Search results for "Observatory"
showing 10 items of 329 documents
The Pros and Cons of Beyond Standard Model Interpretations of ANITA Events
2019
The Antarctic Impulsive Transient Antenna (ANITA) experiment has observed two air shower events with energy $\sim 500~{\rm PeV}$ emerging from the Earth with exit angles $\sim 30^\circ$ above the horizon. As was immediately noted by the ANITA Collaboration, these events (in principle) could originate in the atmospheric decay of an upgoing $\tau$-lepton produced through a charged current interaction of a $\nu_\tau$ inside the Earth. However, the relatively steep arrival angles of these perplexing events create tension with the standard model (SM) neutrino-nucleon interaction cross section. Deepening the conundrum, the IceCube neutrino telescope and the Pierre Auger Observatory with substanti…
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)
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…
Search for magnetically-induced signatures in the arrival directions of ultra-high-energy cosmic rays measured at the Pierre Auger Observatory
2020
We search for signals of magnetically-induced effects in the arrival directions of ultra-high-energy cosmic rays detected at the Pierre Auger Observatory. We apply two different methods. One is a search for sets of events that show a correlation between their arrival direction and the inverse of their energy, which would be expected if they come from the same point-like source, they have the same electric charge and their deflection is relatively small and coherent. We refer to these sets of events as "multiplets". The second method, called "thrust", is a principal axis analysis aimed to detect the elongated patterns in a region of interest. We study the sensitivity of both methods using a …