A METHOD FOR MEASURING VARIATIONS IN THE STELLAR INITIAL MASS FUNCTION

Journal Article · Fri Aug 20 04:00:00 EDT 2010 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/719/2/L158· OSTI ID:21450962

Calzetti, D ^[1]; Chandar, R ^[2]; Lee, J C ^[3]; Elmegreen, B G ^[4]; Kennicutt, R C ^[5]; Whitmore, B ^[6]

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1. Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)
2. Department of Physics and Astronomy, University of Toledo, Toledo, OH (United States)
3. Carnegie Observatories of Washington, Pasadena, CA (United States)
4. IBM T.J. Watson Research Center, Yorktown Heights, NY (United States)
5. Institute of Astronomy, Cambridge University, Cambridge (United Kingdom)
6. Space Telescope Science Institute, Baltimore, MD (United States)

We present a method for investigating variations in the upper end of the stellar initial mass function (IMF) by probing the production rate of ionizing photons in unresolved, compact star clusters with ages {<=}10{sup 7} yr and with different masses. We test this method by performing a pilot study on the young cluster population in the nearby galaxy NGC5194 (M51a), for which multi-wavelength observations from the Hubble Space Telescope are available. Our results indicate that the proposed method can probe the upper end of the IMF in galaxies located out to at least {approx}10 Mpc, i.e., a factor {approx}200 further away than what is possible by counting individual stars in young compact clusters. Our results for NGC5194 show no obvious dependence of the upper mass end of the IMF on the mass of the star cluster down to {approx}10{sup 3} M{sub sun}, although more extensive analyses involving lower mass clusters and other galaxies are needed to confirm this conclusion.

• OSTI ID: 21450962
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 719; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BOSONS
ELEMENTARY PARTICLES
EVOLUTION
GALACTIC EVOLUTION
GALAXIES
LUMINOSITY
MASS
MASSLESS PARTICLES
OPTICAL PROPERTIES
PHOTONS
PHYSICAL PROPERTIES
STAR CLUSTERS
STAR EVOLUTION
STARS
TELESCOPES