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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. (2019) All at once: transient pulsations, spin down and a glitch from the Pulsating Ultraluminous X-ray Source M82 X-2. . (Unpublished)

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M82 X-2 is the first pulsating ultraluminous X-ray source (PULX) to be identified. Since the discovery in 2014, NuSTAR has observed the M82 field 15 times throughout 2015 and 2016. In this paper, we report the results of pulsation searches in all these datasets, 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 5x10^-11 Hz/s, which is in contrast to the strong spin up seen during the 2014 observations and represent 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 dataset. 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:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Bachetti, Matteo0000-0002-4576-9337
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
Tomsick, John A.0000-0001-5506-9855
Walton, Dominic J.0000-0001-5819-3552
Additional Information:MB thanks the Fulbright Visiting Scholar Program for supporting a nine-month visit at Caltech. The authors wish to thank Jim Fuller for insightful conversations on stellar pulsations. Facilities: NuSTAR (Harrison et al. 2013), Chandra (Weisskopf et al. 2002), ATNF pulsar catalogue (Manchester et al. 2005). Software: Stingray (Huppenkothen et al. 2016; Huppenkothen et al. 2019), HENDRICS (Bachetti 2018), astropy (Price-Whelan et al. 2018), PINT (Luo et al. 2019), PRESTO(Ransom 2011).
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Fulbright FoundationUNSPECIFIED
Subject Keywords:stars: neutron - pulsars: individual (M82 X-2) - X-rays: binaries - ULX
Record Number:CaltechAUTHORS:20190617-152050717
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96483
Deposited By: Tony Diaz
Deposited On:17 Jun 2019 22:30
Last Modified:03 Oct 2019 21:22

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