TY - JOUR

T1 - A lower bound on intergalactic magnetic fields from time variability of 1ES 0229+200 from MAGIC and Fermi /LAT observations

AU - Acciari, V. A.

AU - Agudo, I.

AU - Aniello, T.

AU - Ansoldi, S.

AU - Antonelli, L. A.

AU - Arbet Engels, A.

AU - Artero, M.

AU - Asano, K.

AU - Baack, D.

AU - Babic, A.

AU - Baquero, A.

AU - Barres De Almeida, U.

AU - Barrio, J. A.

AU - Batkovic, I.

AU - Becerra González, J.

AU - Bednarek, W.

AU - Bernardini, E.

AU - Bernardos, M.

AU - Berti, A.

AU - Besenrieder, J.

AU - Bhattacharyya, W.

AU - Bigongiari, C.

AU - Biland, A.

AU - Blanch, O.

AU - Bökenkamp, H.

AU - Bonnoli, G.

AU - Корочкин, Александр Алексеевич

N1 - We would like to thank the Instituto de Astrofísica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The financial support of the German BMBF, MPG and HGF; the Italian INFN and INAF; the Swiss National Fund SNF; the ERDF under the Spanish Ministerio de Ciencia e Innovación (MICINN) (PID2019-104114RB-C31, PID2019-104114RB-C32, PID2019-104114RB-C33, PID2019-105510GB-C31,PID2019-107847RB-C41, PID2019-107847RB-C42, PID2019-107847RB-C44, PID2019-107988GB-C22); the Indian Department of Atomic Energy; the Japanese ICRR, the University of Tokyo, JSPS, and MEXT; the Bulgarian Ministry of Education and Science, National RI Roadmap Project DO1-400/18.12.2020 and the Academy of Finland grant nr. 320045 is gratefully acknowledged. This work was also supported by the Spanish Centro de Excelencia “Severo Ochoa” (SEV-2016-0588, SEV-2017-0709, CEX2019-000920-S), the Unidad de Excelencia “María de Maeztu” (CEX2019-000918-M, MDM-2015-0509-18-2) and by the CERCA program of the Generalitat de Catalunya; by the Croatian Science Foundation (HrZZ) Project IP-2016-06-9782 and the University of Rijeka Project uniri-prirod-18-48; by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3; the Polish National Research Centre grant UMO-2016/22/M/ST9/00382; and by the Brazilian MCTIC, CNPq and FAPERJ. Author contributions Ie. Vovk: methodology, simulations, Fermi/LAT and MAGIC data reduction/analysis, statistical analysis; A. Neronov: methodology; P. Da Vela: MAGIC data analysis; A. Stamerra: project supervision, coordination of MAGIC observations, MAGIC data analysis; D. Semikoz: interpretation; A. Korochkin: simulations, statistical analysis. The rest of the authors have contributed in one or several of the following ways: design, construction, maintenance and operation of the MAGIC telescopes; preparation and/or evaluation of the observation proposals; data acquisition, processing, calibration and/or reduction; production of analysis tools and/or related Monte Carlo simulations; discussion and approval of the contents of the draft.

PY - 2023/2/1

Y1 - 2023/2/1

N2 - Context. Extended and delayed emission around distant TeV sources induced by the effects of propagation of ? ray s through the intergalactic medium can be used for the measurement of the intergalactic magnetic field (IGMF). Aims. We search for delayed GeV emission from the hard-spectrum TeV ?-ray emitting blazar 1ES 0229+200, with the goal of detecting or constraining the IGMF-dependent secondary flux generated during the propagation of TeV ? rays through the intergalactic medium. Methods. We analysed the most recent MAGIC observations over a 5 year time span, and complemented them with historic data of the H.E.S.S. and VERITAS telescopes, along with a 12-year-long exposure of the Fermi/LAT telescope. We used them to trace source evolution in the GeV TeV band over a decade and a half. We used Monte Carlo simulations to predict the delayed secondary ?-ray flux, modulated by the source variability, as revealed by TeV-band observations. We then compared these predictions for various assumed IGMF strengths to all available measurements of the ?-ray flux evolution. Results. We find that the source flux in the energy range above 200 GeV experiences variations around its average on the 14-year time span of observations. No evidence for the flux variability is found in the 1100 GeV energy range accessible to Fermi/LAT. The non-detection of variability due to delayed emission from electromagnetic cascade developing in the intergalactic medium imposes a lower bound of B > 1.8 - 1017 G for the long-correlation-length IGMF and B > 1014 G for an IGMF of cosmological origin. Though weaker than the one previously derived from the analysis of Fermi/LAT data, this bound is more robust, being based on a conservative intrinsic source spectrum estimate and accounting for the details of source variability in the TeV energy band. We discuss implications of this bound for cosmological magnetic fields that might explain the baryon asymmetry of the Universe.

AB - Context. Extended and delayed emission around distant TeV sources induced by the effects of propagation of ? ray s through the intergalactic medium can be used for the measurement of the intergalactic magnetic field (IGMF). Aims. We search for delayed GeV emission from the hard-spectrum TeV ?-ray emitting blazar 1ES 0229+200, with the goal of detecting or constraining the IGMF-dependent secondary flux generated during the propagation of TeV ? rays through the intergalactic medium. Methods. We analysed the most recent MAGIC observations over a 5 year time span, and complemented them with historic data of the H.E.S.S. and VERITAS telescopes, along with a 12-year-long exposure of the Fermi/LAT telescope. We used them to trace source evolution in the GeV TeV band over a decade and a half. We used Monte Carlo simulations to predict the delayed secondary ?-ray flux, modulated by the source variability, as revealed by TeV-band observations. We then compared these predictions for various assumed IGMF strengths to all available measurements of the ?-ray flux evolution. Results. We find that the source flux in the energy range above 200 GeV experiences variations around its average on the 14-year time span of observations. No evidence for the flux variability is found in the 1100 GeV energy range accessible to Fermi/LAT. The non-detection of variability due to delayed emission from electromagnetic cascade developing in the intergalactic medium imposes a lower bound of B > 1.8 - 1017 G for the long-correlation-length IGMF and B > 1014 G for an IGMF of cosmological origin. Though weaker than the one previously derived from the analysis of Fermi/LAT data, this bound is more robust, being based on a conservative intrinsic source spectrum estimate and accounting for the details of source variability in the TeV energy band. We discuss implications of this bound for cosmological magnetic fields that might explain the baryon asymmetry of the Universe.

KW - Early Universe

KW - Galaxies: active

KW - Gamma rays: galaxies

KW - Intergalactic medium

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85148666425&origin=inward&txGid=41786ce238fef7f645720915fe7eab40

UR - https://www.mendeley.com/catalogue/5ec5d7d1-9c28-3c19-a1d5-2533159e6230/

U2 - 10.1051/0004-6361/202244126

DO - 10.1051/0004-6361/202244126

M3 - Article

VL - 670

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

M1 - A145

ER -