1. FERMI-LAT OBSERVATIONS OF THE LIGO EVENT GW150914Gabrijela Zaharijas, Collaboration Fermi LAT, Collaboration LIGO, 2016, original scientific article Abstract: 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.
Found in: ključnih besedah
Summary of found: ...these phenomena could be electromagnetic counterparts to gravitational wave (GW) sources. In this paper, we... ...is the first direct detection of gravitational waves and has been interpreted as being due...
Keywords: gravitational waves, gamma rays
Published: 20.06.2016; Views: 3948; Downloads: 0
 Fulltext (2,04 MB) |
2. Detection of gravitational wavesGregor Mrak, 2016, undergraduate thesis Abstract: 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.
Found in: ključnih besedah
Keywords: Gravitational waves, Ligo, Binary black hole merger, gravitational
wave interferometry
Published: 27.09.2016; Views: 6187; Downloads: 305
Fulltext (3,27 MB) |
3. Ultrahigh energy neutrino follow-up of Gravitational Wave Event GW150914 with the Pierre Auger ObservatoryMarta Trini, Pablo Pieroni, Zlatka Zas, Francisco Pedreira, Jaime Alvarez-Muňiz, Lili Yang, treatise, preliminary study, study Found in: ključnih besedah
Keywords: UHE neutrinos, SD detector, Gravitational Waves
Published: 29.11.2016; Views: 4592; Downloads: 0
Fulltext (881,65 KB) |
4. Search for UHE neutrinos – in coincidence with LIGO GW150914 event – with the Pierre Auger ObservatoryLili Yang, 2016, published scientific conference contribution abstract Abstract: 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.
Found in: ključnih besedah
Summary of found: ...The first gravitational wave transient GW150914 was observed by Advanced... ...gravitational waves, neutrinos, black hole physics...
Keywords: gravitational waves, neutrinos, black hole physics
Published: 06.12.2016; Views: 4384; Downloads: 0
Fulltext (627,39 KB) |
5. New Frontiers in Black Hole Astrophysics2017, proceedings of peer-reviewed scientific conference contributions (international and foreign conferences) Found in: ključnih besedah
Summary of found: ...nuclei, gamma ray bursts, tidal disruption events, gravitational waves...
Keywords: astronomy, black holes, active galactic nuclei, gamma ray bursts, tidal disruption events, gravitational waves
Published: 17.08.2017; Views: 3286; Downloads: 0
Fulltext (106,73 KB) |
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8. A hot and fast ultra-stripped supernova that likely formed a compact neutron star binaryTanja Petrushevska, 2018, original scientific article Abstract: Compact neutron star binary systems are produced from binary massive stars through stellar evolution involving up to two supernova explosions. The final stages in the formation of these systems have not been directly observed. We report the discovery of iPTF 14gqr (SN 2014ft), a type Ic supernova with a fast-evolving light curve indicating an extremely low ejecta mass (≈0.2 solar masses) and low kinetic energy (≈2 × 1050 ergs). Early photometry and spectroscopy reveal evidence of shock cooling of an extended helium-rich envelope, likely ejected in an intense pre-explosion mass-loss episode of the progenitor. Taken together, we interpret iPTF 14gqr as evidence for ultra-stripped supernovae that form neutron stars in compact binary systems.
Found in: ključnih besedah
Summary of found: ...supernova, neutron stars, gravitational waves...
Keywords: supernova, neutron stars, gravitational waves
Published: 12.10.2018; Views: 2651; Downloads: 0
Fulltext (3,36 MB) |
9. Studying TDEs in the era of LSSTKatja Bricman, A. Gomboc, 2019, published scientific conference contribution abstract Found in: ključnih besedah
Summary of found: ...conference is supported by the Action CA16104 Gravitational waves, black holes and fundamental physics (GWverse),...
Keywords: The observing strategy with continuous scanning and large sky coverage of the upcoming ground-based Large Synoptic Survey Telescope (LSST) will make it a perfect tool in search of rare transients, such as Tidal Disruption Events (TDEs). Bright optical flares resulting from tidal disruption of stars by their host supermassive black hole (SMBH) can provide us with important information about the mass of the SMBH involved in the disruption and thus enable the study of quiescent SMBHs, which represent a large majority of SMBHs found in centres of galaxies. These types of transients are extremely rare, with only about few tens of candidates discovered so far. It is expected that the LSST will provide a large sample of new TDE light curves. Here we present simulations of TDE observations using an end-to-end LSST simulation framework. Based on the analysis of simulated light curves we estimate the number of TDEs with good quality light curves the LSST is expected to discover in 10 years of observations. In addition, we investigate whether TDEs observed by the LSST could be used to probe the SMBH mass distribution in the universe.
The participation at this conference is supported by the Action CA16104 Gravitational waves, black holes and fundamental physics (GWverse), supported by COST (European Cooperation in Science and Technology).
Published: 04.01.2021; Views: 1837; Downloads: 0 |
10. Space-time ripplesTaj Jankovič, 2017, professional article Abstract: Recent first direct detection of gravitational waves opened a new window on the universe. Gravitational waves arise from small perturbations of space-time and from their characteristics it is possible to determine properties of astrophysical objects from which they originate. In this seminar Einstein equation is introduced to describe gravitational waves and ascertain their properties. Furthermore, possible astrophysical sources are presented, as well as the first directly and indirectly detected event.
Found in: ključnih besedah
Summary of found: ...Recent first direct detection of gravitational waves opened a new window on the...
Keywords: gravitation, gravitational waves, theory of relativity, astrophysics
Published: 29.07.2021; Views: 1234; Downloads: 0 |
