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Distinguishing between HII regions and planetary nebulae with Hi-GAL, WISE, MIPSGAL, and GLIMPSE

Anderson, L. D. and Zavagno, A. and Barlow, M. J. and García-Lario, P. and Noriega-Crespo, A. (2012) Distinguishing between HII regions and planetary nebulae with Hi-GAL, WISE, MIPSGAL, and GLIMPSE. Astronomy and Astrophysics, 537 . Art. No. A1. ISSN 0004-6361. doi:10.1051/0004-6361/201117640.

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Context. H II regions and planetary nebulae (PNe) both emit at radio and infrared (IR) wavelengths, and angularly small H II regions can be mistaken for PNe. This problem of classification is most severe for H II regions in an early evolutionary stage, those that are extremely distant, or those that are both young and distant. Previous work has shown that H II regions and PNe can be separated based on their infrared colors. Aims. Using data from the Herschel Hi-GAL survey, as well as WISE and the Spitzer MIPSGAL and GLIMPSE surveys, we wish to establish characteristic IR colors that can be used to distinguish between H II regions and PNe. Methods. We perform aperture photometry measurements for a sample of 126 H II regions and 43 PNe at wavelengths from 8.0 μm to 500 μm. Results. We find that H II regions and PNe have distinct IR colors. The most robust discriminating color criteria are [F_(12)/F_8] < 0.3, [F_(160)/F_(12)] > 1.3, and [F_(160)/F_(24)] > 0.8 (or alternately [F_(160)/F_(22)] > 0.8), where the brackets indicate the log of the flux ratio. All three of these criteria are individually satisfied by over 98% of our sample of H II regions and by ~10% of our sample of PNe. Combinations of these colors are more robust in separating the two populations; for example all H II regions and no PNe satisfy [F_(12)/F_8] < 0.4 and [F_(160)/F_(22)] > 0.8. When applied to objects of unknown classification, these criteria prove useful in separating the two populations. The dispersion in color is relatively small for H II regions; this suggests that any evolution in these colors with time for H II regions must be relatively modest. The spectral energy distributions (SEDs) of H II regions can be separated into “warm” and “cold” components. The “cold” component is well-fit by a grey-body of temperature 25 K. The SEDs of nearly two-thirds of our sample of H II regions peak at 160 μm and one third peak at 70 μm. For PNe, 67% of the SEDs peak at 70 μm, 23% peak at either 22 μm or 24 μm, and 9% (two sources) peak at 160 μm.

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Noriega-Crespo, A.0000-0002-6296-8960
Additional Information:© 2012 ESO. Received 6 July 2011. Accepted 13 October 2011. Published online 19 December 2011. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. We would like to thank the Hi-GAL team for their continuing work on the survey. PACS has been developed by a consortium of institutes led by MPE (Germany) and including UVIE (Austria); KU Leuven, CSL, IMEC (Belgium); CEA, LAM (France); MPIA (Germany); INAF-IFSI/OAA/OAP/OAT, LENS, SISSA (Italy); IAC (Spain). This development has been supported by the funding agencies BMVIT (Austria), ESAPRODEX (Belgium), CEA/CNES (France), DLR (Germany), ASI/INAF (Italy), and CICYT/MCYT (Spain). SPIRE has been developed by a consortium of institutes led by Cardiff University (UK) and including Univ. Lethbridge (Canada); NAOC (China); CEA, LAM (France); IFSI, Univ. Padua (Italy); IAC (Spain); Stockholm Observatory (Sweden); Imperial College London, RAL, UCL-MSSL, UKATC, Univ. Sussex (UK); and Caltech, JPL, NHSC, Univ. Colorado (USA). This development has been supported by national funding agencies: CSA (Canada); NAOC (China); CEA, CNES, CNRS (France); ASI (Italy); MCINN (Spain); SNSB (Sweden); STFC (UK); and NASA (USA). This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This research has made use of NASA’s Astrophysics Data System Bibliographic Services and the SIMBAD database operated at CDS, Strasbourg, France. L.D.A. acknowledges support by the ANR Agence Nationale for the research project “PROBeS”, number ANR- 08-BLAN-0241.
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ANR Agence NationaleANR-08-BLAN-0241
Subject Keywords:infrared: ISM; stars: formation; dust, extinction; planetary nebulae: general; HII regions
Record Number:CaltechAUTHORS:20120417-082049582
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Official Citation:Distinguishing between HII regions and planetary nebulae with Hi-GAL, WISE, MIPSGAL, and GLIMPSE L. D. Anderson, A. Zavagno, M. J. Barlow, P. García-Lario and A. Noriega-Crespo A&A 537 A1 (2012) DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:30117
Deposited By: Ruth Sustaita
Deposited On:17 Apr 2012 15:49
Last Modified:09 Nov 2021 19:36

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