Title: ToO observations of the "Bursting Pulsar" during outburst with INTEGRAL


Proposal ID: 0120089
Subject category: Compact Object
Principal investigator: Masetti
Institute: Istituto TeSRE, CNR


Abstract

The goal of this proposal is to perform a thorough investigation, with the instruments onboard INTEGRAL, of the broad band hard X-ray properties of the "Bursting Pulsar" GRO J1744-28 in case in will undergo an outburst during AO1. In particular, we intend to search for cyclotron absorption lines in the X-ray spectrum of this object in order to get a direct measurement of the accreting neutron star magnetic field intensity. We also propose to: (i) monitor the spectral and timing behaviours of the hard emission from GRO J1744-28 starting from the outburst onset up to the decay toward quiescence; (ii) obtain phase-resolved spectra of the pulsating X-ray emission; and (iii) to pinpoint the differences between the bursting and the persistent fluxes of this source. Other relevant issues which can be explored with INTEGRAL observations, such as the determination of a pulse period derivative during outburst decay and the comparison with the other peculiar source MXB 1730-335 (the "Rapid Burster") are discussed.