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Classically, optical and near-infrared interferometry have relied on closure phase techniques to produce images. Such techniques allow us to achieve modest dynamic ranges. In order to test the feasibility of next generation optical…

In this document we layout a new method to achieve "bona fide" high precision Very-Long-Baseline-Interferometry (VLBI) astrometric measurements of frequency-dependent positions of celestial sources (even) in the high (mm-wavelength)…

Instrumentation and Methods for Astrophysics · Physics 2009-10-08 Richard Dodson , Maria J. Rioja

VLBI is unique, among the space geodetic techniques, in its contribution to defining and maintaining the International Celestial Reference Frame, providing precise measurements of coordinates of extragalactic radiosources. The quest for…

Sub-micrometer scale light patterns play a pivotal role in various fields, including biology, biophysics, and AMO physics. High-resolution, in situ observation of light profiles is essential for their design and application. However,…

The Atacama Large Millimeter/submillimeter Array (ALMA), an international partnership of Europe, North America and East Asia in cooperation with the Republic of Chile, is the largest astronomical project in existence. While ALMA's…

Instrumentation and Methods for Astrophysics · Physics 2015-04-29 Felix Stoehr , Mark Lacy , Stéphane Leon , Erik Muller , Alisdair Manning , Christophe Moins , Dustin Jenkins

This paper presents a polarization-aware movable antenna (PAMA) framework that integrates polarization effects into the design and optimization of movable antennas (MAs). While MAs have proven effective at boosting wireless communication…

Information Theory · Computer Science 2025-07-25 Runxin Zhang , Yulin Shao , Yonina C. Eldar

A new method for absolute polarimetric calibration of large telescopes is presented. The proposed method is highly accurate and is based on the calibration of a small sub-aperture, which is then extended to the full system by means of…

Astrophysics · Physics 2009-11-10 H. Socas-Navarro

We present new Atacama Large Millimeter/submillimeter Array (ALMA) continuum observations at 336GHz of two transition disks, SR21 and HD135344B. In combination with previous ALMA observations from Cycle 0 at 689GHz, we compare the…

Earth and Planetary Astrophysics · Physics 2015-11-18 P. Pinilla , N. van der Marel , L. M. Pérez , E. F. van Dishoeck , S. Andrews , T. Birnstiel , G. Herczeg , K. M. Pontoppidan , T. van Kempen

We have a project to measure magnetic fields in the obscuring tori of AGNs. We observed five free-free absorbed jets in radio galaxies with polarimetric VLBI at 15 GHz to determine Faraday rotation measures. Surprisingly, all sources are…

Astrophysics · Physics 2007-05-23 E. Middelberg

Interferometric observation of the CMB polarization can be expressed as a linear sum of spherical harmonic coefficients $a_{\pm 2,lm}$ of the CMB polarization. The linear weight for $a_{\pm 2,lm}$ depends on the observational configuration…

Astrophysics · Physics 2009-04-06 Jaiseung Kim

We present a Deep-Learning (DL) pipeline developed for the detection and characterization of astronomical sources within simulated Atacama Large Millimeter/submillimeter Array (ALMA) data cubes. The pipeline is composed of six DL models: a…

Instrumentation and Methods for Astrophysics · Physics 2022-11-22 Michele Delli Veneri , Lukasz Tychoniec , Fabrizia Guglielmetti , Giuseppe Longo , Eric Villard

The ALMACAL survey is based on a database of reprocessed ALMA calibration scans suitable for scientific analysis, observed as part of regular PI observations. We present all the data accumulated from the start of ALMA operations until May…

This paper proposes a bidirectional multibeam hybrid transmitarray (HTA) employing a transmission polarization-rotating metasurface (TPRM). A novel configuration is introduced to facilitate bidirectional beam scanning by combining the…

Systems and Control · Electrical Eng. & Systems 2024-08-05 Fan Qin , Yifei Liu , Chao Gu , Linfeng Zeng , Wenchi Cheng , Hailin Zhang , Steven Gao

Astrometric accuracy of complex modern VLBI arrays cannot be calculated analytically. We study the astrometric accuracy of phase-referenced VLBI observations for the VLBA, EVN and global VLBI array by simulating VLBI data for targets at…

Astrophysics · Physics 2009-11-11 N. Pradel , P. Charlot , J. -F. Lestrade

We describe the processing of the PHANGS-ALMA survey and present the PHANGS-ALMA pipeline, a public software package that processes calibrated interferometric and total power data into science-ready data products. PHANGS-ALMA is a large,…

In this paper we describe a new approach for mm-VLBI calibration that provides bona-fide astrometric alignment of the mm-wavelength images from a single source, for the measurement of frequency dependent effects, such as `core-shifts' near…

Instrumentation and Methods for Astrophysics · Physics 2017-01-18 Richard Dodson , María Rioja , Sol Molina , José-Luis Gómez

We test the accuracy of ALMA flux density calibration by comparing ALMA flux density measurements of extragalactic sources to measurements made by the Planck mission; Planck is absolutely calibrated to sub-percent precision using the dipole…

Instrumentation and Methods for Astrophysics · Physics 2022-01-27 Gerrit S. Farren , Bruce Partridge , Rüdiger Kneissl , Simone Aiola , Rahul Datta , Megan Gralla , Yaqiong Li

Polarization-mode observations from the Atacama Large Millimeter/submillimeter Array (ALMA) are powerful tools for studying the dust grain populations in circumstellar disks. Many sources exhibit polarization signatures consistent with…

A circularly polarized leaky-wave antenna capable of frequency scanning is proposed in this paper. The main objective is to achieve high gain and polarization purity without the need for a complex feed network. The antenna consists of two…

Applied Physics · Physics 2020-07-21 Ali Mohammad Hakimi , Ali Keivaan , Homayoon Oraizi , Amrollah Amini

$\gamma$ rays are emitted by cosmic sources by non-thermal processes that yield either non-polarized photons, such as those from $\pi^0$ decay in hadronic interactions, or linearly polarized photons from synchrotron radiation and the…

Instrumentation and Methods for Astrophysics · Physics 2017-11-02 Denis Bernard
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