EVIDENCE FOR GAMMA-RAY HALOS AROUND ACTIVE GALACTIC NUCLEI AND THE FIRST MEASUREMENT OF INTERGALACTIC MAGNETIC FIELDS

By S. Ando, A. Kusenko. 2010

158 citations recorded by the source corpus.

Intergalactic magnetic fields (IGMFs) can cause the appearance of halos around the gamma-ray images of distant objects because an electromagnetic cascade initiated by a high-energy gamma-ray interaction with the photon background is broadened by magnetic deflections. We report evidence of such gamma-ray halos in the stacked images of the 170 brightest active galactic nuclei (AGNs) in the 11 month source catalog of the Fermi Gamma-Ray Space Telescope. Excess over the point-spread function in the surface brightness profile is statistically significant at 3.5σ (99.95% confidence level), for the nearby, hard population of AGNs. The halo size and brightness are consistent with IGMF, BIGMF ≈ 10−15 G. The knowledge of IGMF will facilitate the future gamma-ray and charged-particle astronomy. Furthermore, since IGMFs are likely to originate from the primordial seed fields created shortly after the big bang, this potentially opens a new window on the origin of cosmological magnetic fields, inflation, and the phase transitions in the early universe.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/90645f477fb5e442af4938a80f63d14b70c92f2f

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. Andrii Y. Neronov
2. R. Durrer
3. E. Orlando
4. Anna Franckowiak
5. J. Biteau
6. E. Zweibel
7. I. Grenier
8. A. Reimer

In Nuclear and High Energy Physics

1. Andrii Y. Neronov
2. R. Durrer
3. J. Biteau
4. E. Orlando
5. Anna Franckowiak
6. I. Grenier
7. S. Razzaque
8. J. Finke

Citations in the corpus

• LOWER LIMIT ON THE STRENGTH AND FILLING FACTOR OF EXTRAGALACTIC MAGNETIC FIELDS (2011, background): “Note that Ando & Kusenko (2010) found evidence for gamma-ray halos in the stacked images of the 170 brightest active galactic nuclei observed with Fermi-LAT.”
• ROLE OF LINE-OF-SIGHT COSMIC-RAY INTERACTIONS IN FORMING THE SPECTRA OF DISTANT BLAZARS IN TeV GAMMA RAYS AND HIGH-ENERGY NEUTRINOS (2010, background): “For the IGMF, we chose the average value of B = 1 fG, coherent over a correlation length ∼1 Mpc; this is consistent with the observations (Ando & Kusenko 2010).”
• Cosmological Magnetic Fields: Their Generation, Evolution and Observation (2013, methodology): “Such a measurement was claimed by Ando and Kusenko (2010), based on data from the Fermi telescope.”
• Magnetic Fields in Galaxies (2010, background): “Recently Neronov & Vovk (2010) have set a lower limit of 3 10−16 G for large scale fields along the line of sight to two TeV blazar sources observed by the Fermi satellite, while Ando & Kusenko (2010) claim to have detected a field of 10−15G, also from Fermi .”
• The Search for Spatial Extension in High-latitude Sources Detected by the Fermi Large Area Telescope (2018, background): “Interest in stacking Fermi-LAT data to search for IGMF induced pair halos was partly triggered by the initial study of Ando & Kusenko (2010), who found a hint of extension in the stacked images of 170AGNs observed over 11months.”