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Spectral energy distributions of HII regions in M33 (HerM33es)

Relaño, M. and Verley, S. and Pérez, I. and Kramer, C. and Calzetti, D. and Xilouris, E. M. and Boquien, M. and Abreu-Vicente, J. and Combes, F. and Israel, F. and Tabatabaei, F. S. and Braine, J. and Buchbender, C. and González, M. and Gratier, P. and Lord, S. and Mookerjea, B. and Quintana-Lacaci, G. and van der Werf, P. (2013) Spectral energy distributions of HII regions in M33 (HerM33es). Astronomy and Astrophysics, 552 . Art. No. A140. ISSN 0004-6361.

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Aims. Within the framework of the Herschel M 33 extended survey HerM33es and in combination with multi-wavelength data we study the spectral energy distribution (SED) of a set of H ii regions in the Local Group galaxy M 33 as a function of the morphology. We analyse the emission distribution in regions with different morphologies and present models to infer the Hα emission measure observed for H ii regions with well defined morphology. Methods. We present a catalogue of 119 H ii regions morphologically classified: 9 filled, 47 mixed, 36 shell, and 27 clear shell H ii regions. For each object we extracted the photometry at twelve available wavelength bands, covering a wide wavelength range from FUV-1516 Å (GALEX) to IR-250 μm (Herschel), and we obtained the SED for each object. We also obtained emission line profiles in vertical and horizontal directions across the regions to study the location of the stellar, ionised gas, and dust components. We constructed a simple geometrical model for the clear shell regions, whose properties allowed us to infer the electron density of these regions. Results. We find trends for the SEDs related to the morphology of the regions, showing that the star and gas-dust configuration affects the ratios of the emission in different bands. The mixed and filled regions show higher emission at 24 μm, corresponding to warm dust, than the shells and clear shells. This could be due to the proximity of the dust to the stellar clusters in the case of filled and mixed regions. The far-IR peak for shells and clear shells seems to be located towards longer wavelengths, indicating that the dust is colder for this type of object. The logarithmic 100 μm/70 μm ratio for filled and mixed regions remains constant over one order of magnitude in Hα and FUV surface brightness, while the shells and clear shells exhibit a wider range of values of almost two orders of magnitude. We derive dust masses and dust temperatures for each H ii region by fitting the individual SEDs with dust models proposed in the literature. The derived dust mass range is between 10^2−10^4 M_⊙ and the cold dust temperature spans T_(cold) ~ 12−27 K. The spherical geometrical model proposed for the Hα clear shells is confirmed by the emission profile obtained from the observations and is used to infer the electron density within the envelope: the typical electron density is 0.7 ± 0.3 cm^(-3), while filled regions can reach values that are two to five times higher.

Item Type:Article
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URLURL TypeDescription
Calzetti, D.0000-0002-5189-8004
Boquien, M.0000-0003-0946-6176
Combes, F.0000-0003-2658-7893
van der Werf, P.0000-0001-5434-5942
Additional Information:© 2013 ESO. Article published by EDP Sciences. Received 22 July 2012. Accepted 23 January 2013. Published online 17 April 2013. Part of this research has been supported by the ERG HERSFR from the EC. This work was partially supported by a Junta de Andalucía Grant FQM108, a Spanish MEC Grant AYA-2007-67625-C02-02, and the Juan de la Cierva fellowship programme. This research made use of APLpy, an opensource plotting package for Python hosted at; of TOPCAT & STIL: Starlink Table/VOTable Processing Software (Taylor 2005); of Matplotlib (Hunter 2007), a suite of open-source python modules that provide a framework for creating scientific plots.
Funding AgencyGrant Number
Junta de AndalucíaFQM108
Ministerio de Educación y Ciencia (MEC)AYA-2007-67625-C02-02
Juan de la Cierva fellowship programmeUNSPECIFIED
Subject Keywords:galaxies: individual: M 33; galaxies: ISM; Local Group; dust; extinction; HII regions; ISM: bubbles
Record Number:CaltechAUTHORS:20130619-081233412
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Official Citation:Spectral energy distributions of H ii regions in M 33 (HerM33es) A140 M. Relaño, S. Verley, I. Pérez, C. Kramer, D. Calzetti, E. M. Xilouris, M. Boquien, J. Abreu-Vicente, F. Combes, F. Israel, et al. (9 more) Published online: 17 April 2013 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:38977
Deposited By: Ruth Sustaita
Deposited On:19 Jun 2013 15:38
Last Modified:09 Mar 2020 13:18

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