Abstract Details
| Name: Gayathri Raman Affiliation: Rama Research Institute Conference ID: ASI2015_683 Title : SALT observation of X-ray pulse reprocessing in 4U 1626-67 Authors and Co-Authors : Biswajit Paul^1, Dipankar Bhattacharya^2 Vijay Mohan^2 1: Raman Research Institute 2: IUCAA Abstract Type : Poster Abstract Category : Stars, The Milky Way Galaxy and its neighbours Abstract : We investigate the optical reprocessing of X-rays in the LMXB pulsar 4U1626-67 in its current spin-up phase using the South African Large Telescope (SALT) and present the results of timing analysis. Using observations carried out on 5th and 6th March, 2014, we detect some interesting reprocessing signatures. The absence of optical Quasi Periodic Oscillations (QPOs) in the power spectrum from both the night’s data was an expected out come, characteristeric of the spin-up phase of the source, as no corresponding X-ray QPO is seen during this phase. In the lightcurve obtained on March 5, we detect a coherent pulsation at the known spin period of ∼7.676 s. A previously known, slightly down-shifted side-band feature is also detected at 129.94 mHz. The frequency spacing between the main pulse and this side-band is currently being examined. The lightcurve of March 6 displays short time-scale variability in the form of flares on timescales of a few minutes. The folded pulse profiles resulting from the data of this night show an interesting trend of the pulse peak drifting with time. Further investigation of the same is in progress. |