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Double-bump showers are a rare class of extensive air showers (EAS) predicted by Monte Carlo simulations. They occur when a high-energy secondary particle, the leading particle, travels significantly farther than the rest, creating a…

We assume a distribution of clouds optically thick for electron scattering (OTCM) which are moderately optically thin for absorption and we consider them as a model of the mean quasar spectrum of Laor et al. (1997). We show that the model…

Astrophysics · Physics 2007-05-23 B. Czerny , A. -M. Dumont

Recent spectropolarimetric observations of Herbig AeBe stellar systems show linear polarization variability with wavelength and epoch near their obscured H-alpha emission. Surprisingly, this polarization is not coincident with the H-alpha…

Astrophysics · Physics 2009-11-13 J. R. Kuhn , S. V. Berdyugina , D. M. Fluri , D. M. Harrington , J. O. Stenflo

We present the first results of a multi-wavelength survey, incoporating Herschel-SPIRE, Spitzer, GALEX and ATCA observations, of a 1 deg x 1 deg field centred on Centaurus A. As well as detecting the inner lobes of the active galactic…

Radiative transfer effects need to be taken into account when analysing spectral line observations. When the data are not sufficient for detailed modelling, simpler methods are needed. The escape probability formalism (EPF) is one such…

Instrumentation and Methods for Astrophysics · Physics 2025-04-16 Mika Juvela

We revisit the problem of thermal bulge of asynchronous hot Jupiters, using HD 209458 b as a fiducial study. We improve upon previous works by using a double-gray atmosphere model and interior structure from MESA as the background state,…

Earth and Planetary Astrophysics · Physics 2020-01-08 Pin-Gao Gu , Da-Kai Peng , Chien-Chang Yen

Future sky surveys in the mm/sub-mm range, like the forthcoming balloon-borne missions LSPE, OLIMPO, SPIDER etc., will need detectors insensitive to cosmic rays (CRs) and with a NEP of the order of $10^{-17} \div 10^{-18}\,$W/sqrt(Hz). The…

Instrumentation and Methods for Astrophysics · Physics 2014-10-23 Maria Salatino , Paolo de Bernardis , Sumedh Mahashabde , Leonid S. Kuzmin , Silvia Masi

The formaldehyde $\rm H_2CO(1_{10} - 1_{11})$ absorption line and H$110\alpha$ radio recombination line (RRL) have been observed toward the Aquila Molecular Cloud using the Nanshan 25 m telescope operated by the Xinjiang Astronomical…

We study the influence of low-level water and high-level ice clouds on low-resolution reflection spectra and planetary albedos of Earth-like planets orbiting different types of stars in both the visible and near infrared wavelength range.…

Earth and Planetary Astrophysics · Physics 2011-08-18 D. Kitzmann , A. B. C. Patzer , P. von Paris , M. Godolt , H. Rauer

We present a method that employs the secondary eclipse light curves of transiting extrasolar planets to probe the spatial variation of their thermal emission. This technique permits an observer to resolve the surface of the planet without…

The narrow line region of active galaxies is formed by gas clouds surrounded by a diluted gas. Standard one-dimensional photoionization models are usually used to model this region in order to reproduce the observed emission lines. Since…

Astrophysics · Physics 2009-11-07 Lucimara P. Martins , Sueli M. Viegas , Ruth Gruenwald

Aims. We analyse SUMER spectral scans of a large sunspot within active region NOAA 10923, obtained on 14-15 November 2006, to determine the morphology and dynamics of the sunspot atmosphere at different heights/temperatures. Methods: The…

Solar and Stellar Astrophysics · Physics 2009-01-22 L. Teriaca , W. Curdt , S. K. Solanki

Future ground-based telescopes will expand our capabilities for simultaneous multi-line polarimetric observations in a wide range of wavelengths, from the near-ultraviolet to the near-infrared. This creates a strong demand to compare…

An analysis of the interaction between a spherical relativistic blast-wave shell and a stationary cloud with a spherical cap geometry is performed assuming that the cloud width << x, where x is the distance of the cloud from the GRB…

Astrophysics · Physics 2009-11-13 Charles D. Dermer

We have used the Submillimeter Array (SMA) to make the first interferometric observations (beam size ~1") of the 12CO J=6-5 line and 435 micron (690 GHz) continuum emission toward the central region of the nearby ULIRG Arp 220. These…

Within the framework of a flat cosmological model a propagation of an instantaneous burst of isotropic radiation is considered from the moment of its beginning at some initial redshift z0 to the moment of its registration now (at z=0).…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-17 V. K. Dubrovich , S. I. Grachev

We perform a multi-wavelength study of a two-ribbon flare on 2002 September 29 and its associated filament eruption, observed simultaneously in the H-alpha line by a ground-based imaging spectrograph and in hard X-rays by RHESSI. The flare…

Astrophysics · Physics 2009-11-10 M. D. Ding , Q. R. Chen , J. P. Li , P. F. Chen

Sub-millimetre observations suggest that the filaments of interstellar clouds have rather uniform widths and can be described with the so-called Plummer profiles. The shapes of the filament profiles are linked to their physical state.…

Astrophysics of Galaxies · Physics 2015-06-05 M. Juvela , J. Malinen , T. Lunttila

We present the first results from applying the spectral inversion technique in the cloudy L dwarf regime. Our new framework provides a flexible approach to modelling cloud opacity which can be built incrementally as the data requires, and…

We analyze thermal emission of radiation in homogeneous clouds. The clouds have negligible horizontal variation, but the temperature can vary vertically. The radiation at optical depth $\tau$ above the cloud bottom is characterized by…

Atmospheric and Oceanic Physics · Physics 2023-01-20 W. A. van Wijngaarden , W. Happer