A third red supergiant rich cluster in the Scutum-Crux arm

Clark, J. S.; Negueruela, I.; Davies, Ben; Larionov, V. M.; Ritchie, B. W.; Figer, Donald F.; Messineo, M.; Crowther, P. A.; Arkharov, A. A.

doi:10.1051/0004-6361/200911945

Cited by 80 publications

(136 citation statements)

References 34 publications

(43 reference statements)

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“…In the line of considering these stars younger than proposed here, we might recall recent results on massive young clusters, where the presence of a noticeable supergiant population is argued (Clark et al 2009;Alexander et al 2009). The assumption that the brightest stars in our CM could indicate such a population would result in a distance from them of around 7 kpc, which would discard them as cluster members, even under a consideration of the largest distance estimates given for Dolidze 25 in the literature.…”

Section: Age Estimatessupporting

confidence: 60%

Analysis of the stellar population in the central area of the HII region Sh 2-284 ,

Delgado

Djupvik

Alfaro

2009

A&A

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Context. There is a lack of state-of-the-art information on very young open clusters with implications for determining the structure of the Galaxy. Aims. Our main objective is to study the timing and location of the star formation processes which yielded the generation of the giant HII region Sh 2-284. This includes the determination of different physical variables of the stars, such as distance, reddening, age and evolutionary stage, including pre-main-sequence (PMS) stars. Methods. The analysis is based on UBVR C I C CCD measurements of a field of 6.5 × 6.5 containing the cluster, and JHK s photometry in the 3.5 × 3.5 subfield, centered in the apparent higher condensation. The determination of cluster distance, reddening and age is carried out through a comparison with ZAMS, post-MS and PMS isochrones. The reference lines used are obtained from theoretical post-MS and PMS isochrones from the Geneva and Yale groups for a metallicity of Z = 0.004, which agrees with the spectroscopic metallicity determination published for several cluster members. Results. The results amount to E(B − V) = 0.78 ± 0.02, DM = 12.8 ± 0.2 (3.6 kpc), Log Age(yr) = 6.51 ± 0.07 (3.2 Myr). The distance result critically depends on the use of low metallicity ZAMS and isochrones. A PMS member sequence is proposed, with an age of Log Age(yr) = 6.7 ± 0.2 (4.7 Myr) which is therefore coeval within the errors with the post-MS cluster age. The mass function for this population in the mass range above 1.3−3.5 M is well fitted by a Salpeter mass function. The presence of a different star generation in the cluster with a distinctly older age of around 40 Myr is suggested. On the other hand, the NIR photometry results indicate a large number of sources with (H − K s ) excess, practically distinct from the optical PMS candidate members. Conclusions. The analysis of our deep UBVRIJHK photometry of Dolidze 25 therefore reveals a young cluster with coeval MS and PMS populations of age 3.2−5 Myr. In addition, a distinctly older cluster member population of the age of 40 Myr is suggested. The distance determined for the cluster from quantitative fits to ZAMS and isochrones is distinctly lower than previously published values. This result originates in the consistent use of low metallicity models for ZAMS fitting, applying published metallicity values for the cluster.

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Section: Age Estimatessupporting

confidence: 60%

Analysis of the stellar population in the central area of the HII region Sh 2-284 ,

Delgado

Djupvik

Alfaro

2009

A&A

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“…2MASS and GLIMPSE Messineo et al 2009). Five young massive stellar clusters (RSGC1, RSGC2, RSGC3, RSGC4, and RSGC5), extraordinarily rich in RSGs (14, 26, >8, >9, 7), have been located between 25 • and 30 • of longitude, at a distance of about 6 kpc probably at the near end-side of the Galactic Bar (Davies et al 2007;Figer et al 2006;Clark et al 2009;Negueruela et al 2010Negueruela et al , 2011. We restricted our analysis to a sample of 119 spectroscopically confirmed RSGs in clusters, because their association with a cluster confirms the luminosity class (Skiff 2010;Eggenberger et al 2002;Mermilliod et al 2008;Pierce et al 2000;Mengel & Tacconi-Garman 2007;Figer et al 1999;Messineo et al 2011Messineo et al , 2010Davies et al 2009a;Bernabei & Polcaro 2001;Caron et al 2003;Figer et al 2006;Davies et al 2008;Clark et al 2009;Negueruela et al 2010Negueruela et al , 2011.…”

Section: Red Supergiant Starsmentioning

confidence: 99%

“…The Q1 parameter was first introduced to photometrically select counterparts of high-mass X-ray binaries (Negueruela & Schurch 2007;Comerón & Pasquali 2005); it has been successfully used for searching clusters of RSGs (e.g. Figer et al 2006;Davies et al 2007;Clark et al 2009;Negueruela et al 2010Negueruela et al , 2011. Since stars with different spectral types have different intrinsic colors, they will also have a different value of Q1, as shown in Table 2 with intrinsic colors by Koornneef (1983).…”

Section: The Q1 Parametermentioning

confidence: 99%

Near- and mid-infrared colors of evolved stars in the Galactic plane. TheQ1 andQ2 parameters

Messineo

Menten

Churchwell

et al. 2011

A&A

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Context. Mass-loss from evolved stars chemically enriches the interstellar medium (ISM). Stellar winds from massive stars and their explosions as supernovae shape the ISM and trigger star formation. Studying evolved stars is fundamental for understanding galaxy formation and evolution at any redshift. Aims. We aim to establish a photometric classification scheme for Galactic mass-losing evolved stars (e.g., WR, RSG, and AGB stars) with the goal of identifying new ones, and subsequently to use these samples as tracers of Galactic structure. Methods. We searched for counterparts of known Galactic WR, LBV, RSG, and O-rich AGB stars in the 2MASS, GLIMPSE, and MSX catalogs, and we analyzed their properties with near-and mid-infrared color-color diagrams. Results. We used the Q1 parameter, which is a measure of the deviation from the interstellar reddening vector in the J − H versus H−K s diagram, and we defined a new parameter, Q2, which is a measure of the deviation from the interstellar reddening vector in the Conclusions. The GLIMPSE catalog is a powerful tool for photometric classification of Galactic mass-losing evolved stars. Our new criteria will yield many new RSGs and WRs.

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“…The catalogue of observed sources is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/578/A3 few years several massive and highly reddened clusters have been discovered in the inner Galaxy (Clark et al 2009b;Davies et al 2007Davies et al , 2008Davies et al , 2012Negueruela et al 2010). As their only observable components are the RSGs, these clusters are known as red supergiant clusters (RSGCs).…”

Section: Introductionmentioning

confidence: 99%

A new survey of cool supergiants in the Magellanic Clouds

González-Fernández

Dorda

Negueruela

et al. 2015

A&A

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Aims. In this study we conduct a pilot program aimed at the red supergiant population of the Magellanic Clouds. We intend to extend the current known sample to the unexplored low end of the brightness distribution of these stars, building a more representative dataset with which to extrapolate their behaviour to other Galactic and extra-galactic environments. Methods. We select candidates using only near infrared photometry, and with medium resolution multi-object spectroscopy, we perform spectral classification and derive their line-of-sight velocities, confirming the nature of the candidates and their membership in the clouds. Results. Around two hundred new red supergiants have been detected, hinting at a yet to be observed large population. Using nearand mid-infrared photometry we study the brightness distribution of these stars, the onset of mass-loss, and the effect of dust in their atmospheres. Based on this sample, new a priori classification criteria are investigated, combining mid-and near-infrared photometry to improve the observational efficiency of similar programs to this.

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A third red supergiant rich cluster in the Scutum-Crux arm

Cited by 80 publications

References 34 publications

Analysis of the stellar population in the central area of the HII region Sh 2-284 ,

Analysis of the stellar population in the central area of the HII region Sh 2-284 ,

Near- and mid-infrared colors of evolved stars in the Galactic plane. TheQ1 andQ2 parameters

A new survey of cool supergiants in the Magellanic Clouds

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