ONGOING MASSIVE STAR FORMATION IN NGC 604

Journal Article · Mon Dec 10 04:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/761/1/3· OSTI ID:22140092

Martinez-Galarza, J. R. ^[1]; Hunter, D. ^[2]; Groves, B.; Brandl, B. ^[3]

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1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2. Lowell Observatory, 1400 W. Mars Hill Road, AZ 86001 (United States)
3. Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300-CA Leiden (Netherlands)

NGC 604 is the second most massive H II region in the Local Group, thus an important laboratory for massive star formation. Using a combination of observational and analytical tools that include Spitzer spectroscopy, Herschel photometry, Chandra imaging, and Bayesian spectral energy distribution fitting, we investigate the physical conditions in NGC 604 and quantify the amount of massive star formation currently taking place. We derive an average age of 4 {+-} 1 Myr and a total stellar mass of 1.6{sup +1.6}{sub -1.0} Multiplication-Sign 10{sup 5} M{sub Sun} for the entire region, in agreement with previous optical studies. Across the region, we find an effect of the X-ray field on both the abundance of aromatic molecules and the [Si II] emission. Within NGC 604, we identify several individual bright infrared sources with diameters of about 15 pc and luminosity-weighted masses between 10{sup 3} M{sub Sun} and 10{sup 4} M{sub Sun }. Their spectral properties indicate that some of these sources are embedded clusters in process of formation, which together account for {approx}8% of the total stellar mass in the NGC 604 system. The variations of the radiation field strength across NGC 604 are consistent with a sequential star formation scenario, with at least two bursts in the last few million years. Our results indicate that massive star formation in NGC 604 is still ongoing, likely triggered by the earlier bursts.

• OSTI ID: 22140092
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 761; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
ASTROPHYSICS
ELEMENT ABUNDANCE
EMISSION SPECTRA
ENERGY SPECTRA
GALAXIES
H2 REGIONS
INFRARED RADIATION
LUMINOSITY
MASS
MOLECULES
PHOTOMETRY
SILICON IONS
STAR EVOLUTION
STARS
VARIATIONS
X RADIATION