## [1302.6049] Studies of waveform requirements for intermediate mass-ratio coalescence searches with advanced detectors

Authors: R. J. E. Smith, I. Mandel, A. Vecchio

Date: 25 Feb 2013

#### Jul 25, 2013

1307.6237 (/preprints)
2013-07-25, 13:10 

## [1307.6283] Migration of massive black hole binaries in self--gravitating accretion discs: Retrograde versus prograde

Authors: Constanze Roedig, Alberto Sesana

Date: 24 Jul 2013

#### Jul 25, 2013

1307.6283 (/preprints)
2013-07-25, 13:10 

## [1307.6331] A strongly magnetized pulsar within grasp of the Milky Way's supermassive black hole

Authors: N. Rea, P. Esposito, J. A. Pons, R. Turolla, D. F. Torres, G. L. Israel, A. Possenti, M. Burgay, D. Vigano&#x27;, R. Perna, L. Stella, G. Ponti, F. Baganoff, D. Haggard, A. Papitto, A. Camero-Arranz, S. Zane, A. Minter, S. Mereghetti, A. Tiengo, R. Schoedel, M. Feroci, R. Mignani, D. Gotz

Date: 24 Jul 2013

Abstract: The center of our Galaxy hosts a supermassive black hole, Sagittarius (Sgr) A*. Young, massive stars within 0.5 pc of SgrA* are evidence of an episode of intense star formation near the black hole a few Myr ago. Some of them might have left behind a young neutron star traveling deep into SgrA*'s gravitational potential. However, no neutron star closer than ~200 parsec from the supermassive black hole has been detected so far. On 2013 April 25, a short X-ray burst was observed from the direction of the Galactic center. Thanks to the superb spatial resolution of the Chandra X-ray Observatory, we could pinpoint the associated, persistent pulsating X-ray source at an angular distance of 2.4+/-0.3 arcsec from SgrA*. Using a series of Chandra and Swift observations we have refined the spin period and its derivative (P=3.7635443(3) and \dot{P}=7.6(2)x10ˆ{-12} s/s), confirmed by radio observations performed with the Green Bank (GBT) and Parkes single dish antennas, that also measured a Dispersion Measure of DM=1750 +/-50 pc cmˆ{-3}, the highest ever detected for a radio pulsar. We have found that this X-ray source is a young magnetar at only ~0.07-2 pc away from SgrA*, and that with high probability (~90%), it is in a bound orbit around the black hole. The passage of radiation fronts produced by the past activity from the magnetar through the molecular clouds surrounding the Galactic center region might also partially explain the light echoes observed in the Fe fluorescence features.

#### Jul 25, 2013

1307.6331 (/preprints)
2013-07-25, 13:10 

## [1301.7074] Gravitational and electromagnetic outputs from binary neutron star mergers

Authors: Carlos Palenzuela, Luis Lehner, Marcelo Ponce, Steven L. Liebling, Matthew Anderson, David Neilsen, Patrick Motl

Date: 29 Jan 2013

Abstract: The late stage of an inspiraling neutron star binary gives rise to strong gravitational wave emission due to its highly dynamic, strong gravity. Moreover, interactions between the stellar magnetospheres can produce considerable electromagnetic radiation. We study this scenario using fully general relativistic, resistive magneto-hydrodynamics simulations. We show that these interactions extract kinetic energy from the system, dissipate heat, and power radiative Poynting flux, as well as develop current sheets. Our results indicate that this power can: (i) outshine pulsars in binaries, (ii) display a distinctive angular- and time-dependent pattern, and (iii) radiate within large opening angles. These properties suggest that some binary neutron star mergers are ideal candidates for multimessenger astronomy.

#### Jul 25, 2013

1301.7074 (/preprints)
2013-07-25, 13:10 

## [1307.6483] A census of transient orbital resonances encountered during binary inspiral

Authors: Uchupol Ruangsri, Scott A. Hughes

Date: 24 Jul 2013

Abstract: Transient orbital resonances have recently been identified as potentially important to the inspiral of small bodies into large black holes. These resonances occur as the inspiral evolves through moments in which two fundamental orbital frequencies, $\Omega_\theta$ and $\Omega_r$, are in a small integer ratio to one another. Previous work has demonstrated that a binary's parameters are "kicked" each time the inspiral passes through a resonance, changing the orbit's characteristics relative to a model that neglects resonant effects. In this paper, we use exact Kerr geodesics coupled to an accurate but approximate model of inspiral to survey orbital parameter space and estimate how commonly one encounters long-lived orbital resonances. We find that the most important resonances last for a few hundred orbital cycles at mass ratio $10ˆ{-6}$, and that resonances are almost certain to occur during the time that a large mass ratio binary would be a target of gravitational-wave observations. Resonances appear to be ubiquitous in large mass ratio inspiral, and to last long enough that they are likely to affect binary evolution in observationally important ways.

#### Jul 25, 2013

1307.6483 (/preprints)
2013-07-25, 13:10