Positions of galactic X-ray sources: 320° &lt; lII &lt;340°

Apparao, K. M. V.; Bradt, H.; Dower, R. G.; Doxsey, R.; Jernigan, J. G.; Li, F.

doi:10.1038/271225a0

Cited by 20 publications

(10 citation statements)

References 25 publications

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“…The transient X‐ray source 2S 1553−542 was discovered at the time of outburst in observations using the rotation modulation collimator onboard Small Astronomy Satellite 3 in 1975 June (Apparao et al 1978 and reference therein) as a part of a systematic survey of the Galactic plane. Later, from the detailed analysis of the same data, Kelley, Rappaport & Ayasli (1983) found that the source is a transient X‐ray pulsar with the period of 9.3 s. They also found large variation in the spin period.…”

Section: Introductionmentioning

confidence: 99%

RXTE observation of recent flaring activity from the transient X-ray pulsar 2S 1553−542

Pahari

Pal

2012

Monthly Notices of the Royal Astronomical Society

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We summarize the analysis of observations made by the Rossi X‐ray Timing Explorer and the Swift/Burst Alert Telescope at the time of the recent flaring activity of the transient X‐ray pulsar 2S 1553−542. The binary system is characterized by the projected semimajor axis ax sin i of 168 ± 18 light‐seconds, the binary orbital period Porb of 29.56 ± 0.53 d and the X‐ray mass function fx(M) of 5.3 ± 1.2 M⊙. We also found Pspin= 9.2829 ± 0.0003 s with s s−1, i.e. a spin‐up rate of yr−1. The spin period is found to decrease more slowly than that of most other X‐ray pulsars. As the flare decays with time, the structure and X‐ray counts in the pulse profile showed considerable variability. However, no significant structural variability is seen in single‐peaked pulse profiles in different energy bands. Pulsed fraction decreases with the decay of the flare but its value at different energy bands showed a discontinuity. Using X‐ray spectroscopy at different orbital cycles, we have detected the presence of the Fe Kα emission line in the spectra with a minimum significance of 3σ. Apart from a consistent increase in blackbody temperature, other spectral parameters are found to be stable throughout orbital cycles. From detailed spectral and timing analysis, we concluded that the X‐ray flare is spectrally hard and we confirmed the nature of the compact object as a transient, accretion‐powered, spin‐up X‐ray pulsar with a Be‐type companion.

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Section: Introductionmentioning

confidence: 99%

RXTE observation of recent flaring activity from the transient X-ray pulsar 2S 1553−542

Pahari

Pal

2012

Monthly Notices of the Royal Astronomical Society

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“…Apparao et al (1978) provided an accurate position of the source (error radius of 30 ) with a list of candidate optical counterparts. Subsequently McClintock et al (1978), by means of spectrophotometric measurements, found that the most likely counterpart was the object #6 of Apparao et al (1978) (magnitude B > ∼ 20), which shows a very blue colour. The corresponding X-ray to optical luminosity is L X /L opt ∼ 1.4×10 3 (Bradt & McClintock 1983), a value quite typical for LMXBs (van Paradijs & McClintock 1995).…”

Section: X1543-624mentioning

confidence: 99%

“…A precise celestial position (error radius of 30 ) was given by Apparao et al (1978) using a SAS-3 observation made on June 1975. This position allowed Charles et al (1979) to identify the optical counterpart of the source with the star #43 (also known as LU TrA) in the finding chart reported by Apparao et al (1978) on the basis of its spectrophotometric characteristics. This object is rather blue (U-B = -0.7) and displays a He  λ4686 line in emission.…”

Section: X1556-605mentioning

confidence: 99%

BeppoSAXobservations of two unclassified LMXBs: X1543–624 and X1556–605

Farinelli

Frontera

Masetti

et al. 2003

A&A

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Abstract.Observations of two unclassified Low Mass X-ray Binaries, X1543-624 and X1556-605, are presented. In the 2-10 keV band the first of the two sources is a factor of two stronger than the other. Both sources do not show X-ray bursts, dips or eclipses in their X-ray light curves. We find that both spectra are described by a two-component model consisting of emission from a cool accretion disk plus a Comptonized blackbody with kT bb ∼ 1.5 keV in a low opacity plasma. The spectrum of X1543-624 hardens from the first to the second observation, when the source slowly moves from right to left in the colour-colour diagram. The spectrum of X1556-605 can also be described by a model consisting of a blackbody plus an unsaturated Comptonization with electron energy kT e ∼ 4 keV. In the first observation, X1543-624 shows evidence of a Fe K emission line at 6.4 keV. Moreover, in both observations, the source spectrum exhibits an emission feature around 0.7 keV, which is interpreted as due to the superposition of the K edge absorption features of O and Ne elements with uncommon relative abundances with respect to the solar one (O/O ∼ 0.3, Ne/Ne ∼ 2.5). In the spectrum of X1556-605 no emission lines are observed. We discuss these results and their implications for the source classification and the accretion geometry of the compact object.

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“…The X-ray transient 2S 1553-542 was discovered using Small Astronomy Satellite 3 (SAS-3) in 1975 (Apparao et al 1978) during the Galactic plane survey. A strong pulsation with the period of 9.3 was found (Kelley et al 1983) with an orbital period P orb of nearly 30 d (Pahari & Pal 2012).…”

Section: Introductionmentioning

confidence: 99%

Multi-Wavelength Study of X-ray Pulsar 2S 1553-542 During Outburst in 2021

Mandal¹,

Pal²

2021

Preprint

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We summarize the results of temporal and spectral analysis of the X-ray pulsar 2S 1553-542 using the Nuclear Spectroscopic Telescope Array (NuSTAR) and Swift during the outburst in January-February 2021. During the outburst, the spin period of the neutron star was P = 9.2822 ± 0.0001 s based on NuSTAR data. The temporal evolution of the spin period, pulse profile, and pulse fraction is studied during the outburst. The spectra of the source are studied for different days of the outburst and can be well described by a model consisting of -a black body emission or a power law. We have investigated the inter-day evolution of different timing and spectral parameters during the outburst. The energy dependence of the pulse profile was studied to investigate the evolution of the individual peaks and emission geometry of the pulsar with a different energy. The pulse profile of the source shows strong single peak nature with a humplike feature of relatively lower intensity and it evolves significantly with different energy ranges. The evolution of the pulse profile is studied during different phases of the outburst and the pulse fraction shows a positive correlation with energy.

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Positions of galactic X-ray sources: 320° < lII <340°

Cited by 20 publications

References 25 publications

RXTE observation of recent flaring activity from the transient X-ray pulsar 2S 1553−542

RXTE observation of recent flaring activity from the transient X-ray pulsar 2S 1553−542

BeppoSAXobservations of two unclassified LMXBs: X1543–624 and X1556–605

Multi-Wavelength Study of X-ray Pulsar 2S 1553-542 During Outburst in 2021

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