The Galactic Center cloud G2 and its gas streamer

Abstract

We present new, deep near-infrared SINFONI @ VLT integral field spectroscopy of the gas cloud G2 in the Galactic Center, from late summer 2013 and spring 2014. G2 is visible in recombination line emission. The spatially resolved kinematic data track the ongoing tidal disruption. As expected for an observation near pericenter passage, roughly half of the gas in 2014 is found at the redshifted, pre-pericenter side of the orbit, while the other half is at the post-pericenter, blueshifted side. We also present an orbital solution for the gas cloud G1, which was discovered a decade ago in L'-band images when it was spatially almost coincident with Sgr A*. The orientation of the G1 orbit in the three angles is almost identical to the one of G2, but it has a lower eccentricity and smaller semi-major axis. We show that the observed astrometric positions and radial velocities of G1 are compatible with the G2 orbit, assuming that (i) G1 was originally on the G2 orbit preceding G2 by 13 years and (ii) a simple drag force acted on it during pericenter passage. Taken together with the previously described tail of G2, which we detect in recombination line emission and thermal broadband emission, we propose that G2 may be a bright knot in a much more extensive gas streamer. This matches purely gaseous models for G2, such as a stellar wind clump or the tidal debris from a partial disruption of a star.

28 pages, paper as accepted by ApJ

References in corpus (4)

• The Two Young Star Disks in the Central Parsec of the Galaxy: Properties, Dynamics and Formation
• Galactic Centre stellar winds and Sgr A* accretion
• On the nature of the fast moving star S2 in the Galactic Center
• A Stellar Wind Origin for the G2 Cloud: Three-Dimensional Numerical Simulations

Cited by in corpus (18)

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• Polarized near-infrared light of the Dusty S-cluster Object (DSO/G2) at the Galactic Center
• Simultaneous Monitoring of X-ray and Radio Variability in Sagittarius A*
• No asymmetric outflows from Sagittarius A* during the pericenter passage of the gas cloud G2
• ALMA and VLA observations of emission from the environment of Sgr A*
• Making SPIFFI SPIFFIER: Upgrade of the SPIFFI instrument for use in ERIS and performance analysis from re-commissioning
• A Luminous X-ray Flare From The Nucleus of The Dormant Bulgeless Spiral Galaxy NGC 247
• Detection of polarized continuum emission of the Dusty S-cluster Object (DSO/G2)
• The Fate of Binary Stars Hosting Planets upon Interaction with Sgr A* Black hole
• 3D AMR simulations of the evolution of the diffuse gas cloud G2 in the Galactic Centre
• 3D AMR simulations of G2 as an outflow