<i>M-type</i>giants as optical counterparts of X-ray sources 4U 1700+24 and 4U 1954+319

Masetti, N.; Orlandini, M.; Palazzi, E.; Amati, L.; Frontera, F.

doi:10.1051/0004-6361:20065025

Cited by 79 publications

(100 citation statements)

References 26 publications

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“…The symbiotic nature of GX 1+4 was confirmed by discovery of flickering from the optical counterpart (Jablonski et al 1997). This makes the system a member of a rare class of symbiotic X-ray binaries (SyXB; Masetti et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Variability of the symbiotic X-ray binary GX 1+4

Iłkiewicz

Mikołajewska

Monard

2017

A&A

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Context. GX 1+4 belongs to a rare class of X-ray binaries with red giant donors, symbiotic X-ray binaries. The system has a history of complicated variability on multiple timescales in the optical light and X-rays. The nature of this variability remains poorly understood. Aims. We study variability of GX 1+4 on long time-scale in X-ray and optical bands. Methods. The presented X-ray observations are from INTEGRAL Soft Gamma-Ray Imager and RXTE All Sky Monitor. The optical observations are from INTEGRAL Optical Monitoring Camera.Results. The variability of GX 1+4 both in optical light and hard X-ray emission (>17 keV) is dominated by ∼50-70d quasi-periodic changes. The amplitude of this variability is highest during the periastron passage, while during the potential neutron star eclipse the system is always at minimum, which confirms the 1161d orbital period that has had been proposed for the system based on radial velocity curve. Neither the quasi-periodic variability or the orbital period are detected in soft X-ray emission (1.3-12.2 keV), where the binary shows no apparent periodicity.

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Section: Introductionmentioning

confidence: 99%

Variability of the symbiotic X-ray binary GX 1+4

Iłkiewicz

Mikołajewska

Monard

2017

A&A

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“…They were identified by finding a red giant counterpart to the primarily detected X-ray source (e.g. Davidsen et al , 1977;Masetti et al , 2006;Nespoli et al , 2010). On the other hand, many classical symbiotic stars have also been detected as X-ray sources (e.g.…”

Section: Introductionmentioning

confidence: 99%

Multiwavelength modelling the SED of supersoft X-ray sources I. The method and examples

Skopal

2015

New Astronomy

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-New method of modelling the spectra of supersoft X-ray sources is introduced. -The method analyses the X-ray/near-IR spectral energy distribution. -The multiwavelength approach overcomes problems of modelling only the X-ray data. -More trustworthy fundamental parameters are derived. AbstractRadiation of supersoft X-ray sources (SSS) dominates both the supersof X-ray and the far-UV domain. A fraction of their radiation can be reprocessed into the thermal nebular emission, seen in the spectrum from the near-UV to longer wavelengths. In the case of symbiotic X-ray binaries (SyXBs) a strong contribution from their cool giants is indicated in the optical/near-IR. In this paper I introduce a method of multiwavelength modelling the spectral energy distribution (SED) of SSSs from the supersoft X-rays to the near-IR with the aim to determine the physical parameters of their composite spectra. The method is demonstrated on two extragalactic SSSs, the SyXB RX J0059.1-7505 (LIN 358) in the Small Magellanic Cloud (SMC), RX J0439.8-6809 in the Large Magellanic Cloud (LMC) and two Galactic SSSs, the classical nova RX J2030.5+5237 (V1974 Cyg) during its supersoft phase and the classical symbiotic star RX J1601.6+6648 (AG Dra) during its quiescent phase. The multiwavelength approach overcomes the problem of the mutual dependence between the temperature, luminosity and amount of absorption, which appears when only the X-ray data are fitted. Thus, the method provides an unambiguous solution. It was found that selection of the model (a blackbody or an atmospheric model) is not of crucial importance in fitting the global X-ray/IR SED. The multiwavelength modelling of the SED of SSSs is essential in determining their physical parameters.

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“…GX 1+4; Lewin, Ricker, & McClintock 1971), and were at first classified as LMXBs, SyXBs display completely different properties (see e.g. Masetti et al 2006;Corbet et al 2008), like slow NS pulsations, M-type giant companions and very wide orbits (for example, GX 1+4, has Pspin=114 s and P orb =1 160.8 d). On the contrary, LMXBs where pulsations have been detected display NS spin periods typically in the millisecond range, reaching, at maximum, a spin period of ∼7.7 s in the LMXB 4U 1626-67 (Liu, van Paradijs, & van den Heuvel 2007; see also figs.…”

Section: Discussionmentioning

confidence: 99%

Swift J201424.9+152930: discovery of a new deeply eclipsing binary with 491-s and 3.4-h modulations

Esposito

Israel

Martino

et al. 2015

Monthly Notices of the Royal Astronomical Society

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We report on the discovery of a new X-ray pulsator, Swift J201424.9+152930 (Sw J2014). Owing to its X-ray modulation at 491 s, it was discovered in a systematic search for coherent signals in the archival data of the Swift X-ray Telescope. To investigate the nature of Sw J2014, we performed multi-wavelength follow-up observations with space-borne (Swift and XMMNewton) and ground-based (the 1.5-m Loiano Telescope and the 3.6-m Telescopio Nazionale Galileo) instruments. The X-ray spectrum of Sw J2014 can be described by a hard and highly absorbed (N H ∼ 5×10 22 cm −2 ) power law (Γ ∼ 1). The optical observations made it possible to single out the optical counterpart to this source, which displays several variable emission lines and total eclipses lasting ≈20 min. Total eclipses of similar length were observed also in X-rays. The study of the eclipses, allowed us to infer a second periodicity of 3.44 h, which we interpret as the orbital period of a close binary system. We also found that the period has not significantly changed over a ∼7 yr timespan. Based on the timing signatures of Sw J2014, and its optical and X-ray spectral properties, we suggest that it is a close binary hosting an accreting magnetic white dwarf. The system is therefore a cataclysmic variable of the intermediate polar type and one of the very few showing deep eclipses.

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M-typegiants as optical counterparts of X-ray sources 4U 1700+24 and 4U 1954+319

Cited by 79 publications

References 26 publications

Variability of the symbiotic X-ray binary GX 1+4

Variability of the symbiotic X-ray binary GX 1+4

Multiwavelength modelling the SED of supersoft X-ray sources I. The method and examples

Swift J201424.9+152930: discovery of a new deeply eclipsing binary with 491-s and 3.4-h modulations

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