A dataset provided by the European Space Agency

Proposal ID 0820033
Obs ID 08200330001, 08200330002, 08200330003
Title Variability of the cyclotron line energy E_cyc in Hercules X-1
Download Data Associated to the proposal https://isla.esac.esa.int/tap/download/bundle?format=ascii_curl&product_id=prop_id:0820033
DOI https://doi.org/10.57780/esa-pf6pqmj
Author Staubert
Abstract We propose to observe Her~X-1 during INTEGRALs AO-8 for a total observingtime of 600 ksec: covering one Main-On with two INTEGRAL orbits,the first near the maximum of the Main-On, the second during its decay, plus oneINTEGRAL}orbit during the following Short-On. Our prime objectives are tosystematically measure the centroid energy of the fundamental cyclotron lineE_cyc as a function of time, X-ray flux, 35 day phase and 1.24 s phaseand to study the variation of the shape of the pulse profile with 35 day phase.These observations will contribute to answering the following questions: Is there a slow seculardecrease in the value of E_cyc with time? Does E_cyc depend on 35 day phase?How stable is the positive correlation of the value of E_cyc with the X-ray luminosity?Does the neutron star itself really show precession?The results will yield infomation about fundamental physics in this disk-accreting binary pulsarwith respect to: the structure of the magnetic field at the polar caps, the physics of sub-Eddingtonaccretion, the generation of spectra and pulse profiles.
Publications
Temporal Coverage 2011-06-25T04:12:36Z / 2011-07-18T17:10:59Z
Version 1.0
Mission Description The INTEGRAL (International Gamma-Ray Astrophysics Laboratory) mission, launched by the European Space Agency (ESA) on October 17, 2002, was designed to study high-energy phenomena in the universe. INTEGRAL was operating until february 2025 and it was equipped with three high-energy instruments: the Imager on Board the INTEGRAL Satellite (IBIS), the Spectrometer on INTEGRAL (SPI), and the JEM-X (Joint European Monitor for X-rays). Its Optical Monitoring Camera (OMC) provided optical V-band magnitude measurements, complementing the high-energy observations.
Creator Contact https://www.cosmos.esa.int/web/integral/helpdesk
Date Published 2025-03-25T09:54:36Z
Publisher And Registrant European Space Agency
Credit Guidelines European Space Agency, Staubert, 2025, 'Variability of the cyclotron line energy E_cyc in Hercules X-1', 1.0, European Space Agency, https://doi.org/10.57780/esa-pf6pqmj