Multiwavelength Approach to Unidentified Gamma-Ray Sources

Multiwavelength Approach to Unidentified Gamma-Ray Sources
Author: K.S. Cheng
Publisher: Springer Science & Business Media
Total Pages: 468
Release: 2005-05-02
Genre: Science
ISBN: 9781402032141

Nearly one half of the point-like gamma-ray sources detected by EGRET instrument of the late Compton satellite are still defeating our attempts at identifying them. To establish the origin and nature of these enigmatic sources has become a major problem of current high-energy astrophysics. The second workshop on Multiwavelength Approach to Unidentified Gamma-ray Sources intends to shed new and fresh light on the problem of the nature of these mysterious sources and the objects behind them. The proceedings contain 46 contributed papers in this subject, which cover theoretical models on gamma-ray sources as well as the best multiwavelength strategies for the identification of the promising candidates. The topics of this conference also include energetic phenomena ocurring both in galactic and extragalactic scenarios, phenomena that might lead to the appearance of what we have called high-energy unidentified sources. The book will be of interest for all active researchers in the high-energy astrophysics and related research areas as well as for scientists and graduate students interested in understanding the recent progress in this field.

The Multiwavelength Atlas of Galaxies

The Multiwavelength Atlas of Galaxies
Author: Glen Mackie
Publisher: Cambridge University Press
Total Pages: 269
Release: 2011-01-06
Genre: Science
ISBN: 1139494465

Since the radio signature of our own Milky Way was detected in 1931, galaxies have been observed from ultra-high energy gamma rays to long wavelength radio waves, providing fundamental insights into their formation, evolution and structural components. Unveiling the secrets of some of the best-observed galaxies, this atlas contains over 250 full-color images spanning the whole electromagnetic spectrum. The accompanying text explains why we see the component stars, gas and dust through different radiation processes, and describes the telescopes and instruments used. This atlas is a valuable reference resource on galaxies for students seeking an overview of multiwavelength observations and what they tell us, and researchers needing detailed summaries of individual galaxies. An accompanying website, hosted by the author, contains slide shows of the galaxies covered in the book. This is available at www.cambridge.org/9780521620628.

Radio Galaxies at TeV Energies

Radio Galaxies at TeV Energies
Author: Dorit Glawion
Publisher: MDPI
Total Pages: 188
Release: 2020-05-13
Genre: Science
ISBN: 3039287508

It is common believe that the centers of all galaxies exhibit supermassive black holes with masses ranging from millions up to billions of the mass of our Sun. By accreting surrounding matter, the luminosity of these galactic nuclei can outshine the emission of their host galaxies. If this is the case, they are called active galactic nuclei. Some of these objects eject powerful outflows composed of plasma, called jets. These jets can produce non-thermal radiation which observable across the entire electromagnetic spectrum from radio up to the gamma-ray frequencies. At highest frequencies (TeV range) most of the detected active galaxies have jets directed along or close to the line of sight. However, also galaxies with larger angles to the line of sight showing fascinating features were discovered, in seeming contradiction to traditional models for these so-called radio galaxies. Thus, the latter are of particular importance for understanding active galactic nuclei in general. This Special Issue contains reviews and research articles about the current knowledge of radio galaxies at TeV energies, including observational results and theoretical models. It is intended to guide the interested reader deeper into this fascinating discipline of modern day astronomy.

Cosmic Gamma-Ray Sources

Cosmic Gamma-Ray Sources
Author: K.S. Cheng
Publisher: Springer Science & Business Media
Total Pages: 412
Release: 2012-11-03
Genre: Science
ISBN: 1402022565

Gamma-ray astronomy has undergone an enormous progress in the last 15 years. The success of satellite experiments like NASA's Comp ton Gamma-Ray Observatory and ESA's INTEGRAL mission, as well as of ground-based instruments have open new views into the high-energy Universe. Different classes of cosmic gamma-ray sources have been now detected at different energies, in addition to young radio pulsars and gamma-ray bursts, the classical ones. The new sources include radio quiet pulsars, microquasars, supernova remnants, starburst galaxies, ra dio galaxies, flat-spectrum radio quasars, and BL Lacertae objects. A large number of unidentified sources strongly suggests that this brief enumeration is far from complete. Gamma-ray bursts are now estab lished as extragalactic sources with tremendous energy output. There is accumulating evidence supporting the idea that massive stars and star forming regions can accelerate charged particles up to relativistic ener gies making them gamma-ray sources. Gamma-ray astronomy has also proved to be a powerful tool for cosmology imposing constraints to the background photon fields that can absorb the gamma-ray flux from dis tant sources. All this has profound implications for our current ideas about how particles are accelerated and transported in both the local and distant U niverse. The evolution of our knowledge on the gamma-ray sky has been so fast that is not easy for the non-specialist scientist and the graduate student to be aware of the full potential of this field or to grasp the fundamentals of a given topic in order to attempt some original contribution.

Multiwavelength Observations of Unidentified High Energy Gamma Ray Sources

Multiwavelength Observations of Unidentified High Energy Gamma Ray Sources
Author: National Aeronautics and Space Adm Nasa
Publisher:
Total Pages: 38
Release: 2018-10-21
Genre:
ISBN: 9781729025710

As was the case for COS B, the majority of high-energy (greater than 100 MeV) gamma-ray sources detected by the EGRET instrument on GRO are not immediately identifiable with cataloged objects at other wavelengths. These persistent gamma-ray sources are, next to the gamma-ray bursts, the least understood objects in the universe. Even a rudimentary understanding of their nature awaits identifications and follow-up work at other wavelengths to tell us what they are. The as yet unidentified sources are potentially the most interesting, since they may represent unrecognized new classes of astronomical objects, such as radio-quiet pulsars or new types of active galactic nuclei (AGN's). This two-year investigation is intended to support the analysis, correlation, and theoretical interpretation of data that we are obtaining at x ray, optical, and radio wavelengths in order to render the gamma-ray data interpretable. According to plan, in the first year concentration was on the identification and study of Geminga. The second year will be devoted to studies of similar unidentified gamma-ray sources which will become available in the first EGRET catalogs. The results obtained so far are presented in the two papers which are reproduced in the Appendix. In these papers, we discuss the pulse profiles of Geminga, the geometry and efficiency of the magnetospheric accelerator, the distance to Geminga, the implications for theories of polar cap heating, the effect of the magnetic field on the surface emission and environment of the neutron star, and possible interpretations of a radio-quiet Geminga. The implications of the other gamma-ray pulsars which were discovered to have high gamma-ray efficiency are also discussed, and the remaining unidentified COS B sources are attributed to a population of efficient gamma-ray sources, some of which may be radio quiet. Halpern, Jules P. Unspecified Center NAG5-2051...

Multiwavelength Cosmology

Multiwavelength Cosmology
Author: Manolis Plionis
Publisher: Springer Science & Business Media
Total Pages: 353
Release: 2006-04-18
Genre: Science
ISBN: 0306485702

The recent scientific efforts in Astrophysics & Cosmology have brought a revolution to our understanding of the Cosmos. Amazing results is the outcome of amazing experiments! The huge scientific, technological & financial effort that has gone into building the 10-m class telescopes as well as many space and balloon observatories, essential to observe the multitude of cosmic phenomena in their manifestations at different wavelengths, from gamma-rays to the millimetre and the radio, has given and is still giving its fruits of knowledge. These recent scientific achievements in Observational and Theoretical Cosmology were presented in the "Multiwavelength Cosmology" conference that took place on beautiful Mykonos island in the Aegean between 17 and 20 June 2003. More than 180 Cosmologists from all over the world gathered for a four-day intense meeting in which recent results from large ground based surveys (AAT/2-df, SLOAN) and space missions (WMAP, Chandra, XMM, ISO, HST) were presented and debated, providing a huge impetus to our knowledge of the Cosmos. The future of the subject (experiments, and directions of research) was also discussed. The conference was devoted mostly on the constraints on Cosmological models and galaxy formation theories that arise from the study of the high redshift Universe, from clusters of galaxies, and their evolution, from the cosmic microwave background, the large-scale structure and star-formation history.

Radio Galaxies at TeV Energies

Radio Galaxies at TeV Energies
Author: Dorit Glawion
Publisher:
Total Pages: 188
Release: 2020
Genre: Astronomy
ISBN: 9783039287512

It is common believe that the centers of all galaxies exhibit supermassive black holes with masses ranging from millions up to billions of the mass of our Sun. By accreting surrounding matter, the luminosity of these galactic nuclei can outshine the emission of their host galaxies. If this is the case, they are called active galactic nuclei. Some of these objects eject powerful outflows composed of plasma, called jets. These jets can produce non-thermal radiation which observable across the entire electromagnetic spectrum from radio up to the gamma-ray frequencies. At highest frequencies (TeV range) most of the detected active galaxies have jets directed along or close to the line of sight. However, also galaxies with larger angles to the line of sight showing fascinating features were discovered, in seeming contradiction to traditional models for these so-called radio galaxies. Thus, the latter are of particular importance for understanding active galactic nuclei in general. This Special Issue contains reviews and research articles about the current knowledge of radio galaxies at TeV energies, including observational results and theoretical models. It is intended to guide the interested reader deeper into this fascinating discipline of modern day astronomy.

Multiwavelength Approach to Unidentified Gamma-Ray Sources

Multiwavelength Approach to Unidentified Gamma-Ray Sources
Author: K.S. Cheng
Publisher: Springer Science & Business Media
Total Pages: 436
Release: 2005-12-05
Genre: Science
ISBN: 140203881X

Nearly one half of the point-like gamma-ray sources detected by EGRET instrument of the late Compton satellite are still defeating our attempts at identifying them. To establish the origin and nature of these enigmatic sources has become a major problem of current high-energy astrophysics. The second workshop on Multiwavelength Approach to Unidentified Gamma-ray Sources intends to shed new and fresh light on the problem of the nature of the unidentified gamma-ray sources. The proceedings contain 46 contributed papers in this subject, which cover theoretical models on gamma-ray sources as well as the best multiwavelength strategies for the identification of the promising candidates. The topics of this conference also include energetic phenomena occurring both in galactic and extragalactic scenarios, phenomena that might lead to the appearance of what we have called high-energy unidentified sources. The book will be of interest for all active researchers in the high-energy astrophysics and related research areas as well as for scientists and graduate students interested in understanding the recent progress in high-energy astrophysics.

Science With The New Generation Of High Energy Gamma-ray Experiments: The Variable Gamma-ray Sources: Their Identifications And Counterparts - Proceedings Of The Fourth Workshop

Science With The New Generation Of High Energy Gamma-ray Experiments: The Variable Gamma-ray Sources: Their Identifications And Counterparts - Proceedings Of The Fourth Workshop
Author: Marco Maria Massai
Publisher: World Scientific
Total Pages: 251
Release: 2007-10-02
Genre: Science
ISBN: 9814474495

The research program in gamma-ray astronomy focuses on increasing our knowledge of the nature and origin of galactic and extragalactic gamma rays, and understanding high-energy processes in the Sun, celestial objects, interstellar medium, and extragalactic space.This book not only provides an overview of the latest research and future plans for space-borne and ground-based experiments dedicated to the observation of the gamma-ray sky, but also addresses the topic of variable gamma-ray sources from the perspective of their identification and counterparts at different wavelengths. It further gives an overview of the theory related to the most qualified emission processes that take place in these sources and of the nature of their variability.