31. Cherenkov Telescope Array: the World's largest VHE gamma-ray observatoryRoberta Zanin, Saptashwa Bhattacharyya, Barbara MARČUN, Judit Pérez Romero, Samo Stanič, Veronika Vodeb, Serguei Vorobiov, Gabrijela Zaharijas, Marko Zavrtanik, Danilo Zavrtanik, Miha Živec, 2021, objavljeni znanstveni prispevek na konferenci (vabljeno predavanje) Opis: Very-High Energy (VHE) gamma-ray astroparticle physics is a relatively young field, and obser-vations over the past decade have surprisingly revealed almost two hundred VHE emitters which appear to act as cosmic particle accelerators. These sources are an important component of the Universe, influencing the evolution of stars and galaxies. At the same time, they also act as a probe of physics in the most extreme environments known - such as in supernova explosions, and around or after the merging of black holes and neutron stars. However, the existing experiments have provided exciting glimpses, but often falling short of supplying the full answer. A deeper understanding of the TeV sky requires a significant improvement in sensitivity at TeV energies, a wider energy coverage from tens of GeV to hundreds of TeV and a much better angular and energy resolution with respect to the currently running facilities. The next generation gamma-ray observatory, the Cherenkov Telescope Array Observatory (CTAO), is the answer to this need. In this talk I will present this upcoming observatory from its design to the construction, and its potential science exploitation. CTAO will allow the entire astronomical community to explore a new discovery space that will likely lead to paradigm-changing breakthroughs. In particular, CTA has an unprecedented sensitivity to short (sub-minute) timescale phenomena, placing it as a key instrument in the future of multi-messenger and multi-wavelength time domain astronomy. I will conclude the talk presenting the first scientific results obtained by the LST-1, the prototype of one CTA telescope type - the Large Sized Telescope, that is currently under commission. Ključne besede: Very-High Energy Gamma-rays, Cherenkov Telescope Array Objavljeno v RUNG: 18.09.2023; Ogledov: 562; Prenosov: 6 Celotno besedilo (2,39 MB) Gradivo ima več datotek! Več... |
32. Investigating the VHE gamma-ray sources using deep neural networksVeronika Vodeb, Saptashwa Bhattacharyya, G. Principe, Gabrijela Zaharijas, R. Austri, F. Stoppa, S. Caron, D. Malyshev, 2023, objavljeni znanstveni prispevek na konferenci Opis: The upcoming Cherenkov Telescope Array (CTA) will dramatically improve the point-source sensitivity compared to the current Imaging Atmospheric Cherenkov Telescopes (IACTs). One of the key science projects of CTA will be a survey of the whole Galactic plane (GPS) using both southern and northern observatories, specifically focusing on the inner galactic region. We extend a deep learning-based image segmentation software pipeline (autosource-id) developed on Fermi-LAT data to detect and classify extended sources for the simulated CTA GPS. Using updated instrument response functions for CTA (Prod5), we test this pipeline on simulated gamma-ray sources lying in the inner galactic region (specifically 0∘Ključne besede: deep neural network, cosmic-rays, CTA, classification Objavljeno v RUNG: 31.08.2023; Ogledov: 860; Prenosov: 6 Celotno besedilo (962,45 KB) Gradivo ima več datotek! Več... |
33. Sensitivity of the Cherenkov Telescope Array to TeV photon emission from the Large Magellanic CloudA. Acharyya, R. Adam, Saptashwa Bhattacharyya, Samo Stanič, Veronika Vodeb, Serguei Vorobiov, Gabrijela Zaharijas, Danilo Zavrtanik, Marko Zavrtanik, Miha Živec, 2023, izvirni znanstveni članek Opis: A deep survey of the Large Magellanic Cloud at ∼ 0.1−100 TeV photon energies with the Cherenkov Telescope Array is planned.
We assess the detection prospects based on a model for the emission of the galaxy, comprising the four known TeV emitters,
mock populations of sources, and interstellar emission on galactic scales. We also assess the detectability of 30 Doradus and SN 1987A, and the constraints that can be derived on the nature of dark matter. The survey will allow for fine spectral studies of N 157B, N 132D, LMC P3, and 30 Doradus C, and half a dozen other sources should be revealed, mainly pulsar-powered
objects. The remnant from SN 1987A could be detected if it produces cosmic-ray nuclei with a flat power-law spectrum at high energies, or with a steeper index 2.3−2.4 pending a flux increase by a factor > 3−4 over ∼ 2015−2035. Large-scale interstellar emission remains mostly out of reach of the survey if its > 10 GeV spectrum has a soft photon index ∼ 2.7, but degree-scale 0.1 − 10 TeV pion-decay emission could be detected if the cosmic-ray spectrum hardens above >100 GeV. The 30 Doradus star-forming region is detectable if acceleration efficiency is on the order of 1 − 10% of the mechanical luminosity and diffusion is suppressed by two orders of magnitude within < 100 pc. Finally, the survey could probe the canonical velocity-averaged cross section for self-annihilation of weakly interacting massive particles for cuspy Navarro-Frenk-White profiles. Ključne besede: very-high energy (VHE) gamma-rays, Cherenkov Telescope Array Observatory, Large Magellanic Cloud, pulsar wind nebulas, galaxiesstar-forming regions, cosmic rays, dark matter Objavljeno v RUNG: 02.06.2023; Ogledov: 1178; Prenosov: 1 Celotno besedilo (3,66 MB) |
34. Sensitivity of the Cherenkov Telescope Array to spectral signatures of hadronic PeVatrons with application to Galactic Supernova RemnantsFabio Acero, Saptashwa Bhattacharyya, Samo Stanič, Veronika Vodeb, Serguei Vorobiov, Gabrijela Zaharijas, Danilo Zavrtanik, Marko Zavrtanik, Miha Živec, 2023, izvirni znanstveni članek Ključne besede: gamma-rays, cosmic rays, Galactic PeVatrons, Galactic supernova remnants, Cherenkov Telescope Array Objavljeno v RUNG: 14.04.2023; Ogledov: 1181; Prenosov: 0 Gradivo ima več datotek! Več... |
35. AutoSourceID-Light : Fast optical source localization via U-Net and Laplacian of GaussianF. Stoppa, P. Vreeswijk, S. Bloemen, Saptashwa Bhattacharyya, S Caron, G. Jóhannesson, R. Ruiz de Austri, C. Van den Oetelaar, Gabrijela Zaharijas, P.J. Groot, E. Cator, G. Nelemans, 2022, izvirni znanstveni članek Opis: Aims: With the ever-increasing survey speed of optical wide-field telescopes and the importance of discovering transients when they
are still young, rapid and reliable source localization is paramount. We present AutoSourceID-Light (ASID-L), an innovative framework that uses computer vision techniques that can naturally deal with large amounts of data and rapidly localize sources in optical
images.
Methods: We show that the ASID-L algorithm based on U-shaped networks and enhanced with a Laplacian of Gaussian filter provides outstanding performance in the localization of sources. A U-Net network discerns the sources in the images from many different artifacts and passes the result to a Laplacian of Gaussian filter that then estimates the exact location.
Results: Using ASID-L on the optical images of the MeerLICHT telescope demonstrates the great speed and localization power of the method. We compare the results with SExtractor and show that our method outperforms this more widely used method rapidly detects more sources not only in low and mid-density fields, but particularly in areas with more than 150 sources per square arcminute. The training set and code used in this paper are publicly available. Ključne besede: astronomical databases, data analysis, image processing Objavljeno v RUNG: 23.01.2023; Ogledov: 1319; Prenosov: 0 Gradivo ima več datotek! Več... |
36. Dark Matter science in the era of LSST : Astro2020 science white paperKeith Bechtol, Alex Drlica-Wagner, Kevork N. Abazajian, Muntazir Abidi, Susmita Adhikari, Yacine Ali-Haïmoud, James Annis, Behzad Ansarinejad, Christopher Eckner, Gabrijela Zaharijas, 2019, projektna dokumentacija (idejni projekt, izvedbeni projekt) Ključne besede: cosmology, nongalactic astrophysics, high energy astrophysical phenomena, high energy physics, experiments Objavljeno v RUNG: 03.05.2022; Ogledov: 1593; Prenosov: 37 Povezava na celotno besedilo Gradivo ima več datotek! Več... |
37. Probing the fundamental nature of Dark Matter with the Large Synoptic Survey Telescope : v1.1Alex Drlica-Wagner, Yao-Yuan Mao, Susmita Adhikari, Robert Armstrong, Arka Banerjee, Nilanjan Banik, Keith Bechtol, Simeon Bird, Christopher Eckner, Gabrijela Zaharijas, 2019, projektna dokumentacija (idejni projekt, izvedbeni projekt) Ključne besede: dark matter, high energy physics, astrophysical observations, cosmological observations, Large Synoptic Survey Telescope (LSST) Objavljeno v RUNG: 03.05.2022; Ogledov: 1531; Prenosov: 42 Povezava na celotno besedilo Gradivo ima več datotek! Več... |
38. Identification of point sources in gamma rays using U-shaped convolutional neural networks and a data challengeBoris Panes, Christopher Eckner, Luc Hendriks, Sascha Caron, Klaas Dijkstra, Gudlaugur Johannesson, Roberto Ruiz de Austri, Gabrijela Zaharijas, 2021, izvirni znanstveni članek Ključne besede: gamma rays, astroparticle physics, data analysis Objavljeno v RUNG: 17.02.2022; Ogledov: 1657; Prenosov: 7 Povezava na celotno besedilo Gradivo ima več datotek! Več... |
39. Catalog of long-term transient sources in the first 10 yr of Fermi-LAT dataL. Baldini, J. Ballet, D. Bastieri, J. Becerra Gonzalez, R. Bellazzini, A. Berretta, E. Bissaldi, R. D. Blandford, E. D. Bloom, Gabrijela Zaharijas, 2021, izvirni znanstveni članek Ključne besede: high energy astrophysics, active galactic nuclei, gamma-ray bursts, solar flares, solar gamma-ray emission Objavljeno v RUNG: 17.02.2022; Ogledov: 1814; Prenosov: 40 Povezava na celotno besedilo Gradivo ima več datotek! Več... |
40. First Fermi-LAT solar flare catalogM. Ajello, L. Baldini, D. Bastieri, R. Bellazzini, A. Berretta, E. Bissaldi, R. D. Blandford, R. Bonino, P. Bruel, Gabrijela Zaharijas, 2021, izvirni znanstveni članek Ključne besede: solar flares, solar gamma-ray emission, gamma-ray sources, gamma-ray telescopes, catalogs Objavljeno v RUNG: 17.02.2022; Ogledov: 2251; Prenosov: 112 Povezava na celotno besedilo Gradivo ima več datotek! Več... |