NEW OBSERVATIONS OF THE GAS CLOUD G2 IN THE GALACTIC CENTER

被引:79
作者
Gillessen, S. [1 ]
Genzel, R. [1 ,2 ,3 ]
Fritz, T. K. [1 ]
Eisenhauer, F. [1 ]
Pfuhl, O. [1 ]
Ott, T. [1 ]
Cuadra, J. [4 ]
Schartmann, M. [1 ,5 ]
Burkert, A. [1 ,5 ]
机构
[1] Max Planck Inst Extraterr Phys, D-85741 Garching, Germany
[2] Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA
[3] Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA
[4] Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago, Chile
[5] Univ Munich, Univ Sternwarte, D-81679 Munich, Germany
关键词
accretion; accretion disks; black hole physics; Galaxy: center; infrared: general; ISM: clouds; SGR-A-ASTERISK; BLACK-HOLE; STELLAR ORBITS; CENTRAL PARSEC; SAGITTARIUS-A; YOUNG STARS; ESO VLT; RESOLUTION; ORIGIN; GALAXY;
D O I
10.1088/0004-637X/763/2/78
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present new observations of the recently discovered gas cloud G2 currently falling toward the massive black hole in the Galactic Center. The new data confirm that G2 is on a highly elliptical orbit with a predicted pericenter passage mid-2013. The updated orbit has an even larger eccentricity of 0.966, an epoch of pericenter two months later than estimated before, and a nominal minimum distance of 2200 Schwarzschild radii only. The velocity gradient of G2 has developed further to 600 km s(-1) FWHM in summer 2012. We also detect the tail of similar total flux and on the same orbit as G2 along the trajectory at high significance. No hydrodynamic effects are detected yet, since the simple model of a tidally shearing gas cloud still describes the data very well. The flux of G2 has not changed by more than 10% between 2008 and 2012, disfavoring models where additional gas from a reservoir is released to the disrupting diffuse gas component.
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页数:10
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