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Aims: Main goal of this work is to study the potential of He II Ly-alpha wavelength-integrated scattering polarisation for probing the magnetism of the solar upper chromosphere. Methods: Radiative transfer calculations are performed in…

Solar and Stellar Astrophysics · Physics 2024-08-14 F. Riva , G. Janett , L. Belluzzi

We present the results of medium resolution (Delta v = 60 km/s) spectropolarimetric observations across Halpha of a sample of B[e] and Herbig Be objects. A change in linear polarization across Halpha is detected in a large fraction of the…

Astrophysics · Physics 2009-10-31 Rene Oudmaijer , Janet Drew

Precision phase readout of optical beat note signals is one of the core techniques required for intersatellite laser interferometry. Future space based gravitational wave detectors like eLISA require such a readout over a wide range of MHz…

EX Hya is one of the few double-lined eclipsing cataclysmic variables that allow an accurate measurement of the binary masses. We analyze orbital phase-resolved UVES/ VLT high resolution spectroscopic observations of EX Hya with the aims of…

Astrophysics · Physics 2008-02-19 K. Beuermann , K. Reinsch

HD149404 is an evolved non-eclipsing O-star binary that has previously undergone a Roche lobe overflow interaction. Understanding some key properties of the system requires a determination of the orbital inclination and of the dimensions of…

The direct detection and imaging of exoplanets requires the use of high-contrast adaptive optics (AO). In these systems quasi-static aberrations need to be highly corrected and calibrated. In order to achieve this, the pupil-modulated…

Instrumentation and Methods for Astrophysics · Physics 2022-05-25 Nicolas Dubost , Nazim Ali Bharmal , Marc Dubbeldam , Richard M. Myers

We report initial observations of coherent optical transition radiation interferometry (COTRI) patterns generated by microbunched electrons from laser-driven plasma accelerators (LPAs). These are revealed in the angular distribution…

Motivated by the recent discovery of an Halpha emission line component originating close to the white dwarf primary in the post-common-envelope binary (PCEB) LTT 560, we have undertaken a spectroscopic snapshot survey on 11 short-period…

Solar and Stellar Astrophysics · Physics 2011-09-09 C. Tappert , B. T. Gänsicke , A. Rebassa-Mansergas , L. Schmidtobreick , M. R. Schreiber

We obtained Halpha diffraction limited data of the LBV star P Cyg using the ONERA Adaptive Optics (AO) facility BOA at the OHP 1.52m telescope on October 1997. Taking P Cyg and the reference star 59 Cyg AO long exposures we find that P Cyg…

Astrophysics · Physics 2009-10-31 O. Chesneau , M. Roche , A. Boccaletti , L. Abe , C. Moutou , F. Charbonnier , C. Aime , H. Lanteri , F. Vakili

A near-IR high-resolution, R=80000 spectrometer has been developed at IPAG to directly characterize the atmosphere of exoplanets using adaptive optics (AO) assisted telescopes, and a single-mode fiber-injection unit. A first technical test…

In this paper we present new observational evidence that supports the presence of an extra source of continuum emission in the binary system beta Lyrae. New VLA and IRAM observations, together with published data from the literature and ISO…

Astrophysics · Physics 2009-11-07 G. Umana , F. Leone , C. Trigilio

One of the aims of next generation optical interferometric instrumentation is to be able to make use of information contained in the visibility phase to construct high dynamic range images. Radio and optical interferometry are at the two…

Since the Lalpha rocket observations of (Gabriel, Solar Phys. 21, 392, 1971), it has been realized that the hydrogen (H) lines could be observed in the corona and offer an interesting diagnostic for the temperature, density, and radial…

Solar and Stellar Astrophysics · Physics 2016-11-15 Jean-Claude Vial , Martine Chane-Yook

The aim of the Laser Interferometer Space Antenna (LISA) is to detect gravitational waves through a phase modulation in long (2.5 Mkm) laser light links between spacecraft. Among other noise sources to be addressed are the phase…

General Relativity and Quantum Cosmology · Physics 2020-06-14 Jean-Yves Vinet , Nelson Christensen , Nicoleta Dinu-Jaeger , Michel Lintz , Nary Man , Mikhaël Pichot

We present the discovery of neutral gas detected in both damped Ly$\alpha$ absorption (DLA) and HI 21-cm emission outside of the stellar body of a galaxy, the first such detection in the literature. A joint analysis between the Cosmic…

We analyze theoretically and experimentally how nonlinear differential-transmission spectroscopy of a lambda-system medium can provide quantitative understanding of the optical dipole moments and transition energies. We focus on the…

Materials Science · Physics 2015-01-07 J. P. de Jong , A. R. Onur , D. Reuter , A. D. Wieck , C. H. van der Wal

A deep (R ~ 19.5) photographic Halpha Survey of the southern Galactic Plane was recently completed using the UK Schmidt Telescope at the AAO. In addition, we have recently started a similar, CCD-based survey of the northern Galactic Plane…

Astrophysics · Physics 2011-03-10 Andrew Witham , Christian Knigge , Janet Drew , Paul Groot , Robert Greimel , Quentin Parker

In this work we present a revised measurement of the phase-averaged optical polarisation of the Vela pulsar (PSR B0833-45), for which only one value has been published so far (Wagner & Seifert 2000). Our measurement has been obtained…

Astrophysics · Physics 2009-11-13 R. P. Mignani , S. Bagnulo , J. Dyks , G. Lo Curto , A. Slowikowska

The Laser Interferometer Space Antenna (LISA) is being designed to detect and study in detail gravitational waves from sources throughout the Universe such as massive black hole binaries. The conceptual formulation of the LISA space-borne…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Scott E Pollack , Robin Tuck Stebbins

Ly$\alpha$ emission is an exceptionally informative tracer of the life cycle of evolving galaxies and the escape of ionising photons. However, theoretical studies of Ly$\alpha$ emission are often limited by insufficient numerical…

Astrophysics of Galaxies · Physics 2024-10-08 Yuxuan Yuan , Sergio Martin-Alvarez , Martin G. Haehnelt , Thibault Garel , Debora Sijacki