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

Abstract

We analyse and report in detail new near-infrared (1.45 - 2.45 microns) 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 ESO VLT/SINFONI between February and September 2014. Before May 2014 we detect spatially compact Br-gamma and Pa-alpha line emission from the DSO at about 40mas east of SgrA*. The velocity of the source, measured from the red-shifted emission, is 2700+-60 km/s. No blue-shifted emission above the noise level is detected at the position of SgrA* or upstream the presumed orbit. After May we find spatially compact Br-gamma blue-shifted line emission from the DSO at about 30mas west of SgrA* at a velocity of -3320+-60 km/s and no indication for significant red-shifted emission. We do not detect any significant extension of velocity gradient across the source. We find a Br-gamma-line full width at half maximum of 50+-10 Angstroem before and 15+-10 Angstroem after the peribothron transit, i.e. no significant line broadening with respect to last year is observed. Br-gamma line maps show that the bulk of the line emission originates from a region of less than 20mas 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 SgrA* may still be upcoming. We discuss details of a source model according to which the DSO is rather a young accreting star than a coreless gas and dust cloud.

32 pages - 3 tables - 17 figure - accepted by ApJ

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Cited by in corpus (17)

• S62 and S4711: Indications of a population of faint fast moving stars inside the S2 orbit -- S4711 on a 7.6 year orbit around Sgr~A*
• Kinematic Structure of the Galactic Center S-cluster
• The Post-Periapse Evolution of Galactic Center Source G1: The second case of a resolved tidal interaction with a supermassive black hole
• The Galactic Center: Improved Relative Astrometry for Velocities, Accelerations, and Orbits near the Supermassive Black Hole
• Monitoring dusty sources in the vicinity of Sgr A*
• Polarized near-infrared light of the Dusty S-cluster Object (DSO/G2) at the Galactic Center
• Stellar Populations in the Central 0.5 pc of Our Galaxy III: The Dynamical Sub-structures
• Near- and mid-infrared observations in the inner tenth of a parsec of the Galactic center -- Detection of proper motion of a filament very close to Sgr~A*
• No asymmetric outflows from Sagittarius A* during the pericenter passage of the gas cloud G2
• A new bow-shock source with bipolar morphology in the vicinity of Sgr A*
• ALMA and VLA observations of emission from the environment of Sgr A*
• Close stellar encounters at the Galactic Centre I: The effect on the observed stellar populations
• The apparent tail of the Galactic center object G2/DSO
• First observed interaction of the circumstellar envelope of an S-star with the environment of Sgr A*
• The evolution of circumstellar discs in the Galactic Centre: an application to the G-clouds
• X3: a high-mass Young Stellar Object close to the supermassive black hole Sgr~A*
• Detection of polarized continuum emission of the Dusty S-cluster Object (DSO/G2)