SRG/eROSITA discovery of 164 s pulsations from the SMC Be/X-ray binary XMMU J010429.4-723136
arXiv:2106.14536 · doi:10.1051/0004-6361/202141082
Abstract
Context. The Small Magellanic Cloud (SMC) hosts many known high-mass X-ray binaries (HMXBs), and all but one (SMC X-1) have a Be companion star. Through the calibration and verification phase of eROSITA on board the Spektrum-Roentgen-Gamma (SRG) spacecraft, the Be/X-ray binary XMMU J010429.4-723136 was in the field of view during observations of the supernova remnant, 1E0102.2-7219, used as a calibration standard. Aims. We report timing and spectral analyses of XMMU J010429.4-723136 based on three eROSITA observations of the field, two of which were performed on 2019 November 7-9, with the third on 2020 June 18-19. We also reanalyse the OGLE-IV light curve for that source in order to determine the orbital period. Methods. We performed a Lomb-Scargle periodogram analysis to search for pulsations (from the X-ray data) and for the orbital period (from the OGLE data). X-ray spectral parameters and fluxes were retrieved from the best-fit model. Results. We detect, for the first time, the pulsations of XMMU J010429.4-723136 at a period of ~164 s, and therefore designate the source as SXP 164. From the spectral fitting, we derive a source flux of ~1x10e-12 erg s-1 cm-2 for all three observations, corresponding to a luminosity of ~4x10e35 erg s-1 at the distance of the SMC. Furthermore, reanalysing the OGLE light curve, including the latest observations, we find a significant periodic signal that we believe is likely be the orbital period; at 22.3d, this is shorter than the previously reported values. The Swift/XRT light curve, extracted from two long monitorings of the field and folded at the same period, suggests that a modulation is also present in the X-ray data.
arXiv comment"To appear on A&A, Special Issue: The Early Data Release of eROSITA and Mikhail Pavlinsky ART-XC on the SRG Mission" 7 pages, 11 figures
References in corpus (21)
- On the Absorption of X-rays in the Interstellar Medium
- Methods and results of an automatic analysis of a complete sample of Swift-XRT observations of GRBs
- An online repository of Swift/XRT light curves of GRBs
- The eROSITA X-ray telescope on SRG
- Be/X-ray binaries
- The eROSITA Final Equatorial Depth Survey (eFEDS): The X-ray catalog
- The XMM-Newton serendipitous survey. VII. The third XMM-Newton serendipitous source catalogue
- High-Mass X-ray binaries in the Small Magellanic Cloud
- Optical properties of SMC X-ray binaries
- The XMM-Newton survey of the Small Magellanic Cloud: The X-ray point-source catalogue
- On the Spin History of the X-ray Pulsar in Kes 73: Further Evidence For an Utramagnetized Neutron Star
- A Long Look at the Be/X-Ray Binaries of the Small Magellanic Cloud
- Catalogue of Be/X-ray binary systems in the Small Magellanic Cloud: X-ray, optical & IR properties
- Very Long-term Optical Variability of High Mass X-ray Binaries in the SMC
- XMM-Newton observations of the Small Magellanic Cloud: Be/X-ray binary pulsars active between October 2006 and June 2007
- A Comprehensive Library of X-ray Pulsars in the Small Magellanic Cloud: Time Evolution of their Luminosities and Spin Periods
- Optical spectroscopy of 20 Be/X-ray Binaries in the Small Magellanic Cloud
- On the periodicities present in the optical light curves of SMC Be/X-ray binaries
- Discovery of a 26.2 day period in the long-term X-ray light curve of SXP 1323: a very short orbital period for a long spin period pulsar
- eROSITA calibration and performance verification phase: High-mass X-ray binaries in the Magellanic Clouds
- Confirmation of six Be X-ray binaries in the Small Magellanic Cloud