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All at once: transient pulsations, spin down and a glitch from the Pulsating Ultraluminous X-ray Source M82 X-2

Bachetti, Matteo and Maccarone, Thomas J. and Brightman, Murray and Brumback, McKinley C. and Fürst, Felix and Harrison, Fiona A. and Heida, Marianne and Israel, Gian Luca and Middleton, Matthew J. and Tomsick, John A. and Webb, Natalie A. and Walton, Dominic J. (2020) All at once: transient pulsations, spin down and a glitch from the Pulsating Ultraluminous X-ray Source M82 X-2. Astrophysical Journal, 891 (1). Art. No. 44. ISSN 1538-4357. https://resolver.caltech.edu/CaltechAUTHORS:20190617-152050717

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Abstract

The first pulsating ultraluminous X-ray source (PULX) to be identified is M82 X-2. After the discovery in 2014, NuSTAR observed the M82 field 15 times throughout 2015 and 2016. In this paper, we report the results of pulsation searches in all of these data sets and find only one new detection. This new detection allows us to refine the orbital period of the source and measure an average spin-down rate between 2014 and 2016 of ~−6 × 10⁻¹¹ Hz s⁻¹, which is in contrast to the strong spin-up seen during the 2014 observations, representing the first detection of spin-down in a PULX system. Thanks to the improved orbital solution allowed by this new detection, we are also able to detect pulsations in additional segments of the original 2014 data set. We find a glitch superimposed on the very strong and variable spin-up already reported—the first positive glitch identified in a PULX system. We discuss the new findings in the context of current leading models for PULXs.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.3847/1538-4357/ab6d00DOIArticle
https://arxiv.org/abs/1905.06423arXivDiscussion Paper
ORCID:
AuthorORCID
Bachetti, Matteo0000-0002-4576-9337
Maccarone, Thomas J.0000-0003-0976-4755
Brightman, Murray0000-0002-8147-2602
Brumback, McKinley C.0000-0002-4024-6967
Fürst, Felix0000-0003-0388-0560
Harrison, Fiona A.0000-0003-2992-8024
Heida, Marianne0000-0002-1082-7496
Middleton, Matthew J.0000-0002-8183-2970
Tomsick, John A.0000-0001-5506-9855
Walton, Dominic J.0000-0001-5819-3552
Additional Information:© 2020 The American Astronomical Society. Received 2019 May 15; revised 2020 January 11; accepted 2020 January 15; published 2020 March 3. M.B. thanks the Fulbright Visiting Scholar Program for supporting a 9 month visit at Caltech. M.M. appreciates support from an STFC Ernest Rutherford Fellowship. Part of the pulsar search and optimization software was developed in the framework of the Citizen Computing Pulsar Search (CICLOPS), a project supported by POR FESR Sardegna 20142020 Asse 1 Azione 1.1.3 (code RICERCA_1C-181), call for proposal "Aiuti per Progetti di Ricerca e Sviluppo 2017," managed by Sardegna Ricerche. The authors wish to thank Jim Fuller for insightful conversations on stellar pulsations, Georgios Vasilopoulos for comments on the manuscript, Sergei Popov for pointing out alternative models for magnetar evolution, and Wynn Ho for pointing out an incorrect citation about glitch models in the first version posted on the arXiv. Thanks also to Deepto Chakrabarty, Fred Lamb, Juri Poutanen, Alexander Mushtukov, and Andrew King for multiple insights on accretion theories and competing models for PULXs. Facilities: NuSTAR (Harrison et al. 2013), Chandra (Weisskopf et al. 2002), ATNF pulsar catalog (Manchester et al. 2005). Software: HEAsoft (HEASARC 2014), FTOOLS (Blackburn et al. 1999; Blackburn 1995), Stingray (Huppenkothen et al. 2016, 2019), HENDRICS (Bachetti 2018), astropy (Astropy Collaboration et al. 2018), PINT (Luo et al. 2019), PRESTO (Ransom 2011).
Group:Astronomy Department, Space Radiation Laboratory
Funders:
Funding AgencyGrant Number
Fulbright FoundationUNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
Sardegna Ricerche20142020 Asse 1 Azione 1.1.3
Subject Keywords:Pulsars ; Pulsar timing method ; Accretion ; X-ray astronomy ; Orbital motion ; Time series analysis ; Fast Fourier transform ; Neutron stars ; Compact objects
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: Pulsars (1306); Pulsar timing method (1305); Accretion (14); X-ray astronomy (1810); Orbital motion (1179); Time series analysis (2109); Fast Fourier transform (1958); Neutron stars (1108); Compact objects (288)
Record Number:CaltechAUTHORS:20190617-152050717
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20190617-152050717
Official Citation:Matteo Bachetti et al 2020 ApJ 891 44
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96483
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:17 Jun 2019 22:30
Last Modified:09 Mar 2020 13:19

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