X-ray emission characteristics of two WR binaries : V444 Cyg and CD Cru (2009)
Bhatt, Himali, Pandey, J. C., Kumar, Brijesh, Singh, K. P., Sagar, Ram
We present X-ray analysis of two Wolf-Rayet (WR) binaries: V444 Cyg and CD Cru using the data from observations with XMM-Newton. The X-ray light curves show the phase locked variability in both...
LO Pegasi: An investigation of multi-band optical polarization (2009)
Pandey, J. C., Medhi, Biman J., Sagar, Ram, Pandey, A. K.
We present BVR polarimetric study of the cool active star LO Peg for the first time. LO Peg was found to be highly polarized among the cool active stars. Our observations yield average values of...
Optical and near-IR photometric study of the open cluster NGC 637 and NGC 957 (2008)
Yadav, R. K. S., Kumar, Brijesh, Subramaniam, A., Sagar, Ram, Mathew, Blesson
We present UBVRI CCD photometry in the region of the open clusters NGC 637 and NGC 957. The radii are found to be 4.2 arcmin and 4.3 arcmin. Their reddenings E(B-V) are 0.64+/-0.05 mag and...
Multi-wavelength study of a young open cluster NGC 7419 (2008)
Joshi, Himali, Kumar, Brijesh, Singh, K. P., Sagar, Ram, Sharma, Saurabh, Pandey, J. C.
Using UBVRI Halpha CCD photometric observations and the archival NIR and X-ray data, we have carried out a multi-wavelength study of a young star cluster NGC 7419. An age of 22.5+/-3.0 Myr and a...
Optical Observations of GRB 050401 Afterglow : A case for Double Jet Model (2008)
Kamble, Atish, Misra, Kuntal, Bhattacharya, D., Sagar, Ram
The afterglow of GRB 050401 presents several novel and interesting features : [1] An initially faster decay in optical band than in X-rays. [2] A break in the X-ray light curve after $\sim$ 0.06 day...
Multiwavelength study of the transient X-ray binary IGR J01583+6713 (2008)
Kaur, Ramanpreet, Paul, Biswajit, Kumar, Brijesh, Sagar, Ram
Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
Dumka, UC, Moorthy, Krishna K, Satheesh, SK, Sagar, Ram, Pant, P
Multiyear measurements of spectral aerosol optical depths (AODs) were made at Manora Peak in the central Himalaya Range ($29^022^{\prime}N$, $79^027^{\prime}E$, \sim1950 m above mean sea level),...
Medhi, Biman J., G, Maheswar., Pandey, J. C., Kumar, T. S., Sagar, Ram
We present new B, V and R linear polarimetric observations for 61 stars towards the region of the young open cluster NGC 654. In this study we found evidence for the presence of at least two layers...
Kaur, Ramanpreet, Paul, Biswajit, Kumar, Brijesh, Sagar, Ram
Restricted Access. Articles older than 2 years are open to all at the journal site (alternative location)
Multiwavelength study of the transient X-ray binary IGR J01583+6713 (2008)
Kaur, Ramanpreet, Paul, Biswajit, Kumar, Brijesh, Sagar, Ram
We have investigated multiband optical photometric variability and stability of the H$\alpha$ line profile of the transient X-ray binary IGR J01583+6713. We set an upper limit of 0.05 mag on...
Kaur, Ramanpreet, Paul, Biswajit, Kumar, Brijesh, Sagar, Ram
We report here a study of the long term properties of Quasi Periodic Oscillations (QPO) in an unusual accreting X-ray pulsar, 4U 1626--67. This is a unique accretion powered X-ray pulsar in which we...
Dumka, UC, Moorthy, Krishna K, Satheesh, SK, Sagar, Ram, Pant, P
Multiyear measurements of spectral aerosol optical depths (AODs) were made at Manora Peak in the central Himalaya Range ($29^022^{\prime}N$, $79^027^{\prime}E$, \sim1950 m above mean sea level),...
Type IIP supernova SN 2004et: a multiwavelength study in X-ray, optical and radio (2007)
Misra, Kuntal, Pooley, Dave, Chandra, Poonam, Bhattacharya, D., Ray, Alak K., Sagar, Ram, ...
Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
Type IIP Supernova SN 2004et: A Multi-Wavelength Study in X-Ray, Optical and Radio (2007)
Misra, Kuntal, Pooley, Dave, Chandra, Poonam, Bhattacharya, D., Ray, Alak K., Sagar, Ram, ...
We present X-ray, broad band optical and low frequency radio observations of the bright type IIP supernova SN 2004et. The \cxo observed the supernova at three epochs, and the optical coverage spans a...
Star formation in young star cluster NGC 1893 (2007)
Sharma, Saurabh, Pandey, A. K., Ojha, D. K., Chen, W. P., Ghosh, S. K., Bhatt, B. C., ...
We present a comprehensive multi-wavelength study of the star-forming region NGC 1893 to explore the effects of massive stars on low-mass star formation. Using near-infrared colours, slitless...
Broad Band Optical Polarimetric Study of IC 1805 (2007)
Medhi, Biman J., G., Maheswar, K., Brijesh, Pandey, J. C., Kumar, T. S., Sagar, Ram
We present the BVR broad band polarimetric observations of 51 stars belonging to the young open cluster IC 1805. Along with the photometric data from the literature we have modeled and subtracted the...
Optical observations of GRB 060124 afterglow: a case for an injection break (2007)
Misra, K, Bhattacharya, D, Sahu, D. K, Ram Sagar, Anupama, G. C, Castro-Tirado, A. J, ...
Aims.We present broad band optical afterglow observations of a long duration GRB 060124 using the 1.04-m Sampurnanand Telescope at ARIES, Nainital and the 2.01-m HCT at IAO, Hanle, including the...
Clear Evidence for Intranight Optical Variability in Radio-quiet Quasars (2003)
Stalin, C. S., Sagar, Ram, Wiita, Paul J.
We present new clues to the problem of the radio loudness dichotomy arising from an extensive search for intranight optical variability in seven sets of optically luminous radio-quiet quasars and...
Observations of GRB afterglows from Nainital : Evidence in favour of jet model (2002)
Broad band optical photometric observations of five Gamma-ray burst (GRB) afterglows (GRB 990123, GRB 991208, GRB 991216, GRB 000301c and GRB 000926) are taken from Nainital during 1999 and 2000....