A global view on star formation: The GLOSTAR Galactic plane survey

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 M⊙ 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.

ATOMS: ALMA three-millimeter observations of massive star-forming regions – XII: Fragmentation and multiscale gas kinematics in protoclusters G12.42+0.50 and G19.88−0.53

“…Pillai et al 2011;Sanhueza et al 2013). Additionally, several surveys like SEDIGISM (Schuller et al 2017;Yu et al 2019;Yang et al 2021;Colombo et al 2022), GLOSTAR (Nguyen et al 2021) are also aimed towards addressing various aspects of the formation mechanism and early evolutionary phases of high-mass stars.…”

Evolutionary Trends in Star Formation

“…The setup includes spectral windows covering the 6.7 GHz methanol maser transition(Ortiz-León et al 2021;Nguyen et al 2022), formaldehyde and radio recombination lines. Analysis of these data is still in the early stages but results are already starting to emerge (e.g.,Medina et al 2019;Nguyen et al 2021;Dokara et al 2021;Dzib et al 2023) that demonstrate the impact this survey will have in the future.…”

Search for Young and Intermediate-age Stellar Populations in the Galactic Center with Subaru/MOIRCS and CO Narrowband Filters

“…We confirmed that the relatively young (<300 Myr) stars found by Feldmeier et al (2014), and the hot candidates recently found by Cano-González et al (2021) are not included in our observed region. Recent studies found young stellar objects in the GC region (Nandakumar et al 2018;Nguyen et al 2021;Jang et al 2022). However, we confirmed that all of them are out of our observed region.…”