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POLAR is a novel compact Compton X-ray polarimeter designed to measure the linear polarization of the prompt emission of Gamma Ray Bursts (GRB) and other strong transient sources such as soft gamma repeaters and solar flares in the energy…

Instrumentation and Methods for Astrophysics · Physics 2019-08-21 Silvio Orsi

We present the results of the new optical polarimetric observations of the superluminal source GRO J1655--40, carried out in July 1997, with the multichannel photopolarimeter of the Torino Observatory, using the 2.15-m telescope of Complejo…

Astrophysics · Physics 2007-05-23 M. Gliozzi , G. Bodo , G. Ghisellini , F. Scaltriti , E. Trussoni

Since 2007, close binary and multiple stars are observed by speckle interferometry at the 4.1 m Southern Astrophysical Research (SOAR) telescope. The HRCam instrument, observing strategy and planning, data processing and calibration…

Instrumentation and Methods for Astrophysics · Physics 2018-02-21 Andrei Tokovinin

Sunspot observations and counting are carried out at the Specola Solare Ticinese in Locarno since 1957 when it was built as an external observing station of the Zurich observatory. When in 1980 the data center responsibility was transferred…

Solar and Stellar Astrophysics · Physics 2019-01-30 Renzo Ramelli , Marco Cagnotti , Sergio Cortesi , Michele Bianda , Andrea Manna

Rossi X-ray Timing Explorer (RXTE)/Proportional Counter Array (PCA) observations of IGR J19294+1816 covering two outburst episodes are reported. The first outburst happened during MJD 54921-54925 (2009 C.E.) and the second one happened…

High Energy Astrophysical Phenomena · Physics 2017-11-07 Jayashree Roy , Manojendu Choudhury , P. C. Agrawal

We present the first simultaneous infrared (IR) and visible spectro-polarimetric observations of a solar internetwork region. The Fe I lines at 6301.6 A, 6302.5 A, 15648 A, and 15652 A were observed, with a lag of only 1 min, using highly…

Astrophysics · Physics 2009-11-10 J. Sanchez Almeida , I. Dominguez Cerdena , F. Kneer

The solar chromosphere has historically been studied from spectral lines in the visible and UV, notably H{\alpha}, Ca ii, Mg ii and Ly{\alpha}. Observations at long UV wavelengths (304, 1600 and 1700 {\AA}) from space have been recently…

Solar and Stellar Astrophysics · Physics 2023-07-14 C. Guillermo Giménez de Castro

A new astronomical photo-polarimeter that can measure linear polarization of point sources simultaneously in three spectral bands was designed and built in Indian Institute of Astrophysics. The polarimeter has a Calcite beam-displacement…

Instrumentation and Methods for Astrophysics · Physics 2015-06-30 A. V. Raveendran , G. Srinivasulu , S. Muneer , M. V. Mekkaden , N. Jayavel , M. R. Somashekar , K. Sagayanathan , S. Ramamoorthy , M. J. Rosario , K. Jayakumar

We report on spectropolarimetric observations across the Mg II h and k-lines at 2800 angstrom made by the Ultraviolet Spectrometer and Polarimeter onboard the Solar Maximum Mission satellite. Our analysis confirms the strong linear…

Solar and Stellar Astrophysics · Physics 2019-10-02 R. Manso Sainz , T. del Pino Alemán , R. Casini , S. McIntosh

The luminosity in the ZEUS detector was measured using photons from electron bremsstrahlung. In 2001 the HERA collider was upgraded for operation at higher luminosity. At the same time the luminosity-measuring system of the ZEUS experiment…

We present some theoretical predictions concerning the amplitude and magnetic sensitivity of the linear polarization signals produced by scattering processes in the hydrogen Ly-alpha line of the solar transition region. To this end, we have…

Solar and Stellar Astrophysics · Physics 2015-05-28 Javier Trujillo Bueno , Jiri Stepan , Roberto Casini

Birmingham Solar Oscillations Network (BiSON) instruments use resonant scattering spectrometers to make unresolved Doppler velocity observations of the Sun. Unresolved measurements are not homogenous across the solar disc and so the…

Solar and Stellar Astrophysics · Physics 2015-05-13 A. M. Broomhall , W. J. Chaplin , Y. Elsworth , R. New

The polarization of radiation by scattering on an atom embedded in combined external quadrupole electric and uniform magnetic fields is studied theoretically. Analytic formulae are derived for the scattering phase matrix. Limiting cases of…

Astrophysics · Physics 2007-05-23 Yee Yee Oo , K. N. Nagendra , Sharath Ananthamurthy , G. Ramachandran

A new technique based on superposition of two speckle patterns is proposed and demonstrated for controlled modulation of the spatial polarization distribution of the resultant speckle. It is demonstrated both theoretically and…

Optics · Physics 2021-11-15 Abhijit Roy , Rakesh K. Singh , Maruthi M. Brundavanam

The Infrared Space Observatory (ISO) was an extremely successful european space mission that gave us an unparallel view of the Universe in the infrared, and provided us with hundreds of observations of star forming regions and bipolar…

Astrophysics · Physics 2007-05-23 Alberto Noriega-Crespo

The dynamic spectra of pulsars frequently exhibit diverse interference patterns, often associated with parabolic arcs in the Fourier-transformed (secondary) spectra. Our approach differs from previous ones in two ways: first, we extend…

High Energy Astrophysical Phenomena · Physics 2024-05-28 Tobias Kramer , Daniel Waltner , Eric J. Heller , Dan R. Stinebring

Over the course of its motion through the Galaxy, our solar system has encountered many interstellar environments of varying characteristics. Interstellar medium (ISM) density variations spanning seven orders of magnitude are commonly seen…

Solar and Stellar Astrophysics · Physics 2015-06-16 Katherine Wyman , Seth Redfield

While X-ray Spectroscopy, Timing and Imaging have improved verymuch since 1962, when the first astronomical non-solar source was discovered, especially with the launch of Newton/X-ray Multi-Mirror Mission, Rossi/X-ray Timing Explorer and…

We present measurements in the context of a survey of southern hemisphere binary and multiple stellar systems observed with the Zorro Speckle dual diffraction-limited optical imaging camera on the 8.1m Gemini-South telescope carried out…

Solar and Stellar Astrophysics · Physics 2025-03-13 Rene A. Mendez , Andrei Tokovinin , Edgardor Costa , Max Dirk
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