The G305 star-forming complex: embedded massive star formation discovered by Herschel Hi-GAL
Abstract
We present a Herschel far-infrared study towards the rich massive star-forming complex G305, utilizing PACS 70, 160 μm and SPIRE 250, 350, and 500 μm observations from the Hi-GAL survey of the Galactic plane. The focus of this study is to identify the embedded massive star-forming population within G305, by combining far-infrared data with radio continuum, H2O maser, methanol maser, MIPS and Red MSX Source survey data available from previous studies. By applying a frequentist technique we are able to identify a sample of the most likely associations within our multiwavelength data set, which can then be identified from the derived properties obtained from fitted spectral energy distributions (SEDs). By SED modelling using both a simple modified blackbody and fitting to a comprehensive grid of model SEDs, some 16 candidate associations are identified as embedded massive star-forming regions. We derive a two-selection colour criterion from this sample of log (F_(70)/F_500) ≥ 1 and log (F_160/F_350) ≥ 1.6 to identify an additional 31 embedded massive star candidates with no associated star formation tracers. Using this result we can build a picture of the present-day star formation of the complex, and by extrapolating an initial mass function, suggest a current population of ≈2 × 10^4 young stellar objects (YSOs) present, corresponding to a star formation rate (SFR) of 0.01–0.02 M_⊙ yr^−1. Comparing this resolved SFR, to extragalactic SFR tracers (based on the Kennicutt–Schmidt relation), we find that the star formation activity is underestimated by a factor of ≥2 in comparison to the SFR derived from the YSO population.
Additional Information
© 2012 The Authors. Monthly Notices of the Royal Astronomical Society. © 2012 RAS. Accepted 2012 July 20; Received 2012 July 19; in original form 2012 May 9. Article first published online: 12 Sep. 2012. AF would first like to thank the Science and Technology Facilities Council for a studentship. The authors would first like to thank the entire Herschel Hi-GAL team for their continuing work on the survey. We would also like to thank Sean Carey and Sachin Shenoy for producing, and making available the MIPSGAL point source catalogue for inclusion in our analysis. This research has made possible with the use of the NASA Astrophysics Data System Bibliographic Services. This paper made use of information from the Red MSX Source survey data base at www.ast.leeds.ac.uk/RMS, which was constructed with support from the Science and Technology Facilities Council of the UK. We made use of positional data on 6.7 GHz methanol masers provided by the Methanol Multi-Beam (MMB) survey, also supported by the Science and Technology Facilities Council, and with a maser data base available at http://astromasers.org. The Herschel spacecraft was designed, built, tested and launched under a contract to ESA managed by the Herschel/Planck Project team by an industrial consortium under the overall responsibility of the prime contractor Thales Alenia Space (Cannes), and including Astrium (Friedrichshafen) responsible for the payload module and for system testing at spacecraft level, Thales Alenia Space (Turin) responsible for the service module and Astrium (Toulouse) responsible for the telescope, with in excess of a hundred subcontractors. 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); INAFIFSI/ OAA/OAP/OAT, LENS, SISSA (Italy); and IAC (Spain). This development has been supported by the funding agencies BMVIT (Austria), ESA-PRODEX (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). Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Attached Files
Published - mnr21765.pdf
Submitted - 1208.0599.pdf
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Additional details
- Eprint ID
- 35433
- Resolver ID
- CaltechAUTHORS:20121113-122648326
- Science and Technology Facilities Council (STFC)
- Bundesministerium für Verkehr, Innovation und Technologie (BMVIT)
- ESA-PRODEX (Belgium)
- Commissariat à l'Energie Atomique (CEA)
- Centre National d'Études Spatiales (CNES)
- Deutsches Zentrum für Luft- und Raumfahrt (DLR)
- Agenzia Spaziale Italiana (ASI)
- Istituto Nazionale di Fisica Nucleare (INFN)
- Comisión Interministerial de Ciencia y Tecnología (CICYT)
- Canadian Space Agency (CSA)
- National Astronomical Observatories, Chinese Academy of Sciences (NAOC)
- Ministerio de Ciencia Y Tecnologia (MCYT)
- Centre National de la Recherche Scientifique (CNRS) (France)
- MCINN (Spain)
- Swedish National Space Board (SNSB)
- NASA
- Created
-
2012-11-14Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)