A WHITE DWARF MERGER AS PROGENITOR OF THE ANOMALOUS X-RAY PULSAR 4U 0142+61?
- Dipartimento di Fisica and ICRA, Sapienza Universita di Roma, P.le Aldo Moro 5, I-00185 Rome (Italy)
- School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom)
- Institut de Ciencies de l'Espai (CSIC), Facultat de Ciencies, Campus UAB, Torre C5-parell, E-08193 Bellaterra (Spain)
It has been recently proposed that massive, fast-rotating, highly magnetized white dwarfs could describe the observational properties of some of soft gamma-ray repeaters and anomalous X-ray pulsars (AXPs). Moreover, it has also been shown that high-field magnetic white dwarfs can be the outcome of white dwarf binary mergers. The products of these mergers consist of a hot central white dwarf surrounded by a rapidly rotating disk. Here we show that the merger of a double degenerate system can explain the characteristics of the peculiar AXP 4U 0142+61. This scenario accounts for the observed infrared excess. We also show that the observed properties of 4U 0142+6 are consistent with an approximately 1.2 M{sub Sun} white dwarf, remnant of the coalescence of an original system made of two white dwarfs of masses 0.6 M{sub Sun} and 1.0 M{sub Sun }. Finally, we infer a post-merging age {tau}{sub WD} Almost-Equal-To 64 kyr and a magnetic field B Almost-Equal-To 2 Multiplication-Sign 10{sup 8} G. Evidence for such a magnetic field may come from the possible detection of the electron cyclotron absorption feature observed between the B and V bands at Almost-Equal-To 10{sup 15} Hz in the spectrum of 4U 0142+61.
- OSTI ID:
- 22140323
- Journal Information:
- Astrophysical Journal Letters, Vol. 772, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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