Universität zu Köln

Ginsburg, Adam, Bally, John, Barnes, Ashley ORCID: 0000-0003-0410-4504, Bastian, Nate ORCID: 0000-0001-5679-4215, Battersby, Cara ORCID: 0000-0002-6073-9320, Beuther, Henrik ORCID: 0000-0002-1700-090X, Brogan, Crystal ORCID: 0000-0002-6558-7653, Contreras, Yanett ORCID: 0000-0002-6388-3635, Corby, Joanna, Darling, Jeremy ORCID: 0000-0003-2511-2060, De Pree, Chris, Galvan-Madrid, Roberto ORCID: 0000-0003-1480-4643, Garay, Guido, Henshaw, Jonathan ORCID: 0000-0001-9656-7682, Hunter, Todd, Kruijssen, J. M. Diederik, Longmore, Steven, Lu, Xing ORCID: 0000-0003-2619-9305, Meng, Fanyi, Mills, Elisabeth A. C., Ott, Juergen ORCID: 0000-0001-8224-1956, Pineda, Jaime E., Sanchez-Monge, Alvaro, Schilke, Peter ORCID: 0000-0003-2141-5689, Schmiedeke, Anika, Walker, Daniel and Wilner, David ORCID: 0000-0003-1526-7587 (2018). Distributed Star Formation throughout the Galactic Center Cloud Sgr B2. Astrophys. J., 853 (2). BRISTOL: IOP PUBLISHING LTD. ISSN 1538-4357

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Abstract

We report ALMA observations with resolution approximate to 0 ''.5 at 3 mm of the extended Sgr B2 cloud in the Central Molecular Zone (CMZ). We detect 271 compact sources, most of which are smaller than 5000 au. By ruling out alternative possibilities, we conclude that these sources consist of a mix of hypercompact H II regions and young stellar objects (YSOs). Most of the newly detected sources are YSOs with gas envelopes that, based on their luminosities, must contain objects with stellar masses M* greater than or similar to 8M(circle dot). Their spatial distribution spread over a similar to 12 x 3 pc region demonstrates that Sgr B2 is experiencing an extended star formation event, not just an isolated starburst within the protocluster regions. Using this new sample, we examine star formation thresholds and surface density relations in Sgr B2. While all of the YSOs reside in regions of high column density (N(H-2) greater than or similar to 2 x 10(23) cm(-2) not all regions of high column density contain YSOs. The observed column density threshold for star formation is substantially higher than that in solar vicinity clouds, implying either that high-mass star formation requires a higher column density or that any star formation threshold in the CMZ must be higher than in nearby clouds. The relation between the surface density of gas and stars is incompatible with extrapolations from local clouds, and instead stellar densities in Sgr B2 follow a linear Sigma(*)-Sigma(gas) relation, shallower than that observed in local clouds. Together, these points suggest that a higher volume density threshold is required to explain star formation in CMZ clouds.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Ginsburg, Adam UNSPECIFIED UNSPECIFIED UNSPECIFIED Bally, John UNSPECIFIED UNSPECIFIED UNSPECIFIED Barnes, Ashley UNSPECIFIED orcid.org/0000-0003-0410-4504 UNSPECIFIED Bastian, Nate UNSPECIFIED orcid.org/0000-0001-5679-4215 UNSPECIFIED Battersby, Cara UNSPECIFIED orcid.org/0000-0002-6073-9320 UNSPECIFIED Beuther, Henrik UNSPECIFIED orcid.org/0000-0002-1700-090X UNSPECIFIED Brogan, Crystal UNSPECIFIED orcid.org/0000-0002-6558-7653 UNSPECIFIED Contreras, Yanett UNSPECIFIED orcid.org/0000-0002-6388-3635 UNSPECIFIED Corby, Joanna UNSPECIFIED UNSPECIFIED UNSPECIFIED Darling, Jeremy UNSPECIFIED orcid.org/0000-0003-2511-2060 UNSPECIFIED De Pree, Chris UNSPECIFIED UNSPECIFIED UNSPECIFIED Galvan-Madrid, Roberto UNSPECIFIED orcid.org/0000-0003-1480-4643 UNSPECIFIED Garay, Guido UNSPECIFIED UNSPECIFIED UNSPECIFIED Henshaw, Jonathan UNSPECIFIED orcid.org/0000-0001-9656-7682 UNSPECIFIED Hunter, Todd UNSPECIFIED UNSPECIFIED UNSPECIFIED Kruijssen, J. M. Diederik UNSPECIFIED UNSPECIFIED UNSPECIFIED Longmore, Steven UNSPECIFIED UNSPECIFIED UNSPECIFIED Lu, Xing UNSPECIFIED orcid.org/0000-0003-2619-9305 UNSPECIFIED Meng, Fanyi UNSPECIFIED UNSPECIFIED UNSPECIFIED Mills, Elisabeth A. C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Ott, Juergen UNSPECIFIED orcid.org/0000-0001-8224-1956 UNSPECIFIED Pineda, Jaime E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Sanchez-Monge, Alvaro UNSPECIFIED UNSPECIFIED UNSPECIFIED Schilke, Peter UNSPECIFIED orcid.org/0000-0003-2141-5689 UNSPECIFIED Schmiedeke, Anika UNSPECIFIED UNSPECIFIED UNSPECIFIED Walker, Daniel UNSPECIFIED UNSPECIFIED UNSPECIFIED Wilner, David UNSPECIFIED orcid.org/0000-0003-1526-7587 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-196327
DOI:	10.3847/1538-4357/aaa6d4
Journal or Publication Title:	Astrophys. J.
Volume:	853
Number:	2
Date:	2018
Publisher:	IOP PUBLISHING LTD
Place of Publication:	BRISTOL
ISSN:	1538-4357
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute of Physics I
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language H-II REGIONS; MILKY-WAY; FORMATION RATES; SAGITTARIUS B2; STELLAR CLUSTERS; MOLECULAR CLOUD; FORMING REGION; H2O MASERS; GAS; SUBMILLIMETER Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/19632