I am strongly interested in future X-ray polarization space missions. My speciality is polarized X-rays from neutron stars. With colleagues at NASA, I am exploring and advancing our understanding of expected X-ray polarization from accreting neutron stars in X-ray binaries, and formulating observational strategies. See my publications list: NASA White Paper on Polarized X-rays from Neutron Stars.
How might white dwarfs with masses above the classical Chandrasekhar limit occur in nature, as suggested by recent supernova observations? If it is differential rotation inside white dwarfs, how can that come about in accreting white-dwarfs in binaries? I am investigating this problem with colleagues at the University of Texas.
With a graduate student, I have constructed a comprenensive theoretical framework for describing collective properties, e.g, luminosity functions and period distributions, of X-ray binary populations of normal galaxies. We have calculated such theoretical distributions for both massive and low-mass X-ray binaries. We have compared these distributions with the observed distributions inferred from studies with X-ray observatories like RXTE and Chandra. See my publications list.
Current Position: Senior Professor at TIFR, and former Chair of the Department of Astronomy and Astrophysics (DAA) of TIFR
Mailing Address: Tata Institute of Fundamental Research (TIFR), Homi Bhabha Road, Mumbai (Bombay) 400005, INDIA
Email Address: pranab @ tifr. res. in
Phone: +91-22-2278-2537 (office), +91-22-2280-4812 (residence)
This page summarizes who I am, and what my achievements and interests are.
My CV is given here .
My list of publications is given here .
A .pdf file containing descriptions of my past and recent/current reasearch activities, as well as my teaching/supervising activities, and my administrative/organizational experience is available upon request. Please send an email to the above address.
Please note that the list of my research interests at the top of the rightmost column of this page do not lead anywhere on clicking. Brief descriptions of four topics (with references and with pictures which enlarge on clicking) are given at the bottom of this page.
Disk-Magnetosphere Interaction. I constructed the pioneering quantitative model of disk accretion by magnetic neutron stars with Fred Lamb of the University of Illinois in 1978-1980. Shown above is a result from the numerical computations by Romanova et al. in 2002 (ApJ, 578, 420), which confirms many of the basic features first proposed by Ghosh and Lamb on the basis of their semi-analytical model of 1978-79 (ApJ, 232, 259 and 234, 296). In particular, see Fig.1 of ApJ Let, 223, L83, and Fig.1 of ApJ, 234, 296. The Ghosh-Lamb picture continues to be the basic paradigm in this subject, and in related subjects like accretion by white dwarfs cataclysmic variables.
My Book on Pulsars. Title: Rotation and accretion Powered Pulsars. Publication Date: 2007. Publisher: World Scientific. ISBN Nos. 978-981-02-4744-7 and 978-981-02-4744-3. A comprehensive introduction for both advanced students and professionals to pulsars of both types: those powered by rotation and those powered by accretion. The book summarizes essential properties of both types of pulsars, and stresses their evolutionary connection. Further book details and reviews available at the following websites. http://www.worldscibooks.com/physics/4806.html http://www.springerlink.com/content/u7k31222rl2044j6/.
X-ray Binaries in Globular Clusters. With a graduate student, I constructed a pioneering, Boltzmann-code formulation of the formation and evolution of compact X-ray binaries in globular clusters in 2007-8, which is computationally not as expensive as full numerical codes, and so tackles problems too difficult to be addressed by current codes (ApJ, 670, 1090 and 680, 1438). Shown above is a plot of galactic globular clusters in parameter space (Fig.1 from ApJ, 670, 1090), overplotted with the (color-coded) numbers of compact X-ray binaries observed in these clusters with Chandra, which are accounted for well by our theory.
Chandra Deep Field North. Shown above is the 2 Ms exposure from the 2005 review by Brandt and Hasinger (Ann Rev Astron Astrophys, 43, 827). I gave a pioneering formulation of the cosmic evolution of the X-ray luminosities of galaxies in response to the cosmic star formation history, with Nick White of NASA/GSFC in 1998-2001 (ApJ Let., 504, L31 and 559, L91). Comparing our results with the X-ray luminosity evolution inferred from observations of such deep fields as above, we could discriminate between various proposed cosmic star formation histories, which inspired many subsequent lines of work.