Monitoring observations of SMC X-1’s excursions (<scp>moose</scp>) III. X-ray spectroscopy of a warped, precessing accretion disc
ABSTRACT The moose (Monitoring Observations of SMC X-1’s Excursions) program uses the Neutron Star Interior Composition Explorer Mission (NICER) to monitor the high-mass X-ray binary SMC X-1 during its superorbital period excursions. Here, we perform X-ray spectral analyses of 26 NICER observations of SMC X-1, taken at the tail-end of the excursion between 2021-04-01 and 2022-01-05. We use a single spectral model to fit spectra observed in high, intermediate, and low states, using a combination of a partial covering fraction model, a blackbody disc, and a power-law component. We find that the partial covering fraction varies significantly with the superorbital state during superorbital excursion. Our findings suggest that the low/high state in SMC X-1 is caused by a very high obscuration of the accretion disc.
Authors
- Rawan Karam
- McKinley C. Brumback (ORCID: https://orcid.org/0000-0002-4024-6967)
- B. E. Tetarenko (ORCID: https://orcid.org/0000-0003-2636-6644)
- W. I. Clarkson (ORCID: https://orcid.org/0000-0002-2577-8885)
- Wasundara Athukoralalage (ORCID: https://orcid.org/0000-0002-2866-6416)
- D. Altamirano (ORCID: https://orcid.org/0000-0002-3422-0074)
- Arash Bahramian (ORCID: https://orcid.org/0000-0003-2506-6041)
- Daryl Haggard (ORCID: https://orcid.org/0000-0001-6803-2138)
- J. A. Kennea (ORCID: https://orcid.org/0000-0002-6745-4790)
- Kristen C. Dage (ORCID: https://orcid.org/0000-0002-8532-4025)
- Ryan C. Hickox (ORCID: https://orcid.org/0000-0003-1468-9526)
- Chin‐Ping Hu (ORCID: https://orcid.org/0000-0001-8551-2002)
- Joey Neilsen
- P. A. Charles
Institutions
- Dartmouth College (US)
- Space Science Institute (US)
- Pennsylvania State University (US)
- Wayne State University (US)
- Middlebury College (US)
- University of Michigan (US)
- Center for Astrophysics Harvard & Smithsonian (US)
- University of Michigan–Dearborn (US)
- International Centre for Radio Astronomy Research (AU)
- University of Southampton (GB)
- McGill University (CA)
- National Changhua University of Education (TW)
- Université de Montréal (CA)
- Villanova University (US)
- Michigan State University (US)
Publication Details
- Journal
- Monthly Notices of the Royal Astronomical Society
- Published
- 2024-12-04
- DOI
- https://doi.org/10.1093/mnras/stae2456
- Citations
- 1
- Primary Topic
- Astrophysical Phenomena and Observations
- Type
- article
- Field-Weighted Citation Impact
- 0.33
Funders
- National Aeronautics and Space Administration
- McGill University
- Space Telescope Science Institute
- Canada Research Chairs
- Nuclear Safety and Security Commission
- National Science and Technology Council
- Fonds de recherche du Québec
- Goddard Space Flight Center
- Natural Sciences and Engineering Research Council of Canada
- Astrophysics Science Division