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arxiv: 1306.1374 · v1 · pith:7O3Q2LGPnew · submitted 2013-06-06 · 🌌 astro-ph.GA

Pericenter passage of the gas cloud G2 in the Galactic Center

classification 🌌 astro-ph.GA
keywords orbitheadpericenteraroundblackbrackett-gammahole
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We have further followed the evolution of the orbital and physical properties of G2, the object currently falling toward the massive black hole in the Galactic Center on a near-radial orbit. New, very sensitive data were taken in April 2013 with NACO and SINFONI at the ESO VLT . The 'head' of G2 continues to be stretched ever further along the orbit in position-velocity space. A fraction of its emission appears to be already emerging on the blue-shifted side of the orbit, past pericenter approach. Ionized gas in the head is now stretched over more than 15,000 Schwarzschild radii RS around the pericenter of the orbit, at ~ 2000 RS ~ 20 light hours from the black hole. The pericenter passage of G2 will be a process stretching over a period of at least one year. The Brackett-{\gamma} luminosity of the head has been constant over the past 9 years, to within +- 25%, as have the line ratios Brackett-{\gamma} / Paschen-{\alpha} and Brackett-{\gamma} / Helium-I. We do not see any significant evidence for deviations of G2's dynamical evolution, due to hydrodynamical interactions with the hot gas around the black hole, from a ballistic orbit of an initially compact cloud with moderate velocity dispersion. The constant luminosity and the increasingly stretched appearance of the head of G2 in the position-velocity plane, without a central peak, is not consistent with several proposed models with continuous gas release from an initially bound zone around a faint star on the same orbit as G2.

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Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. G objects as Primordial Black Hole-Neutron Star Remnants: Population Modeling and Multi-Wavelength Observables

    astro-ph.HE 2026-03 unverdicted novelty 6.0

    G objects are modeled as primordial black hole-neutron star remnants whose population simultaneously accounts for the Galactic Center pulsar deficit.