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MAXI and NuSTAR Observations of the Faint X-Ray Transient MAXI J1848-015 in the GLIMPSE-C01 Cluster

Pike, Sean N. and Negoro, Hitoshi and Tomsick, John A. and Bachetti, Matteo and Brumback, McKinley and Connors, Riley M. T. and García, Javier A. and Grefenstette, Brian and Hare, Jeremy and Harrison, Fiona A. and Jaodand, Amruta and Ludlam, R. M. and Mastroserio, Guglielmo and Mihara, Tatehiro and Shidatsu, Megumi and Sugizaki, Mutsumi and Takagi, Ryohei (2022) MAXI and NuSTAR Observations of the Faint X-Ray Transient MAXI J1848-015 in the GLIMPSE-C01 Cluster. Astrophysical Journal, 927 (2). Art. No. 190. ISSN 0004-637X. doi:10.3847/1538-4357/ac5258.

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We present the results of Monitor of All-sky X-ray Image (MAXI) monitoring and two Nuclear Spectroscopic Telescope Array (NuSTAR) observations of the recently discovered faint X-ray transient MAXI J1848015. Analysis of the MAXI light curve shows that the source underwent a rapid flux increase beginning on 2020 December 20, followed by a rapid decrease in flux after only ∼5 days. NuSTAR observations reveal that the source transitioned from a bright soft state with unabsorbed, bolometric (0.1–100 keV) flux F = 6.9 ± 0.1 × 10⁻¹⁰ erg cm⁻² s⁻¹, to a low hard state with flux F = 2.85 ± 0.04 × 10⁻¹⁰ erg cm⁻² s⁻¹. Given a distance of 3.3 kpc, inferred via association of the source with the GLIMPSE-C01 cluster, these fluxes correspond to an Eddington fraction of the order of 10⁻³ for an accreting neutron star (NS) of mass M = 1.4M⊙, or even lower for a more massive accretor. However, the source spectra exhibit strong relativistic reflection features, indicating the presence of an accretion disk that extends close to the accretor, for which we measure a high spin, a = 0.967 ± 0.013. In addition to a change in flux and spectral shape, we find evidence for other changes between the soft and hard states, including moderate disk truncation with the inner disk radius increasing from R_(in) ≈ 3 R_g to R_(in) ≈ 8 R_g, narrow Fe emission whose centroid decreases from 6.8 ± 0.1 keV to 6.3 ± 0.1 keV, and an increase in low-frequency (10⁻³–10⁻¹ Hz) variability. Due to the high spin, we conclude that the source is likely to be a black hole rather than an NS, and we discuss physical interpretations of the low apparent luminosity as well as the narrow Fe emission.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Pike, Sean N.0000-0002-8403-0041
Negoro, Hitoshi0000-0003-0939-1178
Tomsick, John A.0000-0001-5506-9855
Bachetti, Matteo0000-0002-4576-9337
Brumback, McKinley0000-0002-4024-6967
Connors, Riley M. T.0000-0002-8908-759X
García, Javier A.0000-0003-3828-2448
Grefenstette, Brian0000-0002-1984-2932
Hare, Jeremy0000-0002-8548-482X
Harrison, Fiona A.0000-0003-2992-8024
Jaodand, Amruta0000-0002-3850-6651
Ludlam, R. M.0000-0002-8961-939X
Mastroserio, Guglielmo0000-0003-4216-7936
Mihara, Tatehiro0000-0002-6337-7943
Shidatsu, Megumi0000-0001-8195-6546
Sugizaki, Mutsumi0000-0002-1190-0720
Additional Information:© 2022 The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2021 November 9; revised 2022 January 20; accepted 2022 February 5; published 2022 March 15. This work was partially supported under NASA contract No. NNG08FD60C and made use of data from the NuSTAR mission, a project led by the California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by the National Aeronautics and Space Administration. We thank the NuSTAR Operations, Software, and Calibration teams for support with the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS), jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). R.M.L. acknowledges the support of NASA through Hubble Fellowship Program grant HST-HF2-51440.001. J.H. acknowledges support from an appointment to the NASA Postdoctoral Program at the Goddard Space Flight Center, administered by the Universities Space Research Association under contract with NASA. A.J. would like to acknowledge support from Chandra X-ray Observatory Center's grant GO0-21067X. This work also made use of MAXI data provided by RIKEN, JAXA, and the MAXI team. Part of this work was financially supported by Grants-in-Aid for Scientific Research 21K03620 (H.N.), 17H06362 (H.N.), and 19K14762 (M.S.) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan. Finally, we would like to thank the anonymous reviewer, whose comments and suggestions significantly improved the quality of this work. Software: Astropy (Astropy Collaboration et al. 2013, 2018), Corner (Foreman-Mackey 2016), DS9 (Joye & Mandel 2003), Matplotlib (Hunter 2007), Scipy (Virtanen et al. 2020), Stingray (Huppenkothen et al. 2019), relxill (Dauser et al. 2014; García et al. 2014), XSpec (Arnaud 1996).
Group:Astronomy Department, Space Radiation Laboratory, NuSTAR
Funding AgencyGrant Number
NASA Hubble FellowshipHST-HF2-51440.001
NASA Postdoctoral ProgramUNSPECIFIED
Ministry of Education, Culture, Sports, Science and Technology (MEXT)21K03620
Ministry of Education, Culture, Sports, Science and Technology (MEXT)17H06362
Ministry of Education, Culture, Sports, Science and Technology (MEXT)19K14762
NASA Einstein FellowshipUNSPECIFIED
Subject Keywords:Black holes; High energy astrophysics; Compact objects; Stellar mass black holes; X-ray binary stars; Accretion; Neutron stars
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Black holes (162); High energy astrophysics (739); Compact objects (288); Stellar mass black holes (1611); X-ray binary stars (1811); Accretion (14); Neutron stars (1108)
Record Number:CaltechAUTHORS:20220304-000054911
Persistent URL:
Official Citation:Sean N. Pike et al 2022 ApJ 927 190
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:113722
Deposited By: George Porter
Deposited On:07 Mar 2022 18:04
Last Modified:22 Mar 2022 19:49

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