Department of Physics, Columbia University, New York, New York 10027, USA.
Phys Rev Lett. 2013 May 31;110(22):221102. doi: 10.1103/PhysRevLett.110.221102. Epub 2013 May 30.
Galactic nuclei are expected to be densely populated with stellar- and intermediate-mass black holes. Exploring this population will have important consequences for the observation prospects of gravitational waves as well as understanding galactic evolution. The gas cloud G2 currently approaching Sgr A* provides an unprecedented opportunity to probe the black hole and neutron star population of the Galactic nucleus. We examine the possibility of a G2-cloud-black-hole encounter and its detectability with current x-ray satellites, such as Chandra and NuSTAR. We find that multiple encounters are likely to occur close to the pericenter, which may be detectable upon favorable circumstances. This opportunity provides an additional important science case for leading x-ray observatories to closely follow G2 on its way to the nucleus.
银河系核心预计会密集存在恒星质量和中等质量的黑洞。探索这些黑洞群体会对引力波观测前景以及理解银河系演化产生重要影响。目前正在接近 Sgr A*的气体云 G2 为探测银河系核心的黑洞和中子星种群提供了前所未有的机会。我们研究了 G2 云与黑洞相遇的可能性及其在当前 X 射线卫星（如 Chandra 和 NuSTAR）上的可探测性。我们发现，在接近近日点时，可能会发生多次相遇，在有利的情况下可能会被探测到。这一机会为主要的 X 射线观测站提供了一个额外的重要科学案例，以便在 G2 接近银河系核心的过程中对其进行密切跟踪。
