Astronomy and Astrophysics - An Introductory Survey, A lecture series by Prof. G. Srinivasan - Lecture 25 - Recycled Pulsars

The Astrophysics group of Raman Research Institute (Bangalore) played an important role in Neutron Star research in the 1980 - '90s under the leadership of Prof. G. Srinivasan. In particular, his pioneering ideas about `pulsar recycling' have been (and remain) some of the truly major milestones in the area of Neutron Star Astrophysics. ABOUT THE LECTURE Although the Hulse-Taylor binary discussed in the previous lecture has two neutron stars, only one of them was detectable through its pulsed radio emission. This pulsar was not only the first pulsar to be discovered in a binary, it was also the most peculiar. Its very rapid spin rate suggested that it might be a ``very young pulsar". And yet, its anomalously low magnetic field suggested that it must be a very old pulsar. This intriguing puzzle was solved by the novel idea of ``reincarnation of a dead pulsar". Neutron stars eventually stop functioning as `pulsars' when their period of rotation lengthens and their dynamo weakens. If the `dead pulsar' is in a binary system, then it can be spun back up to short periods by accreting angular momentum from the binary companion. This lecture is devoted to this ``Recycling scenario". Lecture 26: Radio Galaxies Lecture 27: Supermassive Black Holes ABOUT THE LECTURE SERIES This lecture series is organized by the Astronomical Society of India as a part of its Golden Jubilee celebrations. Aimed at undergraduate and graduate students, this series of talks by renowned astrophysicist and teacher, Prof G. Srinivasan, starts from the first principles of Physics and builds up the subject rigorously to the present state of our understanding. Series website: https://astron-soc.in/srini-ana The website hosts a question bank as well as a list of suggested reading for each lecture (prepared by Dr. Sushan Konar) ABOUT THE SPEAKER Professor G. Srinivasan In a research career spanning more than five decades, his interests have spanned many aspects of physics and astrophysics. He is a passionate teacher and has authored two outstanding Astronomy texts titled ‘What Are The Stars?’ and ‘Can Stars Find Peace?’ He is a Past President of the Astronomical Society of India, and a Past President of the Division on Space and High Energy Astrophysics of the International Astronomical Union. In his distinguished career he has worked at the University of Chicago, USA; the IBM Research Laboratory in Zurich, Switzerland; Chalmers University of Technology, Goteborg, Sweden; the Cavendish Laboratory, University of Cambridge, England and the Raman Research Institute, Bengaluru Follow us on social media at https://twitter.com/asipoec https://www.facebook.com/asi.poec/ This series is also supported by the IAU OAE Centre in India https://twitter.com/astro4edu_India https://www.facebook.com/OAE-Center-India-105698322030674