Quasi-Simultaneous Radio/X-ray Observations of the Candidate Transitional Millisecond Pulsar 3FGL J1544.6-1125 During its Low-Luminosity Accretion-Disc State

Abstract

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 $\gamma$-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 $47.7\pm 6.0$ $\mu$Jy down to $\sim$15 $\mu$Jy (3$\sigma$ upper limit) at four epochs spanning three weeks. At the brightest epoch, the radio luminosity is $L_{5GHz}$ $=(2.17\pm 0.17)\times 10^{27}$ erg s${}^{-1}$ for a quasi-simultaneous X-ray luminosity $L_{2-10keV}$ $=(4.32\pm 0.23)\times 10^{33}$ 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.

Accepted for publication in the Astrophysical Journal

References in corpus (16)

• A Radio Pulsar/X-ray Binary Link
• Discovery of PSR J1227-4853: A transition from a low-mass X-ray binary to a redback millisecond pulsar
• The radio/X-ray domain of black hole X-ray binaries at the lowest radio luminosities
• Identification of the High-Energy Gamma-Ray Source 3FGL J1544.6-1125 as a Transitional Millisecond Pulsar Binary in an Accreting State
• Timing Observations of PSR J1023+0038 During a Low-Mass X-ray Binary State
• Disk-jet coupling in low-luminosity accreting neutron stars
• A new radio census of neutron star X-ray binaries
• High-Resolution X-Ray Spectroscopy of the Bursting Pulsar GRO J1744-28
• Spectral differences between the jets in `radio loud' and `radio quiet' hard state black hole binaries
• A new gamma-ray loud, eclipsing low-mass X-ray binary
• Discovery of Gamma-ray Pulsations from the Transitional Redback PSR J1227-4853
• Prolonged sub-luminous state of the new transitional pulsar candidate CXOU J110926.4-650224
• Jet quenching in the neutron star low-mass X-ray binary 1RXS J180408.9$-$342058
• The peculiar Galactic center neutron star X-ray binary XMM J174457-2850.3
• Orbital Dynamics of Candidate Transitional Millisecond Pulsar 3FGL J1544.6-1125: An unusually face-on system
• Observations of the Disk/Jet Coupling of MAXI J1820+070 During its Descent to Quiescence

Cited by in corpus (4)

• XRBcats: Galactic Low Mass X-ray Binary Catalogue
• MeerKAT radio observations of the neutron star low-mass X-ray binary Cen X-4 at low accretion rates
• Detection of low-luminosity X-ray pulsations from the accreting millisecond pulsar IGR J17511-3057: An ever-thinning thread between bright accretion and sub-luminous states
• Probing multi-band variability and mode switching in the candidate transitional millisecond pulsar 3FGL J1544.6-1125