NuSTAR detection of 4s Hard X-ray Lags from the Accreting Pulsar GS 0834-430

Matteo Bachetti, Hiromasa Miyasaka, Fiona Harrison, Felix Fürst, Didier Barret, Eric C. Bellm, Steven E. Boggs, Deepto Chakrabarty, Jérôme Chenevez, Finn Erland Christensen, William W. Craig, Brian W. Grefenstette, Charles J. Hailey, Kristin K. Madsen, Lorenzo Natalucci, Katja Pottschmidt, Daniel Stern, John A. Tomsick, Dominic J. Walton, Jörn WilmsWilliam Zhang

Research output: Contribution to journalConference articleResearchpeer-review

250 Downloads (Pure)


The NuSTAR hard X-ray telescope observed the transient Be/X-ray binary GS 0834&#x100000;430 during its 2012 outburst. The source is detected between 3 – 79 keV with high statistical significance, and we were able to perform very accurate spectral and timing analysis. The phase-averaged spectrum is consistent with that observed in many other magnetized accreting pulsars. We fail to detect cyclotron resonance scattering features in either phase-averaged nor phase-resolved spectra that would allow us to constrain the pulsar’s magnetic field. We detect a pulse period of ∼ 12.29 s in all energy bands. The pulse profile can be modeled with a double Gaussian and shows a strong and smooth hard lag of up to 0.3 cycles in phase, or about 4s between the pulse at ∼ 3 and >∼ 30 keV. This is the first report of such a strong lag in high-mass X-ray binary (HMXB) pulsars. Previously reported lags have been significantly smaller in phase and restricted to low-energies (E<10 keV). We investigate the possible mechanisms that might produce such lags. We find the most likely explanation for this eect to be a complex beam geometry.
Original languageEnglish
Article number06011
JournalE P J Web of Conferences
Number of pages4
Publication statusPublished - 2014
EventInternational Conference on Physics at the Magnetospheric Boundary - Geneva, Switzerland
Duration: 25 Jun 201328 Jun 2013


ConferenceInternational Conference on Physics at the Magnetospheric Boundary

Bibliographical note

This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Fingerprint Dive into the research topics of 'NuSTAR detection of 4s Hard X-ray Lags from the Accreting Pulsar GS 0834-430'. Together they form a unique fingerprint.

Cite this