compared with observations obtained with larger apertures such as ISO, we present mid-infrared spectra of two Magellanic Cloud H II regions, N88 A and N160 A.
Methods. We obtained mid-infrared ( μm), long-slit spectra with TIMMI2 on the ESO 3.6 m telescope. These are combined with archival spectra obtained with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope, and are compared with the low-spatial resolution ISO-SWS data. An inventory of the spectra in terms of atomic fine-structure lines and molecular bands is presented.
Results. Concerning N88 A, an isolated H II region with no adjacent infrared sources, the observations indicate that the line fluxes observed by ISO-SWS and Spitzer-IRS come exclusively from the compact H II region of about 3´´ in diameter. This is not the case for N160 A, which has a more complex morphology. We have spectroscopically
isolated for the first time the individual contributions of the three components of N160 A, two high-excitation blobs, A1 and A2, and the young stellar object (YSO) N160 A-IR. In addition, extended [S IV] emission is observed with TIMMI2 and is most likely associated with the central star cluster located between A1 and A2. We show the value of these high-spatial resolution data in determining source characteristics, such as the degree of ionization of each high-excitation blob or the bolometric luminosity of the YSO. This luminosity (2105
) is about one order of magnitude lower than previously estimated. For each high-excitation blob, we also determine the electron density and the elemental abundances of Ne, S, and Ar.
Key words: ISM: lines and bands / ISM: dust, extinction / ISM: H II regions / ISM: individual objects: N88A / infrared: ISM / ISM: individual objects: N160A
© ESO, 2008
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.