<i>XMM-Newton</i>
                    Observation of the 5.25 Millisecond Transient Pulsar XTE J1807-294 in Outburst

Campana, S.; Ravasio, M. E.; Israel, G. L.; Mangano, V.; Belloni, T.

doi:10.1086/378258

Cited by 43 publications

(60 citation statements)

References 35 publications

(42 reference statements)

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“…A re-analysis of these data enabled Falanga et al (2005) to constrain the companion mass to M c < 0.022 M , suggesting that is a very low mass (likely white) dwarf. INTEGRAL observations of XTE J1807−294 in the 0.5−200 keV carried out during the 2003 outburst (simultaneously with the XMM-Newton and RXTE observations) revealed a spectrum consistent with a combination of thermal Comptonization and blackbody, as found at lower energy by Campana et al (2003) but with a higher equivalent temperature (Falanga et al 2005). During quiescence, XTE J1807−294 was observed with XMM-Newton and the source was not detected down to a 3σ upper limit of L X < 4 × 10 31 erg s −1 (0.5−10 keV) assuming a distance of 8 kpc (Campana et al 2005).…”

Section: Xte J1807−294mentioning

confidence: 70%

The optical counterparts of accreting millisecond X-ray pulsars during quiescence

D’Avanzo

Campana²,

Casares

et al. 2009

A&A

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Context. Eight accreting millisecond X-ray pulsars (AMXPs) are known to date. Although these systems are well studied at high energies, very little information is available for their optical/NIR counterparts. Up to now, only two of them, SAX J1808.4−3658 and IGR J00291+5934, have a secure multi-band detection of their optical counterparts in quiescence. Aims. All these systems are transient low-mass X-ray binaries. Optical and NIR observations carried out during quiescence give a unique opportunity to constrain the nature of the donor star and to investigate the origin of the observed quiescent luminosity at long wavelengths. In addition, optical observations can be fundamental as they ultimately allow us to estimate the compact object mass through mass function measurements. Methods. Using data obtained with the ESO-Very Large Telescope, we performed a deep optical and NIR photometric study of the fields of XTE J1814−338 and of the ultracompact systems XTE J0929−314 and XTE J1807−294 during quiescence in order to look for the presence of a variable counterpart. If suitable candidates were found, we also carried out optical spectroscopy. Results. We present here the first multi-band (VR) detection of the optical counterpart of XTE J1814−338 in quiescence together with its optical spectrum. The optical light curve shows variability in both bands consistent with a sinusoidal modulation at the known 4.3 h orbital period and presents a puzzling decrease of the V-band flux around superior conjunction that may be interpreted as a partial eclipse. The marginal detection of the very faint counterpart of XTE J0929−314 and deep upper limits for the optical/NIR counterpart of XTE J1807−294 are also reported. We also briefly discuss the results reported in the literature for the optical/NIR counterpart of XTE J1751−305. Conclusions. Our findings are consistent with AMXPs being systems containing an old, weakly magnetized neutron star, reactivated as a millisecond radio pulsar during quiescence which irradiates the low-mass companion star. The absence of type I X-ray bursts and of hydrogen and helium lines in outburst spectra of ultracompact (P orb < 1 h) AMXPs suggests that the companion stars are likely evolved dwarf stars.

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Section: Xte J1807−294mentioning

confidence: 70%

The optical counterparts of accreting millisecond X-ray pulsars during quiescence

D’Avanzo

Campana²,

Casares

et al. 2009

A&A

Self Cite

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“…The position of Aql X-1 was re-calculated for d = 4 kpc (Rutledge et al 2001). The luminosities of additional systems come from these authors: SAX J1808.4-3658 (in't Zand et al 2001;Campana et al 2002), 1H 1905+000 (Jonker et al 2006), XTE J1807-294 (Campana et al 2003;Campana et al 2005), XTE J1709-267 (Jonker et al 2003), GRO J1744-28 (Finger et al 1996). For KS 1731-260, L max ≈ 7.9 × 10 37 erg s −1 was determined from the unabsorbed flux, derived by Wijnands et al (2001a).…”

Section: Luminosity Of Ks 1731-260 In the Context Of Ns Sxtsmentioning

confidence: 99%

Echo outbursts in KS 1731–260

Šimon

2010

A&A

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Context. The thermal-viscous instability of the accretion disk is thought to play an important role in the activity of low-mass X-ray binaries (LMXBs). It should also appear when a (quasi)persistent LMXB goes into its low state. Aims. We analyze the long-term X-ray activity of the neutron star LMXB KS 1731-260 during a part of its long main outburst and a complicated transition back to the low state (quiescence). We pay special attention to the variations during the state transition. Methods. We make use of the ASM/RXTE observations for a timeseries analysis of the longterm variations and investigation of the X-ray color changes in the 1.5-12 keV passband. Results. In our interpretation, the mass transfer rateṁ tr between the donor and neutron star significantly increased during the main outburst of KS 1731-260, which prolonged this event by keeping the disk ionized to its outer rim. Later on, a considerable fraction of the outer part of the disk was rapidly brought out of steady-state whenṁ tr decreased again. Only a slow decrease ofṁ tr continued even after the end of the main outburst. This lead to the formation of the central disk region, which was kept thermally stable, ionized by irradiation, and was surrounded by the outer, thermally unstable disk region. This configuration triggered the series of the echo outbursts. These outbursts are outside-in, caused by the still continuingṁ tr via the mass stream impinging the outer rim of the disk without overflow. We argue that introducing any strong bursts of matter from the donor to the disk as the cause of the echo outbursts is superfluous. The spectral evolution suggests that the disk returns to steady-state during the maxima of the echo outbursts. The X-ray emission between the echo outbursts is much higher than in the true quiescence and can be due to the ongoingṁ tr . We place the peculiar long-term activity of KS 1731-260 in the context of the systems with the echo outbursts, both soft X-ray transients and dwarf novae.

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“…Formally, this source is not an accretion-powered X-ray pulsar and belongs to the class of millisecond pulsars. Campana et al (2003) showed that the source's XMM-Newton radiation spectrum at low energies is best fitted by the combination of an absorbed blackbody and Comptonization models or a power law without absorption or emission lines.…”

Section: Gx 1+4 (4u 1728-247)mentioning

confidence: 99%

Hard spectra of X-ray pulsars from INTEGRAL data

et al. 2005

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Abstract.We present spectra for 34 accretion-powered X-ray and one millisecond pulsars that were within the field of view of the INTEGRAL observatory over two years (December 2002-January 2005 of its in-orbit operation and that were detected by its instruments at a statistically significant level (> 8σ in the energy range 18-60 keV). There are seven recently discovered objects of this class among the pulsars studied: 2RXP J130159.6-635806, IGR/AX J16320-4751, IGR J16358-4726, AX J163904-4642, IGR J16465-4507, SAX/IGR J18027-2017 and AX J1841.0-0535. We have also obtained hard X-ray (> 20 keV) spectra for the accretion-powered pulsars A 0114+650, RX J0146.9+6121, AX J1820.5-1434, AX J1841.0-0535 and the millisecond pulsar XTE J1807-294 for the first time. We analyze the evolution of spectral parameters as a function of the intensity of the sources and compare these with the results of previous studies. c 2004 MAIK "Nauka/Interperiodica".

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XMM-Newton Observation of the 5.25 Millisecond Transient Pulsar XTE J1807-294 in Outburst

Cited by 43 publications

References 35 publications

The optical counterparts of accreting millisecond X-ray pulsars during quiescence

The optical counterparts of accreting millisecond X-ray pulsars during quiescence

Echo outbursts in KS 1731–260

Hard spectra of X-ray pulsars from INTEGRAL data

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