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The tilted-wave interferometer is a promising technique for the development of a reference measurement system for the highly accurate form measurement of aspheres and freeform surfaces. The technique combines interferometric measurements,…

We use the measurement of the cosmic microwave background taken during the MAXIMA-1 flight to estimate the bispectrum of cosmological perturbations. We propose an estimator for the bispectrum that is appropriate in the flat sky…

BIFROST will be a short-wavelength ($\lambda$ = 1.0 - 1.7$\mu$m) beam combiner for the VLT Interferometer, combining both high spatial ($\lambda$/2B = 0.8 mas) and spectral (up to R = 25,000) resolution. It will be part of the Asgard Suite…

Instrumentation and Methods for Astrophysics · Physics 2022-08-11 Daniel J. Mortimer , Sorabh Chhabra , Stefan Kraus , Narsireddy Anugu , Romain Laugier , Jean-Baptiste Le Bouquin , John D. Monnier

The Bluebild algorithm is a new technique for image synthesis in radio astronomy which decomposes the sky into distinct energy levels using functional principal component analysis. These levels can be linearly combined to construct a…

Instrumentation and Methods for Astrophysics · Physics 2025-01-30 Emma Tolley , Simon Frasch , Etienne Orliac , Shreyam Krishna , Michele Bianco , Sepand Kashani , Paul Hurley , Matthieu Simeoni , Jean-Paul Kneib

Radio interferometers observe the Fourier space of the sky, at locations determined by the array geometry. Before a real space image is constructed by a Fourier transform, the data is weighted to improve the quality of reconstruction. Two…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Sarod Yatawatta

We have designed and constructed a ``dispersed Fourier Transform Spectrometer'' (dFTS), consisting of a conventional FTS followed by a grating spectrometer. By combining these two devices, we negate a substantial fraction of the sensitivity…

We devise a fast and optimal estimator for the amplitude of the bispectrum of clustered Infrared (IR) point-sources. We show how this estimator can account for the cases of partial sky coverage and inhomogeneous noise. Expected detection…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-24 F. Lacasa , N. Aghanim

A phase shift and sum (PSAS) algorithm to image objects in dispersive media is presented. The algorithm compensates the phase shift of the scattered field from the receiver to the source for each frequency component in an ultrawideband…

Signal Processing · Electrical Eng. & Systems 2019-08-28 Wenyi Shao

Intensity mapping of 21cm emission from neutral hydrogen promises to be a powerful probe of large-scale structure in the post-reionisation epoch. However, HI intensity mapping (IM) experiments will suffer the loss of long-wavelength…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-30 Kavilan Moodley , Warren Naidoo , Heather Prince , Aurelie Penin

In paper I of this series (Yang et al. 2017, ApJ), we proposed an analytical method of blind separation ({\bf ABS}) to extract the cosmic magnification signal in galaxy number distribution and reconstruct the weak lensing power spectrum.…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-14 Pengjie Zhang , Xinjuan Yang , Jun Zhang , Yu Yu

The Laser Interferometer Space Antenna (LISA) will be capable of detecting gravitational waves (GWs) in the milli-Hertz band. Among various sources, LISA will detect the coalescence of supermassive black hole binaries (SMBHBs). Accurate and…

General Relativity and Quantum Cosmology · Physics 2025-02-25 Abhishek Sharma , Anand S. Sengupta , Suvodip Mukherjee

We report a broadband long-wave infrared Fourier transform spectrometer with sensitivity exceeding that of previously reported direct-detection implementations. The system combines dual-comb spectroscopy with electro-optic sampling,…

We study the position-dependent power spectrum and the integrated bispectrum statistic for 2D cosmological fields on the sphere (integrated angular bispectrum). First, we derive a useful, $m$-independent, formula for the full-sky integrated…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-19 Gabriel Jung , Filippo Oppizzi , Andrea Ravenni , Michele Liguori

Radio interferometry invariably suffers from an incomplete coverage of the spatial Fourier space, which leads to imaging artifacts. The current state-of-the-art technique is to create an image by Fourier-transforming the incomplete…

Instrumentation and Methods for Astrophysics · Physics 2024-12-19 F. Geyer , K. Schmidt , J. Kummer , M. Brüggen , H. W. Edler , D. Elsässer , F. Griese , A. Poggenpohl , L. Rustige , W. Rhode

Due to its simultaneous deep imaging and integral field spectroscopic capability, an Imaging Fourier Transform Spectrograph (IFTS) is ideally suited to the Next Generation Space Telescope (NGST) mission, and offers opportunities for…

Astrophysics · Physics 2007-05-23 James R. Graham

Speckle Imaging based on triple correlation is a very efficient image reconstruction technique which is used to retrieve Fourier phase information of the object in presence of atmospheric turbulence. We have developed both Direct Bispectrum…

Instrumentation and Methods for Astrophysics · Physics 2014-09-17 Arun Surya , Swapan K. Saha

In this paper, we study efficient channel estimation design for an extremely large-scale intelligent reflecting surface (XL-IRS) assisted multi-user communication systems, where both the base station (BS) and users are located in the…

Signal Processing · Electrical Eng. & Systems 2024-09-02 Chao Zhou , Changsheng You , Shiqi Gong , Bin Lyu , Beixiong Zheng , Yi Gong

Dual-comb spectroscopy is a promising method for precise optical spectrum analysis with fast data acquisition speed. However, its implementation and applications are often hindered by the complexity of optical comb systems. Here, as a…

Optics · Physics 2020-11-11 Zhen Zhang , Haiyun Xia , Saifen Yu , Lijie Zhao , Tianwen Wei , Manyi Li

Radio Frequency Interference (RFI) increasingly contaminates the radio astronomy spectrum, often exceeding astronomical signal amplitudes by 50-70 dB. Reliable detection and mitigation are therefore essential for studies of faint transient…

Instrumentation and Methods for Astrophysics · Physics 2026-05-08 Natalia A. Schmid , Sasanka Katreddi , Yechan Kweon

We propose an estimator defined in real space for the reconstruction of the weak lensing potential due to the intervening large scale structure from high resolution maps of the cosmic microwave background. This estimator was motivated as an…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-21 C. S. Carvalho , K. Moodley