Cyclotron line features in the spectrum of the transient X-ray pulsar X0115 + 634

Journal Article · Mon Jul 01 04:00:00 EDT 1991 · Astrophysical Journal; (United States)

DOI:https://doi.org/10.1086/186085· OSTI ID:5318706

Nagase, F; Dotani, T; Tanaka, Y; Makishima, K; Mihara, T ^[1]

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1. Institute of Space and Astronautical Science, Sagamihara (Japan) Tokyo, University (Japan)

An outburst of the transient X-ray pulsar X0115 + 634 was detected with the All Sky Monitor (ASM) on board Ginga on February 5, 1990. Follow-up observations with the large-area proportional counters (LACs) revealed complex changes in the energy spectrum which depend on the phase of the 3.6 s pulsation. Characteristic structures in the spectra above 10 keV can be best interpreted as two dips at about 12 and about 23 keV, although not at all phases. The results strongly suggest that the structures in the spectra are due to cyclotron resonant scattering and the two apparent absorption lines are ascribed to the fundamental and second harmonics. This indicates a magnetic field strength on the neutron star surface of about 1 {times} 10 to the 12th G. Equivalent widths of the second harmonic line are about 2 times larger than those of the first harmonic line, depending on the pulse phase. 25 refs.

• OSTI ID: 5318706
• Journal Information: Astrophysical Journal; (United States), Journal Name: Astrophysical Journal; (United States) Vol. 375; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION SPECTRA
BINARY STARS
BREMSSTRAHLUNG
COSMIC GAMMA BURSTS
COSMIC RADIATION
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
CYCLOTRON RADIATION
ELECTROMAGNETIC RADIATION
ENERGY SPECTRA
IONIZING RADIATIONS
LINE WIDTHS
MAGNETIC FIELDS
NEUTRON STARS
PRIMARY COSMIC RADIATION
PULSARS
RADIATIONS
SPECTRA
STARS
TRANSIENTS
X-RAY SPECTRA