Observations of a transient X-ray source with regular periodicity of 6.75 min

Ives, J. C.; Sanford, P. W.; Burnell, S. J. Bell

doi:10.1038/254578a0

Cited by 60 publications

(29 citation statements)

References 5 publications

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“…1A 1118−615 is a hard X-ray transient pulsar which was discovered with Ariel V in an outburst in 1974 (Eyles et al 1975). The same series of observations revealed X-ray pulsations with a duration of 405.6 s (Ives, Sanford & Burnell 1975). The optical counterpart He 3−640 (='WRA 793') is a highly reddened Be star classified as an O9.5IV-Ve star (Chevalier & Ilovaisky 1975).…”

Section: Introductionmentioning

confidence: 88%

Timing and broad-band spectroscopy of 1A 1118−61 with Suzaku

Maitra

Paul

Naik

2012

Monthly Notices of the Royal Astronomical Society

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We present a timing and broad‐band pulse‐phase‐resolved spectral analysis of the transient Be X‐ray binary pulsar 1A 1118−61 observed during its outburst in 2009 January using Suzaku observations. The Suzaku observations were made twice, once at the peak of the outburst, and the other 13 d later at its declining phase. Pulse profiles from both observations exhibit strong energy dependence with several peaks at low energies and a single peak above ∼10 keV. A weak, narrow peak is detected at the main dip of the pulse profiles from both observations in the energy bands below 3 keV, indicating the presence of a phase‐dependent soft excess in the source continuum. The broad‐band energy spectrum of the pulsar could be fitted well with a partial covering cut‐off power‐law model and a narrow iron fluorescence line. We also detect a broad cyclotron feature at ∼50 keV from both observations which is a feature common for accretion‐powered pulsars with high magnetic field strength. The pulse‐phase‐resolved spectral analysis shows an increase in the absorption column density of the partial covering component, as well as variation in the covering fraction at the dips of the pulse profiles, which naturally explains energy dependence of the same. The cyclotron line parameters also show significant variation with pulse phase with an ∼10 keV variation in the cyclotron line energy and a variation in depth by a factor of 3. This can be explained either as the effect of different viewing angles of the dipole field at different pulse phases, or due to a more complex underlying magnetic field geometry.

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Section: Introductionmentioning

confidence: 88%

Timing and broad-band spectroscopy of 1A 1118−61 with Suzaku

Maitra

Paul

Naik

2012

Monthly Notices of the Royal Astronomical Society

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“…The prdfiles fo r H er X-I, 4U0115+63. Cen X-3, OAOI653-40, AI118-61, and 4U1538-52 are from Joss et al (1978a), Johnston et al (1978), Ulmer (1976), , Ives et al (1975), and Becker et al (1977), respectively; the remaining profiles are from unpublished SAS-3 data. (For additional references, see Table 1 and Rappaport& Joss 1977a.…”

Section: Pulse Profiles and Spectramentioning

confidence: 99%

Neutron Stars in Interacting Binary Systems

Joss¹,

Rappaport²

1984

Annu. Rev. Astron. Astrophys.

253

134

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“…It has not been studied with BATSE and is not discussed in this paper. Chakrabarty et al1997b;7] Makishima et al1988;8] Levine et al1993;9] Finger et al1993; 10] Nagase et al1992; 11] Israel et al1995;12] Sa -Harb, Ogelman & Dennerl 1996;13] Chakrabarty et al1993;14] Deeter et al1987; 15] Ilovaisky, Chevalier & Motch 1982;16] Makishima et al1984;17] Rubin et al1994;18] Corbet et al1993;19] Koh et al1997;20] Sato et al1986; 21] Skinner 1981; 22] Cominsky et al1994;23] Rappaport et al1978;24] Stella et al1985; 25] Finger, 26] Stollberg et al1994;27] Parmar et al1989;28] Wilson et al1994b;29] Coe et al1994a; 30] Finger, Wilson & Harmon 1996; 31] Priedhorsky & Terrell 1983;32] Cook & Warwick 1987;33] Ives, Sanford & Bell-Burnell 1975;34] Murakami et al1987; 35] Hellier 1994; 36] Schwentker 1994; 37] Seward, Charles & Smale 1986; 38] Iwasawa, Koyama & Halpern 1992; 39] Haberl et al1996;40]…”

Section: Introductionmentioning

confidence: 99%

Observations of Accreting Pulsars

Bildsten

Chakrabarty

Chiu

et al. 1997

ASTROPHYS J SUPPL S

747

929

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We summarize five years of continuous monitoring of accretion-powered pulsars with the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory. Our 20-70 keV observations have determined or refined the orbital parameters of 13 binaries, discovered 5 new transient accreting pulsars, measured the pulsed flux history during outbursts of 12 transients (GRO J1744-28, 4U 0115+634, GRO J1750-27, GS 0834-430, 2S 1417-624, GRO J1948+32, EXO 2030+375, GRO J1008-57, A 0535+26, GRO J2058+42, 4U 1145-619 and A 1118-616), and also measured the accretion torque history of during outbursts of 6 of those transients whose orbital parameters were also known. We have also continuously measured the pulsed flux and spin frequency for eight persistently accreting pulsars (Her X-1, Cen X-3, Vela X-1, OAO 1657-415, GX 301-2, 4U 1626-67, 4U 1538-52, and GX 1+4). Because of their continuity and uniformity over a long baseline, BATSE observations have provided new insights into the long-term behavior of accreting magnetic stars. We have found that all accreting pulsars show stochastic variations in their spin frequencies and luminosities, including those displaying secular spin-up or spin-down on long time scales, blurring the conventional distinction between disk-fed and wind-fed binaries. Pulsed flux and accretion torque are strongly correlated in outbursts of transient accreting pulsars, but uncorrelated, or even anticorrelated, in persistent sources.Comment: LaTeX, psfig, 90 pages, 42 figures. To appear in Dec. 1997 ApJS, Vol 113, #

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Observations of a transient X-ray source with regular periodicity of 6.75 min

Cited by 60 publications

References 5 publications

Timing and broad-band spectroscopy of 1A 1118−61 with Suzaku

Timing and broad-band spectroscopy of 1A 1118−61 with Suzaku

Neutron Stars in Interacting Binary Systems

Observations of Accreting Pulsars

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