Astronomy and Astrophysics - An Introductory Survey, A lecture series by Prof. G. Srinivasan - Lecture 30 - Millisecond Pulsars

AstroPHYSICS with Srini (https://www.youtube.com/@astrophysicswithsrini1094) The newly launched youtube channel of Prof. Srinivasan. WATCH it, SUBSCRIBE to it, and bring it to the attention of your friends! And here is why.   The present course of introductory lectures will end with the 41st lecture. There are many topics in basic physics, as well as astrophysics, that you encountered in this course that deserves a 'revisit'. Prof. Srinivasan plans to make new videos on these topics and upload them to this channel. This will start to happen after the last lecture of this series has been released. Meanwhile, this channel is up. Currently, the PLAYLIST contains the 40 lectures that he delivered at the International Centre for Theoretical Sciences, a few years ago. You are welcome to contact Prof. Srinivasan at [email protected] if you have suggestions for topics, or if you have questions. -------------------------------------------------------------------------------- If one tries to describe the development of our understanding of "Millisecond Pulsars", it would look very much like the work report of the Astrophysics Group of Raman Research Institute in the 1980s-'90s. The group was headed by Prof. G. Srinivasan at that time, and it was he (along with Prof. V. Radhakrishnan) took the main initiative in this activity. In fact, great strides were made by this group in the overall area of the evolution of Neutron Stars during this period. ABOUT THE LECTURE A neutron star spinning 642 times a second was discovered in 1982! Although it was a `solitary pulsar', a bold conjecture was made that it must be a ``recycled pulsar" - like the Hulse-Taylor pulsar - spun up in a low-mass binary, which somehow `got rid' of its binary companion. This scenario led to the prediction that its magnetic field must be more than 10,000 times weaker than that of the Crab pulsar. Later observations confirmed this prediction. Forty years later, nearly 150 such "Millisecond Pulsars" have been discovered, all with very nearly the same magnetic field. Millisecond Pulsars are remarkable objects for several reasons. As "clocks", they are more stable than even "atomic clocks" which define the `standard of time'. They spin fast enough for the next generation of terrestrial detectors to detect gravitational waves emitted by them. Plans are also underway to use an "array" of such pulsars as a `detector' of low-frequency gravitational waves. 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