Black holes have appetites. HNGN previously reported on a black hole choking on former sun-star. "Dougie," as well as the G1 and G2 gas clouds teetering on the brink of black hole-snackdom, but it turns out, G2 is a survivor (cue Destiny's Child).
Judging by observations by ESO's Very Large Telescope (VLT), G2 does not appear stretched out - it remains compact - and the black hole has not shown any increase in activity, according to a press release by the European Southern Observatory (ESO).
At the center of the Milky Way lies a supermassive black hole with a mass four million times the mass of the sun. The black hole is orbited by a group of stars and the mysterious object called G2, which has been observed during its fall toward the black hole. Peribothron, or the object's closest approach to the mouth of the black hole, was predicted to occur in May 2014.
Scientists expected gravity to tear G2 apart, feeding material to the black hole which would lead to flaring and other gobbling black hole events, according to the press release. Andreas Eckart, from the University of Cologne in Germany, and his team used VLT over the span of many years, including the critical period from February to September 2014.
Glowing hydrogen emitted infrared light, indicating G2's compactness before and after peribothron and as it swing around the monster's mouth.
The VLT's SINFONI instrument splits the light into its component infrared colors, allowing the velocity of the cloud to be estimated. Before closest approach, the cloud was found to be travelling away from the Earth at around ten million kph. After swinging around the black hole, it was measured to be approaching the Earth at about twelve million kph.
PhD student Florian Peissker did much of the observing. "Being at the telescope and seeing the data arriving in real time was a fascinating experience," Peissker said, according to the press release. Monica Valencia-S., a post-doctoral researcher worked on the data processing. "It was amazing to see that the glow from the dusty cloud stayed compact before and after the close approach to the black hole," she said, according to the press release.
Earlier observations of the object suggested it was stretched out, but new evidence did not show significant smearing and the black hole appears stable, judging from light polarization measured by the NACO instrument on the VLT.
"We looked at all the recent data and in particular the period in 2014 when the closest approach to the black hole took place," Eckart concluded. "We cannot confirm any significant stretching of the source. It certainly does not behave like a coreless dust cloud. We think it must be a dust-shrouded young star."
A video sequence, available here, shows the path of G2 as it nears the black hole and then moves on. (Video credit: ESO/A. Eckart)