Time delay of cascade radiation for TeV blazars and the measurement of the intergalactic magnetic field

Charles D. Dermer; Massimo Cavadini; Soebur Razzaque; Justin D. Finke; James Chiang; Benoit Lott

doi:10.1088/2041-8205/733/2/L21

Time delay of cascade radiation for TeV blazars and the measurement of the intergalactic magnetic field

Charles D. Dermer, Massimo Cavadini, Soebur Razzaque, Justin D. Finke, James Chiang, Benoit Lott

Research output: Contribution to journal › Article › peer-review

198 Citations (Scopus)

Abstract

Recent claims that the strength B _IGMF of the intergalactic magnetic field (IGMF) is ≳ 10^-15G are based on upper limits to the expected cascade flux in the GeV band produced by blazar TeV photons absorbed by the extragalactic background light. This limit depends on an assumption that the mean blazar TeV flux remains constant on timescales ≳ 2(B _IGMF/10^-18G)²/(E/10 GeV)²yr for an IGMF coherence length 1Mpc, where E is the measured photon energy. Restricting TeV activity of 1ES 0229+200 to 3-4 years during which the source has been observed leads to a more robust lower limit of B _IGMF ≳ 10^-18 G, which can be larger by an order of magnitude if the intrinsic source flux above 5-10TeV from 1ES 0229+200 is strong.

Original language	English
Article number	L21
Journal	Astrophysical Journal Letters
Volume	733
Issue number	2 PART 2
DOIs	https://doi.org/10.1088/2041-8205/733/2/L21
Publication status	Published - 1 Jun 2011
Externally published	Yes

Keywords

galaxies: jets
gamma rays: galaxies
radiation mechanisms: non-thermal

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1088/2041-8205/733/2/L21

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title = "Time delay of cascade radiation for TeV blazars and the measurement of the intergalactic magnetic field",

abstract = "Recent claims that the strength B IGMF of the intergalactic magnetic field (IGMF) is ≳ 10-15G are based on upper limits to the expected cascade flux in the GeV band produced by blazar TeV photons absorbed by the extragalactic background light. This limit depends on an assumption that the mean blazar TeV flux remains constant on timescales ≳ 2(B IGMF/10-18G)2/(E/10 GeV)2yr for an IGMF coherence length 1Mpc, where E is the measured photon energy. Restricting TeV activity of 1ES 0229+200 to 3-4 years during which the source has been observed leads to a more robust lower limit of B IGMF ≳ 10-18 G, which can be larger by an order of magnitude if the intrinsic source flux above 5-10TeV from 1ES 0229+200 is strong.",

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AU - Dermer, Charles D.

AU - Cavadini, Massimo

AU - Razzaque, Soebur

AU - Finke, Justin D.

AU - Chiang, James

AU - Lott, Benoit

PY - 2011/6/1

Y1 - 2011/6/1

N2 - Recent claims that the strength B IGMF of the intergalactic magnetic field (IGMF) is ≳ 10-15G are based on upper limits to the expected cascade flux in the GeV band produced by blazar TeV photons absorbed by the extragalactic background light. This limit depends on an assumption that the mean blazar TeV flux remains constant on timescales ≳ 2(B IGMF/10-18G)2/(E/10 GeV)2yr for an IGMF coherence length 1Mpc, where E is the measured photon energy. Restricting TeV activity of 1ES 0229+200 to 3-4 years during which the source has been observed leads to a more robust lower limit of B IGMF ≳ 10-18 G, which can be larger by an order of magnitude if the intrinsic source flux above 5-10TeV from 1ES 0229+200 is strong.

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KW - galaxies: jets

KW - gamma rays: galaxies

KW - radiation mechanisms: non-thermal

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Time delay of cascade radiation for TeV blazars and the measurement of the intergalactic magnetic field

Abstract

Keywords

ASJC Scopus subject areas

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