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Distribution of cold gas in the post-reionization era provides an important link between distribution of galaxies and the process of star formation. Redshifted 21 cm radiation from the Hyperfine transition of neutral Hydrogen allows us to…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-22 Bharat Kumar Gehlot , Jasjeet Singh Bagla

Phase noise caused by an inhomogeneous, time-variable water vapor distribution in our atmosphere reduces the angular resolution, visibility amplitude and coherence time of millimeter and submillimeter wavelength interferometers. We present…

Astrophysics · Physics 2009-11-10 James B. Battat , Raymond Blundell , James M. Moran , Scott Paine

A novel, to the best of our knowledge, ultralow-temperature luminescence thermometry strategy is proposed, based on a measurement of relative intensities of hyperfine components in the spectra of Ho$^{3+}$ ions doped into a crystal. A…

Optics · Physics 2025-11-25 Marina N. Popova , Mosab Diab , Boris Z. Malkin

We explore the possibilities of measuring the longitudinal profile of individual air showers beyond $X_{\rm max}$ when using very dense radio arrays such as SKA. The low-frequency part of the Square Kilometre Array, to be built in…

We present new high-resolution (R=40000) spectroscopic observations of 18 bright northern Cepheids carried out at David Dunlap Observatory, in 1997. The measurements mainly extend those of presented in Paper I adding three more stars (AW…

Astrophysics · Physics 2009-10-31 L. L. Kiss , J. Vinko

We explore the feasibility of HI galaxy redshift surveys with the Five-hundred-meter Aperture Spherical Telescope (FAST) and its proposed Core Array interferometry. Using semi-analytical simulations, we compare the performance of the FAST…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-25 Zhenglong Li , Diyang Liu , Chengliang Xu , Yichao Li , Xin Zhang

Spectroscopy of Earth-like exoplanets and ultra-faint galaxies are priority science cases for the coming decades. Here, broadband source flux rates are measured in photons per square meter per hour, imposing extreme demands on detector…

We present results from cryogenic tests of a Volume-Phase Holographic (VPH) grating at 200 K measured at near-infrared wavelengths. The aims of these tests were to see whether the diffraction efficiency and angular dispersion of a VPH…

Objective: This paper introduces a novel PET imaging methodology called 3-dimensional positron imaging (3D{\pi}), which integrates total-body (TB) coverage, time-of-flight (TOF) technology, ultra-low dose imaging capabilities, and…

We have developed, built, and tested a new feed design for interferometric radio telescopes with "large-$N$, small-$D$" designs. Those arrays require low-cost and low-complexity feeds for mass production on reasonable timescales and…

Instrumentation and Methods for Astrophysics · Physics 2025-09-17 Vincent MacKay , Mark Lai , Peter Shmerko , Dallas Wulf , Leonid Belostotski , Keith Vanderlinde

Spectrometers based on high-finesse optical cavities have proven to be powerful tools for applied and fundamental studies. Extending this technology to the deep cryogenic regime is beneficial in many ways: Doppler broadening is reduced,…

Synthesized beam (PSF) synthetic observations with and without the antennas in Mexico are analyzed. For a simple continuum observing setup, we generated visibility files and their associated PSF images for a grid of parameters (robust…

We gathered more than 1130 high-resolution optical spectra for more than 250 Galactic classical Cepheids. The spectra were collected with different optical spectrographs: UVES at VLT, HARPS at 3.6m, FEROS at 2.2m MPG/ESO, and STELLA. To…

We have performed an extensive Voigt profile analysis of the neutral hydrogen (HI) and metal absorption present in a sample of 18 high resolution, high signal-to-noise QSO spectra observed with VLT/UVES. We use this analysis to separate the…

Astrophysics · Physics 2009-11-13 T. -S. Kim , J. S. Bolton , M. Viel , M. G. Haehnelt , R. F. Carswell

Context. In this paper we present the first system test in which we demonstrate the concept of using an array of Distributed Read Out Imaging Devices (DROIDs) for optical photon detection. Aims. After the successful S-Cam 3 detector the…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 R. A. Hijmering , P. Verhoeve , D. D. E. Martin , R. Venn , A. van Dordrecht , P. J. Groot

The optimal source-finding strategy for linear polarization data is an unsolved problem, with many inhibitive factors imposed by the technically-challenging nature of polarization observations. Such an algorithm is essential for Square…

Instrumentation and Methods for Astrophysics · Physics 2017-12-27 J. S. Farnes , G. Heald , H. Junklewitz , D. D. Mulcahy , M. Haverkorn , C. L. Van Eck , C. J. Riseley , M. Brentjens , C. Horellou , V. Vacca , D. I. Jones , A. Horneffer , R. Paladino

With the purpose of assessing classic spectroscopic methods on high-resolution and high signal-to-noise ratio spectra in the near-infrared wavelength region, we selected a sample of 65 F-, G-, and K-type stars observed with CARMENES, the…

The Five-Hundred-Meter Aperture Spherical Radio Telescope(FAST) is the largest single-dish radio telescope in the world. In this paper, we make forecast on the FAST HI large scale structure survey by mock observations. We consider a drift…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-30 Wenkai Hu , Xin Wang , Fengquan Wu , Yougang Wang , Pengjie Zhang , Xuelei Chen

Transient imaging or light-in-flight techniques capture the propagation of an ultra-short pulse of light through a scene, which in effect captures the optical impulse response of the scene. Recently, it has been shown that we can capture…

Computer Vision and Pattern Recognition · Computer Science 2015-12-22 Ryuichi Tadano , Adithya Kumar Pediredla , Kaushik Mitra , Ashok Veeraraghavan

The design of low-profile linear microstrip arrays with wide-band spatial filtering capabilities is dealt with. An innovative architecture, leveraging the angular selectivity of offset stacked patch (OSP) radiators, is proposed to implement…

Signal Processing · Electrical Eng. & Systems 2024-06-26 Arianna Benoni , Marco Salucci , Andrea Massa
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