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13. Search for UHE neutrinos – in coincidence with LIGO GW150914 event – with the Pierre Auger ObservatoryLili Yang, 2016, objavljeni povzetek znanstvenega prispevka na konferenci Opis: The first gravitational wave transient GW150914 was observed by Advanced LIGO on September 14th, 2015 at 09:50:45 Universal Time. In addition to follow-up electromagnetic observations, the detection of neutrinos will probe deeply and more on the nature of astrophysical sources, especially in the ultra-high energy regime. Neutrinos in the EeV energy range were searched in data collected at the surface detector of the Pierre Auger Observatory within ± 500 s and 1 day after the GW150914 event. No neutrino candidates were found. Based on this non-observation, we derive the first and only one neutrino fluence upper limit at EeV energies for this event at 90% CL, and report constraints on existence of accretion disk around mergers.
Ključne besede: gravitational waves, neutrinos, black hole physics
Objavljeno v RUNG: 06.12.2016; Ogledov: 6363; Prenosov: 0
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14. Ultrahigh energy neutrino follow-up of Gravitational Wave Event GW150914 with the Pierre Auger ObservatoryJaime Alvarez-Muňiz, Francisco Pedreira, Zlatka Zas, Pablo Pieroni, Marta Trini, Lili Yang, elaborat, predštudija, študija Ključne besede: UHE neutrinos, SD detector, Gravitational Waves
Objavljeno v RUNG: 29.11.2016; Ogledov: 6544; Prenosov: 0
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15. Detection of gravitational waves : Diploma thesisGregor Mrak, 2016, diplomsko delo Opis: This report mainly focuses on the first two detections of gravitational waves
(GW). At the beginning of the thesis the historical background of GW explorations
is discussed by pointing out some arguments and researchers
that were essential for the progress. Continuing with the derivation based
on the theory of general relativity, in order to express where certain properties
derive. In the main part of the report, the subject of interest becomes
Laser interferometer gravitational-wave observatory (LIGO), beginning
with the problems occurring on the way to detection, describing different
noise sources one by one. After pointing out the problems, solutions
are discussed, namely the technological advances made to lower the background
noise as much as possible. The chapter (4) points out different parts
of the detector which are implemented to produce a clearer signal. As only
physical noise reduction methods are not enough, digital signal processing
algorithms are mentioned as well which are used to analyze the data. Subsequently
the required theoretical knowledge is given, so the main part ends
with the analysis of actual data taken from LIGO’s public release for both
GW150914 and GW151226 events (first and second official detections). In
the conclusion of the report a brief descriptions of various detectors besides
Ligo are given and some insight of the future detectors that are planned to
be built.
Ključne besede: Gravitational waves, Ligo, Binary black hole merger, gravitational
wave interferometry
Objavljeno v RUNG: 27.09.2016; Ogledov: 8639; Prenosov: 327
 Celotno besedilo (3,27 MB) |
16. FERMI-LAT OBSERVATIONS OF THE LIGO EVENT GW150914Gabrijela Zaharijas, Collaboration Fermi LAT, Collaboration LIGO, 2016, izvirni znanstveni članek Opis: The Fermi Large Area Telescope (LAT) has an instantaneous field of view (FoV) covering ~1 5 of the sky and it completes a survey of the entire sky in high-energy gamma-rays every 3 hr. It enables searches for transient phenomena over timescales from milliseconds to years. Among these phenomena could be electromagnetic counterparts to gravitational wave (GW) sources. In this paper, we present a detailed study of the LAT observations relevant to Laser Interferometer Gravitational-wave Observatory (LIGO) event GW150914, which is the first direct detection of gravitational waves and has been interpreted as being due to the coalescence of two stellar-mass black holes. The localization region for GW150914 was outside the LAT FoV at the time of the GW signal. However, as part of routine survey observations, the LAT observed the entire LIGO localization region within ∼70 minutes of the trigger and thus enabled a comprehensive search for a γ-ray counterpart to GW150914. The study of the LAT data presented here did not find any potential counterparts to GW150914, but it did provide limits on the presence of a transient counterpart above 100 MeV on timescales of hours to days over the entire GW150914 localization region.
Ključne besede: gravitational waves, gamma rays
Objavljeno v RUNG: 20.06.2016; Ogledov: 6001; Prenosov: 0
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