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NuSTAR Observations of the State Transition of Millisecond Pulsar Binary PSR J1023+0038

Tendulkar, Shriharsh P. and Yang, Chengwei and An, Hongjun and Kaspi, Victoria M. and Archibald, Anne M. and Bassa, Cees and Bellm, Eric and Bogdanov, Slavko and Harrison, Fiona A. and Hessels, Jason W. T. and Janssen, Gemma H. and Lyne, Andrew G. and Patruno, Alessandro and Stappers, Benjamin and Stern, Daniel and Tomsick, John A. and Boggs, Steven E. and Chakrabarty, Deepto and Christensen, Finn E. and Craig, William W. and Hailey, Charles A. and Zhang, William (2014) NuSTAR Observations of the State Transition of Millisecond Pulsar Binary PSR J1023+0038. Astrophysical Journal, 791 (2). Art. No. 77. ISSN 0004-637X. doi:10.1088/0004-637X/791/2/77.

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We report NuSTAR observations of the millisecond pulsar-low-mass X-ray binary (LMXB) transition system PSR J1023+0038 from 2013 June and October, before and after the formation of an accretion disk around the neutron star. Between June 10 and 12, a few days to two weeks before the radio disappearance of the pulsar, the 3-79 keV X-ray spectrum was well fit by a simple power law with a photon index of Γ = 1.17^(+0.08)_(-0.07) (at 90% confidence) with a 3-79 keV luminosity of 7.4 ± 0.4 × 10^(32) erg s^(–1). Significant orbital modulation was observed with a modulation fraction of 36% ± 10%. During the October 19-21 observation, the spectrum is described by a softer power law (Γ = 1.66^(+0.06)_(-0.05)) with an average luminosity of 5.8 ± 0.2 × 10^(33) erg s^(–1) and a peak luminosity of ≈1.2 × 10^(34) erg s^(–1) observed during a flare. No significant orbital modulation was detected. The spectral observations are consistent with previous and current multiwavelength observations and show the hard X-ray power law extending to 79 keV without a spectral break. Sharp-edged, flat-bottomed dips are observed with widths between 30 and 1000 s and ingress and egress timescales of 30-60 s. No change in hardness ratio was observed during the dips. Consecutive dip separations are log-normal in distribution with a typical separation of approximately 400 s. These dips are distinct from dipping activity observed in LMXBs. We compare and contrast these dips to observations of dips and state changes in the similar transition systems PSR J1824–2452I and XSS J1227.0–4859 and discuss possible interpretations based on the transitions in the inner disk.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Tendulkar, Shriharsh P.0000-0003-2548-2926
Kaspi, Victoria M.0000-0001-9345-0307
Bellm, Eric0000-0001-8018-5348
Bogdanov, Slavko0000-0002-9870-2742
Harrison, Fiona A.0000-0003-2992-8024
Hessels, Jason W. T.0000-0003-2317-1446
Stern, Daniel0000-0003-2686-9241
Tomsick, John A.0000-0001-5506-9855
Boggs, Steven E.0000-0001-9567-4224
Chakrabarty, Deepto0000-0001-8804-8946
Christensen, Finn E.0000-0001-5679-1946
Zhang, William0000-0002-1426-9698
Additional Information:© 2014 American Astronomical Society. Received 2014 February 18; accepted 2014 June 25; published 2014 July 29. We thank the anonymous referee for detailed suggestions and comments. This work was supported under NASA Contract No. NNG08FD60C and made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. We thank the NuSTAR Operations, Software, and Calibration teams for support with the execution and analysis of these observations. This research made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). VMK receives support from an NSERC Discovery Grant and Accelerator Supplement, from the Centre de Recherche en Astrophysique du Québec, an R. Howard Webster Foundation Fellowship from the Canadian Institute for Advanced Study, the Canada Research Chairs Program, and the Lorne Trottier Chair in Astrophysics and Cosmology. J.W.T.H. acknowledges funding for this work from ERC starting grant DRAGNET. A.P. acknowledges support from the Netherlands Organization for Scientic Research (NWO) Vidi fellowship.
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Centre de Recherche en Astrophysique du QuébecUNSPECIFIED
Canadian Institute for Advanced Research (CIFAR)UNSPECIFIED
Canada Research Chairs ProgramUNSPECIFIED
Lorne Trottier Chair in Astrophysics and CosmologyUNSPECIFIED
European Research Council (ERC)UNSPECIFIED
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)UNSPECIFIED
Subject Keywords:pulsars: general; pulsars: individual (PSR J1023+0038); stars: neutron; X-rays: stars
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2014-40
Issue or Number:2
Record Number:CaltechAUTHORS:20140903-141705608
Persistent URL:
Official Citation:NuSTAR Observations of the State Transition of Millisecond Pulsar Binary PSR J1023+0038 Shriharsh P. Tendulkar et al. 2014 ApJ 791 77
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:49205
Deposited By: Ruth Sustaita
Deposited On:04 Sep 2014 16:17
Last Modified:10 Nov 2021 18:40

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