MOPTOP: Polarimetry for time domain astrophysics

Optical polarimetry can play a key role in diagonistic of magnetic field strength/order/geometry in diverse time varying astrophysical sources such as active galactic nuclei (AGN), X-ray binaries (XRBs), and gamma ray bursts (GRBs). For these sources, polarization can probe the physical conditions at spatial scale that is not possible via other observational techniques. Traditionally polarization is measured via ratio of fluxes by taking consecutive exposures which is not an effective way to observe polarization in rapidly varying object such as GRBs. Liverpool Telescope (LT) has utilized rapidly rotating Polaroid to overcome this problem and created series of polarimeters RINGO, RINGO2, and RINGO3 which have successfully detected early-time optical polarimetry of GRB, studied blazar variability, contributed in projects related to novae and XRBs. MOPTOP is a next generation dual beam polarimeter that will replace RINGO3 in LT. I will present the results of preliminary data taken using prototype MOPTOP instrument in lab and on-site in LT, which shows that the sensitivity is higher for MOPTOP compared to RINGO3. And discuss various time domain science it can be used for in the future.