We have extended and refined the existing young stellar object (YSO) catalogs for the Orion A molecular cloud, the closest massive star-forming region to Earth. This updated catalog is driven by the large spatial coverage (18.3 deg 2 , ∼950 pc 2 ), seeing limited resolution (∼0.7″), and sensitivity (Ks < 19 mag) of the ESO-VISTA near-infrared survey of the Orion A cloud (VISION). Combined with archival mid- to far-infrared data, the VISTA data allow for a refined and more robust source selection. We estimate that among previously known protostars and pre-main-sequence stars with disks, source contamination levels (false positives) are at least ∼6.4% and ∼2.3%, respectively, mostly due to background galaxies and nebulosities. We identify 274 new YSO candidates using VISTA/Spitzer based selections within previously analyzed regions, and VISTA/WISE based selections to add sources in the surroundings, beyond previously analyzed regions. The WISE selection method recovers about 59% of the known YSOs in Orion A's low-mass star-forming part L1641, which shows what can be achieved by the all-sky WISE survey in combination with deep near-infrared data in regions without the influence of massive stars. The new catalog contains 2980 YSOs, which were classified based on the de-reddened mid-infrared spectral index into 188 protostars, 185 flat-spectrum sources, and 2607 pre-main-sequence stars with circumstellar disks. We find a statistically significant difference in the spatial distribution of the three evolutionary classes with respect to regions of high dust column-density, confirming that flat-spectrum sources are at a younger evolutionary phase compared to Class IIs, and are not a sub-sample seen at particular viewing angles.
VISION - Vienna survey in Orion III. Young stellar objects in Orion A / J.E. Groschedl, J. Alves, P.S. Teixeira, H. Bouy, J. Forbrich, C.J. Lada, S. Meingast, A. Hacar, J. Ascenso, C. Ackerl, B. Hasenberger, R. Kohler, K. Kubiak, I. Larreina, L. Linhardt, M. Lombardi, T. Moller. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - 622(2019), pp. A149.1-A149.38.
|Titolo:||VISION - Vienna survey in Orion III. Young stellar objects in Orion A|
LOMBARDI, MARCO [Membro del Collaboration Group]
|Parole Chiave:||Infrared: stars; ISM: clouds; Methods: observational; Methods: statistical; Stars: formation; Stars: pre-main sequence|
|Settore Scientifico Disciplinare:||Settore FIS/05 - Astronomia e Astrofisica|
|Data di pubblicazione:||2019|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1051/0004-6361/201832577|
|Appare nelle tipologie:||01 - Articolo su periodico|