English
Related papers

Related papers: Detection of mesogranulation at the upper chromosp…

200 papers

The Earth's mesopause region between about 75 and 105 km is characterised by chemiluminescent emission from various lines of different molecules and atoms. This emission was and is important for the study of the chemistry and dynamics in…

We obtained a long exposure vector magnetogram of the quiet Sun photosphere at the disk center with wide FOV of $51" \times 82"$. The observation was performed at Fe I 525.0 nm with the shutter-less mode of the Narrow Band Filter Imager of…

Solar and Stellar Astrophysics · Physics 2015-05-27 Ryohko Ishikawa , Saku Tsuneta

We use state-of-the-art radiation-MHD simulations and 3D non-LTE radiative transfer computations to investigate \Halpha\ line formation in the solar chromosphere and apply the results of this investigation to develop the potential of…

Solar and Stellar Astrophysics · Physics 2015-06-04 Jorrit Leenaarts , Mats Carlsson , Luc Rouppe van der Voort

The Luminosity Oscillations Imager (LOI) of the Variability of Solar Irradiance and Gravity Oscillations (VIRGO) instrument aboard the SoHO mission has been operating for almost the past 30 years. I report on the effect of solar activity…

Solar and Stellar Astrophysics · Physics 2026-01-21 Thierry Appourchaux

The chromospheric Lyman-alpha line of neutral hydrogen (\lya; 1216\AA) is the strongest emission line in the solar spectrum. Fluctuations in \lya\ are known to drive changes in planetary atmospheres, although few instruments have had the…

Solar and Stellar Astrophysics · Physics 2020-08-26 Ryan O. Milligan , Hugh S. Hudson , Phillip C. Chamberlin , Iain G. Hannah , Laura A. Hayes

We provide a new interpretation of ultraviolet transition region emission line widths observed by the SUMER instrument on the Solar and Heliospheric Observatory (SOHO). This investigation is prompted by observations of the chromosphere at…

Astrophysics · Physics 2009-11-13 Scott W. McIntosh , Bart De Pontieu , Theodore D. Tarbell

It is predicted that sources emitting UV radiation in the Lyman band during the epoch of reionization (EoR) showed a series of discontinuities in their Ly-alpha flux radial profile as a consequence of the thickness of the Lyman line series…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 P. Vonlanthen , B. Semelin , S. Baek , Y. Revaz

The Sun is the only star where the superficial turbulent convection can be observed at very high spatial resolution. The Solar Dynamics Observatory (SDO) has continuously observed the full Sun from space with multi-wavelength filters since…

Solar and Stellar Astrophysics · Physics 2021-08-18 J. Ballot , T. Roudier , J. M. Malherbe , Z. Frank

We report measurements of ten custom-made high-homogeneity LYSO crystals. The investigation is motivated by the need for a compact, high-resolution, and fast electromagnetic calorimeter for a new rare pion decay experiment. Each $2.5\times…

Lyman $\alpha$ (Ly$\alpha$) is now routinely used as a tool for studying high-redshift galaxies and its resonant nature means it can trace neutral hydrogen around star-forming galaxies. Integral field spectrograph measurements of…

We present the results of deep Lyman limit imaging in four new fields as part of a continuing search for galaxies at $3.0 \le z \le 3.5$. The technique uses a custom broad--band filter set ($U_n G {\cal R}$) designed to isolate objects…

Astrophysics · Physics 2009-10-28 C. Steidel , M. Pettini , D. Hamilton

We analyze a series of full-Sun observations, which was performed with the SoHO/SUMER instrument between March and October 1996. Some parameters (radiance, shift and width) of the S VI 93.3 nm, S VI 94.4 nm, and Lyman Epsilon line profiles…

Astrophysics · Physics 2009-11-13 E. Buchlin , J. -C. Vial , P. Lemaire

Observations of the Sun's surface suggest a nonuniform radiated flux as related to the presence of bright active regions and darker coronal holes. The variations of the FUV/EUV source radiation can be expected to affect the Lyman-alpha…

Solar and Stellar Astrophysics · Physics 2021-10-04 Marek Strumik , Maciej Bzowski , Marzena A. Kubiak

There are very few reports of flare signatures in the solar irradiance at H i Lyman {\alpha} at 121.5 nm, i.e. the strongest line of the solar spectrum. The LYRA radiometer onboard PROBA2 has observed several flares for which unambiguous…

Solar and Stellar Astrophysics · Physics 2015-06-11 M. Kretzschmar , M. Dominique , I. E. Dammasch

In this work, we present for the first time the Lyman $\alpha$ intensities measured by Voyager 1/UVS in 2003-2014 (at 90-130 AU from the Sun). During this period Voyager 1 measured the Lyman $\alpha$ emission in the outer heliosphere at an…

Solar and Stellar Astrophysics · Physics 2017-10-20 O. A. Katushkina , E. Quemerais , V. V. Izmodenov , R. Lallement , B. R. Sandel

We present a rest-frame ultraviolet analysis of ~120 z~3.1 Lyman Alpha Emitters (LAEs) in the Extended Chandra Deep Field South (ECDF-S). Using Hubble Space Telescope (HST) images taken as part of the Galaxy Evolution From Morphology and…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 N. A. Bond , E. Gawiser , C. Gronwall , R. Ciardullo , M. Altmann , K. Schawinski

Context: Studying the motions on the solar surface is fundamental for understanding how turbulent convection transports energy and how magnetic fields are distributed across the solar surface. Aims: From horizontal velocity measurements all…

Solar and Stellar Astrophysics · Physics 2015-06-22 Th. Roudier , M. Švanda , M. Rieutord , J. M. Malherbe , R. Burston , L. Gizon

Chromospheric swirls are considered to play a significant role in the dynamics and heating of the upper solar atmosphere. It is important to automatically detect and track them in chromospheric observations and determine their properties.…

Solar and Stellar Astrophysics · Physics 2022-07-20 I. Dakanalis , G. Tsiropoula , K. Tziotziou , I. Kontogiannis

The mesosphere of Venus is a critical range of altitudes in which complex temperature variability has been extensively studied by the space mission Venus Express (Vex) during its eight-years mission (2006-2014). Data collected at different…

Earth and Planetary Astrophysics · Physics 2016-11-09 C. Pere , P. Tanga , Th. Widemann , Ph. Bendjoya , A. Mahieux , V. Wilquet , A. C. Vandaele

In this work, I investigate the properties of Lyman limit systems (LLSs) using state-of-the-art zoom-in cosmological galaxy formation simulations with on the fly radiative transfer, which includes both the cosmic UV background (UVB) and…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-25 Denis Erkal