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Ginsburg, A, Bally, J, Barnes, AT, Battersby, C, Budaiev, N, Butterfield, NO, Caselli, P, Colzi, L, Dutkowska, KM, García, P, Gramze, S, Henshaw, JD, Hu, Y, Jeff, D, Jiménez-Serra, I, Kauffmann, J, Klessen, RS, Levesque, EM, Longmore, SN, Lu, X , Mills, EAC, Morris, MR, Nogueras-Lara, F, Oka, T, Pineda, JE, Pillai, TGS, Rivilla, VM, Sánchez-Monge, Á, Santa-Maria, MG, Smith, HA, Sofue, Y, Sormani, MC, Tremblay, GR, Vermariën, G, Vikhlinin, A, Viti, S, Walker, D, Wang, QD, Xu, F and Zhang, Q (2024) A Broad Line-width, Compact, Millimeter-bright Molecular Emission Line Source near the Galactic Center. The Astrophysical Journal Letters, 968 (1). ISSN 2041-8205
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A Broad Line width Compact Millimeter bright Molecular Emission Line Source near the Galactic Center.pdf - Published Version Available under License Creative Commons Attribution. Download (3MB) | Preview |
Abstract
A compact source, G0.02467-0.0727, was detected in Atacama Large Millimeter/submillimeter Array 3 mm observations in continuum and very broad line emission. The continuum emission has a spectral index α ≈ 3.3, suggesting that the emission is from dust. The line emission is detected in several transitions of CS, SO, and SO2 and exhibits a line width FWHM ≈ 160 km s−1. The line profile appears Gaussian. The emission is weakly spatially resolved, coming from an area on the sky ≲1″ in diameter (≲104 au at the distance of the Galactic center, GC). The centroid velocity is v LSR ≈ 40-50 km s−1, which is consistent with a location in the GC. With multiple SO lines detected, and assuming local thermodynamic equilibrium (LTE) conditions, the gas temperature is T LTE = 13 K, which is colder than seen in typical GC clouds, though we cannot rule out low-density, subthermally excited, warmer gas. Despite the high velocity dispersion, no emission is observed from SiO, suggesting that there are no strong (≳10 km s−1) shocks in the molecular gas. There are no detections at other wavelengths, including X-ray, infrared, and radio. We consider several explanations for the millimeter ultra-broad-line object (MUBLO), including protostellar outflow, explosive outflow, a collapsing cloud, an evolved star, a stellar merger, a high-velocity compact cloud, an intermediate-mass black hole, and a background galaxy. Most of these conceptual models are either inconsistent with the data or do not fully explain them. The MUBLO is, at present, an observationally unique object.
| Item Type: | Article |
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| Uncontrolled Keywords: | 0201 Astronomical and Space Sciences; Astronomy & Astrophysics |
| Subjects: | Q Science > QB Astronomy Q Science > QC Physics |
| Divisions: | Astrophysics Research Institute |
| Publisher: | American Astronomical Society |
| SWORD Depositor: | A Symplectic |
| Date Deposited: | 23 Jul 2024 13:06 |
| Last Modified: | 23 Jul 2024 13:15 |
| DOI or ID number: | 10.3847/2041-8213/ad47fa |
| URI: | https://researchonline.ljmu.ac.uk/id/eprint/23784 |
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