Iskanje po repozitoriju

A+ | A- | | SLO | ENG

Opis: The birth of gravitational-wave / electromagnetic astronomy was heralded by the joint observation of gravitational waves (GWs) from a binary neutron star (BNS) merger by Advanced LIGO and Advanced Virgo, GW170817, and of gamma-rays from the short gamma-ray burst GRB170817A by the Fermi Gamma-ray Burst Monitor (GBM) and INTEGRAL. This detection provided the first direct evidence that at least a fraction of BNSs are progenitors of short GRBs. GRBs are now also known to emit very-high-energy (VHE, > 100 GeV) photons as has been shown by recent independent detections of the GRBs 1901114C and 180720B by the ground-based gamma-ray detectors MAGIC and H.E.S.S. In the next years, the Cherenkov Telescope Array (CTA) will boost the searches for VHE counterparts thanks to its unprecedented sensitivity, rapid response and capability to monitor large sky areas via survey-mode operation. In this contribution, we present the CTA program of observations following the detection of GW events. We discuss various follow-up strategies and links to multi-wavelength and multi-messenger observations. Finally we outline the capabilities and prospects of detecting VHE emission from GW counterparts.
Ključne besede: multi-messenger astrophysics, the Cherenkov Telescope Array (CTA) Observatory, gravitational waves, very-high-energy photons, gravitational-wave follow-up program
Objavljeno v RUNG: 08.11.2024; Ogledov: 441; Prenosov: 4
Celotno besedilo (939,48 KB)
Gradivo ima več datotek! Več...

Opis: Multimessenger astronomy has become increasingly important during the past decade. Some astronomical objects have already been successfully observed in the light of multiple messenger signals, allowing for a much deeper understanding of their physical properties. The Pierre Auger Observatory has taken part in multimessenger astronomy with an exhaustive exploration of the ultra-high-energy sky. In this contribution, for the first time, a search for UHE photons from the sources of gravitational waves is presented. Interactions with the cosmic background radiation fields are expected to attenuate any possible flux of ultra-high-energy photons from distant sources and a non-negligible background of air shower events with hadronic origin makes an unambiguous identification of primary photons a challenging task. In the analysis presented here, a selection strategy is applied to both GW sources and air shower events aiming to provide maximum sensitivity to a possible photon signal. At the same time, a window is kept open for hypothetical new-physics processes, which might allow for much larger interaction lengths of photons in the extragalactic medium. Preliminary results on the UHE photon fluence from a selection of GW sources, including the binary neutron star merger GW170817 are presented.
Ključne besede: Pierre Auger Observatory, indirect detection, fluorescence detection, ultra-high energy, photons, cosmic rays, anisotropy, gravitational waves, multimessenger
Objavljeno v RUNG: 29.09.2023; Ogledov: 1694; Prenosov: 7
Celotno besedilo (940,08 KB)
Gradivo ima več datotek! Več...

Opis: The detection of gravitational waves (GWs) from a binary neutron star (BNS) merger by Advanced LIGO and Advanced Virgo (GW170817), along with the discovery of the electromagnetic counterparts of this GW event, ushered in a new era of multimessenger astronomy, providing the first direct evidence that BNS mergers are progenitors of short gamma-ray bursts (GRBs). Such events may also produce very-high-energy (VHE, > 100 GeV) photons which have yet to be detected in coincidence with a GW signal. The Cherenkov Telescope Array (CTA) is a next-generation VHE observatory which aims to be indispensable in this search, with an unparalleled sensitivity and ability to slew anywhere on the sky within a few tens of seconds. Achieving such a feat will require a comprehensive real-time strategy capable of coordinating searches over potentially very large regions of the sky. This work will evaluate and provide estimations on the number of GW-CTA events determined from simulated BNS systems and short GRBs, considering both on and off-axis emission. In addition, we will present and discuss the prospects of potential follow-up strategies with CTA.
Ključne besede: gravitational waves, binary neutron star merger, short gamma-ray bursts
Objavljeno v RUNG: 15.09.2023; Ogledov: 1941; Prenosov: 7
Celotno besedilo (1,66 MB)
Gradivo ima več datotek! Več...

Ključne besede: 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).
Objavljeno v RUNG: 04.01.2021; Ogledov: 3686; Prenosov: 0

Ključne besede: gamma-ray burst, gamma rays, gravitational waves
Objavljeno v RUNG: 23.08.2018; Ogledov: 4647; Prenosov: 0
Gradivo ima več datotek! Več...