Search for radio pulsations in LS I +61 303

Abstract

Context. LS I +61 303 is a member of the select group of gamma-ray binaries: galactic binary systems that contain a massive star and a compact object, show a changing milliarcsecond morphology and a similar broad spectral energy distribution (SED) that peaks at MeV-TeV energies and is modulated by the orbital motion. The nature of the compact object is unclear in LS I +61 303, LS 5039 and HESS J0632+057, whereas PSR B1259-63 harbours a 47.74 ms radio pulsar. Aims. A scenario in which a young pulsar wind interacts with the stellar wind has been proposed to explain the very high energy (VHE, E > 100 GeV) gamma-ray emission detected from LS I +61 303, although no pulses have been reported from this system at any wavelength. We aim to find evidence of the pulsar nature of the compact object. Methods. We performed phased array observations with the Giant Metrewave Radio Telescope (GMRT) at 1280 MHz centred at phase 0.54. Simultaneous data from the multi-bit phased array (PA) back-end with a sampling time of tsamp = 128 microsec and from the polarimeter (PMT) back-end with tsamp = 256 microsec where taken. Results. No pulses have been found in the data set, with a minimum detectable mean flux density of \sim 0.38 mJy at 8-sigma level for the pulsed emission from a putative pulsar with period P >2 ms and duty cycle D = 10% in the direction of LS I +61 303. Conclusions. The detection of posible radio pulsations will require deep and sensitive observations at frequencies \sim0.5-5 GHz and orbital phases 0.6-0.7. However, it may be unfeasible to detect pulses if the putative pulsar is not beamed at the Earth or if there is a strong absorption within the binary system.

8 pages. 5 figures. Accepted for publication in Astronomy and Astrophysics

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• Search for radio pulsations in LS I +61 303

Cited by in corpus (9)

• Gamma-ray binaries and related systems
• H-alpha observations of the gamma-ray-emitting Be/X-ray binary LSI+61303: orbital modulation, disk truncation, and long-term variability
• Search for radio pulsations in LS I +61 303
• Radio absorption in high-mass gamma-ray binaries
• Multiwavelength Observations of The TeV Binary LS I +61 303 with VERITAS, Fermi-LAT and Swift-XRT During a TeV Outburst
• Modelling the correlated keV/TeV light curves of Be/gamma-ray binaries
• Orbital and superorbital variability of LS I +61 303 at low radio frequencies with GMRT and LOFAR
• A complete radio study of SNR G15.4+0.1 from new GMRT observations
• Owens Valley Radio Observatory monitoring of LS I +61°303 completes three cycles of the super-orbital modulation