The MAVERIC Survey: Simultaneous Chandra and VLA observations of the transitional millisecond pulsar candidate NGC 6652B

Abstract

Transitional millisecond pulsars are millisecond pulsars that switch between a rotation-powered millisecond pulsar state and an accretion-powered X-ray binary state, and are thought to be an evolutionary stage between neutron star low-mass X-ray binaries and millisecond pulsars. So far, only three confirmed systems have been identified in addition to a handful of candidates. We present the results of a multi-wavelength study of the low-mass X-ray binary NGC 6652B in the globular cluster NGC 6652, including simultaneous radio and X-ray observations taken by the Karl G. Jansky Very Large Array and the Chandra X-ray Observatory, and optical spectroscopy and photometry. This source is the second brightest X-ray source in NGC 6652 ($L_{\text{X}}\sim 1.8\times 10^{34}$ erg s${}^{-1}$) and is known to be variable. We observe several X-ray flares over the duration of our X-ray observations, in addition to persistent radio emission and occasional radio flares. Simultaneous radio and X-ray data show no clear evidence of anti-correlated variability. Optical spectra of NGC 6652B indicate variable, broad H $\alpha$ emission which transitions from double-peaked emission to absorption over a time-scale of hours. We consider a variety of possible explanations for the source behaviour, and conclude that based on the radio and X-ray luminosities, short time-scale variability and X-ray flaring, and optical spectra, NGC 6652B is best explained as a transitional millisecond pulsar candidate that displays prolonged X-ray flaring behaviour. However, this could only be confirmed with observations of a change to the rotation-powered millisecond pulsar state.

15 pages, 8 figures, accepted for publication in MNRAS

References in corpus (22)

• Array Programming with NumPy
• A Radio Pulsar/X-ray Binary Link
• A radio pulsing white dwarf binary star
• The radio/X-ray domain of black hole X-ray binaries at the lowest radio luminosities
• Optical spectroscopy and demographics of redback millisecond pulsar binaries
• X-ray states of redback millisecond pulsars
• Identification of the High-Energy Gamma-Ray Source 3FGL J1544.6-1125 as a Transitional Millisecond Pulsar Binary in an Accreting State
• Disk-jet coupling in low-luminosity accreting neutron stars
• NuSTAR Observations of the State Transition of Millisecond Pulsar Binary PSR J1023+0038
• The 2015 Decay of the Black Hole X-ray Binary V404 Cygni: Robust Disk-Jet Coupling and a Sharp Transition into Quiescence
• The nature of very faint X-ray binaries; hints from light curves
• Wind-accreting Symbiotic X-ray Binaries
• The Quiescent X-ray Spectrum of Accreting Black Holes
• Discovery of Gamma-ray Pulsations from the Transitional Redback PSR J1227-4853
• The MAVERIC Survey: Chandra/ACIS Catalog of Faint X-ray sources in 38 Galactic globular clusters
• Prolonged sub-luminous state of the new transitional pulsar candidate CXOU J110926.4-650224
• A Highly Eccentric 3.9-Millisecond Binary Pulsar in the Globular Cluster NGC 6652
• The Flare-Dominated Accretion Mode of a Radio-Bright Candidate Transitional Millisecond Pulsar
• The binary millisecond pulsar PSR J1023+0038 -- II. Optical spectroscopy
• The MAVERIC Survey: Radio catalogs and source counts from deep Very Large Array imaging of 25 Galactic globular clusters
• Identifications of Faint Chandra Sources in the Globular Cluster M3
• A propeller model for the sub-luminous disk state of the transitional millisecond pulsar PSR J1023+0038

Cited by in corpus (6)

• A Census of X-ray Millisecond Pulsars in Globular Clusters
• Multiwavelength evidence for a new flare-mode transitional millisecond pulsar
• Ultra-deep ATCA imaging of 47 Tucanae reveals a central compact radio source
• The MAVERIC survey: A catalogue of radio sources in southern globular clusters from the Australia Telescope Compact Array
• MeerKAT radio observations of the neutron star low-mass X-ray binary Cen X-4 at low accretion rates
• The MAVERIC Survey: The first radio and X-ray limits on the detached black holes in NGC 3201