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arXiv · 1510.06401

High-mass star-forming cloud G0.38+0.04 in the Galactic Center Dust Ridge contains H2CO and SiO masers

Adam Ginsburg·Andrew Walsh·Christian Henkel·Paul A. Jones·Maria Cunningham·Jens Kauffmann·Thushara Pillai·Elisabeth A. C. Mills·Juergen Ott·J. M. Diederik Kruijssen·Karl M. Menten·Cara Battersby·Jill Rathborne·Yanett Contreras·Steven Longmore·Daniel Walker·Joanne Dawson·John A. P. Lopez
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Abstract

We have discovered a new H$_2$CO (formaldehyde) $1_{1,0}-1_{1,1}$ 4.82966 GHz maser in Galactic Center Cloud C, G0.38+0.04. At the time of acceptance, this is the eighth region containing an H$_2$CO maser detected in the Galaxy. Cloud C is one of only two sites of confirmed high-mass star formation along the Galactic Center Ridge, affirming that H$_2$CO masers are exclusively associated with high-mass star formation. This discovery led us to search for other masers, among which we found new SiO vibrationally excited masers, making this the fourth star-forming region in the Galaxy to exhibit SiO maser emission. Cloud C is also a known source of CH$_3$OH Class-II and OH maser emission. There are now two known SiO and H$_2$CO maser containing regions in the CMZ, compared to two and six respectively in the Galactic disk, while there is a relative dearth of H$_2$O and CH$_3$OH Class-II masers in the CMZ. SiO and H$_2$CO masers may be preferentially excited in the CMZ, perhaps due to higher gas-phase abundances from grain destruction and heating, or alternatively H$_2$O and CH$_3$OH maser formation may be suppressed in the CMZ. In any case, Cloud C is a new testing ground for understanding maser excitation conditions.

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Adam Ginsburg, Andrew Walsh, Christian Henkel, Paul A. Jones, Maria Cunningham, Jens Kauffmann, Thushara Pillai, Elisabeth A. C. Mills, Juergen Ott, J. M. Diederik Kruijssen, Karl M. Menten, Cara Battersby, Jill Rathborne, Yanett Contreras, Steven Longmore, Daniel Walker, Joanne Dawson, John A. P. Lopez. 2015-11-16. High-mass star-forming cloud G0.38+0.04 in the Galactic Center Dust Ridge contains H2CO and SiO masers. https://doi.org/10.1051/0004-6361%2F201527452

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