Discovery of an Extraordinarily Massive Cluster of Red Supergiants

By D. Figer, J. Mackenty, M. Robberto, Kester W. Smith, F. Najarro, R. Kudritzki, A. Herrero. 2006

137 citations recorded by the source corpus.

We report the discovery of an extraordinarily massive young cluster of stars in the Galaxy, having an inferred total initial cluster mass comparable to the most massive young clusters in the Galaxy. Using IRMOS, 2MASS, and Spitzer observations, we conclude that there are 14 red supergiants in the cluster, compared with five, in what was previously thought to be the richest Galactic cluster of such stars. We infer spectral types from near-infrared spectra that reveal deep CO bandhead absorption that can only be fit by red supergiants. We identify a gap of ΔKs ~ 4 mag between the stars and the bulk of the other stars in the region that can only be fit by models if the brightest stars in the cluster are red supergiants. We estimate a distance of 5.8 kpc to the cluster by associating an OH maser with the envelope of one of the stars. We also identify a "yellow" supergiant of G6 I type in the cluster. Assuming a Salpeter IMF, we infer an initial cluster mass of 20,000-40,000 M☉ for cluster ages of 7-12 Myr. Continuing with these assumptions, we find that 80% of the initial mass and 99% of the number of stars remain at the present time. We associate the cluster with an X-ray source (detected by ASCA and Einstein), a recently discovered very high energy γ-ray source (detected by INTEGRAL and HESS), and several nonthermal radio sources, finding that these objects are likely related to recent supernovae in the cluster. In particular, we claim that the cluster has produced at least one recent supernova remnant with properties similar to the Crab Nebula.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/09136f9a8f835319a75ce1ae34ea4e51eb00f365

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In Astronomy and Astrophysics

Citations in the corpus

THE DISRUPTION OF GIANT MOLECULAR CLOUDS BY RADIATION PRESSURE & THE EFFICIENCY OF STAR FORMATION IN GALAXIES (2009, background): “4-0.3 Recent work has revealed that the Milky Way harbors a number of very young massive star clusters, with masses ranging up to 105M⊙ (Figer et al. 1999; Brandner et al. 2008; Figer et al. 2006; Murray & Rahman 2009).”
TOWARD A UNIFICATION OF STAR FORMATION RATE DETERMINATIONS IN THE MILKY WAY AND OTHER GALAXIES (2011, background): “Prominent excluded clusters include Westerlund 1, one of the most massive young clusters in the Milky Way (Clark et al. 2005), and several Red Supergiant Clusters (Figer et al. 2006; Davies et al. 2007; Alexander et al. 2009), all of which contain significant populations of Wolf-Rayet stars, yellow ”
STAR FORMATION IN MASSIVE CLUSTERS VIA THE WILKINSON MICROWAVE ANISOTROPY PROBE AND THE SPITZER GLIMPSE SURVEY (2009, unknown): “25-0.15M ∼ 3×104M⊙ (Figer et al. 2006), RSGC2 (l = 26.2◦ b = −0.06◦) with M ∼ 4× 104M⊙ (Davies et al. 2007), and RSCG3 (l = 29.2◦ b = −0.2◦) with M ≈ 3×104M⊙ (Clark et al. 2009).”