{"title":"Active galactic nuclei horizons from the gamma-ray perspective","authors":"Andrew M. Taylor","doi":"10.1016/j.newar.2017.06.001","DOIUrl":null,"url":null,"abstract":"<div><p><span>Recent results in the field of high energy active galactic nuclei (AGN) astrophysics, benefiting from improvements to gamma-ray instruments and observational strategies, have revealed a surprising wealth of unexpected phenomena. These developments have been brought about both through observational efforts to discover new very high energy gamma-ray emitters, as well as from further in-depth observations of previously detected and well studied objects. I here focus specifically on the discovery of repeated temporal structures observed in AGN lightcurves, and new hard spectral components within the </span>spectral energy distributions of other AGN systems. The challenges that these new features place on the modeling of the sources are highlighted, along with some reflections on what these results tell us about the underlying nature of the emission processes at play.</p></div>","PeriodicalId":19718,"journal":{"name":"New Astronomy Reviews","volume":"78 ","pages":"Pages 16-25"},"PeriodicalIF":11.7000,"publicationDate":"2017-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.newar.2017.06.001","citationCount":"2","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"New Astronomy Reviews","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1387647316300896","RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
引用次数: 2
Abstract
Recent results in the field of high energy active galactic nuclei (AGN) astrophysics, benefiting from improvements to gamma-ray instruments and observational strategies, have revealed a surprising wealth of unexpected phenomena. These developments have been brought about both through observational efforts to discover new very high energy gamma-ray emitters, as well as from further in-depth observations of previously detected and well studied objects. I here focus specifically on the discovery of repeated temporal structures observed in AGN lightcurves, and new hard spectral components within the spectral energy distributions of other AGN systems. The challenges that these new features place on the modeling of the sources are highlighted, along with some reflections on what these results tell us about the underlying nature of the emission processes at play.
期刊介绍:
New Astronomy Reviews publishes review articles in all fields of astronomy and astrophysics: theoretical, observational and instrumental. This international review journal is written for a broad audience of professional astronomers and astrophysicists.
The journal covers solar physics, planetary systems, stellar, galactic and extra-galactic astronomy and astrophysics, as well as cosmology. New Astronomy Reviews is also open for proposals covering interdisciplinary and emerging topics such as astrobiology, astroparticle physics, and astrochemistry.