Search results for "observator"
showing 10 items of 410 documents
Astronoma Alfrēda Žaggera publikācijas
2020
Latvijas Universitātes Muzeja virtuālajā izstādē „Astronoma Alfrēda Žaggera publikācijas” iespējams iepazīties ar pazīstamā astronoma dzīves gājumu (1878 – 1956) un darbību Latvijas Universitātes Astronomiskās observatorijas direktora amatā, lūkojoties caur viņa publikāciju prizmu.
Solar Coronal Loops Associated with Small-scale Mixed Polarity Surface Magnetic Fields
2017
L. P. Chitta et. al.
Neutrinos below 100 TeV from the southern sky employing refined veto techniques to IceCube data
2020
Many Galactic sources of gamma rays, such as supernova remnants, are expected to produce neutrinos with a typical energy cutoff well below 100 TeV. For the IceCube Neutrino Observatory located at the South Pole, the southern sky, containing the inner part of the Galactic plane and the Galactic Center, is a particularly challenging region at these energies, because of the large background of atmospheric muons. In this paper, we present recent advancements in data selection strategies for track-like muon neutrino events with energies below 100 TeV from the southern sky. The strategies utilize the outer detector regions as veto and features of the signal pattern to reduce the background of atm…
All-sky search in early O3 LIGO data for continuous gravitational-wave signals from unknown neutron stars in binary systems
2021
Rapidly spinning neutron stars are promising sources of continuous gravitational waves. Detecting such a signal would allow probing of the physical properties of matter under extreme conditions. A significant fraction of the known pulsar population belongs to binary systems. Searching for unknown neutron stars in binary systems requires specialized algorithms to address unknown orbital frequency modulations. We present a search for continuous gravitational waves emitted by neutron stars in binary systems in early data from the third observing run of the Advanced LIGO and Advanced Virgo detectors using the semicoherent, GPU-accelerated, binaryskyhough pipeline. The search analyzes the most s…
RTS2: Lessons learned from a widely distributed telescope network
2008
RTS2 (Remote Telescope System 2) is a highly modular open source telescope and observatory management software package. It evolved from RTS, which was developed in Python to control a telescope aimed at observing optical transients of γ ray burts. The development of a network system capable of operating robotic telescopes is both difficult and complicated. Along with continued software development one must be concerned with maintaining operations and obtaining results. This is a review of experiences gained building a network of robotic telescopes. It focuses on describing which issues are important during development of the robotic observatory software and requirements for future developme…
Observatory science with eXTP
2019
Disponible preprint en: arXiv:1812.04023v1 [astro-ph.HE] [v1] Mon, 10 Dec 2018 19:00:52 UTC (4,376 KB)
Modèle des voies réflexes et cérébelleuses, permettant le calcul de fonctions inverses et la commande d'un segment mécanique mobile
2004
14/07/2004; La commande et le contrôle des mouvements des membres par les voies cérébelleuses et réflexes sont modélisées au moyen d'un circuit dont la structure est déduite de contraintes fonctionnelles. 1/ La première contrainte est que les mouvements rapides des membres doivent être précis, quoiqu'ils ne puissent pas être commandés en boucle fermée au moyen de signaux sensoriels. Les voies qui préparent les ordres moteurs doivent donc contenir des fonctions inverses approximées des fonctions biomécaniques du membre et des muscles. Or une telle fonction peut être calculée au moyen de boucles de rétroaction parallèles, dont la structure est comparable à l'anatomie des voies cérébelleuses. …
Simulation Study of a Space-Based detector for UHECR observation.
2005
The next generation of experiments devoted to the study of the cosmic rays spectrum above 10(20) eV will be most likely done by means of space based detectors. In order to detect the fluorescence and Cerenkov signal generated by an EAS in atmosphere, severe requirements on the photon collection efficiency and on the triggering capability need to be met. In this paper we report about of preliminary studies of the triggering efficiency of a space based detector as a function of the main detector parameters. All results are obtained by means of a detailed simulation of the shower development, atmospheric response, detector geometry and electronics and trigger behavior in realistic conditions b…
Probing the origin of ultra-high-energy cosmic rays with neutrinos in the EeV energy range using the Pierre Auger Observatory
2019
Neutrinos with energies above 1017 eV are detectable with the Surface Detector Array of the Pierre Auger Observatory. The identification is efficiently performed for neutrinos of all flavors interacting in the atmosphere at large zenith angles, as well as for Earth-skimming τ neutrinos with nearly tangential trajectories relative to the Earth. No neutrino candidates were found in ∼ 14.7 years of data taken up to 31 August 2018. This leads to restrictive upper bounds on their flux. The 90% C.L. single-flavor limit to the diffuse flux of ultra-high-energy neutrinos with an Eν -2 spectrum in the energy range 1.0 × 1017 eV -2.5 × 1019 eV is E2 dNν/dEν < 4.4 × 10-9 GeV cm-2 s-1 sr-1, placing str…
Limits on point-like sources of ultra-high-energy neutrinos with the Pierre Auger Observatory
2019
With the Surface Detector array (SD) of the Pierre Auger Observatory we can detect neutrinos with energy between 1017 eV and 1020 eV from point-like sources across the sky, from close to the Southern Celestial Pole up to 60 in declination, with peak sensitivities at declinations around ∼-53 and ∼+55, and an unmatched sensitivity for arrival directions in the Northern hemisphere. A search has been performed for highly-inclined air showers induced by neutrinos of all flavours with no candidate events found in data taken between 1 Jan 2004 and 31 Aug 2018. Upper limits on the neutrino flux from point-like steady sources have been derived as a function of source declination. An unrivaled sensit…