Sgr A* and Its Environment: Low-mass Star Formation, the Origin of X-Ray Gas and Collimated Outflow

dc.contributor.authorYusef-Zadeh, F.
dc.contributor.authorWardle, M.
dc.contributor.authorSchödel, R.
dc.contributor.authorRoberts, D. A.
dc.contributor.authorCotton, W.
dc.contributor.authorBushouse, H.
dc.contributor.authorArendt, Richard
dc.contributor.authorRoyster, M.
dc.date.accessioned2022-06-08T17:34:44Z
dc.date.available2022-06-08T17:34:44Z
dc.date.issued2016-02-29
dc.description.abstractWe present high-resolution multiwavelength radio continuum images of the region within 150'' of Sgr A*, revealing a number of new extended features and stellar sources in this region. First, we detect a continuous 2'' east–west ridge of radio emission, linking Sgr A* and a cluster of stars associated with IRS 13 N and IRS 13E. The ridge suggests that an outflow of east–west blob-like structures is emerging from Sgr A*. In particular, we find arc-like radio structures within the ridge with morphologies suggestive of photoevaporative protoplanetary disks. We use infrared Ks and L' fluxes to show that the emission has similar characteristics to those of a protoplanetary disk irradiated by the intense radiation field at the Galactic center. This suggests that star formation has taken place within the S-cluster 2'' from Sgr A*. We suggest that the diffuse X-ray emission associated with Sgr A* is due to an expanding hot wind produced by the mass loss from B-type main sequence stars, and/or the disks of photoevaporation of low mass young stellar objects (YSOs) at a rate of ∼10−6 ${M}_{\odot }$ yr−1. The proposed model naturally reduces the inferred accretion rate and is an alternative to the inflow–outflow style models to explain the underluminous nature of Sgr A*. Second, on a scale of 5'' from Sgr A*, we detect new cometary radio and infrared sources at a position angle PA ∼ 50° which is similar to that of two other cometary sources X3 and X7, all of which face Sgr A*. In addition, we detect a striking tower of radio emission at a PA ∼ 50°–60° along the major axis of the Sgr A East supernova remnant shell on a scale of 150'' from Sgr A*. We suggest that the cometary sources and the tower feature are tracing interaction sites of a mildly relativistic jet from Sgr A* with the atmosphere of stars and the nonthermal Sgr A East shell at a PA ∼ 50°–60° with $\dot{M}\sim 1\times {10}^{-7}\;{M}_{\odot }\;{\mathrm{yr}}^{-1}$, and opening angle 10°. Lastly, we suggest that the east–west ridge of radio emission traces an outflow that is potentially associated with past flaring activity from Sgr A*. The position angle of the outflow driven by flaring activity is close to −90°.en_US
dc.description.sponsorshipThis work is partially supported by grants AST-0807400 and AST-1517246 from the NSF. The research leading to these results has also received funding from the European Research Council under the Europeans Unions Seventh Framework Programme (FP/2007-2013)/ERC grant agreement No. 614922.en_US
dc.description.urihttps://iopscience.iop.org/article/10.3847/0004-637X/819/1/60en_US
dc.format.extent25 pagesen_US
dc.genrejournal articlesen_US
dc.identifierdoi:10.13016/m2hmw6-ex30
dc.identifier.citationF. Yusef-Zadeh et al. "Sgr A* and Its Environment: Low-mass Star Formation, the Origin of X-Ray Gas and Collimated Outflow". The Astrophysical Journal 819, 60 (2016). https://doi.org/10.3847/0004-637X/819/1/60en_US
dc.identifier.urihttps://doi.org/10.3847/0004-637X/819/1/60
dc.identifier.urihttp://hdl.handle.net/11603/24856
dc.language.isoen_USen_US
dc.publisherIOP Scienceen_US
dc.relation.isAvailableAtThe University of Maryland, Baltimore County (UMBC)
dc.relation.ispartofUMBC Center for Space Sciences and Technology
dc.relation.ispartofUMBC Faculty Collection
dc.rightsThis item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.en_US
dc.titleSgr A* and Its Environment: Low-mass Star Formation, the Origin of X-Ray Gas and Collimated Outflowen_US
dc.typeTexten_US
dcterms.creatorhttps://orcid.org/0000-0001-8403-8548en_US

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