1. Galactic transient sources with the Cherenkov Telescope Array ObservatoryK. Abe, Saptashwa Bhattacharyya, Christopher Eckner, Judit Pérez Romero, Samo Stanič, Serguei Vorobiov, Gabrijela Zaharijas, Danilo Zavrtanik, Marko Zavrtanik, Miha Živec, 2025, izvirni znanstveni članek Opis: A wide variety of Galactic sources show transient emission at soft and hard X-ray energies: low- and high-mass X-ray binaries containing compact objects, isolated neutron stars exhibiting extreme variability as magnetars as well as pulsar-wind nebulae. Although most of them can show emission up to MeV and/or GeV energies, many have not yet been detected in the TeV domain by Imaging Atmospheric Cherenkov Telescopes. In this paper, we explore the feasibility of detecting new Galactic transients with the Cherenkov Telescope Array Observatory (CTAO) and the prospects for studying them with Target of Opportunity observations. We show that CTAO will likely detect new sources in the TeV regime, such as the massive microquasars in the Cygnus region, low-mass X-ray binaries with low-viewing angle, flaring emission from the Crab pulsar-wind nebula or other novae explosions, among others. Since some of these sources could also exhibit emission at larger time-scales, we additionally test their detectability at longer exposures. We finally discuss the multiwavelength synergies with other instruments and large astronomical facilities.
Ključne besede: very-high-energy gamma-rays, Cherenkov Telescope Array Observatory, galactic transient sources, microquasars, X-ray binaries, flaring emission, crab pulsar-wind nebula, novae explosions
Objavljeno v RUNG: 21.05.2025; Ogledov: 24; Prenosov: 0
 Celotno besedilo (6,79 MB)
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2. Equal abundance of summertime natural and wintertime anthropogenic Arctic organic aerosolsVaios Moschos, Katja Dzepina, Deepika Bhattu, Houssni Lamkaddam, Roberto Casotto, Kaspar R. Daellenbach, Francesco Canonaco, Pragati Rai, Wenche Aas, Silvia Becagli, Giulia Calzolai, Konstantinos Eleftheriadis, Claire E. Moffett, Jürgen Schnelle-Kreis, Mirko Severi, Sangeeta Sharma, Henrik Skov, Mika Vestenius, Wendy Zhang, Hannele Hakola, Heidi Hellén, Lin Huang, Jean-Luc Jaffrezo, Andreas Massling, Jakob K. Nøjgaard, Tuuka Petäjä, Olga Popovicheva, Rebecca J. Sheesley, Rita Traversi, Karl Espen Yttri, Julia Schmale, André S. H. Prévôt, Urs Baltensperger, Imad El Haddad, 2022, izvirni znanstveni članek Opis: Aerosols play an important yet uncertain role in modulating the radiation balance of the sensitive Arctic atmosphere. Organic aerosol is one of the most abundant, yet least understood, fractions of the Arctic aerosol mass. Here we use data from eight observatories that represent the entire Arctic to reveal the annual cycles in anthropogenic and biogenic sources of organic aerosol. We show that during winter, the organic aerosol in the Arctic is dominated by anthropogenic emissions, mainly from Eurasia, which consist of both direct combustion emissions and long-range transported, aged pollution. In summer, the decreasing anthropogenic pollution is replaced by natural emissions. These include marine secondary, biogenic secondary and primary biological emissions, which have the potential to be important to Arctic climate by modifying the cloud condensation nuclei properties and acting as ice-nucleating particles. Their source strength or atmospheric processing is sensitive to nutrient availability, solar radiation, temperature and snow cover. Our results provide a comprehensive understanding of the current pan-Arctic organic aerosol, which can be used to support modelling efforts that aim to quantify the climate impacts of emissions in this sensitive region.
Ključne besede: Arctic, Organic aerosols, Emission sources, Climate change
Objavljeno v RUNG: 01.03.2022; Ogledov: 3078; Prenosov: 0
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