The giant outburst of EXO 2030+375: I. Spectral and pulse profile evolution

Thalhammer P, Ballhausen R, Sokolova-Lapa E, Stierhof J, Zainab A, Staubert R, Pottschmidt K, Coley JB, Rothschild RE, Jaisawal GK, West B, Becker PA, Pradhan P, Kretschmar P, Wilms J (2024)

Publication Language: English

Publication Type: Journal article

Publication year: 2024

Journal

Book Volume: 688

Article Number: A213

DOI: 10.1051/0004-6361/202348594

Abstract

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 × 10³⁶ 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 with CRIS profile

Involved external institutions

University of Maryland United States (USA) (US) Eberhard Karls Universität Tübingen Germany (DE) University of Maryland, Baltimore County (UMBC) United States (USA) (US) University of California, San Diego United States (USA) (US) Technical University of Denmark / Danmarks Tekniske Universitet (DTU) Denmark (DK) U.S. Naval Academy United States (USA) (US) George Mason University United States (USA) (US) Massachusetts Institute of Technology (MIT) United States (USA) (US) European Space Astronomy Centre (ESAC) Spain (ES) Howard University United States (USA) (US)

How to cite

APA:

Thalhammer, P., Ballhausen, R., Sokolova-Lapa, E., Stierhof, J., Zainab, A., Staubert, R.,... Wilms, J. (2024). The giant outburst of EXO 2030+375: I. Spectral and pulse profile evolution. Astronomy & Astrophysics, 688. https://doi.org/10.1051/0004-6361/202348594

MLA:

Thalhammer, Philipp, et al. "The giant outburst of EXO 2030+375: I. Spectral and pulse profile evolution." Astronomy & Astrophysics 688 (2024).

BibTeX: Download