1. France:

    I have succesfully completed two  Indo-French projects and the third one is ongoing under the IFCPAR programme.   The first project was  entitled Stability of giant high power laser cavities and its duration was from 1994 - 1997. The investigators on the Indian side were S. V. Dhurandhar and B. S. Sathyaprakash of IUCAA and on the French side were J. Y. Vinet and P. Hello of the Orsay group of the VIRGO.  The second project was entitled Gravitational wave data analysis of LISA and ran from 2000 - 2003. This project was awarded excellent rank by the IFCPAR. The current one has begun in May 2006 and is on the physical and mathematical modelling of LISA.

  2. US:

    The IUCAA gravitational wave data analysis group joined the Ligo Science Collaboration (LSC) in 2000.  In LSC  the work was on extending the hierarchical search for inspiraling binaries to three parameters: the two masses and the time-of-arrival and also improving the efficiency of the overall search by interpolation methods. The work on hierarchical search was the content of the Ph.D. thesis of Anand Sengupta. We are now currently working with the stochastic group on the directed search and mapping the gravitational wave sky.  Part of Sanjit Mitra's thesis has been  based on the work done for the LSC. The collaboration with US was partly funded under the NSF-DST, Indo-US project from 2002 - 2006. The US collaborators were Albert Lazzarini, LIGO, Caltech and Sam Finn from Penn State. On the US side we continue to have grants from the NSF, the collaborators being Sukanta Bose, WSU and A. Lazzarini, LIGO, Caltech.

  3. Japan:

    With N. Kanda from Osaka City University, H. Tagoshi from Osaka University and M. Fujimoto, NAOJ, Tokyo the IUCAA group collaborates on the comparing the coincident versus coherent searches for inspirals with a network of detectors. Himan Mukhopadhyay is involved in this work. The work is facilitated by short (1 week - 2 weeks) bilateral visits between Japan and India supported by DST and JSPS on a yearly basis.  The Japanese have the TAMA300 detector and are planning a fullscale detector LCGT in the future.  I am  a collaborator in the LCGT  project.

  4. Informal collaborations:

          I have had informal but strong collaborations with AEI, Max Planck, Potsdam, Germany;  UWA, Perth, and ANU,   
          Canberra,   Australia and Cardiff, U.K.