Valencia-S, M., Eckart, A., Zajacek, M., Peissker, F., Parsa, M., Grosso, N., Mossoux, E., Porquet, D., Jalali, B., Karas, V., Yazici, S., Shahzamanian, B., Sabha, N., Saalfeld, R., Smajic, S., Grellmann, R., Moser, L., Horrobin, M., Borkar, A., Garcia-Marin, M., Dovciak, M., Kunneriath, D., Karssen, G. D., Bursa, M., Straubmeier, C. and Bushouse, H. (2015). MONITORING THE DUSTY S-CLUSTER OBJECT (DSO/G2) ON ITS ORBIT TOWARD THE GALACTIC CENTER BLACK HOLE. Astrophys. J., 800 (2). BRISTOL: IOP PUBLISHING LTD. ISSN 1538-4357

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Abstract

We analyze and report in detail new near-infrared (1.45-2.45 mu m) 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 Br gamma and Pa alpha 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. After May we find spatially compact Br. blueshifted line emission from the DSO at about 30 mas west of Sgr A* at a velocity of -3320 +/- 60 km s-1 and no indication for significant redshifted emission. We do not detect any significant extension of the velocity gradient across the source. We find a Br gamma line FWHM of 50 +/- 10 angstrom before and 15 +/- 10 A after the peribothron transit, i.e., no significant line broadening with respect to last year is observed. Br. 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. For the moment, the flaring activity of the black hole in the near-infrared regime has not shown any statistically significant increment. 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.

Item Type: Journal Article
Creators:
CreatorsEmailORCIDORCID Put Code
Valencia-S, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Eckart, A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Zajacek, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Peissker, F.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Parsa, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Grosso, N.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Mossoux, E.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Porquet, D.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Jalali, B.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Karas, V.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Yazici, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Shahzamanian, B.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Sabha, N.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Saalfeld, R.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Smajic, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Grellmann, R.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Moser, L.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Horrobin, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Borkar, A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Garcia-Marin, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Dovciak, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Kunneriath, D.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Karssen, G. D.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Bursa, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Straubmeier, C.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Bushouse, H.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
URN: urn:nbn:de:hbz:38-407313
DOI: 10.1088/0004-637X/800/2/125
Journal or Publication Title: Astrophys. J.
Volume: 800
Number: 2
Date: 2015
Publisher: IOP PUBLISHING LTD
Place of Publication: BRISTOL
ISSN: 1538-4357
Language: English
Faculty: Unspecified
Divisions: Unspecified
Subjects: no entry
Uncontrolled Keywords:
KeywordsLanguage
SAGITTARIUS-A-ASTERISK; T-TAURI STARS; MAGNETOSPHERIC ACCRETION MODELS; HERBIG AE/BE STARS; CENTER SOURCE G2; CENTER CLOUD G2; X-RAY-EMISSION; LINE EMISSION; GAS CLOUD; BRIGHTEST FLAREMultiple languages
Astronomy & AstrophysicsMultiple languages
URI: http://kups.ub.uni-koeln.de/id/eprint/40731

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