Related papers: Stellar Multiplicity via Speckle Interferometry wi…
In this work we present an observational technique and a detailed analysis of the stellar interferograms produced by three bright stars: Betelgeuse, Rigel and Sirius. It is shown that the atmospheric turbulence is responsible for the…
Spectral imaging is a fundamental diagnostic technique with widespread application. Conventional spectral imaging approaches have intrinsic limitations on spatial and spectral resolutions due to the physical components they rely on. To…
A low dispersion spectrograph-cum-imager has been developed and assembled in ARIES, Nainital. The optical design of the spectrograph consists of a collimator and a focal reducer converting the f/9 beam from the 3.6-m Devasthal optical…
Astronomers have been measuring the separations and position angles between the two components of binary stars since William Herschel began his observations in 1781. In 1970, Anton Labeyrie pioneered a method, speckle interferometry, that…
We present results from Speckle inteferometric observations of fifteen visual binaries and one double-line spectroscopic binary, carried out with the HRCam Speckle camera of the SOAR 4.1 m telescope. These systems were observed as a part of…
Here I review the current state of the field of optical stellar interferometry, concentrating on ground-based work although a brief report of space interferometry missions is included. We pause both to reflect on decades of immense progress…
In this paper, we review the various ways in which an infrared stellar interferometer can be used to perform direct detection of extrasolar planetary systems. We first review the techniques based on classical stellar interferometry, where…
While optical and quantum efficiency are on the rise, and spectrographs becoming massively multiplexed, measuring spectral energy distributions of astronomical sources with accuracy remains a challenge. In addition to atmospheric…
Results of speckle interferometry observations at the 4.1 m SOuthern Astrophysical Research (SOAR) telescope obtained during 2024-2025 are presented. We present 5316 measurements of relative positions and magnitude differences in 3532 pairs…
The resolution limits of classical spectroscopy can be surpassed by quantum-inspired methods leveraging the information contained in the phase of the complex electromagnetic field. Their counterpart in spatial imaging has been widely…
Improved quantum sensing of photons from astronomical objects could provide high resolution observations in the optical benefiting numerous fields, including general relativity, dark matter studies, and cosmology. It has been recently…
Results of the speckle-interferometry observations at the 4.1 m Southern Astrophysical Research Telescope (SOAR) obtained during 2023 are presented: 1913 measurements of 1533 resolved pairs or subsystems (median separation 0.16") and…
Transmission spectroscopy is currently the technique best suited to study a wide range of planetary atmospheres, leveraging the filtering of a star's light by a planet's atmosphere rather than its own emission. However, as both a planet and…
Resolving fine details of astronomical objects provides critical insights into their underlying physical processes. This drives in part the desire to construct ever-larger telescopes and interferometer arrays and to observe at shorter…
Bright single and binary stars were observed at the 4.1-m telescope with a fast electron-multiplication camera in the regime of partial turbulence correction by the visible-light adaptive optics system. We compare the angular resolution…
Stars are not smooth. Their photosphere is covered by a granulation pattern associated with the heat transport by convection. The convection-related surface structures have different size, depth, and temporal variations with respect to the…
Long baseline optical interferometry and aperture synthesis using ground-based telescopes can enable unprecedented angular resolution astronomy in the optical domain. However, atmospheric turbulence leads to large, dynamic phase errors…
Speckle polarimeter (SPP) is a facility instrument of the 2.5-m telescope of the Caucasian Mountain Observatory of SAI MSU. By design it is a combination of a speckle interferometer and a dual--beam polarimeter. In 2022 we performed a major…
Astrometry is a powerful technique in astrophysics to measure three-dimensional positions of stars and other astrophysical objects, including exoplanets and the gravitational influence they have on each other. Interferometric astrometry is…
The signal measured by an astronomical spectrometer may be due to radiation from a multi-component mixture of plasmas with a range of physical properties (e.g. temperature, Doppler velocity). Confusion between multiple components may be…