VLT/X-shooter spectroscopy of massive young stellar objects in the 30 Doradus region of the Large Magellanic Cloud

Autor: Lex Kaper, J. Japelj, Götz Gräfener, L. E. Ellerbroek, Nolan R. Walborn, M. L. van Gelder, Joachim M. Bestenlehner, Rodolfo H. Barbá, Jorick S. Vink, A. de Koter, S. E. de Mink, A. Bik, Elena Sabbi, M. C. Ramírez-Tannus, Hugues Sana, Marta Sewilo
Přispěvatelé: High Energy Astrophys. & Astropart. Phys (API, FNWI), Low Energy Astrophysics (API, FNWI)
Rok vydání: 2020
Předmět:
HII regions
NEAR-INFRARED SPECTROSCOPY
PROTOSTELLAR CANDIDATES
Young stellar object
Metallicity
Extinction (astronomy)
Population
FOS: Physical sciences
Starburst region
Astrophysics
Astronomy & Astrophysics
CHEMICAL-COMPOSITION
01 natural sciences
CO OUTFLOWS
STAR-FORMATION
Luminosity
SPITZER LEGACY PROGRAM
massive [stars]
0103 physical sciences
Magellanic Clouds
pre-main sequence [stars]
INTEGRAL FIELD SPECTROSCOPY
Large Magellanic Cloud
education
010303 astronomy & astrophysics
Solar and Stellar Astrophysics (astro-ph.SR)
clusters: individual: 30 Doradus [galaxies]
POINT-SOURCE CLASSIFICATION
Physics
education.field_of_study
Very Large Telescope
Science & Technology
formation [stars]
INTERMEDIATE-MASS
010308 nuclear & particles physics
Astronomy and Astrophysics
Astrophysics - Astrophysics of Galaxies
LIFE-CYCLE
Astrophysics - Solar and Stellar Astrophysics
Space and Planetary Science
Astrophysics of Galaxies (astro-ph.GA)
Physical Sciences
Zdroj: Astronomy & Astrophysics, 636:A54. EDP Sciences
Astronomy & Astrophysics, 636, A54
ISSN: 1432-0746
0004-6361
Popis: The process of massive star ($M\geq8~M_\odot$) formation is still poorly understood. Observations of massive young stellar objects (MYSOs) are challenging due to their rarity, short formation timescale, large distances, and high circumstellar extinction. Here, we present the results of a spectroscopic analysis of a population of MYSOs in the Large Magellanic Cloud (LMC). We took advantage of the spectral resolution and wavelength coverage of X-shooter (300-2500 nm), mounted on the European Southern Observatory Very Large Telescope, to detect characteristic spectral features in a dozen MYSO candidates near 30 Doradus, the largest starburst region in the Local Group hosting the most massive stars known. The X-shooter spectra are strongly contaminated by nebular emission. We used a scaling method to subtract the nebular contamination from our objects. We detect H$\alpha,\beta$, [O I] 630.0 nm, Ca II infrared triplet, [Fe II] 1643.5 nm, fluorescent Fe II 1687.8 nm, H$_2$ 2121.8 nm, Br$\gamma$, and CO bandhead emission in the spectra of multiple candidates. This leads to the spectroscopic confirmation of 10 candidates as bona fide MYSOs. We compare our observations with photometric observations from the literature and find all MYSOs to have a strong near-infrared excess. We compute lower limits to the brightness and luminosity of the MYSO candidates, confirming the near-infrared excess and the massive nature of the objects. No clear correlation is seen between the Br$\gamma$ luminosity and metallicity. Combining our sample with other LMC samples results in a combined detection rate of disk features such as fluorescent Fe II and CO bandheads which is consistent with the Galactic rate (40\%). Most of our MYSOs show outflow features.
Comment: Accepted to A&A, 26 pages, 19 figures, 4 tables
Databáze: OpenAIRE
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