We propose a 500 ks long INTEGRAL observation of the X-ray pulsar 4U 1626-67 to fully constrain its spectral shape in the hard X-ray band. This X-ray pulsar is rather peculiar among its class, as it shows a resonant cyclotron feature at 37 keV (indicating a magnetic field of a few 10E12 G), but the companion mass is a very low-mass star (less than 0.08 Msun). A recent observation made with NuSTAR revealed a complex spectral curvature in the 50-70 keV band, that could be accounted for by a moderately broadened absorption line at 61 keV. This could be the second cyclotron harmonic, even though its energy is lower than the expected value. INTEGRAL is presently the only observatory able to definitively detect this feature and constrain its parameters.
Primordial black hole dark matter in the context of extra dimensions - Friedlander, Avi, Mack, Katherine J.,Schon, Sarah,Song, Ningqiang,Vincent, Aaron C. (2022-05-01) http://ui.adsabs.harvard.edu/#abs/2022PhRvD.105j3508F
Temporal Coverage
2021-05-08T18:29:47Z / 2021-09-18T22:24:03Z
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.
European Space Agency, D'Ai', 2025, 'Search for a second harmonic in the accreting X-ray pulsar 4U 1626-67', 1.0, European Space Agency, https://doi.org/10.57780/esa-u0pukfq
