Shrishmoy Ray
A5039176680- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- Spectroscopy and Laser Applications
- Astro and Planetary Science
- Astrophysical Phenomena and Observations
- Calibration and Measurement Techniques
- Spectroscopy and Chemometric Analyses
- Thermodynamic properties of mixtures
- Spacecraft and Cryogenic Technologies
- Astronomical and nuclear sciences
- Gamma-ray bursts and supernovae
- Planetary Science and Exploration
University of Exeter
2021-2024
The University of Queensland
2024
Phillips Exeter Academy
2022
We present the highest fidelity spectrum to date of a planetary-mass object. VHS 1256 b is $<$20 M$_\mathrm{Jup}$ widely separated ($\sim$8\arcsec, = 150 au), young, companion that shares photometric colors and spectroscopic features with directly imaged exoplanets HR 8799 c, d, e. As an L-to-T transition object, exists along region color-magnitude diagram where substellar atmospheres from cloudy clear. observed 1256~b \textit{JWST}'s NIRSpec IFU MIRI MRS modes for coverage 1 $\mu$m 20 at...
We present JWST Early Release Science (ERS) coronagraphic observations of the super-Jupiter exoplanet, HIP 65426 b, with Near-Infrared Camera (NIRCam) from 2-5 $\mu$m, and Mid-Infrared Instrument (MIRI) 11-16 $\mu$m. At a separation $\sim$0.82" (86$^{+116}_{-31}$ au), b is clearly detected in all seven our observational filters, representing first images an exoplanet to be obtained by JWST, ever direct detection beyond 5 These demonstrate that exceeding its nominal predicted performance up...
The direct characterization of exoplanetary systems with high contrast imaging is among the highest priorities for broader exoplanet community. As large space missions will be necessary detecting and characterizing exo-Earth twins, developing techniques technology exoplanets a driving focus For first time, JWST directly observe extrasolar planets at mid-infrared wavelengths beyond 5$\mu$m, deliver detailed spectroscopy revealing much more precise chemical abundances atmospheric conditions,...
ABSTRACT Retrieval methods are a powerful analysis technique for modelling exoplanetary atmospheres by estimating the bulk physical and chemical properties that combine in forward model to best fit an observed spectrum, they increasingly being applied observations of directly imaged exoplanets. We have adapted taurex3, Bayesian retrieval suite, near-infrared spectrophotometry from gas giant exoplanets brown dwarfs. demonstrate taurex3’s applicability sub-stellar presenting results dwarf...
Abstract The unprecedented medium-resolution ( R λ ∼ 1500–3500) near- and mid-infrared (1–18 μ m) spectrum provided by JWST for the young (140 ± 20 Myr) low-mass (12–20 M Jup ) L–T transition (L7) companion VHS 1256 b gives access to a catalog of molecular absorptions. In this study, we present comprehensive analysis data set utilizing forward-modeling approach applying our Bayesian framework, ForMoSA . We explore five distinct atmospheric models assess their performance in estimating key...
Aims. HD 206893 is a nearby debris disk star that hosts previously identified brown dwarf companion with an orbital separation of ∼10 au. Long-term precise radial velocity (RV) monitoring, as well anomalies in the system proper motion, has suggested presence additional, inner system. Methods. Using information from ongoing precision RV measurements HARPS spectrograph, Gaia host astrometry, we have undertaken multi-epoch search for purported additional planet using VLTI/GRAVITY instrument....
Abstract We present a performance analysis for the aperture masking interferometry (AMI) mode on board James Webb Space Telescope Near Infrared Imager and Slitless Spectrograph (JWST/NIRISS). Thanks to self-calibrating observables, AMI accesses inner working angles down even within classical diffraction limit. The scientific potential of this has recently been demonstrated by Early Release Science (ERS) 1386 program with deep search close-in companions in HIP 65426 exoplanetary system. As...
Abstract We observed the planet-hosting system PDS 70 with James Webb Interferometer, JWST's aperture masking interferometric mode within NIRISS. Observing F480M filter centered at 4.8 μ m, we simultaneously fit geometrical models to outer disk and two known planetary companions. redetect protoplanets b c a signal-to-noise ratio (SNR) of 14.7 7.0, respectively. Our photometry both provides tentative evidence mid-IR circumplanetary emission through fitting spectral energy distribution these...
Abstract We present aperture masking interferometry (AMI) observations of the star HIP 65426 at 3.8 μ m, as part JWST Direct Imaging Early Release Science program, obtained using Near Infrared Imager and Slitless Spectrograph instrument. This mode provides access to very small inner working angles (even separations slightly below Michelson limit 0.5 λ / D for an interferometer), which are inaccessible with classical coronagraphs. When combined JWST’s unprecedented infrared sensitivity, this...
ABSTRACT Satellites around substellar companions are a heterogeneous class of objects with variety different formation histories. Focusing on potentially detectable satellites exoplanets and brown dwarfs (BDs), we might expect to find belonging two main populations: planet-like similar Titan or the Galileian – likely formed within scope core accretion; binary-like objects, scenarios, such as disc instability. The properties these potential would be very from each other. Additionally, that...
We present the highest fidelity spectrum to date of a planetary-mass object. VHS 1256 b is $<$20 M$_\mathrm{Jup}$ widely separated ($\sim$8\arcsec, = 150 au), young, companion that shares photometric colors and spectroscopic features with directly imaged exoplanets HR 8799 c, d, e. As an L-to-T transition object, exists along region color-magnitude diagram where substellar atmospheres from cloudy clear. observed 1256~b \textit{JWST}'s NIRSpec IFU MIRI MRS modes for coverage 1 $μ$m 20 at...
We report the discovery of a circumstellar debris disk viewed nearly edge-on and associated with young, K1 star BD+45$^{\circ}$598 using high-contrast imaging at 2.2$\mu$m obtained W.M.~Keck Observatory. detect in scattered light peak significance $\sim$5$\sigma$ over three epochs, our best-fit model is an almost $\sim$70 AU ring, inclination angle $\sim$87$^\circ$. Using NOEMA interferometer Plateau de Bure Observatory operating 1.3mm, we find resolved continuum emission aligned ring...
We observed the planet-hosting system PDS 70 with James Webb Interferometer, JWST's Aperture Masking Interferometric (AMI) mode within NIRISS. Observing F480M filter centered at 4.8 $\mu$m, we simultaneously fit a geometric model to outer disk and two known planetary companions. re-detect protoplanets b c an SNR of 21 11, respectively. Our photometry both provide evidence for circumplanetary emission through fitting SED models these new measurements those found in literature. also newly...
The JWST Early Release Science Program 1386: "High Contrast Imaging of Exoplanets and Exoplanetary Systems includes a NIRISS aperture masking interferometry (AMI) component to demonstrate achievable contrast in deep observation. As part this program, we have developed SAMpy: data reduction tools tailored for AMI, which are also flexible enough arbitrary setups (e.g. LBT/LMIRCam, Keck/NIRC2, VLT/SPHERE). SAMpy takes Fourier-plane approach processing AMI data, describe here. We detail the...
JWST promises to be the most versatile infrared observatory for next two decades. The Near Infrared and Slitless Spectrograph (NIRISS) instrument, when used in Aperture Masking Interferometry (AMI) mode, will provide an unparalleled combination of angular resolution sensitivity compared any existing at mid-infrared wavelengths. Using simulated observations conjunction with evolutionary models, we present capability this mode image planetary mass companions around nearby stars small orbital...
The direct characterization of exoplanetary systems with high contrast imaging is among the highest priorities for broader exoplanet community. As large space missions will be necessary detecting and characterizing exo-Earth twins, developing techniques technology exoplanets a driving focus For first time, JWST directly observe extrasolar planets at mid-infrared wavelengths beyond 5$μ$m, deliver detailed spectroscopy revealing much more precise chemical abundances atmospheric conditions,...
We present JWST Early Release Science (ERS) coronagraphic observations of the super-Jupiter exoplanet, HIP 65426 b, with Near-Infrared Camera (NIRCam) from 2-5 $μ$m, and Mid-Infrared Instrument (MIRI) 11-16 $μ$m. At a separation $\sim$0.82" (86$^{+116}_{-31}$ au), b is clearly detected in all seven our observational filters, representing first images an exoplanet to be obtained by JWST, ever direct detection beyond 5 These demonstrate that exceeding its nominal predicted performance up...
The James Webb Space Telescope Aperture Masking Interferometer provides NIRISS with its highest angular resolution imaging mode, an ultra-stable non-redundant masking Fizeau interferometer. Until recently, the precision of interferometric visibilities has been limited to ~ 1% by systematic uncertainties in optical state and detector noise properties. Using a data-driven calibration AMI differentiable forwards model, this can be improved more than order magnitude, uniquely enabling high...
Long term precise radial velocity (RV) monitoring of the nearby star HD206893, as well anomalies in system proper motion, have suggested presence an additional, inner companion system. Here we describe results a multi-epoch search for responsible this RV drift and motion anomaly using VLTI/GRAVITY instrument. Utilizing information from ongoing precision measurements with HARPS spectrograph, Gaia host astrometry, report high significance detection HD206893c over three epochs, clear evidence...
The direct characterization of exoplanetary systems with high contrast imaging is among the highest priorities for broader exoplanet community. As large space missions will be necessary detecting and characterizing exo-Earth twins, developing techniques technology exoplanets a driving focus For first time, JWST directly observe extrasolar planets at mid-infrared wavelengths beyond 5 μm, deliver detailed spectroscopy revealing much more precise chemical abundances atmospheric conditions,...
We present a set of recommended best practices for JWST data collection members the community focussed on direct imaging and spectroscopy exoplanetary systems. These findings recommendations are based early analysis Early Release Science Program 1386, "High-Contrast Imaging Exoplanets Exoplanetary Systems with JWST." Our goal is this information to be useful observers in preparation proposals Cycle 2 beyond. In addition compiling from our ERS program, few cases we also draw expertise gained...
Retrieval methods are a powerful analysis technique for modelling exoplanetary atmospheres by estimating the bulk physical and chemical properties that combine in forward model to best-fit an observed spectrum, they increasingly being applied observations of directly-imaged exoplanets. We have adapted TauREx3, Bayesian retrieval suite, near-infrared spectrophotometry from gas giant exoplanets brown dwarfs. demonstrate TauREx3's applicability sub-stellar presenting results dwarf benchmark GJ...
We present a performance analysis for the aperture masking interferometry (AMI) mode on board James Webb Space Telescope Near Infrared Imager and Slitless Spectrograph (JWST/NIRISS). Thanks to self-calibrating observables, AMI accesses inner working angles down even within classical diffraction limit. The scientific potential of this has recently been demonstrated by Early Release Science (ERS) 1386 program with deep search close-in companions in HIP 65426 exoplanetary system. As part ERS...
We present aperture masking interferometry (AMI) observations of the star HIP 65426 at $3.8\,\rm{\mu m}$ as a part \textit{JWST} Direct Imaging Early Release Science (ERS) program obtained using Near Infrared Imager and Slitless Spectrograph (NIRISS) instrument. This mode provides access to very small inner working angles (even separations slightly below Michelson limit ${}0.5\lambda/D$ for an interferometer), which are inaccessible with classical coronagraphs. When combined \textit{JWST}'s...
The unprecedented medium-resolution (R~1500-3500) near- and mid-infrared (1-18um) spectrum provided by JWST for the young (140+/-20Myr) low-mass (12-20MJup) L-T transition (L7) companion VHS1256b gives access to a catalogue of molecular absorptions. In this study, we present comprehensive analysis dataset utilizing forward modelling approach, applying our Bayesian framework, ForMoSA. We explore five distinct atmospheric models assess their performance in estimating key parameters: Teff,...