Gravitational lensing as a possible explanation for some unidentified gamma-ray sources at high latitudes

We propose that some of the high-latitude unidentified EGRET γ-ray sources could be the result of gravitational lensing amplification of the innermost regions of distant, faint, active galactic nuclei. These objects have γ-ray-emitting regions small enough to be affected by microlensing of stars in...

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Autores principales:	Torres, D.F., Romero, G.E., Eiroa, E.F.
Formato:	JOUR
Materias:	Galaxies: active Gamma rays: observations Gravitational lensing
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_0004637X_v569_n2I_p600_Torres
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	todo:paper_0004637X_v569_n2I_p600_Torres
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spelling	todo:paper_0004637X_v569_n2I_p600_Torres2023-10-03T14:01:50Z Gravitational lensing as a possible explanation for some unidentified gamma-ray sources at high latitudes Torres, D.F. Romero, G.E. Eiroa, E.F. Galaxies: active Gamma rays: observations Gravitational lensing We propose that some of the high-latitude unidentified EGRET γ-ray sources could be the result of gravitational lensing amplification of the innermost regions of distant, faint, active galactic nuclei. These objects have γ-ray-emitting regions small enough to be affected by microlensing of stars in interposed galaxies. We compute the gravitational amplification, taking into account effects of the host galaxy of the lens, and prove that, whereas the innermost γ-ray regions can be magnified up to a thousand times, there is no amplification at radio frequencies, which leads to the observed absence of strong counterparts. Some new effects in the spectral evolution of a gravitational microlensed γ-ray active galactic nuclei are predicted. Within a reasonable range of lensing parameters and/or types of sources, both variable and nonvariable EGRET detections at high latitudes can be explained by microlensing. The same phenomenon could also have an important incidence among the future GLAST detections at high latitudes. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0004637X_v569_n2I_p600_Torres
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Galaxies: active Gamma rays: observations Gravitational lensing
spellingShingle	Galaxies: active Gamma rays: observations Gravitational lensing Torres, D.F. Romero, G.E. Eiroa, E.F. Gravitational lensing as a possible explanation for some unidentified gamma-ray sources at high latitudes
topic_facet	Galaxies: active Gamma rays: observations Gravitational lensing
description	We propose that some of the high-latitude unidentified EGRET γ-ray sources could be the result of gravitational lensing amplification of the innermost regions of distant, faint, active galactic nuclei. These objects have γ-ray-emitting regions small enough to be affected by microlensing of stars in interposed galaxies. We compute the gravitational amplification, taking into account effects of the host galaxy of the lens, and prove that, whereas the innermost γ-ray regions can be magnified up to a thousand times, there is no amplification at radio frequencies, which leads to the observed absence of strong counterparts. Some new effects in the spectral evolution of a gravitational microlensed γ-ray active galactic nuclei are predicted. Within a reasonable range of lensing parameters and/or types of sources, both variable and nonvariable EGRET detections at high latitudes can be explained by microlensing. The same phenomenon could also have an important incidence among the future GLAST detections at high latitudes.
format	JOUR
author	Torres, D.F. Romero, G.E. Eiroa, E.F.
author_facet	Torres, D.F. Romero, G.E. Eiroa, E.F.
author_sort	Torres, D.F.
title	Gravitational lensing as a possible explanation for some unidentified gamma-ray sources at high latitudes
title_short	Gravitational lensing as a possible explanation for some unidentified gamma-ray sources at high latitudes
title_full	Gravitational lensing as a possible explanation for some unidentified gamma-ray sources at high latitudes
title_fullStr	Gravitational lensing as a possible explanation for some unidentified gamma-ray sources at high latitudes
title_full_unstemmed	Gravitational lensing as a possible explanation for some unidentified gamma-ray sources at high latitudes
title_sort	gravitational lensing as a possible explanation for some unidentified gamma-ray sources at high latitudes
url	http://hdl.handle.net/20.500.12110/paper_0004637X_v569_n2I_p600_Torres
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Gravitational lensing as a possible explanation for some unidentified gamma-ray sources at high latitudes

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