The giant outburst of EXO 2030+375
The Be X-ray binary EXO 2030+375 went through its third recorded giant outburst from June 2021 to early 2022. We present the results of both spectral and timing analysis based on NICER monitoring, covering the 2−10 keV flux range from 20 to 310 mCrab. Dense monitoring with observations carried out about every second day and a total exposure time of ∼160 ks allowed us to closely track the source evolution over the outburst. Changes in the spectral shape and pulse profiles showed a stable luminosity dependence during the rise and decline. The same type of dependence has been seen in past outbursts. The pulse profile is characterized by several distinct peaks and dips. The profiles show a clear dependence on luminosity with a stark transition at a luminosity of ∼2 × 10 36 erg s −1 , indicating a change in the emission pattern. Using relativistic raytracing, we demonstrate how anisotropic beaming of emission from an accretion channel with a constant geometrical configuration can give rise to the observed pulse profiles over a range of luminosities.
Authors
- Pragati Pradhan (ORCID: https://orcid.org/0000-0002-1131-3059)
- R. Staubert
- J. Wilms (ORCID: https://orcid.org/0000-0003-2065-5410)
- Brent West (ORCID: https://orcid.org/0009-0007-1219-7508)
- Jakob Stierhof (ORCID: https://orcid.org/0000-0001-9537-7887)
- E. Sokolova-Lapa (ORCID: https://orcid.org/0000-0001-7948-0470)
- Gaurava K. Jaisawal (ORCID: https://orcid.org/0000-0002-6789-2723)
- P. Kretschmar (ORCID: https://orcid.org/0000-0001-9840-2048)
- R. Rothschild (ORCID: https://orcid.org/0000-0003-0396-0659)
- P. Thalhammer (ORCID: https://orcid.org/0000-0001-6269-2821)
- Peter A. Becker (ORCID: https://orcid.org/0000-0002-3718-1293)
- A. Zainab
- Joel B. Coley (ORCID: https://orcid.org/0000-0001-7532-8359)
- Ralf Ballhausen (ORCID: https://orcid.org/0000-0002-1118-8470)
- K. Pottschmidt (ORCID: https://orcid.org/0000-0002-4656-6881)
Institutions
- Vassar College (US)
- Goddard Space Flight Center (US)
- Howard University (US)
- George Mason University (US)
- Friedrich-Alexander-Universität Erlangen-Nürnberg (DE)
- United States Naval Academy (US)
- University of California San Diego (US)
- European Space Astronomy Centre (ES)
- Astrophysics Science Division (US)
- Massachusetts Institute of Technology (US)
- University of Maryland, College Park (US)
- University of Maryland, Baltimore County (US)
- University of Tübingen (DE)
- Embry–Riddle Aeronautical University (US)
- Technical University of Denmark (DK)
Publication Details
- Journal
- Astronomy and Astrophysics
- Published
- 2024-08-01
- DOI
- https://doi.org/10.1051/0004-6361/202348594
- Citations
- 7
- Primary Topic
- Gamma-ray bursts and supernovae
- Type
- article
- Field-Weighted Citation Impact
- 2.32
Funders
- National Aeronautics and Space Administration
- European Space Agency
- Deutsche Forschungsgemeinschaft
- Nuclear Safety and Security Commission
- Goddard Space Flight Center