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The process of data taking, reduction and calibration of near-infrared imaging polarimetry data taken with the ESO Adaptive Optics System ADONIS is described. The ADONIS polarimetric facility is provided by a rotating wire grid polarizer.…

Astrophysics · Physics 2009-10-31 N. Ageorges , J. R. Walsh

The X/$\gamma$ ray polarimetry of the Crab pulsar/nebula is believed to hold crucial information on their emission models. In the past, several missions have shown evidence of polarized emission from the Crab. The significance of these…

A pulsar timing system has been operating in the 18-cm band at the Urumqi Astronomical Observatory 25-m telescope since mid-1999. Frequency resolution allowing dedispersion of the pulsar signals is provided by a 2X128X2.5 MHz…

Astrophysics · Physics 2009-11-07 N. Wang , R. N. Manchester , J. Zhang , X. J. Wu , A. Yusup , A. G. Lyne , K. S. Cheng , M. Z. Chen

We present timing observations of four millisecond pulsars, using data obtained over three years at the ATNF Parkes and NRAL Jodrell Bank radio telescopes. Astrometric, spin, and binary parameters are updated, and substantially improved for…

Astrophysics · Physics 2015-06-24 J. F. Bell , M. Bailes , R. N. Manchester , A. G. Lyne , F. Camilo , J. S. Sandhu

Three pulsar timing arrays are now producing high quality data sets. As reviewed in this paper, these data sets are been processed to 1) develop a pulsar-based time standard, 2) search for errors in the solar system planetary ephemeris and…

Solar and Stellar Astrophysics · Physics 2015-06-11 G. Hobbs

PolarBase is an evolving data base that contains all stellar data collected with the ESPaDOnS and NARVAL high-resolution spectropolarimeters, in their reduced form, as soon as they become public. As of early 2014, observations of 2,000…

Solar and Stellar Astrophysics · Physics 2016-03-09 P. Petit , T. Louge , S. Théado , F. Paletou , N. Manset , J. Morin , S. C. Marsden , S. V. Jeffers

In a sequential regression setting, a decision-maker may be primarily concerned with whether the future observation will increase or decrease compared to the current one, rather than the actual value of the future observation. In this…

Machine Learning · Computer Science 2023-06-09 Youngseog Chung , Aaron Rumack , Chirag Gupta

The calibration and analysis of polarization observations in Very Long Baseline Interferometry (VLBI) requires the use of specific algorithms that suffer from several limitations, closely related to assumptions in the data properties that…

Instrumentation and Methods for Astrophysics · Physics 2021-02-10 Ivan Marti-Vidal , Alejandro Mus , Michael Janssen , Pablo de Vicente , Javier Gonzalez

This paper considers the problem of accurate measurement of circular polarization in imaging spectral-line VLBI observations in the lambda=7 mm and lambda=3 mm wavelength bands. This capability is especially valuable for the full…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 A. J. Kemball , L. Richter

Current mm/submm interferometers, like the Atacama Large mm/submm Array (ALMA), use receivers that register the sky signal in a linear polarization basis. In the case of observations performed in full-polarization mode (where the…

Instrumentation and Methods for Astrophysics · Physics 2016-09-21 I. Marti-Vidal , W. H. T. Vlemmings , S. Muller

It has long been recognised that quasi-periodic oscillations (QPOs) in the X-ray light curves of accreting black hole and neutron star binaries have the potential to be powerful diagnostics of strong field gravity. However, this potential…

High Energy Astrophysical Phenomena · Physics 2015-05-04 Adam Ingram , Thomas Maccarone , Juri Poutanen , Henric Krawczynski

In this paper we present an error analysis for polarimetric data obtained with dual-beam instruments. After recalling the basic concepts, we introduce the analytical expressions for the uncertainties of polarization degree and angle. These…

Astrophysics · Physics 2009-11-11 Ferdinando Patat , Martino Romaniello

We use optical photometric and polarimetric data of BL Lacertae that cover a period of 22 years to study the variability of the source. The long-term observations are employed for establishing parameters of a stochastic model consisting of…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-17 D. A. Blinov , V. A. Hagen-Thorn

We present results of numerical simulations of flux and linear polarization variations in transiting exoplanetary systems, caused by the host star disk symmetry breaking. We consider different configurations of planetary transits depending…

Solar and Stellar Astrophysics · Physics 2015-06-17 N. M. Kostogryz , T. M. Yakobchuk , S. V. Berdyugina

Stabilization of a coupled system consisting of a parabolic partial differential equation and an elliptic partial differential equation is considered. Even in the situation when the parabolic equation is exponentially stable on its own, the…

Optimization and Control · Mathematics 2023-09-04 Ala' Alalabi , Kirsten Morris

The BICEP3 CMB Polarimeter is a small-aperture refracting telescope located at the South Pole and is specifically designed to search for the possible signature of inflationary gravitational waves in the Cosmic Microwave Background (CMB).…

The RoboPol instrument and the relevant program was developed in order to conduct a systematic study of the optical polarisation variability of blazars. Driven by the discovery that long smooth rotations of the optical polarisation plane…

Heterodyne receivers register the sky signal on either a circular polarization basis (where it is split into left-hand and right-hand circular polarization) or a linear polarization basis (where it is split into horizontal and vertical…

Instrumentation and Methods for Astrophysics · Physics 2016-03-09 Ivan Marti-Vidal , Alan Roy , John Conway , Anton J. Zensus

We point out some advantages of making observations of extrasolar planets in linearly polarized (LP) light. Older cool stars have quite low levels (~ 10^-4 to 10^-5) of fractional LP, while extrasolar planets can have relatively high…

Astrophysics · Physics 2007-05-23 S. Saar , S. Seager

There is a growing interest in characterizing circular data found in biological systems. Such data are wide ranging and varied, from signal phase in neural recordings to nucleotide sequences in round genomes. Traditional clustering…

Machine Learning · Computer Science 2023-09-19 Xiaoxiao Sun , Paul Sajda