The Astrophysical Journal Letters (Jan 2024)
NICER Discovery that SRGA J144459.2–604207 Is an Accreting Millisecond X-Ray Pulsar
- Mason Ng,
- Paul S. Ray,
- Andrea Sanna,
- Tod E. Strohmayer,
- Alessandro Papitto,
- Giulia Illiano,
- Arianna C. Albayati,
- Diego Altamirano,
- Tuğba Boztepe,
- Tolga Güver,
- Deepto Chakrabarty,
- Zaven Arzoumanian,
- D. J. K. Buisson,
- Elizabeth C. Ferrara,
- Keith C. Gendreau,
- Sebastien Guillot,
- Jeremy Hare,
- Gaurava K. Jaisawal,
- Christian Malacaria,
- Michael T. Wolff
Affiliations
- Mason Ng
- ORCiD
- MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA ; [email protected]
- Paul S. Ray
- ORCiD
- Space Science Division, U.S. Naval Research Laboratory , Washington, DC 20375, USA
- Andrea Sanna
- ORCiD
- Dipartimento di Fisica, Università degli Studi di Cagliari , SP Monserrato-Sestu km 0.7, I-09042 Monserrato, Italy
- Tod E. Strohmayer
- ORCiD
- Astrophysics Science Division, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA; Joint Space-Science Institute, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA
- Alessandro Papitto
- ORCiD
- INAF-Osservatorio Astronomico di Roma , Via Frascati 33, I-00040 Monte Porzio Catone (RM), Italy
- Giulia Illiano
- ORCiD
- INAF-Osservatorio Astronomico di Roma , Via Frascati 33, I-00040 Monte Porzio Catone (RM), Italy; Dipartimento di Fisica, Università degli Studi di Roma “Tor Vergata,” Via della Ricerca Scientifica 1, I-00133 Roma, Italy; Dipartimento di Fisica, Università degli Studi di Roma “La Sapienza,” Piazzale Aldo Moro 5, I-00185 Roma, Italy
- Arianna C. Albayati
- ORCiD
- School of Physics and Astronomy, University of Southampton , Southampton SO17 1BJ, UK
- Diego Altamirano
- ORCiD
- School of Physics and Astronomy, University of Southampton , Southampton SO17 1BJ, UK
- Tuğba Boztepe
- ORCiD
- Istanbul University , Graduate School of Sciences, Department of Astronomy and Space Sciences, Beyazıt, 34119, İstanbul, Türkiye
- Tolga Güver
- ORCiD
- Istanbul University , Science Faculty, Department of Astronomy and Space Sciences, Beyazıt, 34119, İstanbul, Türkiye; Istanbul University Observatory Research and Application Center , Istanbul University, 34119, İstanbul, Türkiye
- Deepto Chakrabarty
- ORCiD
- MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA ; [email protected]
- Zaven Arzoumanian
- ORCiD
- Astrophysics Science Division, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA
- D. J. K. Buisson
- ORCiD
- Independent Researcher
- Elizabeth C. Ferrara
- ORCiD
- Astrophysics Science Division, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA; Department of Astronomy, University of Maryland , College Park, MD 20742, USA; Center for Research and Exploration in Space Science & Technology II (CRESST II) , NASA/GSFC, Greenbelt, MD 20771, USA
- Keith C. Gendreau
- ORCiD
- Astrophysics Science Division, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA
- Sebastien Guillot
- ORCiD
- IRAP , CNRS, 9 avenue du Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4, France; Université de Toulouse , CNES, UPS-OMP, F-31028 Toulouse, France
- Jeremy Hare
- ORCiD
- Astrophysics Science Division, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA; Center for Research and Exploration in Space Science & Technology II (CRESST II) , NASA/GSFC, Greenbelt, MD 20771, USA; The Catholic University of America , 620 Michigan Avenue, N.E. Washington, DC 20064, USA
- Gaurava K. Jaisawal
- ORCiD
- DTU Space, Technical University of Denmark , Elektrovej 327-328, DK-2800 Lyngby, Denmark
- Christian Malacaria
- ORCiD
- International Space Science Institute , Hallerstrasse 6, 3012 Bern, Switzerland
- Michael T. Wolff
- ORCiD
- Space Science Division, U.S. Naval Research Laboratory , Washington, DC 20375, USA
- DOI
- https://doi.org/10.3847/2041-8213/ad4edb
- Journal volume & issue
-
Vol. 968,
no. 1
p. L7
Abstract
We present the discovery, with the Neutron Star Interior Composition Explorer (NICER), that SRGA J144459.2−604207 is a 447.9 Hz accreting millisecond X-ray pulsar (AMXP), which underwent a 4 week long outburst starting on 2024 February 15. The AMXP resides in a 5.22 hr binary, orbiting a low-mass companion donor with M _d > 0.1 M _⊙ . We report on the temporal and spectral properties from NICER observations during the early days of the outburst, from 2024 February 21 through 2024 February 23, during which NICER also detected a type I X-ray burst that exhibited a plateau lasting ∼6 s. The spectra of the persistent emission were well described by an absorbed thermal blackbody and power-law model, with blackbody temperature kT ≈ 0.9 keV and power-law photon index Γ ≈ 1.9. Time-resolved burst spectroscopy confirmed the thermonuclear nature of the burst, where an additional blackbody component reached a maximum temperature of nearly kT ≈ 3 keV at the peak of the burst. We discuss the nature of the companion as well as the type I X-ray burst.
Keywords
