MAGNETARS VERSUS HIGH MAGNETIC FIELD PULSARS: A THEORETICAL INTERPRETATION OF THE APPARENT DICHOTOMY

Journal Article · Thu Nov 10 00:00:00 EST 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/741/2/123; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21612678

Pons, Jose A ^[1]; Perna, Rosalba ^[2]

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1. Department de Fisica Aplicada, Universitat d'Alacant, Ap. Correus 99, E-03080 Alacant (Spain)
2. JILA and Department of Astrophysical and Planetary Science, University of Colorado at Boulder, 440 UCB, Boulder, CO 80304 (United States)

Highly magnetized neutron stars (NSs) are characterized by a bewildering range of astrophysical manifestations. Here, building on our simulations of the evolution of magnetic stresses in the NS crust and its ensuing fractures, we explore in detail, for the middle-aged and old NSs, the dependence of starquake frequency and energetics on the relative strength of the poloidal (B{sub p}) and toroidal (B{sub tor}) components. We find that, for B{sub p} {approx}> 10{sup 14} G, since a strong crustal toroidal field B{sub tor} {approx} B{sub p} is quickly formed on a Hall timescale, the initial toroidal field needs to be B{sub tor} >> B{sub p} to have a clear influence on the outbursting behavior. For initial fields B{sub p} {approx}< 10{sup 14} G, it is very unlikely that a middle-aged (t {approx} 10{sup 5} years) NS shows any bursting activity. This study allows us to solve the apparent puzzle of how NSs with similar dipolar magnetic fields can behave in a remarkably different way: an outbursting 'magnetar' with a high X-ray luminosity, or a quiet, low-luminosity, 'high-B' radio pulsar. As an example, we consider the specific cases of the magnetar 1E 2259+586 and the radio pulsar PSR J1814-1744, which at present have a similar dipolar field {approx}6 Multiplication-Sign 10{sup 13} G. We determine for each object an initial magnetic field configuration that reproduces the observed timing parameters at their current age. The same two configurations also account for the differences in quiescent X-ray luminosity and for the 'magnetar/outbursting' behavior of 1E 2259+586 but not of PSR J1814-1744. We further use the theoretically predicted surface temperature distribution to compute the light curve for these objects. In the case of 1E 2259+586, for which data are available, our predicted temperature distribution gives rise to a pulse profile whose double-peaked nature and modulation level are consistent with the observations.

• OSTI ID: 21612678
• Journal Information: Astrophysical Journal, Vol. 741, Issue 2; Other Information: DOI: 10.1088/0004-637X/741/2/123; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASTROPHYSICS
LUMINOSITY
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC FIELDS
NEUTRON STARS
NEUTRONS
PULSARS
PULSES
SIMULATION
STAR EVOLUTION
TEMPERATURE DISTRIBUTION
BARYONS
COSMIC RADIO SOURCES
ELEMENTARY PARTICLES
EVOLUTION
FERMIONS
HADRONS
NUCLEONS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PHYSICS
STARS