1. Prospects for a survey of the galactic plane with the Cherenkov Telescope ArrayK. Abe, Saptashwa Bhattacharyya, Judit Pérez Romero, Samo Stanič, Veronika Vodeb, Serguei Vorobiov, Gabrijela Zaharijas, Danilo Zavrtanik, Marko Zavrtanik, Miha Živec, 2024, izvirni znanstveni članek Opis: Approximately one hundred sources of very-high-energy (VHE) gamma rays are known in the Milky Way, detected with a combination of targeted observations and surveys. A survey of the entire Galactic Plane in the energy range from a few tens of GeV to a few hundred TeV has been proposed as a Key Science Project for the upcoming Cherenkov Telescope Array Observatory (CTAO). This article presents the status of the studies towards the Galactic Plane Survey (GPS). We build and make publicly available a sky model that combines data from recent observations of known gamma-ray emitters with state-of-the-art physically-driven models of synthetic populations of the three main classes of established Galactic VHE sources (pulsar wind nebulae, young and interacting supernova remnants, and compact binary systems), as well as of interstellar emission from cosmic-ray interactions in the Milky Way. We also perform an optimisation of the observation strategy (pointing pattern and scheduling) based on recent estimations of the instrument performance. We use the improved sky model and observation strategy to simulate GPS data corresponding to a total observation time of 1620 hours spread over ten years. Data are then analysed using the methods and software tools under development for real data. Under our model assumptions and for the realisation considered, we show that the GPS has the potential to increase the number of known Galactic VHE emitters by almost a factor of five. This corresponds to the detection of more than two hundred pulsar wind nebulae and a few tens of supernova remnants at average integral fluxes one order of magnitude lower than in the existing sample above 1 TeV, therefore opening the possibility to perform unprecedented population studies. The GPS also has the potential to provide new VHE detections of binary systems and pulsars, to confirm the existence of a hypothetical population of gamma-ray pulsars with an additional TeV emission component, and to detect bright sources capable of accelerating particles to PeV energies (PeVatrons). Furthermore, the GPS will constitute a pathfinder for deeper follow-up observations of these source classes. Finally, we show that we can extract from GPS data an estimate of the contribution to diffuse emission from unresolved sources, and that there are good prospects of detecting interstellar emission and statistically distinguishing different scenarios. Thus, a survey of the entire Galactic plane carried out from both hemispheres with CTAO will ensure a transformational advance in our knowledge of Galactic VHE source populations and interstellar emission.
Ključne besede: very-high-energy gamma rays, Cherenkov Telescope Array Observatory, CTAO Galactic Plane Survey, galactic cosmic rays, pulsar wind nebulae, supernova remnants, galactic PeVatrons, binary systems, diffuse emission
Objavljeno v RUNG: 28.10.2024; Ogledov: 389; Prenosov: 0
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2. Strongly lensed supernovae, the past and the future : lecture at the University of Cambridge, 26. 6. 2024Tanja Petrushevska, 2024, predavanje na tuji univerzi Opis: The searches and observations of supernovae (SNe) have been motivated by the fact that they are exceptionally useful for various astrophysical and cosmological applications. Most prominently, Type Ia SNe (SNe Ia) have been used as distance indicators showing that the expansion rate of the Universe is accelerating. The strong gravitational lensing effect provides another powerful tool and occurs when a foreground mass distribution is located along the line of sight to a background source. It can happen so that galaxies and galaxy clusters can act as “gravitational telescopes”, boosting the faint signals from distant SNe and galaxies. Thanks to the magnification boost provided by the gravitational telescope, we are able to probe galaxies and SNe that otherwise would be undetectable. Therefore, the combination of the two tools, SNe and strong lensing, in the single phenomenon of strongly lensed SNe, provides a powerful simultaneous probe of several cosmological and astrophysical phenomena. By measuring the time delays of strongly lensed supernovae and having a high-quality strong lensing model of the galaxy cluster, it is possible to measure the Hubble constant with competitive precision. In this talk, I will present some of the past and recent results that have been possible due to the observations of strongly lensed supernovae and anticipate what we can expect in the future from the upcoming telescope surveys, such as the Vera C. Rubin Observatory and Nancy G. Roman Space Telescope.
Ključne besede: supernova, strong lensing, Hubble constant
Objavljeno v RUNG: 26.06.2024; Ogledov: 778; Prenosov: 13
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4. Lensed type Ia supernova “Encore” at z=2 : the first instance of two multiply imaged supernovae in the same host galaxyJustin Pierel, A. B. Newman, S. Dhawan, M. Gu, B. A. Joshi, T. Li, S. Schuldt, L. G. Strolger, S. H. Suyu, Tanja Petrushevska, 2024, izvirni znanstveni članek Ključne besede: supernova, James Webb Space Telescope, Hubble constant
Objavljeno v RUNG: 31.05.2024; Ogledov: 1088; Prenosov: 9
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5. JWST photometric time-delay and magnification measurements for the triply imaged type ia "SN H0pe" at z=1.78Justin Pierel, B. L. Frye, M. Pascale, Gabriel Bartosch Caminha, W. Chen, S. Dhawan, D. Gilman, M. Grayling, Mateusz Bronikowski, Tanja Petrushevska, 2024, izvirni znanstveni članek Ključne besede: supernova, strong lensing, cosmology, Hubble constant, James Webb Space Telescope
Objavljeno v RUNG: 21.05.2024; Ogledov: 1141; Prenosov: 8
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6. Hevreka (Supernove tipa 1a)Tanja Petrushevska, Japelj Jure, radijska ali televizijska oddaja, podkast, intervju, novinarska konferenca Opis: V vesolju tudi poka kot za stavo. Zvezde, ki večino življenja ne počnejo nič drugega kot spreminjajo vodik v helij, si včasih zaželijo pozornosti in eksplodirajo kot supernove. Zvezda kar naenkrat postana svetlejša od celotne galaksije, zato supernove vidimo tudi, ko eksplodirajo daleč, daleč stran. Astronomi vesoljski ognjemet seveda z veseljem opazujejo. Supernove namreč niso zgolj izjemno svetle, ampak igrajo pomembno vlogo pri številnih procesih v vesolju. Kozmične eksplozije so različnih tipov in okusov, verjetno najbolj slavne med njimi pa so supernove tipa 1a. Te nam je približala doktorica Tanja Petrushevska, docentka na Fakulteti za naravoslovje Univerze v Novi Gorici. Pred mikrofon jo je povabil dr. Jure Japelj.
Ključne besede: radio, intervju, supernova
Objavljeno v RUNG: 24.11.2023; Ogledov: 1313; Prenosov: 4
 Povezava na datoteko
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7. A population of Type Ibc supernovae with massive progenitors : broad lightcurves not uncommon in (i)PTFE. Karamehmetoglu, Jesper Sollerman, F. Taddia, C. Barbarino, U. Feindt, U. C. Fremling, Avishay Gal-Yam, M. M. Kasliwal, Tanja Petrushevska, S. Schulze, 2023, izvirni znanstveni članek Ključne besede: astronomy, supernova progenitors
Objavljeno v RUNG: 10.10.2023; Ogledov: 1367; Prenosov: 5
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8. Potential of the Cherenkov Telescope Array for studying the young nearby supernova remnantsDmitry A. Prokhorov, Saptashwa Bhattacharyya, Judit Pérez Romero, Samo Stanič, Veronika Vodeb, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Miha Živec, 2023, objavljeni znanstveni prispevek na konferenci Opis: Modern imaging atmospheric Cherenkov telescopes have extensively observed young nearby su-pernova remnants (SNRs), with ages of about 1000 years or less, in the very-high-energy (VHE) gamma-ray band. These efforts resulted in the detection of VHE emission from three young SNRs – Cassiopeia A, Tycho, and SN 1006 – and provided significant evidence for emission from the more distant Kepler’s SNR. However, many questions on the production of VHE gamma rays in these remnants remain unanswered. Using detailed physical models for Tycho’s SNR based on the CR-hydro-NEI code and physically motivated models for the other young nearby remnants, we simulated observations with the Cherenkov Telescope Array (CTA) of these gamma-ray sources. We highlight properties of these remnants accessible for investigation with future CTA observa-tions and discuss which questions are expected to be answered.
Ključne besede: Cherenkov Telescope Array, CTA, supernova remnants, young nearby supernova
Objavljeno v RUNG: 26.09.2023; Ogledov: 1530; Prenosov: 5
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9. LensWatch. I. resolved HST observations and constraints on the strongly lensed type Ia supernova 2022qmx (ʺSN Zwickyʺ)Justin Pierel, N. Arendse, S. Ertl, X. Huang, L. A. Moustakas, S. Schuldt, A. J. Shajib, Y. Shu, Mateusz Bronikowski, Tanja Petrushevska, 2023, izvirni znanstveni članek Ključne besede: supernova, strong lensing, astronomy
Objavljeno v RUNG: 16.05.2023; Ogledov: 2429; Prenosov: 14
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10. 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: 2056; Prenosov: 0
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