V. KOTESWARA RAO
Articles written in Journal of Astrophysics and Astronomy
Volume 40 Issue 1 February 2019 Article ID 0001
Relation between solar flares and halo coronal mass ejections
V. KOTESWARA RAO K. RAMA GOPAL R. RAMAKRISHNA REDDY K. AMARESWARI K. SANKARASUBRAMANIAN
Solar flares and coronal mass ejections (CMEs) are two very important active events from Sun. Inspite of several theoretical and statistical analyses, the relation between solar flares and CMEs is so far not well established, and strong opinions and arguments still continue. Statistical approaches use a lot of dataavailable from many measurements by space and ground instruments. They try to map the measured parameters of one event to that of another event and try to establish the relation between them. Halo CMEs are a kind of special CMEs in the sense that they are directed towards Earth and hence can influence Earth’s atmosphere. For a scientist interested in Sun–Earth interactions and the effect on Earth’s atmosphere, study of Halo CMEs is extremely important. In this paper the relation between solar flares and Halo CMEs is studied. The data setsused are for the period from October 2006 to March 2017. For the first time, the Halo CMEs are categorized into four different groups based on the relative time of occurrence with respect to the flares and the relation between the flare and Halo CME parameters is studied. It is shown that: (a) there is a good correlation between certain flare parameters (like flare flux and peak intensity) and CME parameters (like kinetic energy, linear speed, and mass) especially when the Halo CME occurs during the flare; (b) For the same set of CMEs, the correlation is poor with flare duration; and (c) For CMEs before or after the flare, the correlation is lesser than the CMEs occurring during the flare.
Volume 42 All articles Published: 29 May 2021 Article ID 0024 MISSION
Challenges of realizing and operating AstroSat in-orbit
V. KOTESWARA RAO K. SURYANARAYANA SARMA
AstroSat, a dedicated Space Observatory of India, has completed five successful years of operation in space on 28th September 2020. AstroSat is a quite complex satellite, as it is a multi-wavelength observatory with many scientific instruments. The saga of many agencies, including Indian Space ResearchOrganisation, the lead agency, and many scientists and engineers has resulted in realizing and operating this mission with excellent performance and highly satisfactory results. This mission generated a lot of observations leading to enhanced research activity for Indian astronomers, as well as international astronomers. It has also kindled interest, as expected, in young scientists and science students. The mission still continues in orbit contributing to celestial observations. AstroSat is a collaborative effort of many agencies not only fromIndia but also from international agencies. The managers and the project team had to face many technological and managerial challenges at various stages of the mission. In this paper we present the challenges in conceiving a space science mission in India, and methods adopted to overcome them to make the mission successful. This may help in planning and executing future space science missions, more efficiently, meeting the growing demands from the scientific community involved in the frontier areas of space research.
Volume 42 All articles Published: 17 July 2021 Article ID 0078 BEYOND ASTROSAT
Beyond AstroSat: Astronomy missions under review
India has an expanding program in using space as a platform for research. Astrophysics research from satellites increasingly complement ground-based observations with unique wavelength coverage, more frequent temporal coverage and diffraction-limited observations. India’s first dedicated space astronomy mission, AstroSat has completed five years in orbit and continues to generate important results. Most onboard systems are healthy and the mission is expected to continue to operate for many more years. Plans for space astronomy missions beyond AstroSat, are under discussion for some time. These are based on responses from the Indian research community to an announcement of Opportunity call in early 2018. Here we discuss, an outline of the science focus of future space astronomy missions, under consideration.
Volume 44, 2023
Continuous Article Publishing mode
Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles.
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