3D MHD Simulations of accreting neutron stars: evidence of QPO emission from the surface

Journal Article · Thu Jul 15 00:00:00 EDT 2010 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3475164· OSTI ID:21413473

Bachetti, Matteo; Burderi, Luciano ^[1]; Romanova, Marina M; Kulkarni, Akshay ^[2]; Salvo, Tiziana di ^[3]

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1. Universita degli Studi di Cagliari (Italy)
2. Cornell University (United States)
3. Universita degli Studi di Palermo (Italy)

3D Magnetohydrodynamic simulations show that when matter accretes onto neutron stars, in particular if the misalignment angle is small, it does not constantly fall at a fixed spot. Instead, the location at which matter reaches the star moves. These moving hot spots can be produced both during stable accretion, where matter falls near the magnetic poles of the star, and unstable accretion, characterized by the presence of several tongues of matter which fall on the star near the equator, due to Rayleigh-Taylor instabilities. Precise modeling with Monte Carlo simulations shows that those movements could be observed as high frequency Quasi Periodic Oscillations. We performed a number of new simulation runs with a much wider set of parameters, focusing on neutron stars with a small misalignment angle. In most cases we observe oscillations whose frequency is correlated with the mass accretion rate M. Moreover, in some cases double QPOs appear, each of them showing the same correlation with M.

• OSTI ID: 21413473
• Journal Information: AIP Conference Proceedings, Vol. 1248, Issue 1; Conference: International conference on X-ray astronomy 2009: Present status, multi-wavelength approach and future perspectives, Bologna (Italy), 7-11 Sep 2009; Other Information: DOI: 10.1063/1.3475164; (c) 2010 American Institute of Physics; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCRETION DISKS
COMPUTERIZED SIMULATION
CORRELATIONS
EMISSION
EQUATOR
HOT SPOTS
MAGNETOHYDRODYNAMICS
MASS
MONTE CARLO METHOD
NEUTRON STARS
OSCILLATIONS
PERIODICITY
RAYLEIGH-TAYLOR INSTABILITY
SURFACES
CALCULATION METHODS
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
MECHANICS
SIMULATION
STARS
VARIATIONS