Probing multi-band variability and mode switching in the candidate transitional millisecond pulsar 3FGL J1544.6-1125

Abstract

We present the most extensive high-time resolution multi-band campaign to date on the candidate transitional millisecond pulsar (tMSP) 3FGL J1544.6-1125 in the sub-luminous disk state, with coordinated observations from the radio to the X-ray band. While XMM-Newton and NuSTAR X-ray light curves exhibit the characteristic high- and low-mode bimodality, the source faintness prevents firm evidence for similar bimodality in the ultraviolet and near-infrared light curves, presented here for the first time. A re-analysis of archival XMM-Newton/OM data reveals an optical flare without an X-ray counterpart, likely originating from the outer accretion disk or the companion star. During our observations, no radio emission was detected, with a 3$\sigma$ flux density upper limit of 8 $\mu$Jy at 6 GHz. While past works have already reported radio variability in the source, this limit is a factor of 3.5 below the average value measured in 2019 in similar conditions, underscoring significant radio variability despite the relatively stable X-ray flux. Simultaneous optical light curves in five filters with GTC/HiPERCAM revealed flickering and dipping activities that resemble the observed X-ray variability, along with a reddening trend at lower fluxes. The latter is consistent with discrete mass ejections that disrupt the inner flow and reduce both X-ray and optical fluxes, thereby driving the high-to-low-mode switches. This suggests a common origin for most optical and X-ray emission at the boundary region between the pulsar wind and the inner disk, as also supported by our modelling of the spectral energy distribution in the high mode. Overall, our findings reinforce the mini-pulsar nebula picture for tMSPs in the sub-luminous state and demonstrate how coordinated, high-time resolution, multi-wavelength campaigns are essential to probe the processes governing rapid mode switches in these systems.

Accepted for publication in A&A

References in corpus (52)

• The ATNF Pulsar Catalogue
• The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• On characterising the variability properties of X-ray light curves from active galaxies
• CASA, the Common Astronomy Software Applications for Radio Astronomy
• A Radio Pulsar/X-ray Binary Link
• Swings between rotation and accretion power in a millisecond binary pulsar
• An Analysis of the Shapes of Interstellar Extinction Curves. VII. Milky Way Spectrophotometric Optical-through-Ultraviolet Extinction and Its R-Dependence
• A state change in the missing link binary pulsar system PSR J1023+0038
• Discovery of PSR J1227-4853: A transition from a low-mass X-ray binary to a redback millisecond pulsar
• FUSE Measurements of Far-Ultraviolet Extinction. III. The Dependence on R(V) and Discrete Feature Limits from 75 Galactic Sightlines
• Probing X-ray Absorption and Optical Extinction in the Interstellar Medium Using Chandra Observations of Supernova Remnants
• X-ray follow-ups of XSSJ12270-4859: a low-mass X-ray binary with gamma ray FERMI-LAT association
• Milky Way Mid-Infrared Spitzer Spectroscopic Extinction Curves: Continuum and Silicate Features
• X-ray coherent pulsations during a sub-luminous accretion disk state of the transitional millisecond pulsar XSS J12270-4859
• The intriguing nature of the high energy gamma ray source XSSJ12270-4859
• X-ray states of redback millisecond pulsars
• HiPERCAM: a quintuple-beam, high-speed optical imager on the 10.4-m Gran Telescopio Canarias
• Optical pulsations from a transitional millisecond pulsar
• Identification of the High-Energy Gamma-Ray Source 3FGL J1544.6-1125 as a Transitional Millisecond Pulsar Binary in an Accreting State
• Characterizing Rocky and Gaseous Exoplanets with 2-meter Class Space-based Coronagraphs
• SpeX near-infrared spectroscopic extinction curves in the Milky Way
• Timing Observations of PSR J1023+0038 During a Low-Mass X-ray Binary State
• Transitional millisecond pulsars
• NuSTAR Observations of the State Transition of Millisecond Pulsar Binary PSR J1023+0038
• Pulsating in unison at optical and X-ray energies: simultaneous high-time resolution observations of the transitional millisecond pulsar PSR J1023+0038
• Simultaneous Chandra and VLA Observations of the Transitional Millisecond Pulsar PSR J1023+0038: Anti-correlated X-ray and Radio Variability
• Engulfing a radio pulsar: the case of PSR J1023+0038
• The binary millisecond pulsar PSR J1023+0038 during its accretion state - I. Optical variability
• Unveiling the redback nature of the low-mass X-ray binary XSSJ1227.0-4859 through optical observations
• Pulsar wind-heated accretion disk and the origin of modes in transitional millisecond pulsar PSR J1023+0038
• Kepler K2 observations of the transitional millisecond pulsar PSR J1023+0038
• Prolonged sub-luminous state of the new transitional pulsar candidate CXOU J110926.4-650224
• Orbital Dynamics of Candidate Transitional Millisecond Pulsar 3FGL J1544.6-1125: An unusually face-on system
• The first continuous optical monitoring of the transitional millisecond pulsar PSR J1023+0038 with Kepler
• A New Candidate Transitional Millisecond Pulsar in the Sub-luminous Disk State: 4FGL J0407.7--5702
• Matter ejections behind the highs and lows of the transitional millisecond pulsar PSR J1023+0038
• Evidence for hot clumpy accretion flow in the transitional millisecond pulsar PSR J1023+0038
• Variable polarisation and Doppler tomography of PSR J1023+0038 - Evidence for the magnetic propeller during flaring?
• Probing X-ray emission in different modes of PSR J1023+0038 with a radio pulsar scenario
• The Flare-Dominated Accretion Mode of a Radio-Bright Candidate Transitional Millisecond Pulsar
• A NuSTAR Observation of the Gamma-Ray-Emitting X-ray Binary and Transitional Millisecond Pulsar Candidate 1RXS J154439.4-112820
• The binary millisecond pulsar PSR J1023+0038 -- II. Optical spectroscopy
• Investigating the origin of optical and X-ray pulsations of the transitional millisecond pulsar PSR J1023+0038
• The accretion/ejection link in the neutron star X-ray binary 4U 1820-30 I: A boundary layer-jet coupling?
• UV and X-ray pulse amplitude variability in the transitional millisecond pulsar PSR J1023+0038
• Peering at the outflow mechanisms in the transitional pulsar PSR J1023+0038: simultaneous VLT, XMM-Newton, and Swift high-time resolution observations
• Quasi-Simultaneous Radio/X-ray Observations of the Candidate Transitional Millisecond Pulsar 3FGL J1544.6-1125 During its Low-Luminosity Accretion-Disc State
• Near-Infrared and X-Ray Observations of XSS J12270-4859
• Tracking the Enigmatic Globular Cluster Ultracompact X-ray Binary X1850--087: Extreme Radio Variability in the Hard State
• Polarized multiwavelength emission from pulsar wind - accretion disk interaction in a transitional millisecond pulsar
• Millisecond pulsars phenomenology under the light of graph theory

Cited by in corpus (1)

• 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