| Name: | Ankita Ghosh |
| Affiliation: | National Centre For Radio Astrophysics |
| Conference ID : | ASI2024_583 |
| Title : | Investigation of the orbital characteristics for J1242-4712, a newly discovered millisecond pulsar with the GHRSS. |
| Authors : | Ankita Ghosh, Bhaswati Bhattacharyya, Andrew Lyne, David L. Kaplan, Jayanta Roy, Paul S. Ray, Ben Stappers, Sangita Kumari, Shubham Singh, Rahul Sharan |
| Authors Affiliation: | 1 Ankita Ghosh, Bhaswati Bhattacharyya, Jayanta Roy, Sangita Kumari, Shubham Singh, Rahul Sharan Affiliation (National Centre for Radio Astrophysics, Pune-411007,India)
2 Andrew Lyne, Ben Stappers Affiliation (Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, UK)
3 David L. Kaplan Affiliation (Center for Gravitation, Cosmology, and Astrophysics, Department of Physics, University of Wisconsin-Milwaukee, PO Box 413, Milwaukee, WI, 53201, USA)
4 Paul S. Ray Affiliation (Space Science Division, U.S. Naval Research Laboratory, Washington, DC 20375-5352, USA) |
| Mode of Presentation: | Oral |
| Abstract Category : | Stars, Interstellar Medium, and Astrochemistry in Milky Way |
| Abstract : | We present the timing analysis for the redback millisecond pulsar (MSP) J1242-4712 with a pulse period of 5.31 ms, discovered with the GMRT High-Resolution Southern Sky (GHRSS) survey. Redback and black widow spider MSP systems offer excellent opportunities for studying neutron star masses and the equation of state. The redback systems transitioning between accretion-powered low-mass X-ray binary and rotation-powered radio pulsar states contribute significantly to a better understanding of the recycling process. We conducted 4.5 years of phase-connected timing using uGMRT band-3 and band-4 observations and found that J1242-4712 is in orbit with a companion that has a minimum mass of 0.08 Msun and an orbital period of 7.7 hours. This MSP represents a quite unexplored region in the parameter space of orbital period versus companion mass. We did not detect gamma-ray pulsations from this MSP and were also unable to identify its optical counterpart in the available optical and near-infrared data. The pulse profile of this MSP exhibits frequency-dependent variations, shifting from a clear single component at lower frequencies to a three-component profile at 650 MHz. Eclipses in spider MSPs are often frequency-dependent; however, our coarse data sampling prevented a detailed exploration of the eclipses near superior conjunction (orbital phase ~ 0.25). However, we detected mild eclipsing near inferior conjunction (orbital phase ~ 0.7) in several epochs, resulting in an excess delay in dispersion measure and large errors in pulse arrival times. The presence of observed eclipses, alongside the significant variability in the orbital period, suggests that J1242-4712 is not a Helium-White Dwarf binary but rather harbors a non-degenerate companion, strongly indicating that J1242-4712 is a "redback spider" MSP. It's measure Edot and pulsar wind flux at the companion aligns with values typically found for Galactic redback MSPs, further contributing to our understanding of these intriguing systems. |
