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

Astronomy & Astrophysics 19 nucleosynthesis events that occurred before these stars formed. Although detailed spectroscopic observations of the chemical evolution of our Galaxy constitute a major accomplishment in the field, there still are ambiguities due to the lack of isotopic information, particularly those of the heavy elements. Observations of isotopic abundances are therefore extremely important. The interesting open questions that one seeks to answer are: what is the Deuterium abundance in the metal poor gas, what are Li abundance and Li isotope ratios in metal-poor stars, and what are the sites of Li production in stars with Li enhancement?An accurate measurement of isotopic ratios of heavy elements in stars are important to understand their implications on the chemical evolution of the Galaxy. What drives the abundance pattern of the very metal poor stars, andwhat is the abundance pattern of metal poor galaxies are the other interesting, but poorly understood questions. 2.8 Compact Objects andBlackHoles The remnants at the end of stellar life such as white dwarfs, neutron stars, and black holes as well as super-massive black holes located at the center of galaxies are usually referred to as “compact objects”. They tend to attract and eventually swallowmatter from their surroundings or a binary companion, if present. The surrounding matter plunges toward the compact object due to their strong gravitational force in the form of a planar disk, termed accretion disk. A fraction of the accretedmatter forms an outflowwhichmay be in the formof a wind or a highly collimated powerful jet of magnetized plasma moving at speed close to the speed of light in a direction perpendicular to the plane of accretion. Properties of the compact objects along with the inflow and outflow near them are probed using X-rays, ɤ -rays, and radio waves. Due to their strong gravitational field, they are the best laboratories to test the predictions of General Relativity. Probing their properties, e.g., equation of state of the matter inside a neutron star, accreted material very close to a black hole, or relativistic particles in powerful jets, can help us understand the physics of matter in environments that are difficult or impossible to produce in the lab, and hence may lead to the discovery of new physics or confirmexisting complex theories. After painstaking efforts for decades, scientists have finally been able to detect gravitational waves from cosmic sources since 2015. As of now, the detected sources are black holes and neutron stars in binary systems a few seconds before they merge with each other producing powerful gravitational waves. This new window provides us an important tool to probe compact object binaries in a way that is not dependent on the electromagnetic signal such as X- rays emitted by them. It is expected that as the gravitational wave detectors becomes increasingly sensitive, many more sources will be detected and that will provide an opportunity to probe the physics of these systems with more details through this unique window. Some important aspects one would like to probe are: strong field tests of gravity using pulsars and black holes; understand the nature of inflow (accretion) and outflow (jets, wind) associated with compact objects; the origin of intermediate mass black holes (IMBH); understanding strong gravity, superdense matter and accretion-ejection mechanism of and around black holes and neutron stars; physics and evolution of millisecond pulsars and their binary system and explanation of the observed parameters; study of continuous gravitational waves from the ellipticity of neutron stars (from future observations with an advanced version of LIGO, and future observatories such as Cosmic Explorer and Einstein Telescope) and orbital rotation of compact binaries (future observations with LISA); multi- messenger observations of neutron star mergers and; search of gravitationally lensed gravitywave signal. MEGA SCIENCE VISION-2035