NTT infrared imaging of star cluster candidates towards the central parts of the Galaxy

Dutra, Carlos Maximiliano; Ortolani, S.; Bica, E.; Barbuy, B.; Zoccali, M.; Momany, Y.

doi:10.1051/0004-6361:20030944

Cited by 28 publications

(51 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, bright spatially extended emission might be incorrectly classified as unresolved star clusters embedded in nebulae. Confirmation of a real cluster can be achieved through deeper, high-resolution IR photometry or through spectroscopic observations of the candidate stellar members (e.g., Dutra et al 2003b;Borissova et al 2005Borissova et al , 2006Messineo et al 2009;Hanson et al 2010;Davies et al 2012), which in some 18 According to unpublished data, there seem to be more than 300 new clusters detected so far by the UKIDSS team. An independent automated search on UKIDSS, leading to the discovery of 167 additional clusters and multiple star forming regions, has already been published by Solin et al (2012), after the last update of our cluster compilation was done.…”

Section: A4 Spurious Cluster Candidatesmentioning

confidence: 99%

Stellar clusters in the inner Galaxy and their correlation with cold dust emission

Morales

Wyrowski

Schüller

et al. 2013

A&A

View full text Add to dashboard Cite

Context. Stars are born within dense clumps of giant molecular clouds, and constitute young stellar agglomerates known as embedded clusters, which only evolve into bound open clusters under special conditions. Aims. We statistically study all embedded clusters (ECs) and open clusters (OCs) known so far in the inner Galaxy, in particular investigating their interaction with the surrounding molecular environment and the differences in their evolution. Methods. We first compiled a merged list of 3904 clusters from optical and infrared cluster catalogs in the literature, including 75 new (mostly embedded) clusters discovered by us in the GLIMPSE survey. From this list, 695 clusters are within the Galactic range | | ≤ 60 • and |b| ≤ 1.5 • covered by the ATLASGAL survey, which was used to search for correlations with submm dust continuum emission tracing dense molecular gas. We defined an evolutionary sequence of five morphological types: deeply embedded cluster (EC1), partially embedded cluster (EC2), emerging open cluster (OC0), OC still associated with a submm clump in the vicinity (OC1), and OC without correlation with ATLASGAL emission (OC2). Together with this process, we performed a thorough literature survey of these 695 clusters, compiling a considerable number of physical and observational properties in a catalog that is publicly available. Results. We found that an OC defined observationally as OC0, OC1, or OC2 and confirmed as a real cluster is equivalent to the physical concept of OC (a bound exposed cluster) for ages in excess of ∼16 Myr. Some observed OCs younger than this limit can actually be unbound associations. We found that our OC and EC samples are roughly complete up to ∼1 kpc and ∼1.8 kpc from the Sun, respectively, beyond which the completeness decays exponentially. Using available age estimates for a few ECs, we derived an upper limit of 3 Myr for the duration of the embedded phase. Combined with the OC age distribution within 3 kpc of the Sun, which shows an excess of young exposed clusters compared to a theoretical fit that considers classical disruption mechanisms, we computed an embedded and young cluster dissolution fraction of 88 ± 8%. This high fraction is thought to be produced by several factors and not only by the classical paradigm of fast gas expulsion.

show abstract

Section: A4 Spurious Cluster Candidatesmentioning

confidence: 99%

Stellar clusters in the inner Galaxy and their correlation with cold dust emission

Morales

Wyrowski

Schüller

et al. 2013

A&A

View full text Add to dashboard Cite

show abstract

“…If the 10-th most massive star of the cluster would have been of B0V type -as proposed by Dutra et al (2003) -the presence of several O stars would be expected. We ruled this out by showing that both the nebular emission and the radio flux are consistent with the brightest stars being B-type.…”

Section: Mass Estimates Of the Db10 And Db11 Clustersmentioning

confidence: 91%

“…The cluster DB11 was already studied in Dutra et al (2003) without the help of spectroscopy and with very different results. After performing statistical field subtraction, the authors identified a much redder main sequence for the region with a color of H − K S ∼ 1.12 mag.…”

Section: Mass Estimates Of the Db10 And Db11 Clustersmentioning

confidence: 99%

“…If the main sequence of DB11 in the K S vs. H − K S diagram were indeed at H − K S ∼ 1.12 mag we would expect the two YSOs to be ∼0.6 mag redder than they are. Assuming that the 10th brightest star of the group that they identified as cluster members was a B0V star, Dutra et al (2003) derived a distance to the cluster of 7.6 kpc. This scenario was corroborated by the value of the kinematic distance for the associated H ii region.…”

Section: Mass Estimates Of the Db10 And Db11 Clustersmentioning

confidence: 99%

“…The second (DB10) is still deeply embedded and the high extinction only allows the detection of the brightest sources. Dutra et al (2003) further studied the clusters using H and K S band imaging also obtained with NTT/SofI. In addition, a third, very deeply embedded SFR is present.…”

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

Multiple episodes of star formation in the CN15/16/17 molecular complex

Gennaro¹,

Bik²,

Brandner³

et al. 2012

A&A

View full text Add to dashboard Cite

Context. We have started a campaign to identify massive star clusters inside bright molecular bubbles towards the Galactic center. The CN15/16/17 molecular complex is the first example of our study. The region is characterized by the presence of two young clusters, DB10 and DB11, visible in the near-infrared, an ultra-compact H ii region identified in the radio, several young stellar objects visible in the mid infrared, a bright diffuse nebulosity at 8 μm coming from PAHs and sub-mm continuum emission revealing the presence of cold dust. Aims. Given its position on the sky (l = 0.• 58, b = −0.• 85) and its kinematic distance of 7.5 kpc, the region was thought to be a very massive site of star formation in proximity of the central molecular zone. One of the two identified clusters, DB11, was estimated to be as massive as ∼10 4 M . However the region's properties were known only through photometry and its kinematic distance was very uncertain given its location at the tangential point. We aimed at better characterizing the region and assess whether it could be a site of massive star formation located close to the Galactic center. Methods. We have obtained NTT/SofI deep JHK S photometry and long slit K band spectroscopy of the brightest members. We have additionally collected data in the radio, sub-mm and mid infrared, resulting in a quite different picture of the region. Results. We have confirmed the presence of massive early B type stars and have derived a spectro-photometric distance of ∼1.2 kpc, much smaller than the estimated kinematic distance. Adopting this distance we obtain clusters masses of M DB10 ≈ 170 M and M DB11 ≈ 275 M . This is consistent with the absence of any O star, confirmed by the excitation/ionization status of the nebula. No He i diffuse emission is detected in our spectroscopic observations at 2.113 μm, which would be expected if the region was hosting more massive stars. Radio continuum measurements are also consistent with the region hosting at most early B stars.

show abstract