Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Missing black holes in brightest cluster galaxies as evidence for the
  occurrence of superkicks in nature   We investigate the consequences of superkicks on the population of
supermassive black holes (SMBHs) in the Universe residing in brightest cluster
galaxies (BCGs). There is strong observational evidence that BCGs grew
prominently at late times (up to a factor 2-4 in mass from z=1), mainly through
mergers with satellite galaxies from the cluster, and they are known to host
the most massive SMBHs ever observed. Those SMBHs are also expected to grow
hierarchically, experiencing a series of mergers with other SMBHs brought in by
merging satellites. Because of the net linear momentum taken away from the
asymmetric gravitational wave emission, the remnant SMBH experiences a kick in
the opposite direction. Kicks may be as large as ~5000 Km/s ("superkicks"),
pushing the SMBHs out in the cluster outskirts for a time comparable to
galaxy-evolution timescales. We predict, under a number of plausible
assumptions, that superkicks can efficiently eject SMBHs from BCGs, bringing
their occupation fraction down to a likely range 0.9<f<0.99 in the local
Universe. Future thirty-meter-class telescopes like ELT and TMT will be capable
of measuring SMBHs in hundreds of BCGs up to z=0.2, testing the occurrence of
superkicks in nature and the strong-gravity regime of SMBH mergers.

18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci