AO-assisted BVRI+Ha imaging of NGC330 with SAMI

H{alpha} emission is a clear indicator of circumstellar activity in Be stars, historically employed to assess the classical Be star (CBe) population in young open clusters (YOCs). The YOC NGC 330 in the Small Magellanic Cloud exhibits a large known fraction of CBe stars and was selected for a pilot study to establish a comprehensive methodology for identifying H{alpha} emitters in the Magellanic Clouds, encompassing the entire B-type spectral range. Using the SOAR Adaptive Module Imager (SAMI), we investigated the stellar population of NGC 330 using multiband BVRI+H{alpha} imaging. We identified H{alpha} emitters within the entire V-band range covered by SAMI/SOAR observations (V<~22), comprising the complete B-type stellar population and offering a unique opportunity to explore the Be phenomenon across all spectral subclasses. The stellar radial distribution shows a clear bimodal pattern between the most massive (B5 or earlier) and the lower mass main-sequence objects (later than B6) within the cluster. The former is concentrated toward the cluster center (showing a dispersion {sigma}=4.26+/-0.20pc), whereas the latter extends across larger radii ({sigma}=10.83+/-0.65pc), indicating mass stratification within NGC 330. The total fraction of emitters is 4.4%+/-0.5%, notably smaller than previous estimates from flux- or seeing- limited observations. However, a higher fraction of H{alpha} emitters is observed among higher mass stars (32.8%+/-3.4%) than within lower mass (4.4%+/-0.9%). Consequently, the putative CBe population exhibits distinct dynamical characteristics compared to the bulk of the stellar population in NGC 330. These findings highlight the significance of the current observations in providing a complete picture of the CBe population in NGC 330.

Cone search capability for table J/ApJ/970/113/table3 (Calibrated BVRI+Halpha SAMI Photometry for NGC330)

Identifier
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/ApJ/970/113
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/970/113
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/970/113
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/ApJ/970/113
Provenance
Creator Navarete F.; Ticiani Dos Santos P.; Carciofi A.C.; Figueiredo A.L.
Publisher CDS
Publication Year 2024
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Galactic and extragalactic Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy