Universe最新文献_第3页

About Jordan and Einstein Frames: A Study in Inflationary Magnetogenesis 关于约旦和爱因斯坦框架：胀磁发生研究

IF 2.9 4区物理与天体物理

Universe Pub Date : 2024-09-01 DOI: 10.3390/universe10090350

Joel Velásquez, Héctor J. Hortua, Leonardo Castañeda

引用次数: 0

Characterisation of the Atmosphere in Very High Energy Gamma-Astronomy for Imaging Atmospheric Cherenkov Telescopes 用于大气切伦科夫望远镜成像的甚高能伽马天文学中的大气特征描述

IF 2.9 4区物理与天体物理

Universe Pub Date : 2024-08-30 DOI: 10.3390/universe10090349

Dijana Dominis Prester, Jan Ebr, Markus Gaug, Alexander Hahn, Ana Babić, Jiří Eliášek, Petr Janeček, Sergey Karpov, Marta Kolarek, Marina Manganaro, Razmik Mirzoyan

{"title":"Characterisation of the Atmosphere in Very High Energy Gamma-Astronomy for Imaging Atmospheric Cherenkov Telescopes","authors":"Dijana Dominis Prester, Jan Ebr, Markus Gaug, Alexander Hahn, Ana Babić, Jiří Eliášek, Petr Janeček, Sergey Karpov, Marta Kolarek, Marina Manganaro, Razmik Mirzoyan","doi":"10.3390/universe10090349","DOIUrl":"https://doi.org/10.3390/universe10090349","url":null,"abstract":"Ground-based observations of Very High Energy (VHE) gamma rays from extreme astrophysical sources are significantly influenced by atmospheric conditions. This is due to the atmosphere being an integral part of the detector when utilizing Imaging Atmospheric Cherenkov Telescopes (IACTs). Clouds and dust particles diminish atmospheric transmission of Cherenkov light, thereby impacting the reconstruction of the air showers and consequently the reconstructed gamma-ray spectra. Precise measurements of atmospheric transmission above Cherenkov observatories play a pivotal role in the accuracy of the analysed data, among which the corrections of the reconstructed energies and fluxes of incoming gamma rays, and in establishing observation strategies for different types of gamma-ray emitting sources. The Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes and the Cherenkov Telescope Array Observatory (CTAO), both located on the Observatorio del Roque de los Muchachos (ORM), La Palma, Canary Islands, use different sets of auxiliary instruments for real-time characterisation of the atmosphere. In this paper, historical data taken by MAGIC LIDAR (LIght Detection And Ranging) and CTAO FRAM (F/Photometric Robotic Telescope) are presented. From the atmospheric aerosol transmission profiles measured by the MAGIC LIDAR and CTAO FRAM aerosol optical depth maps, we obtain the characterisation of the clouds above the ORM at La Palma needed for data correction and optimal observation scheduling.","PeriodicalId":48646,"journal":{"name":"Universe","volume":"268 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Infrared Regularization of Very Special Relativity Models 非常狭义相对论模型的红外正则化

IF 2.9 4区物理与天体物理

Universe Pub Date : 2024-08-29 DOI: 10.3390/universe10090348

Jorge Alfaro

引用次数: 0

Strange and Odd Morphology Extragalactic Radio Sources (STROMERSs): A Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) Look at the Strange and Odd Radio Sources 银河系外奇异形貌射电源（STROMERSs）：二十厘米射电天空的微弱图像（FIRST）--奇异射电源的观察

IF 2.9 4区物理与天体物理

Universe Pub Date : 2024-08-28 DOI: 10.3390/universe10090347

Soumen Kumar Bera, Tapan K. Sasmal, Soumen Mondal, Taotao Fang, Xuelei Chen

{"title":"Strange and Odd Morphology Extragalactic Radio Sources (STROMERSs): A Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) Look at the Strange and Odd Radio Sources","authors":"Soumen Kumar Bera, Tapan K. Sasmal, Soumen Mondal, Taotao Fang, Xuelei Chen","doi":"10.3390/universe10090347","DOIUrl":"https://doi.org/10.3390/universe10090347","url":null,"abstract":"We report the identification of an extremely rare and peculiar set of irregular radio sources, termed “STROMERSs” (STRange and Odd Morphology Extragalactic Radio Sources).ingThe irregular radio sources with very anomalous morphologies that make them exceptionally different from all the known classes and subclasses of irregular radio sources are detected as STROMERSs. A thorough search for this class of sources from the Very Large Array (VLA) Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) gave a total of nine such candidates. We checked the corresponding morphology of the identified sources in other frequency surveys. We found a detectable radio emission for all of the nine sources in the NRAO VLA Sky Survey (NVSS) at 1.4 GHz and in the TIFR GMRT Sky Survey (TGSS) at 150 MHz, while the same was found for only three sources in the Westerbork Northern Sky Survey (WENSS) at 625 MHz. However, the strange morphology was not found in all of those other survey images. We also characterized the sources with their corresponding physical parameters like optical counterpart, size, spectral index, and radio luminosity. ingThe estimated spectral values of the sources indicated that the STROMERSs were most likely radio galaxies. The presence of any nearby galaxy clusters for the STROMERSs was also checked.","PeriodicalId":48646,"journal":{"name":"Universe","volume":"4 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

First Results of the CREDO-Maze Cosmic Ray Project CREDO-Maze 宇宙射线项目的首批成果

IF 2.9 4区物理与天体物理

Universe Pub Date : 2024-08-28 DOI: 10.3390/universe10090346

Tadeusz Wibig, Michał Karbowiak, Punsiri Dam-O, Karol Jȩdrzejczak, Jari Joutsenvaara, Julia Puputti, Juha Sorri, Ari-Pekka Leppänen

引用次数: 0

On Quark–Lepton Mixing and the Leptonic CP Violation 关于夸克-质子混合和质子 CP Violation

IF 2.9 4区物理与天体物理

Universe Pub Date : 2024-08-28 DOI: 10.3390/universe10090345

Alessio Giarnetti, Simone Marciano, Davide Meloni

引用次数: 0

The Intrinsic Correlations between Prompt Emission and X-ray Flares of Gamma-Ray Bursts 伽马射线暴的瞬时发射与 X 射线耀斑之间的内在相关性

IF 2.9 4区物理与天体物理

Universe Pub Date : 2024-08-27 DOI: 10.3390/universe10090343

Xing-Ting Zhong, Si-Yuan Zhu, Li-Ming Zhuo, Zeng Zhang, Fu-Wen Zhang

{"title":"The Intrinsic Correlations between Prompt Emission and X-ray Flares of Gamma-Ray Bursts","authors":"Xing-Ting Zhong, Si-Yuan Zhu, Li-Ming Zhuo, Zeng Zhang, Fu-Wen Zhang","doi":"10.3390/universe10090343","DOIUrl":"https://doi.org/10.3390/universe10090343","url":null,"abstract":"X-ray flare (XRF) is a common phenomenon in the X-ray afterglow of gamma-ray bursts (GRBs). Although it is commonly believed that XRFs may share a common origin with prompt emission, i.e., the “internal” origin, the origin of XRFs is still unknown. In this work, we compile a GRB sample containing 31 GRBs with a single XRF, a well-measured spectrum, and a redshift, and investigate the intrinsic properties and correlations between prompt emission and the XRFs of these events. We find that the distributions of main physical parameters of prompt emission and XRFs are basically log-normal. The median value of the rise time is shorter than the decay time for all flares, with a ratio of about 1:2, which is similar to the fast rise and exponential decay structure of prompt emission pulses. We also find that the prompt emission energy (Eiso) and peak luminosity (Liso) have tight correlations with XRF energy (EX,iso) and peak luminosity (LX,p), Eiso∝EX,iso0.74 (LX,p0.62) and Liso∝EX,iso0.85 (LX,p0.68). However, the durations of prompt emissions are independent of the temporal properties of XRFs. Furthermore, we also analyze the three-parameter correlations between prompt emissions and XRFs, and find that there are tight correlations among the XRF peak time (Tp,z), LX,p, and Eiso/Liso, LX,p∝Tp,z−1.08Eiso0.84 and LX,p∝Tp,z−1.09Liso0.71. Interestingly, these results are very similar to the properties of an X-ray plateau in GRBs, which indicates that X-ray flares and plateaus may have the same physical origin, and strongly supports that the two emission components originate from the late-time activity of the central engine.","PeriodicalId":48646,"journal":{"name":"Universe","volume":"4 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Stellar Modeling via the Tolman IV Solution: The Cases of the Massive Pulsar J0740+6620 and the HESS J1731-347 Compact Object 通过托尔曼 IV 解决方案建立恒星模型：大质量脉冲星J0740+6620和HESS J1731-347紧凑天体的案例

IF 2.9 4区物理与天体物理

Universe Pub Date : 2024-08-27 DOI: 10.3390/universe10090342

Grigoris Panotopoulos

{"title":"Stellar Modeling via the Tolman IV Solution: The Cases of the Massive Pulsar J0740+6620 and the HESS J1731-347 Compact Object","authors":"Grigoris Panotopoulos","doi":"10.3390/universe10090342","DOIUrl":"https://doi.org/10.3390/universe10090342","url":null,"abstract":"We model compact objects of known stellar mass and radius made of isotropic matter within Einstein’s gravity. The interior solution describing hydrostatic equilibrium we are using throughout the manuscript corresponds to the Tolman IV exact analytic solution obtained a long time ago. The three free parameters of the solutions are determined by imposing the matching conditions for objects of known stellar mass and radius. Finally, using well established criteria, it is shown that, contrary to the Kohler Chao solution, the Tolman IV solution is compatible with all requirements for well-behaved and realistic solutions, except for the relativistic adiabatic index that diverges at the surface of stars. The divergence of the index Γ may be resolved, including a thin crust assuming a polytropic equation of state, which is precisely the case seen in studies of neutron stars. To the best of our knowledge, we model here for the first time the recently discovered massive pulsar PSR J0740+6620 and the strangely light HESS compact object via the Tolman IV solution. The present work may be of interest to model builders as well as a useful reference for future research.","PeriodicalId":48646,"journal":{"name":"Universe","volume":"44 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142210907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Ionosonde Measurement Comparison during an Interplanetary Coronal Mass Ejection (ICME)- and a Corotating Interaction Region (CIR)-Driven Geomagnetic Storm over Europe 欧洲上空行星际日冕物质抛射（ICME）和同向相互作用区（CIR）驱动的地磁暴期间的电离层测量比较

IF 2.9 4区物理与天体物理

Universe Pub Date : 2024-08-27 DOI: 10.3390/universe10090344

Kitti Alexandra Berényi, Loredana Perrone, Dario Sabbagh, Carlo Scotto, Alessandro Ippolito, Árpád Kis, Veronika Barta

{"title":"Ionosonde Measurement Comparison during an Interplanetary Coronal Mass Ejection (ICME)- and a Corotating Interaction Region (CIR)-Driven Geomagnetic Storm over Europe","authors":"Kitti Alexandra Berényi, Loredana Perrone, Dario Sabbagh, Carlo Scotto, Alessandro Ippolito, Árpád Kis, Veronika Barta","doi":"10.3390/universe10090344","DOIUrl":"https://doi.org/10.3390/universe10090344","url":null,"abstract":"A comparison of three types of ionosonde data from Europe during an interplanetary coronal mass ejection (ICME)- and a corotating interaction region (CIR)-driven geomagnetic storm event is detailed in this study. The selected events are 16–20 March 2015 for the ICME-driven storm and 30 May to 4 June 2013 for the CIR-driven one. Ionospheric data from three European ionosonde stations, namely Pruhonice (PQ), Sopron (SO) and Rome (RO), are investigated. The ionospheric F2-layer responses to these geomagnetic events are analyzed with the ionospheric foF2 and h’F2 parameters, the calculated deltafoF2 and deltahF2 values, the ratio of total electron content (rTEC) and Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) satellite Global Ultraviolet Imager (GUVI) thermospheric [O]/[N2] measurement data. The storm-time and the quiet-day mean values are also compared, and it can be concluded that the quiet-day curves are similar at all the stations while the storm-time ones show the latitudinal dependence during the development of the storm. As a result of the electron density comparison, during the two events, it can be concluded that the sudden storm commencement (SSC) that characterized the ICME induced a traveling atmospheric disturbance (TAD) seen in the European stations in the main phase, while this is not seen in the CIR-driven ionospheric storm, which shows a stronger and more prolonged negative effect in all the stations, probably due to the season and the depleted O/N2 ratio.","PeriodicalId":48646,"journal":{"name":"Universe","volume":"188 1","pages":""},"PeriodicalIF":2.9,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Modeling the TESS Light Curve of Ap Si Star MX TrA 模拟弧矽星 MX TrA 的 TESS 光曲线

IF 2.9 4区物理与天体物理

Universe Pub Date : 2024-08-26 DOI: 10.3390/universe10090341

Yury Pakhomov, Ilya Potravnov, Anna Romanovskaya, Tatiana Ryabchikova

引用次数: 0