SEMINAR

Title : FIELD-ANGLE OPTIMIZED DESIGN FOR WIDE-FIELD IMAGING X-RAY TELESCOPES

Date : 03-04-2025
Time : 16:00:00
Speaker : Mr. Neeraj K. Tiwari
Area : Astronomy & Astrophysics Division
Venue : Seminar Room # 113/114 (Thaltej campus)

Abstract

Wide field of view (FOV) imaging X-ray telescopes play a crucial role in addressing some of the most challenging and unresolved questions in modern astrophysics. For example, they are crucial for probing the early formation of supermassive black holes (SMBH), rigorously testing the hypothesis that nanoflares are the primary mechanism sustaining coronal temperatures above million Kelvin, and detecting the electromagnetic counterparts of gravitational wave events. However, existing optical designs for X-ray telescopes, such as the Wolter type-1 (W1) and Wolter-Schwarzschild (WS) configurations, offer high angular resolution only along the optical axis and are therefore limited to narrow FOVs (a few arcminutes), while the scientific cases mentioned above require high angular resolution across a much wider FOV (up to 60 arcminutes). In this talk, I will introduce a new optical design, the field-angle optimized (FO) design, specifically developed for wide FOV X-ray imaging telescopes. I will discuss the methodology behind this design, compare its performance with existing optical designs, and explore its feasibility for implementation in wide FOV solar X-ray telescopes.

Title : Time domain photometric study of peculiar Blazars

Date : 01-04-2025
Time : 11:00:00
Speaker : Dr. Shubham Kishore
Area : Astronomy & Astrophysics Division
Venue : Online: https://meet.google.com/ihi-bmxq-syc

Abstract

Blazars often exhibit random, aperiodic, and stochastic behaviours in their flux across all observational electromagnetic (EM) bands over a wide range of timescales. However, the underlying causes are not yet fully understood regarding which flux variations on the intra-day/day timescales are most poorly comprehended. These variations are primarily related to accretion or jet physics, as jets are powered by accretion. In the talk, I will elucidate my findings that include the quasi-periodic oscillatory signatures and flare episodes detected in three individual Blazar candidates observed with Transiting Exoplanet Survey Satellite (TESS).

Title : Habitat Selection by Early Humans in the Indian Subcontinent

Date : 01-04-2025
Time : 16:00:00
Speaker : Ms. Nandini Sharma
Area : Geosciences Division
Venue : Ground Floor Lecture Hall

Abstract

The dispersal of our species out of Africa is believed to have occurred in multiple phases from the middle to late Pleistocene. Earliest fossil evidences for this migration of Homo sapiens is documented around 200-100 kya. These dispersals are influenced by the climate shifts, which shaped their habitats during migration. According to the Southern Dispersal Hypothesis, the dispersal of Homo sapiens from Africa into South Asia (130–75 kya) coincided with periods of favorable monsoon-driven green corridors, which influenced migration pathways and habitat selection. In this seminar, we will explore hominin habitat selection patterns by reconstructing woody cover along these dispersal routes using pedogenic carbonates as a vegetation proxy, providing insights into the environments they might have encountered and adapted.