14.6k citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- Centre National de la Recherche ScientifiqueFR1.6k papers
- Institut National de Physique Nucléaire et de Physique des ParticulesFR1.4k papers
- Heidelberg UniversityDE1.3k papers
- Max Planck SocietyDE1.1k papers
- University of ZurichCH1.1k papers
- European Organization for Nuclear ResearchCH1k papers
- Laboratoire de Physique Nucléaire et de Hautes ÉnergiesFR990 papers
- Institute of Nuclear Physics, Polish Academy of SciencesPL973 papers
- University of Maryland, College ParkUS940 papers
- Rutherford Appleton LaboratoryGB939 papers
- Institute for Nuclear ResearchRU922 papers
- Istituto Nazionale di Fisica Nucleare, Sezione di BolognaIT912 papers
39 papers · 2 filters
Implications of a Nonthermal Origin of the Excess EUV Emission from the Coma Cluster of Galaxies
A. M. Atoyan, H. J. Voelk
The inverse Compton (IC) interpretation of the excess EUV emission, that was recently reported from several clusters of galaxies, suggests that the amount of relativistic electrons…
A spectrophotometric catalogue of HII galaxies
Cristina C. Popescu, Ulrich Hopp
We present a spectrophotometric catalogue of 90 emission-line galaxies (ELGs) discovered during an objective - prism survey that aimed to search for dwarf galaxies within the voids…
On the radio spectral index of galaxies
U. Lisenfeld, H. J. Voelk
The radio emission of a galaxy consists of thermal bremsstrahlung, synchrotron emission from discrete supernova remnants, and diffuse synchrotron emission from cosmic ray electrons…
1.65 micrometers (H-band) surface photometry of galaxies. III: observations of 558 galaxies with the TIRGO 1.5m telescope
G. Gavazzi, P. Franzetti, M. Scodeggio +5
We present near-infrared H-band (1.65 micron) surface photometry of 558 galaxies in the Coma Supercluster and in the Virgo cluster. This data set, obtained with the Arcetri NICMOS3…
1.65 micrometers (H-band) surface photometry of galaxies. IV:observations of 170 galaxies with the Calar Alto 2.2m telescope
A. Boselli, G. Gavazzi, P. Franzetti +2
We present near-infrared (H band) surface photometry of 170 galaxies, obtained in 1997 using the Calar Alto 2.2m telescope equipped with the NICMOS3 camera MAGIC. The majority of o…
X-ray/TeV-gamma-ray observations of several strong flares of Mkn 501 during 1997 and implications
H. Krawczynski, P. S. Coppi, T. Maccarone +1
During more than 6 months in 1997, the BL Lac object Mkn 501 was in an exceptionally bright state, both in the X-ray band and in the Very High Energy (VHE) band. In this paper we p…
Effect of intergalactic absorption in the TeV gamma-ray spectrum of Mkn 501
Alexander K. Konopelko
We discuss an effect of the intergalactic absorption of the TeV gamma-rays in time-averaged spectrum of Mkn 501 measured by the HEGRA Collaboration. Analysis of the spectral behavi…
"Convergent observations" with the stereoscopic HEGRA CT system
Hubert Lampeitl, Werner Hofmann
Observations of air showers with the stereoscopic HEGRA IACT system are usually carried out in a mode where all telescopes point in the same direction. Alternatively, one could tak…
Data analysis techniques for stereo IACT systems
W. Hofmann
Based on data and Monte-Carlo simulations of the HEGRA IACT system, improved analysis techniques were developed for the determination of the shower geometry and shower energy from…
On the optimum spacing of stereoscopic imaging atmospheric Cherenkov telescopes
HEGRA Collaboration, W. Hofmann, G. Hermann +4
For stereoscopic systems of imaging atmospheric Cherenkov telescopes (IACTs), a key parameter to optimize the sensitivity for VHE gamma-ray point sources is the intertelescope spac…
Critical self-organization of astrophysical shocks
M. A. Malkov, P. H. Diamond, H. J. Voelk
There are two distinct regimes of the first order Fermi acceleration at shocks. The first is a linear (test particle) regime in which most of the shock energy goes into thermal and…
On the star-formation properties of emission-line galaxies in and around voids
Cristina C. Popescu, Ulrich Hopp, Michael R. Rosa
We present a study of the star formation properties of a sample of emission line galaxies (ELGs) with respect to their environment. This study is part of a bigger project that aime…
IRAS 17393-3004, a late-type supergiant surrounded by a dust shell
Sabine Philipp, Richard J. Tuffs, Peter G. Mezger +1
Infrared observations of IRAS 17393-3004, including a full scan ISOSWS are presented. The ISOSWS spectrum shows two prominent dust emission peaks at lambda 10.4mu and 17.5mu confir…
Probing Pulsar Winds Using Inverse Compton Scattering
Lewis Ball, J. G. Kirk
We investigate the effects of inverse Compton scattering by electrons and positrons in the unshocked winds of rotationally-powered binary pulsars. This process can scatter low ener…
Impact of atmospheric parameters on the atmospheric Cherenkov technique
Konrad Bernloehr
Atmospheric density profiles as well as several light absorption and scattering processes depend on geographic position and are generally time-variable. Their impact on the atmosph…
Improved energy resolution for VHE gamma-ray astronomy with systems of Cherenkov telescopes
W. Hofmann, H. Lampeitl, A. Konopelko +1
We present analysis techniques to improve the energy resolution of stereoscopic systems of imaging atmospheric Cherenkov telescopes, using the HEGRA telescope system as an example.…
Techniques for Galactic Dust Measurements in the Heliosphere
Eberhard Grün, Markus Landgraf, Mihaly Horány +5
Galactic interstellar dust (ISD) is the major ingredient in planetary formation. However, information on this important material has been extremely limited. Recently the Ulysses du…
Effectiveness of TeV Gamma-Ray Observations at Large Zenith Angles with a Stereoscopic System of Imaging Atmospheric Cherenkov Telescopes
A. Konopelko, F. Aharonian, M. Hemberger +4
The sensitivity of imaging atmospheric Cherenkov telescopes (IACTs) in TeV gamma-ray observations reachs its maximum at small zenith angles (< 30 degree) which provide the minimum…
Monte-Carlo simulation of particle acceleration in braided magnetic fields
U. D. J. Gieseler, J. G. Kirk
Supernova remnants are expected to contain braided (or stochastic) magnetic fields, which are in some regions directed mainly perpendicular to the shock normal. For particle accele…
Computation of diffusive shock acceleration using stochastic differential equations
A. Marcowith, J. G. Kirk
The present work considers diffusive shock acceleration at non-relativistic shocks using a system of stochastic differential equations (SDE) equivalent to the Fokker-Planck equatio…
Dust in the Local Interstellar Wind
P. C. Frisch, J. M. Dorschner, J. Geiss +13
The gas-to-dust mass ratios found for interstellar dust within the Solar System, versus values determined astronomically for the cloud around the Solar System, suggest that large a…
Particle acceleration and relativistic shocks
J. G. Kirk, P. Duffy
Observations of both gamma-ray burst sources and certain classes of active galaxy indicate the presence of relativistic shock waves and require the production of high energy partic…
Near-infrared observations of galaxies in Pisces-Perseus: I. H-band surface photometry of 174 spirals
G. Moriondo, C. Baffa, S. Casertano +7
We present near-infrared, H-band (1.65 um), surface photometry of 174 spiral galaxies in the area of the Pisces-Perseus supercluster. The images, acquired with the ARNICA camera mo…
Comparison of techniques to reconstruct VHE gamma-ray showers from multiple stereoscopic Cherenkov images
W. Hofmann, I. Jung, A. Konopelko +3
For air showers observed simultaneously by more than two imaging atmospheric Cherenkov telescopes, the shower geometry is overconstrained by the images and image information should…