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Title: Soft gamma-ray repeaters and anomalous X-ray pulsars as highly magnetized white dwarfs

Abstract

We explore the possibility that soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are powered by highly magnetized white dwarfs (B-WDs). We take a sample of SGRs and AXPs and provide the possible parameter space in mass, radius, and surface magnetic field based on their observed properties (period and its derivative) and the assumption that these sources obey the mass-radius relation derived for the B-WDs. The radius and magnetic field of B-WDs are adequate to explain energies in SGRs/AXPs as the rotationally powered energy. In addition, B-WDs also adequately explain the perplexing radio transient GCRT J1745-3009 as a white dwarf pulsar. Note that the radius and magnetic fields of B-WDs are neither extreme (unlike of highly magnetized neutron stars) nor ordinary (unlike of magnetized white dwarfs, yet following the Chandrasekhar's mass-radius relation (C-WDs)). In order to explain SGRs/AXPs, while the highly magnetized neutron stars require an extra, observationally not well established yet, source of energy, the C-WDs predict large ultra-violet luminosity which is observationally constrained from a strict upper limit. Finally, we provide a set of basic differences between the magnetar and B-WD hypotheses for SGRs/AXPs.

Authors:
 [1]
  1. Department of Physics, Indian Institute of Science, Bangalore 560012 (India)
Publication Date:
OSTI Identifier:
22667586
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2016; Journal Issue: 05; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; GAMMA RADIATION; HYPOTHESIS; LUMINOSITY; MAGNETIC FIELDS; MASS; NEUTRON STARS; PULSARS; SPACE; WHITE DWARF STARS; X RADIATION

Citation Formats

Mukhopadhyay, Banibrata, and Rao, A.R., E-mail: bm@physics.iisc.ernet.in, E-mail: arrao@tifr.res.in. Soft gamma-ray repeaters and anomalous X-ray pulsars as highly magnetized white dwarfs. United States: N. p., 2016. Web. doi:10.1088/1475-7516/2016/05/007.
Mukhopadhyay, Banibrata, & Rao, A.R., E-mail: bm@physics.iisc.ernet.in, E-mail: arrao@tifr.res.in. Soft gamma-ray repeaters and anomalous X-ray pulsars as highly magnetized white dwarfs. United States. https://doi.org/10.1088/1475-7516/2016/05/007
Mukhopadhyay, Banibrata, and Rao, A.R., E-mail: bm@physics.iisc.ernet.in, E-mail: arrao@tifr.res.in. 2016. "Soft gamma-ray repeaters and anomalous X-ray pulsars as highly magnetized white dwarfs". United States. https://doi.org/10.1088/1475-7516/2016/05/007.
@article{osti_22667586,
title = {Soft gamma-ray repeaters and anomalous X-ray pulsars as highly magnetized white dwarfs},
author = {Mukhopadhyay, Banibrata and Rao, A.R., E-mail: bm@physics.iisc.ernet.in, E-mail: arrao@tifr.res.in},
abstractNote = {We explore the possibility that soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are powered by highly magnetized white dwarfs (B-WDs). We take a sample of SGRs and AXPs and provide the possible parameter space in mass, radius, and surface magnetic field based on their observed properties (period and its derivative) and the assumption that these sources obey the mass-radius relation derived for the B-WDs. The radius and magnetic field of B-WDs are adequate to explain energies in SGRs/AXPs as the rotationally powered energy. In addition, B-WDs also adequately explain the perplexing radio transient GCRT J1745-3009 as a white dwarf pulsar. Note that the radius and magnetic fields of B-WDs are neither extreme (unlike of highly magnetized neutron stars) nor ordinary (unlike of magnetized white dwarfs, yet following the Chandrasekhar's mass-radius relation (C-WDs)). In order to explain SGRs/AXPs, while the highly magnetized neutron stars require an extra, observationally not well established yet, source of energy, the C-WDs predict large ultra-violet luminosity which is observationally constrained from a strict upper limit. Finally, we provide a set of basic differences between the magnetar and B-WD hypotheses for SGRs/AXPs.},
doi = {10.1088/1475-7516/2016/05/007},
url = {https://www.osti.gov/biblio/22667586}, journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 05,
volume = 2016,
place = {United States},
year = {Sun May 01 00:00:00 EDT 2016},
month = {Sun May 01 00:00:00 EDT 2016}
}