INTEGRAL,Swift, andRXTEobservations of the 518 Hz accreting transient pulsar Swift J1749.4−2807

Ferrigno, C.; Bozzo, E.; Falanga, M.; Stella, L.; Campana, S.; Belloni, T.; Israel, G. L.; Pavan, L.; Kuulkers, E.; Papitto, A.

doi:10.1051/0004-6361/201015033

Cited by 33 publications

(41 citation statements)

References 52 publications

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“…Similar eclipse behaviour has been observed for other LMXBs and explained in terms of a dust-scattering halo (e.g. Homan et al 2003;Ferrigno et al 2011). …”

Section: X-ray Eclipsesupporting

confidence: 84%

A four-yearXMM-Newton/Chandramonitoring campaign of the Galactic centre: analysing the X-ray transients

Degenaar

Wijnands

Cackett

et al. 2012

A&A

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We report on the results of a four-year long X-ray monitoring campaign of the central 1.2 square degrees of our Galaxy, performed with Chandra and XMM-Newton between 2005 and 2008. Our study focuses on the properties of transient X-ray sources that reach 2-10 keV luminosities of L X 10 34 erg s −1 for an assumed distance of 8 kpc. There are 17 known X-ray transients within the field of view of our campaign, eight of which were detected in outburst during our observations: the transient neutron star low-mass X-ray binaries GRS 1741-2853, AX J1745.6-2901, SAX J1747.0-2853, KS 1741-293 (all four are also known X-ray bursters), and GRO J1744-28 (a 2.1 Hz X-ray pulsar), and the unclassified X-ray transients XMM J174457-2850.3, CXOGC J174535.5-290124 and CXOGC J174541.0-290014. We present their X-ray spectra and flux evolution during our campaign, and discuss our results in light of their historic activity. Our main results include the detection of two thermonuclear X-ray bursts from SAX J1747.0-2853 that were separated by an unusually short time interval of 3.8 min. Investigation of the lightcurves of AX J1745.6-2901 revealed one thermonuclear X-ray burst and a ∼1600-s long X-ray eclipse. We found that both XMM J174457-2850.3 and GRO J1744-28 displayed weak X-ray activity above their quiescent levels at L X ∼ 10 33−34 erg s −1 , which is indicative of low-level accretion. We compare this kind of activity with the behaviour of low-luminosity X-ray transients that display 2-10 keV peak luminosities of L X ∼ 10 34 erg s −1 and have never been seen to become brighter. In addition to the eight known X-ray transients, we discovered a previously unknown X-ray source that we designate XMMU J174654.1-291542. This object emits most of its photons above 2 keV and appears to be persistent at a luminosity of L X ∼ 10 34 erg s −1 , although it exhibits strong spectral variability on a time scale of months. Based on its X-ray properties and the possible association with an infrared source, we tentatively classify this object as a cataclysmic variable. No new transients were found during our campaign, reinforcing the conclusion of previous authors that most X-ray transients recurring on a time scale of less than a decade have now been identified near the Galactic centre.

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“…Similar eclipse behaviour has been observed for other LMXBs and explained in terms of a dust-scattering halo (e.g. Homan et al 2003;Ferrigno et al 2011). …”

Section: X-ray Eclipsesupporting

confidence: 84%

A four-yearXMM-Newton/Chandramonitoring campaign of the Galactic centre: analysing the X-ray transients

Degenaar

Wijnands

Cackett

et al. 2012

A&A

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“…The detection of a type-I X-ray burst during the 2006 outburst provided an upper limit to the source distance of 6.7 ± 1.3 kpc (Wijnands et al 2009). The measured X-ray absorbing column density (N H = 3.0×10 22 cm −2 ; Ferrigno et al 2011) is considerably higher than the total Galactic column density in the direction of the source (N H = 1.1 × 10 22 cm −2 ). This might indicate that a fraction of it is local to the system and possibly ionized (i.e.…”

Section: Discussionmentioning

confidence: 75%

“…This was ascribed to a dust-scattering halo located along the line of sight to Swift J1749.4-2807 ). X-ray pulsations are not detected during these intervals, testifying to their genuine eclipse nature (Markwardt & Strohmayer 2010;Altamirano et al 2011;Ferrigno et al 2011). The detection of X-ray eclipses enables the system inclination to be constrained in the 74.4 • −77.9 • range (depending on the assumed neutron star mass; Markwardt & Strohmayer 2010;Altamirano et al 2011).…”

Section: Introductionmentioning

confidence: 99%

A search for the near-infrared counterpart of the eclipsing millisecond X-ray pulsar Swift J1749.4–2807

D’Avanzo

Campana

Muñoz-Darias

et al. 2011

A&A

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Context. Swift J1749.4-2807 is a transient accreting millisecond X-ray pulsars and the first to display X-ray eclipses. It therefore holds a strong potential for accurate mass measurements in a low-mass X-ray binary system. Aims. Determining the companion star's radial velocity would make it possible to fully resolve the system and to accurately measure the mass of the neutron star based on dynamical measurements. Unfortunately, no optical or near infrared (NIR) counterpart has been identified to date for this system, whether in outburst or in quiescence.Methods. We performed a photometric study of the field of Swift J1749.4-2807 during quiescence to search for a variable counterpart. The source direction lies on the Galactic plane, making any search for its optical/NIR counterpart challenging. To minimize the effects of field crowding and interstellar extinction, we carried out our observations using the adaptive optics NIR imager NACO mounted at the ESO Very Large Telescope (VLT).Results. From the analysis of public Swift X-ray data obtained during outburst, we derived the most precise (1.6 radius) position for this source. Due to the extreme stellar crowding of the field, 41 sources are detected in our VLT images within the X-ray error circle, with some of them possibly showing variability consistent with the expectations. Conclusions. We carried out the first deep imaging campaign devoted to the search for the quiescent NIR counterpart of Swift J1749.4-2807. Our results allow us to provide constraints on the nature of the companion star of this system. Furthermore, they suggest that future phase-resolved NIR observations (performed with large-aperture telescopes and adaptive optics) covering the full orbital period of the system are likely to identify the quiescent counterpart of Swift J1749.4-2807, through measuring its orbital variability, opening the possibility of dynamical studies of this unique source.

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“…RXTE /PCA observations (55 804.5-55 864 MJD) were analyzed with standard tecniques, as described in Ferrigno et al (2011). We used only data from the PCU2 because this was always active throughout the outburst of MAXI J1836−194 (observations ID 96438 and 96371; total exposure time 62 ks).…”

Section: Rxte Datamentioning

confidence: 99%

The first outburst of the black-hole candidate MAXI J1836−194 observed by INTEGRAL,Swift, and RXTE

Ferrigno

Bozzo

Santo

et al. 2012

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MAXI J1836−194 is a transient black-hole candidate discovered in outburst on 30 August 2011. We report on the available INTEGRAL, Swift, and RXTE observations performed in the direction of the source during this event before 55 864 MJD. Combining the broad band (0.6-200 keV) spectral and timing information obtained from these data with the results of radio observations, we show that the event displayed by MAXI J1836−194 is another example of "failed" outburst. During the first ∼20 days after the onset of the event, the source underwent a transition from the canonical low/hard to the hard intermediate state, while reaching the highest X-ray flux. In the ∼40 days following the peak of the outburst, the source displayed a progressive spectral hardening and a decrease in the X-ray flux, thus it entered again the low/hard state and began its return to quiescence.

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INTEGRAL,Swift, andRXTEobservations of the 518 Hz accreting transient pulsar Swift J1749.4−2807

Cited by 33 publications

References 52 publications

A four-yearXMM-Newton/Chandramonitoring campaign of the Galactic centre: analysing the X-ray transients

A four-yearXMM-Newton/Chandramonitoring campaign of the Galactic centre: analysing the X-ray transients

A search for the near-infrared counterpart of the eclipsing millisecond X-ray pulsar Swift J1749.4–2807

The first outburst of the black-hole candidate MAXI J1836−194 observed by INTEGRAL,Swift, and RXTE

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