Timing and spectral properties of the accreting millisecond pulsar SWIFT J1756.9-2508

Abstract

SWIFT J1756.9-2508 is one of the few accreting millisecond pulsars (AMPs) discovered to date. We report here the results of our analysis of its aperiodic X-ray variability, as measured with the Rossi X-ray Timing Explorer during the 2007 outburst of the source. We detect strong (~35%) flat-topped broadband noise throughout the outburst with low characteristic frequencies (~0.1 Hz). This makes SWIFT J1756.9-2508 similar to the rest of AMPs and to other low luminosity accreting neutron stars when they are in their hard states, and enables us to classify this AMP as an atoll source in the extreme island state. We also find a hard tail in its energy spectrum extending up to 100 keV, fully consistent with such source and state classification.

Accepted for publication in The Astrophysical Journal. Scheduled for the ApJ May 10, 2008, v678n 2 issue. 6 pages, 5 figures. Uses \emulateapj

References in corpus (3)

• Discovery of coherent millisecond X-ray pulsations in Aql X-1
• Intermittent millisecond X-ray pulsations from the neutron-star X-ray transient SAX J1748.9-2021 in the globular cluster NGC 6440
• Intermittent pulsations in an accretion-powered millisecond pulsar

Cited by in corpus (7)

• A Double Outburst from IGR J00291+5934: Implications for Accretion Disk Instability Theory
• Discovery of a new accreting millisecond X-ray pulsar in the globular cluster NGC 2808
• Indications of non-conservative mass-transfer in AMXPs
• The aperiodic X-ray variability of the accreting millisecond pulsar SAX J1808.4-3658
• Swift J1734.5-3027: a new long type-I X-ray bursting source
• Testing jet geometries and disk-jet coupling in the neutron star LMXB 4U 0614+091 with the internal shocks model
• Broad-band X-ray spectra and timing of the accretion-powered millisecond pulsar Swift J1756.9$-$2508 during its 2018 and 2019 outbursts