Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: State of the field: Binary black hole natal kicks and prospects for
  isolated field formation after GWTC-2   Advanced LIGO and Advanced Virgo's newly-released GWTC-2 catalog of
gravitational-wave detections offers unprecedented information about the spin
magnitudes and orientations of merging binary black holes (BBHs). Notably,
analysis of the BBH population suggests the presence of binaries whose
component spins are significantly misaligned with respect to their orbital
angular momenta. Significantly misaligned spins are typically predicted to be
at odds with isolated field formation via standard common envelope (CE)
evolution, and hence a "smoking gun" signature of dynamical binary formation
inside dense stellar clusters. Here, we explore whether the LIGO/Virgo
observation of spin-orbit misalignment indeed rules out the possibility that
BBHs are formed entirely in the field via standard CE evolution. In particular,
we seek to understand whether, by varying the natal kicks black holes receive
upon formation, we can invoke the CE scenario to self-consistently explain both
the observed spin distribution and merger rate of BBHs. We find that, if
isolated black holes are born with small natal spins, then BBHs formed through
CE require extreme natal kicks to match the observed BBH population, with a
velocity dispersion $\sigma =
9.7^{+26.7}_{-5.9}\times10^2\,\mathrm{km}\,\mathrm{s}^{-1}$ and
$\sigma>260\,\mathrm{km}\,\mathrm{s}^{-1}$ at 99% credibility. To avoid this
condition, we argue that it is necessary to assume that isolated black holes
are born with non-vanishing natal spins, that one or more alternative channels
contribute to the observed BBH population, and/or that other unforeseen
mechanisms serve to yield large spin-orbit misalignment in the field.

20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex