@Article{CoelhoCáLiMaRuRu:2017:RoNaSo,
author = "Coelho, Jaziel Goulart and C{\'a}ceres, D. L. and Lima, R. C. R.
and Malheiro, M. and Rueda, J. A. and Ruffini, R.",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Sapienza
Universit{\`a} di Roma} and ICRANet and {Instituto
Tecnol{\'o}gico de Aeron{\'a}utica (ITA)} and {Sapienza
Universit{\`a} di Roma} and {Sapienza Universit{\`a} di Roma}",
title = "The rotation-powered nature of some soft gamma-ray repeaters and
anomalous X-ray pulsars",
journal = "Astronomy \& Astrophysics",
year = "2017",
volume = "599",
number = "A87",
month = "Mar.",
keywords = "pulsars: general, stars: rotation, stars: neutron, stars: magnetic
field.",
abstract = "Context. Soft gamma-ray repeaters (SGRs) and anomalous X-ray
pulsars (AXPs) are slow rotating isolated pulsars whose energy
reservoir is still matter of debate. Adopting neutron star (NS)
fiducial parameters; mass M = 1 : 4 M-circle dot, radius R = 10
km, and moment of inertia, I = 1045 g cm(2), the rotational energy
loss,. E-rot, is lower than the observed luminosity (dominated by
the X-rays) L-X for many of the sources. Aims. We investigate the
possibility that some members of this family could be canonical
rotation-powered pulsars using realistic NS structure parameters
instead of fiducial values. Methods. We compute the NS mass,
radius, moment of inertia and angular momentum from numerical
integration of the axisymmetric general relativistic equations of
equilibrium. We then compute the entire range of allowed values of
the rotational energy loss,. E-rot, for the observed values of
rotation period P and spin-down rate. P. We also estimate the
surface magnetic field using a general relativistic model of a
rotating magnetic dipole. Results. We show that realistic NS
parameters lowers the estimated value of the magnetic field and
radiation efficiency, LX/Erot, with respect to estimates based on
fiducial NS parameters. We show that nine SGRs/AXPs can be
described as canonical pulsars driven by the NS rotational energy,
for L-X computed in the soft (2-10 keV) X-ray band. We compute the
range of NS masses for which LX/Erot < 1. We discuss the observed
hard X-ray emission in three sources of the group of nine
potentially rotation-powered NSs. This additional hard X-ray
component dominates over the soft one leading to LX/Erot > 1 in
two of them. Conclusions. We show that 9 SGRs/AXPs can be
rotation-powered NSs if we analyze their X-ray luminosity in the
soft 2-10 keV band. Interestingly, four of them show radio
emission and six have been associated with supernova remnants
(including Swift J1834.9-0846 the first SGR observed with a
surrounding wind nebula). These observations give additional
support to our results of a natural explanation of these sources
in terms of ordinary pulsars. Including the hard X-ray emission
observed in three sources of the group of potential
rotation-powered NSs, this number of sources with L-X/E-rot < 1
becomes seven. It remains open to verification 1) the accuracy of
the estimated distances and 2) the possible contribution of the
associated supernova remnants to the hard X-ray emission.",
doi = "10.1051/0004-6361/201629521",
url = "http://dx.doi.org/10.1051/0004-6361/201629521",
issn = "0004-6361 and 1432-0746",
language = "en",
urlaccessdate = "27 abr. 2024"
}