Monitoring the Dusty S-cluster Object (DSO/G2) on its Orbit toward the Galactic Center Black Hole

0441745 - ASÚ 2016 RIV US eng J - Článek v odborném periodiku
Valencia-S, M. - Eckart, A. - Zajaček, Michal - Peissker, F. - Parsa, M. - Grosso, N. - Mossoux, E. - Porquet, D. - Jalali, B. - Karas, Vladimír - Yazici, S. - Shahzamanian, B. - Sabha, N. - Saalfeld, R. - Smajic, S. - Grellmann, R. - Moser, L. - Horrobin, M. - Borkar, A. - García-Marín, M. - Dovčiak, Michal - Kunneriath, Devaky - Karssen, G. - Bursa, Michal - Straubmeier, C. - Bushouse, H.
Monitoring the Dusty S-cluster Object (DSO/G2) on its Orbit toward the Galactic Center Black Hole.
Astrophysical Journal. Roč. 800, č. 2 (2015), 125/1-125/21. ISSN 0004-637X. E-ISSN 1538-4357
Grant CEP: GA ČR(CZ) GC13-00070J
Grant ostatní: EU(XE) COST Action MP0905
Institucionální podpora: RVO:67985815
Klíčová slova: black holes * galactic center * Milky way
Kód oboru RIV: BN - Astronomie a nebeská mechanika, astrofyzika
Impakt faktor: 5.909, rok: 2015

We analyze and report in detail new near-infrared (1.45-2.45 μm) observations of the Dusty S-cluster Object (DSO/G2) during its approach to the black hole at the center of the Galaxy that were carried out with the ESO Very Large Telescope/SINFONI between 2014 February and September. Before 2014 May we detect spatially compact Brγ and Paα line emission from the DSO at about 40 mas east of Sgr A*. The velocity of the source, measured from the redshifted emission, is 2700 ± 60 km s–1. No blueshifted emission above the noise level is detected at the position of Sgr A* or upstream of the presumed orbit. We do not detect any significant extension of the velocity gradient across the source. We find a Brγ line FWHM of 50 ± 10 Å before and 15 ± 10 Å after the peribothron transit, i.e., no significant line broadening with respect to last year is observed. Brγ line maps show that the bulk of the line emission originates from a region of less than 20 mas diameter. This is consistent with a very compact source on an elliptical orbit with a peribothron time passage in 2014.39 ± 0.14. Increased accretion activity of Sgr A* may still be upcoming. We discuss details of a source model according to which the DSO is a young accreting star rather than a coreless gas and dust cloud.
Trvalý link: http://hdl.handle.net/11104/0246910