MSV-2035 Astronomy Document - Inside Design - FINAL - FINAL

Astronomy & Astrophysics 42 chemically heterogeneous surface, having variation in abundance of carbon chain molecules and dust to gas ratio similar to solar system comets. Studies of comets also include modelling of various cometary structures, especially cometary jets, dust grains, shells and fans. Understanding of the mass, angular momentum, magnetic field structure of different planets, comets, and other minor bodies of the solar system are some of the other topics that have been pursued. Genesis of magnetic field structure of solar system objects from the catastrophic events (such as bombardments with comets and asteroids) have been explored. It is shown that the genesis and diverse intensity of magnetic field structure of terrestrial planets (such as Mercury) and their satellites, and some of Jupiter's satellites, are mainly due to catastrophic events which occurred during the early history of solar system formation. Indian astronomers are participating in international collaborations for the studies of NEOs. These include follow-up for orbit determination and photometric characterization of the NEOs. Observations of asteroids using the 0.7m wide field telescope located in Hanle, in collaboration with the ZTF survey group as a part of the international GROWTH collaboration, have led to the discovery of 6 asteroids, including asteroid 2020QG that had the closest approach to the Earth in recent times. The longitudinal advantage of India's geographical location will be best utilised in the studies of NEOs with the availability of a network of wide field telescopes in the country that can be part of a larger international network of telescopes. 4.1.3 InterstellarMedium The interstellar medium is a main gas reservoir fromwhich new stars are formed. Physical conditions prevailing in the ISM (metallicity, gas temperature and pressure, turbulence etc.) are linked to the stars and their evolution. Indian astronomers have contributed to our understanding of star formation, nature of H I and H II regions, photo- dissociation regions, dust formation, molecular chemistry, cosmic ray propagation and excitations, SNe-ISM interactions and measuring the power-spectrum of ISM turbulence etc. In the radio wavelengths, Indian astronomers have made unique contributions to the studies of radio recombination lines, H I emission and absorption from galactic ISM, establishing the link between 21-cm spin-temperature and H rotational excitation temperature, measuring the 2 rotation and dispersion measures using pulsars, measuring the power-spectrum of density fluctuation using H I spectroscopy towards SNe remnants. These studies involve spectroscopic observations using ORT, GMRT and other international radio facilities like VLA, WSRT and ATCA. In the optical front, original contributions were made on measuring gas phase metallicity and dust, nature of molecular excitations, mapping molecular and dusty star forming regions. These studies mostly used high resolution spectroscopic observations (from Indian and other international facilities including space telescopes) and polarisation measurements using imaging and spectropolarimetry available in Indian facilities. In the theoretical side, important contributions were made in understanding the multi-phase nature of the ISM, formation and excitations of complex molecules and dust and physical modelling (equilibrium and non- equilibrium) of photo-dissociation regions. Indian astronomers have also contributed to the measurement and theoretical estimation of ionizing UV background. Utilising the archival data from the Galaxy Evolution Explorer (GALEX) mission, the diffuse ultraviolet cosmic background in two wavelength bands (FUV: 1530 Å and NUV: 2310 Å) was mapped over almost 75%of the sky. Most of the diffuse flux was found to be due to dust-scattered starlight having a strong correlation with the 100μm Infrared Astronomy Satellite (IRAS) flux. MEGA SCIENCE VISION-2035