Cas A Cooling Part Deux

  arXiv:1011.6142 [pdf, ps, other]

Title: Rapid Cooling of the Neutron Star in Cassiopeia A Triggered by Neutron Superfluidity in Dense Matter

Authors: Dany Page (1), Madappa Prakash (2), James M. Lattimer (3), Andrew W. Steiner (4

J1718-3718

 arXiv:1011.5697 [pdf, ps, other]

Title: Chandra Observations of the High-Magnetic-Field Radio Pulsar J1718-3718

Authors: W. W. Zhu, V. M. Kaspi, M. A. McLaughlin, G. G. Pavlov, C.-Y. Ng, R. N. Manchester, B. M. Gaensler, P. M. Woods

J1903+0327

arXiv:1011.5809 [pdf, ps, other]

Title: On the nature and evolution of the unique binary pulsar J1903+0327

Authors: P. C. C. Freire, C. G. Bassa, N. Wex, I. H. Stairs, D. J. Champion, S. M. Ransom, P. Lazarus, V. M. Kaspi, J. W. T. Hessels, M. Kramer, J. M. Cordes, J. P. W. Verbiest, P. Podsiadlowski, D.~J. Nice, J. S. Deneva, D. R. Lorimer, B. W. Stappers, M. A. McLaughlin, F. Camilo

Classifying the QPOs of Magnetars

Magnetars after their large flare exhibit quasi-periodic oscillations as they cool.  This paper looks at this modes in GR and includes the effects of the magnetic field with a realistic field geometry.   They find n=0 modes with low l at frequencies of around 10-50 Hz  and n=1 modes at 1 kHz.   The frequencies of course depend on the properties of the underlying star --- wow!

arXiv:1011.5406 [pdf, ps, other]

Title: Magneto-elastic torsional oscillations of magnetars

Authors: Michael Gabler, Pablo Cerdá-Durán, José A. Font, Ewald Müller, Nikolaos Stergioulas

A Bit Far-Fetched But Interesting

The key point is that spacecraft can accurately know the distance to Earth with radio ranging but they don't know their position well perpendicular to the Earth-spacecraft line, so by using x-ray pulsars they could do better.   Some other possibly more realistic ideas:  how about using brighter radio pulsars or other spacecraft.   Spacecraft often use other spacecraft to relay data back to Earth, the timing of the response should be sufficient to determine range if the other systematics could be ironed out.

arXiv:1011.5095 [pdf, ps, other]
Title: Timing X-ray Pulsars with Application to Spacecraft Navigation
Authors: Mike Georg Bernhardt, Tobias Prinz, Werner Becker, Ulrich Walter

Kozai and Compact Objects

This paper dovetails nicely with Yanquin Wu's talk here last week.  Quite a fun idea.

arXiv:1011.4322 [pdf, ps, other]

Title: Accelerating Compact Object Mergers in Triple Systems with the Kozai Resonance: A Mechanism for "Prompt'' Type Ia Supernovae, Gamma-Ray Bursts, and Other Exotica

Authors: Todd A. Thompson

What if you could watch the universe change?

The authors propose an experiment where you actually measure the redshifts of objects changing with time (almost achievable now) and how the CMD changes with time (more fantastical).

 arXiv:1011.2646 [pdf, ps, other] Real-time Cosmology

Claudia Quercellini, Luca Amendola, Amedeo Balbi, Paolo Cabella, Miguel Quartin

Three Generations

The actual argument for three generations is a bit weak; however, this paper is definitely an interesting read with a quick history of the need for three generations to explain the experiments in the sixties and to account for baryogenesis.   As for why not more than three, is it just too unlikely.

 arXiv:1011.2761 (cross-list from hep-ph) [pdf, ps, other]

Anthropic Argument for Three Generations

Andrew Gould

Is the universe isotropic?

I reckoned that it is a good idea to check this out.  Ralston outlines how to quantify the anisotropy of various observations and of course finds it.   The quantification and potential observations are useful, the finding it is a lot harder to believe.

arXiv:1011.2240 [pdf, ps, other] Question Isotropy John P. Ralston

The Chameleon and the Giant

A Chameleon scalar field in scalar-tensor gravity is a field that modifies the strength of gravity at low densities and large length scales.  It disappears below a thin layer of high density material, so it would affect the structure of most stars.   However, the outer layers of giant stars especially supergiants like Betelgeuse are essentially hot vacuums, so the chameleon would not be fully shielded here and would change the structure of these stars.

arXiv:1011.4107 [pdf, ps, other]

Stellar Structure and Tests of Modified Gravity

Philip Chang, Lam Hui

Neutron-Star Optics

Researchers have generally assumed that the spacetime surrounding a neutron star is well approximated by Schwarschild or Kerr to calculate ray tracing because of the high degree of symmetry of these spacetimes.  Psaltis and Jonahannsen present a new algorithm that goes beyond these toy models and use a metric with an arbitrary quadrupole moment.  This requires integrating 2nd-order ODES (rather than the 1st-order in the case of Kerr).  They outline some systems where this technique provides potentially important diagnostics.

 arXiv:1011.4078 [pdf, ps, other]

A Ray-Tracing Algorithm for Spinning Compact Object Spacetimes with Arbitrary Quadrupole Moments. I. Quasi-Kerr Black Holes

Dimitrios Psaltis, Tim Johannsen (Arizona)

Modelling MSXP Disk

The authors present a model of a radiation pressure dominated accretion disk around a millisecond x-ray pulsar including the interaction of the stellar magnetic field with the disk.

[277]  arXiv:1011.2621 [pdf, ps, other]

Thin accretion discs around millisecond X-ray pulsars

Solomon Belay Tessema, Ulf Torkelsson

Mount Ararat

Two astronomer-mountainers obtained permission to climb Mt Ararat in 2004.  They took a rarely travelled route and discovered a much of interesting things including a possible meteor crater and an ancient fortress.

 arXiv:1011.3715 [pdf] A meteorite crater on Mt. Ararat? V.G.Gurzadyan, S.Aarseth

Fermionic Molecular Dynamics

The authors present a technique better to account for the antisymmetry of fermionic wavefunctions in molecular dynamic simulations.

arXiv:1011.2928 (cross-list from nucl-th) [pdf, other] Title: Towards a quantal dynamical simulation of the neutron-star crust Authors: Klaas Vantournhout, Thomas Neff, Hans Feldmeier, Natalie Jachowicz,Jan Ryckebusch

SGR Bursts from Kes 73

Yet another AXP is found to emit gamma-ray bursts further cementing the common heritage of AXPs and SGRs.

 arXiv:1011.3537 [pdf, ps, other] Title: SWIFT study of the first SGR-like burst from AXP 1E 1841-045 in SNR Kes 73

Faraday Rotation

Whenever I see papers about asymmetries in Faraday rotation or other polarization stuff, I am reminded of a bunch of wacky papers from about five to ten years ago about quasar polarizations. This paper on the other hand argues that the observed Faraday rotation correlations come not from extra physics nor the Galactic magnetic field but from a nearby bubble of HI about 100 pc away toward the Galactic center. The bubble supposedly has compressed the magnetic field on either side of it, increasing its strength and therefore the Faraday rotation. These observations were performed at DRAO in Penticton in the beautiful Okanagan valley of BC.

arXiv:1011.0341 [pdf, ps, other]

Title: Antisymmetry in the Faraday Rotation Sky Caused by a Nearby Magnetized Bubble Authors: M. Wolleben, A. Fletcher, T. L. Landecker, E. Carretti, J. M. Dickey, B. M. Gaensler, M. Haverkorn, N. McClure-Griffiths, W. Reich, A. R. Taylor Comments: Published in Astrophysical Journal Letters 724 (2010) L48-L52 Subjects: Galaxy Astrophysics (astro-ph.GA)

Supernova Progenitors

As of 2010 over thirty core-collapse SN progenitors have been identified. What do they look like? Generally they are all massive stars (a plus for SN theory); furthermore Type II-P supernova typically have progenitors that are red supergiants at the low-mass end. The question is whether all massive stars result in SN. Kochanek has suggested we look for massive stars vanishing from nearby galaxies. This might be quite feasible and interesting.

arXiv:1011.0203 [pdf, ps, other]

Title: On the Progenitors of Core-Collapse Supernovae Authors: Douglas C. Leonard (San Diego State University) Comments: 7 Pages, invited review accepted for publication by Astrophysics and Space Science (special HEDLA 2010 issue) Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Cosmology and Extragalactic Astrophysics (astro-ph.CO)

No Gamma-Rays from Magnetars

Fermi has looked for gamma-rays from magnetars from 100 MeV to 10 GeV and found none.  This eliminates (or makes things really difficult) for some models of the hard x-ray emission from magnetars such as mine ( http://lanl.arxiv.org/pdf/astro-ph/0502349 ).  Nothing ventured, nothing gained.

arXiv:1011.0091 [pdf, other]

Title: Search for gamma-ray emission from magnetars with the Fermi Large Area Telescope Authors: The Fermi-LAT collaboration Comments: ApJ Letters in press; Corresponding authors: Caliandro G. A., Hadasch D., Rea N., Burnett T Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Galaxy Astrophysics (astro-ph.GA)