PhD Defenses


Wed May 25th 2022, 1:00 - 2:00pm
Varian 355
Stanford overview

Photo by Linda Cicero

Ph.D. Candidate:  Dinesh Kandel

Research Advisor:  Roger Romani

Date: 05/25/2022
Time: 1 pm

Location: Varian 355

Zoom Link:

Zoom Password: email for password


X-ray and Optical Studies of Black Widow Pulsars

Some millisecond pulsars (MSPs) form a close binary system with a low-mass companion, where the companion is irradiated by the MSP. Such system are broadly known as `spiders`. In recent years, several of these systems have been discovered through  Fermi LAT and targeted follow-ups. The companion of such system has highly complex atmospheres due to extreme pulsar heating on the front side, their surface heating patterns offers a rich and complex view of the physical system, allowing one to indirectly probe these MSPs. Several of such systems are relatively bright and near distant for detailed optical and x-ray study. In this talk, I wll present numerical and analytical study of optical and x-ray emissions from these systems. I will also discuss how we explore the possibility that companion atmospheres are altered due to pulsar irradiation as well as magnetic activity, thus the atmosphere might exhibit phenomenons like heat circulation, diffusion or local increase in surface temperature through spots generated from magnetic activity. Finally I will show how we model the system and estimate important parameters of the system, including the pulsar mass, and show that the spider systems are ideal for search of heavy neutron stars, potentially providing excellent constraint on neutron star equation-of-state.