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HERA is a highly-redundant transit interferometer with 14\,m-diameter parabolic dish elements. We exploit the fact that the Galactic centre transits through the main beam of the telescope to attempt a conventional self-calibration approach…

Instrumentation and Methods for Astrophysics · Physics 2017-09-18 Bojan Nikolic , Chris Carilli , HERA Collaboration

More than 600 high resolution spectra of stars with spectral type F and later were obtained in order to search for signatures of differential rotation in line profiles. In 147 stars, the rotation law could be measured, 28 of them are found…

Astrophysics · Physics 2016-08-30 Ansgar Reiners

The presence of dips in the gravity modes period spacing versus period diagram of gamma Doradus stars is now well established by recent asteroseismic studies. Such Lorentzian-shaped inertial dips arise from the interaction of…

Solar and Stellar Astrophysics · Physics 2025-02-19 L. Barrault , L. Bugnet , S. Mathis

Grid stars and reference stars provide the fundamental global and local astrometric reference frames for observations by the Space Interferometry Mission. They must therefore be astrometrically stable at the ~1 uas level. I present simple…

Astrophysics · Physics 2009-11-06 Andrew Gould

The detection of mixed modes that are split by rotation in Kepler red giants has made it possible to probe the internal rotation profiles of these stars, which brings new constraints on the transport of angular momentum in stars. Mosser et…

Solar and Stellar Astrophysics · Physics 2015-08-12 S. Deheuvels , J. Ballot , P. G. Beck , B. Mosser , R. Østensen , R. A. García , M. J. Goupil

An interferometric imaging technique has been proposed to instantly measure the diameter of individual spherical dust particles suspended in a gas discharge plasma. The technique is based on the defocused image analysis of both spherical…

Plasma Physics · Physics 2016-04-06 M. Chaudhuri , V. Nosenko , H. M. Thomas

By means of numerical experiments we explore the application of interferometry to the detection and characterization of abundance spots in chemically peculiar (CP) stars using the brightest star eps~Uma as a case study. We find that the…

Solar and Stellar Astrophysics · Physics 2015-06-22 D. Shulyak , C. Paladini , G. Li Causi , K. Perraut , O. Kochukhov

Asteroseismic modelling of the internal structure of main-sequence stars born with a convective core has so far been based on homogeneous analyses of space photometric Kepler light curves of 4 years duration, to which most often incomplete…

The image subtraction method is a powerful tool to analyze the light variations in crowded fields. This method is able to achieve a nearly optimal differential photometry, even in very dense regions. However, image subtraction is not…

Astrophysics · Physics 2007-05-23 C. Alard

Context : We still do not know which mechanisms are responsible for the transport of angular momentum inside stars. The recent detection of mixed modes that contain the signature of rotation in the spectra of Kepler subgiants and red giants…

We describe a "spatio-spectral" deconvolution algorithm for wide-band imaging in radio interferometry. In contrast with the existing multi-frequency reconstruction algorithms, the proposed method does not rely on a model of the…

Instrumentation and Methods for Astrophysics · Physics 2016-03-01 André Ferrari , Jérémy Deguignet , Chiara Ferrari , David Mary , Antony Schutz , Oleg Smirnov

We present measurements of fundamental astrophysical properties of nearby, low-mass, K- and M-dwarfs from our DISCOS survey (DIameterS of COol Stars). The principal goal of our study is the determination of linear radii and effective…

We propose a method to overcome the usual limitation of current data processing techniques in optical and infrared long-baseline interferometry: most reduction pipelines assume uncorrelated statistical errors and ignore systematics. We use…

Instrumentation and Methods for Astrophysics · Physics 2019-01-23 Régis Lachaume , Markus Rabus , Andrés Jordán , Rafael Brahm , Tabetha Boyajian , Kaspar von Braun , Jean-Philippe Berger

We pose the question of how much information on the atmospheric parameters of late-type stars can be retrieved purely from colors using standard photometric systems. We carried out numerical experiments using stellar fluxes from model…

Solar and Stellar Astrophysics · Physics 2016-11-16 C. Allende Prieto

Intensity interferometry -- the correlation of spatially separated light intensities -- has historically been an important tool for precision optical astronomical observations. However, due to the extremely narrow field of view, its scope…

Instrumentation and Methods for Astrophysics · Physics 2023-07-10 Ken Van Tilburg , Masha Baryakhtar , Marios Galanis , Neal Weiner

With four years of nearly-continuous photometry from Kepler, we are finally in a good position to apply asteroseismology to $\gamma$ Doradus stars. In particular several analyses have demonstrated the possibility to detect non-uniform…

Solar and Stellar Astrophysics · Physics 2017-01-18 Rhita-Maria Ouazzani , S. J. A. J. Salmon , V. Antoci , T. R. Bedding , S. J. Murphy , I. W. Roxburgh

Stellar activity interferes with precise radial velocity measurements and limits our ability to detect and characterize planets, particularly Earth-like planets. We introduce \aestra (Auto-Encoding STellar Radial-velocity and Activity), a…

Earth and Planetary Astrophysics · Physics 2023-12-01 Yan Liang , Joshua N. Winn , Peter Melchior

In this article we present a modification of classical Radial Basis Function (RBF) interpolation techniques aimed at reducing oscillations near discontinuities in one and two dimensions. Our approach introduces an adaptive mechanism by…

Numerical Analysis · Mathematics 2026-03-25 José Kuruc , David Levin , Pep Mulet , Juan Ruiz-Álvarez , Dionisio F. Yáñez

Context. The circumstellar disks ejected by many rapidly rotating B stars (so-called Be stars) offer the rare opportunity of studying the structure and dynamics of gaseous disks at high spectral as well as angular resolution. Aims. This…

Solar and Stellar Astrophysics · Physics 2013-06-06 D. M. Faes , A. C. Carciofi , Th. Rivinius , S. Štefl , D. Baade , A. Domiciano de Souza

In this paper, we propose a protocol for angular displacement estimation based upon orbital angular momentum coherent state and a SU(1,1)-SU(2) hybrid interferometer. This interferometer consists of an optical parametric amplifier, a beam…

Quantum Physics · Physics 2018-12-06 Jian-Dong Zhang , Zi-Jing Zhang , Long-Zhu Cen , Jun-Yan Hu , Yuan Zhao