A global view on star formation: The GLOSTAR Galactic plane survey: IV. Radio continuum detections of young stellar objects in the Galactic Centre region

Nguyen, H and Rugel, MR and Menten, KM and Brunthaler, A and Dzib, SA and Yang, AY and Kauffmann, J and Pillai, TGS and Nandakumar, G and Schultheis, M and Urquhart, JS and Dokara, R and Gong, Y and Medina, S-NX and Ortiz-León, GN and Reich, W and Wyrowski, F and Beuther, H and Cotton, WD and Csengeri, T and Pandian, JD and Roy, N (2021) A global view on star formation: The GLOSTAR Galactic plane survey: IV. Radio continuum detections of young stellar objects in the Galactic Centre region. In: Astronomy and Astrophysics, 651 .

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Abstract

Context. The Central Molecular Zone (CMZ), a �200 pc sized region around the Galactic Centre, is peculiar in that it shows a star formation rate (SFR) that is suppressed with respect to the available dense gas. To study the SFR in the CMZ, young stellar objects (YSOs) can be investigated. Here we present radio observations of 334 2.2 μm infrared sources that have been identified as YSO candidates. Aims. Our goal is to investigate the presence of centimetre wavelength radio continuum counterparts to this sample of YSO candidates which we use to constrain the current SFR in the CMZ. Methods. As part of the GLObal view on STAR formation (GLOSTAR) survey, D-configuration Very Large Array data were obtained for the Galactic Centre, covering -2° < l < 2° and -1° < b < 1° with a frequency coverage of 4-8 GHz. We matched YSOs with radio continuum sources based on selection criteria and classified these radio sources as potential H II regions and determined their physical properties. Results. Of the 334 YSO candidates, we found 35 with radio continuum counterparts. We find that 94 YSOs are associated with dense dust condensations identified in the 870 μm ATLASGAL survey, of which 14 have a GLOSTAR counterpart. Of the 35 YSOs with radio counterparts, 11 are confirmed as H II regions based on their spectral indices and the literature. We estimated their Lyman continuum photon flux in order to estimate the mass of the ionising star. Combining these with known sources, the present-day SFR in the CMZ is calculated to be �0.068 MO yr-1, which is �6.8 of the Galactic SFR. Candidate YSOs that lack radio counterparts may not have yet evolved to the stage of exhibiting an H II region or, conversely, are older and have dispersed their natal clouds. Since many lack dust emission, the latter is more likely. Our SFR estimate in the CMZ is in agreement with previous estimates in the literature. © H. Nguyen et al. 2021.

Item Type:	Journal Article
Publication:	Astronomy and Astrophysics
Publisher:	EDP Sciences
Additional Information:	The copyright for this article belongs to Authors
Keywords:	Dust; Light sources; Object detection; Radio astronomy; Surveys, Galactic centres; Galactic plane surveys; Radio observation; Selection criteria; Spectral indices; Star formation rates; Very large arrays; Young stellar objects, Stars
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	20 Nov 2021 11:34
Last Modified:	20 Nov 2021 11:34
URI:	http://eprints.iisc.ac.in/id/eprint/69887

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