Please use this identifier to cite or link to this item:
|Title:||A Propeller Model for the Sub-luminous State of the Transitional Millisecond Pulsar PSR J1023+0038||Authors:||PAPITTO, ALESSANDRO
Torres, D. F.
|Issue Date:||2015||Journal:||THE ASTROPHYSICAL JOURNAL||Number:||807||Issue:||1||First Page:||33||Abstract:||The discovery of millisecond pulsars switching between states powered either by the rotation of their magnetic field or by the accretion of matter has recently proved the tight link shared by millisecond radio pulsars and neutron stars in low-mass X-ray binaries. Transitional millisecond pulsars also show an enigmatic intermediate state in which the neutron star is surrounded by an accretion disk and emits coherent X-ray pulsations, but is sub-luminous in X-rays with respect to accreting neutron stars, and is brighter in gamma-rays than millisecond pulsars in the rotation-powered state. Here, we model the X-ray and gamma-ray emission observed from PSR J1023+0038 in such a state based on the assumptions that most of the disk in-flow is propelled away by the rapidly rotating neutron star magnetosphere, and that electrons can be accelerated to energies of a few GeV at the turbulent disk-magnetosphere boundary. We show that the synchrotron and self-synchrotron Compton emission coming from such a region, together with the hard disk emission typical of low states of accreting compact objects, is able to explain the radiation observed in the X-ray and gamma-ray bands. The average emission observed from PSR J1023+0038 is modeled by a disk in-flow with a rate of 1-3 × 10<SUP>-11</SUP> M<SUB>☉</SUB> yr<SUP>-1</SUP>, truncated at a radius ranging between 30 and 45 km, compatible with the hypothesis of a propelling magnetosphere. We compare the results we obtained with models that assume that a rotation-powered pulsar is turned on, showing how the spin-down power released in similar scenarios is hardly able to account for the magnitude of the observed emission.||Acknowledgments:||We acknowledge support from the the grants AYA2012-39303 and SGR 2014-1073. A.P. is supported by a Juan de la Cierva fellowship. D.F.T. further acknowledges the National Natural Science Foundation of China via NSFC-11473027 and the Chinese Academy of Sciences visiting professorship program 2013-T2J0007. We thank L. Burderi, E. de Oña Wilhelmi, T. Di Salvo, J. Li, N. Rea, and M. Romanova for useful discussions and comments. We acknowledge the International Space Science Institute (ISSI), which funded and hosted an international team devoted to the study of transitional millisecond pulsars, and we thank all the members of the team for fruitful discussions. We thank the anonymous referee for useful comments and suggestions.||URI:||http://hdl.handle.net/20.500.12386/24007||URL:||https://iopscience.iop.org/article/10.1088/0004-637X/807/1/33||ISSN:||0004-637X||DOI:||10.1088/0004-637X/807/1/33||Bibcode ADS:||2015ApJ...807...33P||Fulltext:||open|
|Appears in Collections:||1.01 Articoli in rivista|
Show full item record
Files in This Item:
|Papitto_2015_ApJ_807_33.pdf||PDF editoriale||511.18 kB||Adobe PDF||View/Open|
checked on Sep 26, 2020
checked on Sep 26, 2020
Items in DSpace are published in Open Access, unless otherwise indicated.