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Quasi-simultaneous Radio/X-Ray Observations of the Candidate Transitional Millisecond Pulsar 3FGL J1544.6−1125 during its Low-luminosity Accretion-disk State

Jaodand, Amruta D. and Deller, Adam T. and Gusinskaia, Nina and Hessels, Jason W. T. and Miller-Jones, James C. A. and Archibald, Anne M. and Bogdanov, Slavko and Bassa, Cees and Wijnands, Rudy and Patruno, Alessandro and Sanidas, Sotiris (2021) Quasi-simultaneous Radio/X-Ray Observations of the Candidate Transitional Millisecond Pulsar 3FGL J1544.6−1125 during its Low-luminosity Accretion-disk State. Astrophysical Journal, 923 (1). Art. No. 3. ISSN 0004-637X. doi:10.3847/1538-4357/ac1ff7.

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3FGL J1544.6−1125 is a candidate transitional millisecond pulsar (tMSP). Similar to the well-established tMSPs—PSR J1023+0038, IGR J18245−2452, and XSS J12270−4859—3FGL J1544.6−1125 shows γ-ray emission and discrete X-ray “low” and “high” modes during its low-luminosity accretion-disk state. Coordinated radio/X-ray observations of PSR J1023+0038 in its current low-luminosity accretion-disk state showed rapidly variable radio continuum emission—possibly originating from a compact, self-absorbed jet, the “propellering” of accretion material, and/or pulsar moding. 3FGL J1544.6−1125 is currently the only other (candidate) tMSP system in this state, and can be studied to see whether tMSPs are typically radio-loud compared to other neutron star binaries. In this work, we present a quasi-simultaneous Very Large Array and Swift radio/X-ray campaign on 3FGL J1544.6−1125. We detect 10 GHz radio emission varying in flux density from 47.7 ± 6.0 μJy down to ≲15 μJy (3σ upper limit) at four epochs spanning three weeks. At the brightest epoch, the radio luminosity is L_(5 GHz) = (2.17 ± 0.17) × 10²⁷ erg s⁻¹ for a quasi-simultaneous X-ray luminosity L_(2–10 keV) = (4.32 ± 0.23) × 10³³ erg s⁻¹ (for an assumed distance of 3.8 kpc). These luminosities are close to those of PSR J1023+0038, and the results strengthen the case that 3FGL J1544.6−1125 is a tMSP showing similar phenomenology to PSR J1023+0038.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Jaodand, Amruta D.0000-0002-3850-6651
Deller, Adam T.0000-0001-9434-3837
Gusinskaia, Nina0000-0001-6128-3735
Hessels, Jason W. T.0000-0003-2317-1446
Miller-Jones, James C. A.0000-0003-3124-2814
Archibald, Anne M.0000-0003-0638-3340
Bogdanov, Slavko0000-0002-9870-2742
Bassa, Cees0000-0002-1429-9010
Wijnands, Rudy0000-0002-3516-2152
Patruno, Alessandro0000-0002-6459-0674
Additional Information:© 2021. The American Astronomical Society. Received 2020 December 23; revised 2021 August 20; accepted 2021 August 21; published 2021 December 7. We thank Tom Russell for discussions about the radio analysis. A.J. and J.W.T.H. acknowledge funding from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement nr. 337062 (DRAGNET). A.J. also acknowledges support from the NuSTAR mission. A.P. acknowledges support from an NWO Vidi Fellowship. J.C.A.M.-J. is the recipient of an Australian Research Council Future Fellowship (FT 140101082). S.B. was supported in part by NASA Swift Guest Investigator Cycle 12 program grant NNX16AN79G awarded through Columbia University. We thank B. Clark and the VLA schedulers for granting these DDT observations on short notice. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. This research has made use of data and software provided by the High Energy Astrophysics Science Archive Research Center (HEASARC), which is a service of the Astrophysics Science Division at NASA/GSFC and the High Energy Astrophysics Division of the Smithsonian Astrophysical Observatory. The data postprocessing and results preparation for this work relied heavily on Common Astronomy Software Applications (CASA 5.1) (McMullin et al. 2007). We would like to thank the staff at NRAO and externals involved in maintaining an extensive updated documentation and tutorials for CASA. This research also made use of Astropy, a community-developed core Python package for Astronomy (The Astropy Collaboration et al. 2013; Astropy Collaboration et al. 2018). Other important softwares used in this research are Matplotlib (Hunter 2007), Seaborn, and Scipy (Jones et al. 2001). Lastly, we have made extensive use of the NASA Astrophysics Data System (Eichhorn et al. 2000) and the arXiv e-print service (Ginsparg 2011).
Funding AgencyGrant Number
European Research Council (ERC)337062
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)UNSPECIFIED
Australian Research CouncilFT 140101082
Subject Keywords:Millisecond pulsars; Binary pulsars; Radio continuum emission; Accretion
Issue or Number:1
Classification Code:Unified Astronomy Thesaurus concepts: Millisecond pulsars (1062); Binary pulsars (153); Radio continuum emission (1340); Accretion (14)
Record Number:CaltechAUTHORS:20211207-393224000
Persistent URL:
Official Citation:Amruta D. Jaodand et al 2021 ApJ 923 3
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:112249
Deposited By: George Porter
Deposited On:07 Dec 2021 23:42
Last Modified:07 Dec 2021 23:42

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