A5012589245- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Calibration and Measurement Techniques
- Advanced Semiconductor Detectors and Materials
- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Astrophysics and Star Formation Studies
- Ionosphere and magnetosphere dynamics
- Meteorological Phenomena and Simulations
- Optical Systems and Laser Technology
- Advanced Optical Sensing Technologies
- Geophysics and Gravity Measurements
- Spacecraft Design and Technology
- Imbalanced Data Classification Techniques
- Precipitation Measurement and Analysis
- GNSS positioning and interference
- Atmospheric aerosols and clouds
- Oceanographic and Atmospheric Processes
- Data Mining Algorithms and Applications
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Critical Theory and Philosophy
- Diverse Scientific and Engineering Research
- Advanced optical system design
- Astronomical Observations and Instrumentation
Indian Institute of Technology Kanpur
2024
Shri Mata Vaishno Devi University
2023
The Sanskrit College and University
2022
University of Liège
2022
European Southern Observatory
2019-2021
Government Medical College
2019
National Astronomical Observatory of Japan
2015-2018
National Institutes of Natural Sciences
2015-2018
Subaru (Japan)
2016-2018
The Graduate University for Advanced Studies, SOKENDAI
2018
Of the approximately 25 directly imaged planets to date, all are younger than 500 Myr, and but six 100 Myr (ref.
Giant exoplanets on wide orbits have been directly imaged around young stars. If the thermal background in mid-infrared can be mitigated, then with lower masses also imaged. Here we present a ground-based observing approach that enables imaging low-mass temperate nearby stars, and particular within closest stellar system, α Centauri. Based 75-80% of best quality images from 100 h cumulative observations, demonstrate sensitivity to warm sub-Neptune-sized planets throughout much habitable zone...
State-of-the-art coronagraphs employed on extreme adaptive optics enabled instruments, are constantly improving the contrast detection limit for companions at ever closer separations to host star. In order constrain their properties and ultimately compositions, it is important precisely determine orbital parameters contrasts with respect stars they orbit. This can be difficult in post coronagraphic image plane, as by definition central star has been occulted coronagraph. We demonstrate...
The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is an extremely modular high- contrast installed on the telescope in Hawaii. SCExAO has a dual purpose. Its position northern hemisphere 8-meter makes it prime for detection and characterization of exoplanets stellar environments over large portion sky. In addition, SCExAO's unique design ideal to test innovative technologies algorithms quickly laboratory setup subsequently deploy them on-sky. benefits from first stage...
The direct imaging of rocky exoplanets is one the major science goals for upcoming large telescopes. contrast requirement such planets challenging. However, mid-IR (InfraRed) regime provides optimum to directly detect thermal signatures in our solar neighbourhood. We aim exploit novel fast chopping techniques newly developed astronomy with aid adaptive optics look around bright stars use upgraded VISIR (Very Large Telescope Imager and Spectrometer mid-InfraRed) instrument high (HCI)...
Direct imaging is a powerful exoplanet discovery technique that complementary to other techniques and offers great promise in the era of 30 m class telescopes. Space-based transit surveys have revolutionized our understanding frequency planets at small orbital radii around Sun-like stars. The next generation extremely large ground-based telescopes will angular resolution sensitivity directly image with R < 4 ⊕ very nearest Here, we predict yields from direct survey volume-limited sample...
According to the World Health Organization (WHO) breast cancer is major reason of death among women and its impact on 2.1 million per year.Only in 2018 approximately 15% (62700) are died due cancer.To detect this oncologist rely two methods i.e. early diagnosis screening.To identify cancers before any symptoms appear screening plays an important role Mammography heart detection.Apart from Clinical Breast Exams, Self-Exam many other methodologies used.Screening for too long time consuming...
We present early laboratory simulations and extensive on-sky tests validating of the performance a shaped pupil coronagraph (SPC) behind an extreme-AO corrected beam Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system. In with SCExAO internal source/wavefront error simulator, normalized intensity profile for SPC degrades more slowly than Lyot as low-order aberrations reduce Strehl ratio from extremely high values (S.R. $\sim$ 0.93--0.99) to those characteristic current ground-based...
SCExAO is the premier high-contrast imaging platform for Subaru Telescope. It offers high Strehl ratios at near-IR wavelengths (y-K band) with stable pointing and coronagraphs extremely small inner working angles, optimized faint companions very close to host. In visible, it has several interferometric imagers which offer polarimetric spectroscopic capabilities. A recent addition RHEA spectrograph enabling spatially resolved resolution spectroscopy of surfaces giant stars, example. New...
ESO, in collaboration with the Breakthrough Initiatives, has modified VLT mid-infrared imager VISIR to greatly enhance its ability as a planet finder. It conducted 100-hour observing campaign search for low-mass planets around both components of binary Centauri, part closest stellar system Earth. Using adaptive optics and high-performance coronagraphy, instrument reached unprecedented contrast sensitivity allowing it see Neptune-sized habitable zone, if present. The experiment allowed us...
Direct detection and spectroscopy of exoplanets requires high contrast imaging. For habitable in particular, located at small angular separation from the host star, it is crucial to employ inner working angle (IWA) coronagraphs that efficiently suppress starlight. These coronagraphs, turn, require careful control wavefront which directly impacts their performance. ground-based telescopes, atmospheric refraction also an important factor, since results a smearing PSF, can no longer be...
Vortex coronagraphs have been shown to be a promising avenue for high-contrast imaging in the close-in environment of stars at thermal infrared (IR) wavelengths. They are included baseline design mid-infrared extremely large telescope imager and spectrograph. To ensure good performance these coronagraphs, precise control centering star image real time is needed. We previously developed validated quadrant analysis coronagraphic images tip-tilt sensing estimator (QACITS) pointing address this...
In this paper we present the first results ever obtained by applying autoregressive (AR) technique to precipitable water vapour (PWV). The study is performed at Very Large Telescope. AR has been recently proposed provide forecasts of atmospheric and astroclimatic parameters short time scales (up a few hours) achieving much better performances with respect 'standard forecasts' provided early afternoon for coming night. method uses real-time measurements parameter interest improve...
The past decade has seen increasing efforts in detecting and characterising exoplanets by high contrast imaging the near/mid-infrared, which is optimal wavelength domain for studying old, cold planets. In this work, we present deep AO observations of nearby Sun-like star $\epsilon$ Ind A with NaCo ($L^{\prime}$) NEAR (10-12.5 microns) instruments at VLT, an attempt to directly detect its planetary companion whose presence been indicated from radial velocity (RV) astrometric trends. We derive...
In the field of exoplanetary sciences, high contrast imaging is crucial for direct detection of, and answering questions about habitability exoplanets. For habitable exoplanets, it important to employ low inner working angle (IWA) coronagraphs, which can image exoplanets close PSF. To achieve full performance such correct atmospheric dispersion highest degree, as any leakage will limit contrast. with state-of-the-art coronagraphs in SCExAO instrument, spread point-spread function due...
METIS is one of the three first-light instruments planned for ELT, mainly dedicated to high contrast imaging in mid-infrared. On SPHERE high-contrast instrument currently installed at VLT, we observe that main limitations wind driven halo, due limited AO running speed with respect atmospheric turbulence temporal evolution. From this observation, extrapolate signature ELT/METIS instrument, which equipped a single conjugated adaptive optics system and several coronagraphic devices. By making...
The Mid-infrared ELT Imager and Spectrograph (METIS) is one of the first-generation scientific instruments for ELT, built under supervision ESO by a consortium research institutes across beyond Europe. Designed to cover 3 13 $\mu$m wavelength range, METIS had its final design reviewed in Fall 2022, has then entered earnest manufacture, assembly, integration, test (MAIT) phase. Here, we present high-contrast imaging (HCI) modes. We detail implementation two main coronagraphic solutions...
Cooling ages of white dwarfs are routinely determined by mapping effective temperatures and masses to using evolutionary models. Typically, the reported uncertainties on cooling only consider error propagation spectroscopically or photometrically $T_{\rm eff}$ mass. However, models themselves uncertain, given their dependence many poorly constrained inputs. This paper estimates these systematic model uncertainties. We use MESA generate sequences $0.5-1.0 M_{\odot}$ hydrogen-atmosphere with...