Here are four interesting papers from arXiv astrophysics:
1) Francesca Valsecchi, Evert Glebbeek, et al, "Formation of the black-hole binary M33 X-7 via mass-exchange in a tight massive system",
M-33 X-7 is a mystery that this paper proports to solve, maybe. This binary object seems to be a ~16 solar mass black hole orbiting a ~70 solar mass hydrogen-rich O-type companion star. This binary system has a period of ~3.5 days. Up until now, no model explained all of the weird things about this system. This paper contrives a set of circumstances to explain it all.
2) Shigehiro Nagataki, "Rotating BHs as Central Engines of Long GRBs: Faster is Better,"
This paper relates the rotational rate of a black hole to the strength of any relativistic jet produced by it. This is based on numerical relativity calculations using a magnetohydrodynamic code. Four different models are run.
3) Joan M. Centrella, John G. Baker, "Black-hole binaries, gravitational waves, and numerical relativity,"
This is a very nice review of black hole modeling and numerical relativity. Of course, one of the primary applications is the support of gravitational wave detectors.
4) Rachid Ouyed, Mathew Kostka, et al, "Quark nova imprint in the extreme supernova explosion SN 2006gy: the advent of the Quark Star,"
A fascinating possibility is that at the center of neutron stars a special form of matter is produced, one where there is a region of free quarks surrounded by a screen of gluons. This is called a quark-gluon plasma. Such a state of matter was speculative for many decades, but recent results from RHIC (Relativistic Heavy Ion Collider) have given indications that this has been achieved. The authors of this paper suggest that the supernova SN2006gy was in fact a supernova that included a boost to the explosion through the release of energy by the conversion of neutons at the center of the developing neutron star, converting the center into more stable strange quark matter. If true, this is a significant event!
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