XMM-Newton observations of IGR J00291+5934: signs of a thermal spectral component during quiescence

Abstract

We present X-ray observations of the transient accretion-powered millisecond pulsar IGR J00291+5934 during quiescence. IGR J00291+5934 is the first source among accretion powered millisecond pulsars to show signs of a thermal component in its quiescent spectrum. Fitting this component with a neutron star atmosphere or a black body model we obtain soft temperatures (~64 eV and ~110 eV, respectively). As in other sources of this class a hard spectral component is also present, comprising more than 60% of the unabsorbed 0.5-10 keV flux. Interpreting the soft component as cooling emission from the neutron star, we can conclude that the compact object can be spun up to milliscond periods by accreting only <0.2 solar masses.

5 pages - 2 figures. Accepted for publication on ApJL

References in corpus (4)

• Swift observations of SAX J1808.4-3658: monitoring the return to quiescence
• Observations of the 599 Hz Accreting X-ray Pulsar IGR J00291+5934 during the 2004 Outburst and in Quiescence
• Discovery of the INTEGRAL X/Gamma-ray transient IGR J00291+5934: a Comptonised accreting ms pulsar ?
• Nucleon superfluidity versus thermal states of isolated and transiently accreting neutron stars

Cited by in corpus (5)

• Cooling of Accretion-Heated Neutron Stars
• UltraCompCAT: a comprehensive Catalogue of Ultra-Compact and Short Orbital Period X-ray Binaries
• A cold neutron star in the transient low-mass X-ray binary HETE J1900.1-2455 after 10 years of active accretion
• A systematic study of the advection-dominated accretion flow for the origin of the X-ray emission in weakly magnetized low-level accreting neutron star
• The quiescent counterpart of the peculiar X-ray burster SAX J2224.9+5421