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Related papers: Solving the polarization problem in ALMA-VLBI obse…

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The work describes a system for converting VLBI observation data using the algorithms of coherent dedispersion and compensation of two-bit signal sampling. Coherent dedispersion is important for processing pulsar observations to obtain the…

Instrumentation and Methods for Astrophysics · Physics 2023-03-31 Girin I. A. , Likhachev S. F. , Andrianov A. S. , Burgin M. S. , Popov M. V. , Rudnitskiy A. G. , Soglasnov V. A. , Zuga V. A

Here we will discuss which calibrations are needed, how to perform them and how the calibration affect ALMA observations. This first part concentrates on aspects related to a single antenna, namely antenna pointing (including the antenna…

Instrumentation and Methods for Astrophysics · Physics 2012-10-09 T. van Kempen , S. Corder , R. Lucas , R. Mauersberger

The polarization of photons emitted by astrophysical sources might be altered as they travel through a dark matter medium composed of ultra light axion-like particles (ALPs). In particular, the coherent oscillations of the ALP background in…

High precision astrometric Space Very Long Baseline Interferometry (S-VLBI) at the low end of the conventional frequency range, i.e. 20cm, is a requirement for a number of high priority science goals. These are headlined by obtaining…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 R. Dodson , M. Rioja , Y. Asaki , H. Imai , X. -Y. Hong , Z. Shen

High-frequency long-baseline experiments with the Atacama Large Millimeter/submillimeter Array were organized to test the high angular resolution imaging capabilities in the submillimeter wave regime using baselines up to 16 km. Four…

Up to now, the completion of an ALMA interferometric observation is determined based on the achievement of a given shape and size of the synthesized beam and the noise RMS in the representative spectral range. This approach with respect to…

Instrumentation and Methods for Astrophysics · Physics 2020-12-17 Dirk Petry , María Díaz Trigo , Rüdiger Kneissl , Ignacio Toledo , Stefano Facchini

The Atacama B-mode Search (ABS) is an experiment designed to measure cosmic microwave background (CMB) polarization at large angular scales ($\ell>40$). It operated from the ACT site at 5190~m elevation in northern Chile at 145 GHz with a…

Characterizing the variability of the extragalactic sources used for calibration in the Atacama Large Millimeter/Sub-millimeter Array (ALMA) is key to assess the flux scale uncertainty of science observations. To this end, we model the…

Instrumentation and Methods for Astrophysics · Physics 2019-08-12 A. E. Guzmán , C. Verdugo , H. Nagai , Y. Contreras , G. Marinello , R. Kneissl , K. Nakanishi , J. Ueda

We present high angular resolution dust polarization and molecular line observations carried out with the Atacama Large Millimeter/submillimeter Array (ALMA) toward the Class 0 protostar Serpens SMM1. By complementing these observations…

By direct measurements of the gas temperature, the Atacama Large Millimeter/sub-millimeter Array (ALMA) has yielded a new diagnostic tool to study the solar chromosphere. Here we present an overview of the brightness-temperature…

The Cosmology Large Angular Scale Surveyor (CLASS) is an array of polarization-sensitive millimeter wave telescopes that observes ~70% of the sky at frequency bands centered near 40GHz, 90GHz, 150GHz, and 220GHz from the Atacama desert of…

Very long baseline interferometry (VLBI) provides the resolution needed to make precision measurements of a pulsar's parallax and proper motion. In making these measurements, the astronomer is faced with difficult calibration problems and a…

Astrophysics · Physics 2007-05-23 Walter Brisken

Modern interferometric imaging relies on advanced calibration that incorporates direction-dependent effects. Their increasing number of antennas (e.g. in LOFAR, VLA, MeerKAT/SKA) and sensitivity are often tempered with the accuracy of their…

Instrumentation and Methods for Astrophysics · Physics 2019-03-20 K. Iheanetu , J. N. Girard , O. Smirnov , K. M. B. Asad , M. de Villiers , K. Thorat , S. Makhathini , R. A. Perley

In this paper we present the European Low Frequency Survey (ELFS), a project that will enable foregrounds-free measurements of primordial $B$-mode polarization to a level 10$^{-3}$ by measuring the Galactic and extra-Galactic emissions in…

This paper introduces a method for aligning solar observations from different telescopes. We utilized helioprojective coordinates from the Solar Dynamics Observatory (SDO) as a reference to align images from ALMA and IRIS. The alignment is…

Solar and Stellar Astrophysics · Physics 2024-04-09 Francisco J. Ordoñez Araujo , Juan Camilo Guevara Gómez , Benjamín Calvo Mozo

We describe the POLAMI program for the monitoring of all four Stokes parameters of a sample of bright radio-loud active galactic nuclei with the IRAM 30m telescope at 3.5 and 1.3mm. The program started in October 2006 and accumulated, until…

We discuss the present performance and the future perspectives of VLBI in the 3 mm to 0.85 mm observing bands (so called mm-VLBI). The availability of new telescopes and the recent technical development towards larger observing bandwidth…

Astrophysics · Physics 2008-12-23 T. P. Krichbaum , U. Bach , D. A. Graham , W. Alef , A. Roy , A. Witzel , J. A. Zensus , M. Bremer , S. Sanchez

We present an estimate of the Atacama Cosmology Telescope (ACT) detector polarization angle systematic uncertainty from optics perturbation analysis using polarization-sensitive ray tracing in CODE V optical design software. Uncertainties…

Once completed, the Atacama Large Millimeter Array (ALMA) will be the most powerful (sub)millimeter interferometer in terms of sensitivity, spatial resolution and imaging. This paper presents the capabilities of ALMA applied to the…

Earth and Planetary Astrophysics · Physics 2015-05-27 A. Moullet , E. Lellouch , R. Moreno , M. Gurwell