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

Astronomy & Astrophysics 21 understood. The connection between long GRBs and super-luminous SNe is still poorly understood, leading to questions as to whether the distribution of massive stars in the local universe can be scaled to the very high red shifts to explain the progenitors of long duration GRBs at these red shifts. Also of importance will be the use of the long duration GRBs as standardisable candles in cosmic distance estimation. With the help of upcoming facilities, understanding the demographics of compact binary mergers/short-duration GRBs to probe the nature of the electromagnetic counterpart of the GW sources in more detail and understanding the synthesis of r-process elements in the nearbyUniverse will be amajor aspect of transients studies. Over the past decade, wide-area optical surveys have discovered a population of transients with fast rise times (of the order of 1-7 days), fast decay times (1/2 peakmagnitude in 3-12 days), over a range of peak optical luminosities. These are sometimes called “Rapidly Evolving Transients” (RETs), or “Fast-Evolving Luminous Transients” (FELTs) or “Fast Blue Optical Transients” (FBOTs). So far, very few such objects have been studied in detail. The intrinsic rarity and fleeting nature of these events have made it difficult to identify additional examples early enough to acquire the observations necessary to constrain their nature. Similar to the fast optical transients, in the radio region, “Fast Radio Burst” (FRB) events have been detected with transient radio pulse of length ranging from a fraction of a millisecond to a few milliseconds, caused by some high-energy astrophysical process not yet well understood. The confirmed association of at least one FRB with a flare from a soft gamma-ray repeater suggests at least some of them are associatedwith very highmagnetic field neutron stars. It is also observed that some of the super-luminous SNe are also powered by magnetars. In general, most FRBs are seemingly single flashes. However, some FRBs emit multiple bursts. Thus, the question of what causes FRBs, whether all FRBs can repeat, and whether repeating and non- repeating FRBs arise fromdifferent astrophysical channels remain unanswered. Understanding the nature of these fast transients and their progenitors will gain importance withmore such events being discovered in the future. With the given advancement of technology, transients are expected to be explored in detail to not only know more about stellar deaths, mergers of compact binaries, nucleosynthesis of heavy elements and cosmic-ray production, but also to understand the nature of darkmatter, dark energy and the initial mass function of the first stars. 2.10 Exoplanetary Science The 1995 discovery of a Jovian companion to the star 51 Pegasi marked the beginning of a new era in modern astronomy where speculations were laid to rest with the first detection of an extrasolar planet. With the advancement of technology, novel techniques like radial velocity measurements, transit photometry, astrometry, gravitational microlensing, direct imaging, pulsar timing method have now led to the discovery of over 5000 planets and the number is ever increasing. The field of exoplanetary science is focused towards three broad regimes of demographics, atmospheric characterization, and search for habitable planets. The architecture and demographics of the detected population throw open several questions – is the solar system unique? How do we explain the significant fraction of hot-Jupiters and the relatively close-in, super-Earths and/or sub-Neptunes which have no solar system analogs? Further, though some studies have shown possible evidence of universality of planet/star mass ratio, determining whether this or only the planetary mass defines the observed demographics in all mass regimes is crucial to understanding the formation and evolution of planetary systems. The interlink between the architecture of planetary systems and the host star properties is yet to be firmly established. MEGA SCIENCE VISION-2035