Ram Sagar

TL;DR: In this article, the mass concentrations of aerosol black carbon (BC) and composite aerosols near the surface were carried out along with spectral aerosol optical depths (AODs) from a high-altitude station, Manora Peak in central Himalayas, during a comprehensive aerosol field campaign in December 2004.

TL;DR: In this paper, multi-year measurements of near surface aerosol black carbon (BC) mass concentration, made from a high altitude station at Manora Peak (29.4° N, 79.5° E, 1958 mmsl) in the Central Himalayas, using a 7-channel Aethalometer for 38 months from November 2004 to December 2007, are examined.

Abstract: Gamma-ray bursts (GRBs) are thought to arise when an extremely relativistic outflow of particles from a massive explosion (the nature of which is still unclear) interacts with material surrounding the site of the explosion. Observations of the evolving changes in emission at many wavelengths allow us to investigate the origin of the photons, and so potentially determine the nature of the explosion. Here we report the results of γ-ray, optical, infrared, submillimetre, millimetre and radio observations of the burst GRB990123 and its afterglow. Our interpretation of the data indicates that the initial and afterglow emissions are associated with three distinct regions in the fireball. The peak flux of the afterglow, one day after the burst, has a lower frequency than observed for other bursts; this explains the short-lived radio emission. We suggest that the differences between bursts reflect variations in the magnetic-field strength in the afterglow-emitting regions.

TL;DR: In this article, the mass concentrations of aerosol black carbon (BC) and composite aerosols near the surface were carried out along with spectral aerosol optical depths (AODs) from a high altitude station, Manora Peak in Central Himalayas, during a comprehensive aerosol field campaign in December 2004.

TL;DR: In this article, the relative proper motions and membership probabilities of stars in the open cluster M 67 (C0847+120, NGC 2682) were determined using the Wide Field Imager (WFIM) at the 2.2 m MPG/ESO telescope.