The Spectrum of Smc X-1

B. A. Peterson; N. V. Vidal

doi:10.1017/s132335800001393x

The Spectrum of Smc X-1

Publications of the Astronomical Society of Australia ◽

10.1017/s132335800001393x ◽

1974 ◽

Vol 2 (5) ◽

pp. 286-289

Author(s):

B. A. Peterson ◽

N. V. Vidal

Keyword(s):

Magellanic Cloud ◽

Small Magellanic Cloud ◽

Optical Counterpart ◽

X Ray

The variable X-ray source in the direction of the Small Magellanic Cloud (SMC), SMC X-1 (2U 0115-73) was discovered by Leong et al. (1971). X-ray eclipses with a period of 3.8927 ± 0.0010 days were subsequently reported by Schreier et al. (1972). Identification of the X-ray source with SK 160, star number 160 in the list of Sanduleak (1968), was proposed by Webster et al. (1972) on the basis of the similarity of its spectrum with that of the optical counterpart of Cyg X-1.

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Swift J004427.3−734801 – a probable Be/white dwarf system in the Small Magellanic Cloud

Monthly Notices of the Royal Astronomical Society Letters ◽

10.1093/mnrasl/slaa112 ◽

2020 ◽

Vol 497 (1) ◽

pp. L50-L55 ◽

Cited By ~ 1

Author(s):

M J Coe ◽

J A Kennea ◽

P A Evans ◽

A Udalski

Keyword(s):

Gravitational Lensing ◽

White Dwarf ◽

Magellanic Cloud ◽

Optical Monitoring ◽

Small Magellanic Cloud ◽

Optical Counterpart ◽

Infrared Excess ◽

X Ray ◽

Be Star ◽

Soft Spectrum

ABSTRACT Swift J004427.3−734801 is an X-ray source in the Small Magellanic Cloud (SMC) that was first discovered as part of the Swift S-CUBED programme in 2020 January. It was not detected in any of the previous 3 yr worth of observations. The accurate positional determination from the X-ray data has permitted an optical counterpart to be identified that has the characteristics of an O9V−B2III star. Evidence for the presence of an infrared excess and significant I-band variability strongly suggests that this is an OBe-type star. Over 17 yr worth of optical monitoring by the OGLE (Optical Gravitational Lensing Experiment) project reveals periods of time in which quasi-periodic optical flares occur at intervals of ∼21.5 d. The X-ray data obtained from the S-CUBED project reveal a very soft spectrum, too soft to be that from accretion on to a neutron star or black hole. It is suggested here that this is a rarely identified Be star–white dwarf binary in the SMC.

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Searching for New Be/X–ray Binaries in the SMC: the case of 1SAXJ0103–7209, XTEJ0055–724, RXJ0052–7319, XTEJ0111–7317 and 2E0050–7247

International Astronomical Union Colloquium ◽

10.1017/s0252921100056736 ◽

2000 ◽

Vol 175 ◽

pp. 681-684

Author(s):

S. Covino ◽

G.L. Israel ◽

V.F. Polcaro ◽

S. Campana ◽

S. Mereghetti ◽

...

Keyword(s):

Magellanic Cloud ◽

Optical Observations ◽

Small Magellanic Cloud ◽

Optical Counterpart ◽

X Ray ◽

X Ray Binaries

AbstractWe obtained X–ray (ROSAT, BeppoSAX and ASCA) and optical observations of a sample of newly discovered X–ray pulsars. We here report on the discovery of the likely optical counterpart of five of them in the Small Magellanic Cloud: 1SAXJ0103–7209, XTEJ0055–724, RXJ0052–7319, XTEJ0111–7317 and 2E0050–7247.

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