Detection of extended γ-ray emission around the Geminga pulsar with H.E.S.S.

F. Aharonian; F. Ait Benkhali. F.; J. Aschersleben; H. Ashkar; M. Backes; V. Barbosa Martins; R. Batzofin; Y. Becherini; D. Berge; K. Bernlöhr; B. Bi; M. Böttcher; C. Boisson; J. Bolmont; J. Borowska; M. Bouyahiaoui; F. Bradascio; R. Brose; F. Brun; B. Bruno; T. Bulik; C. Burger-Scheidlin; F. Cangemi; S. Caroff; S. Casanova; J. Celic; M. Cerruti; P. Chambery; T. Chand; S. Chandra; A. Chen; J. Chibueze; O. Chibueze; G. Cotter; J. Damascene Mbarubucyeye; J. Devin; A. Djannati-Ataï; A. Dmytriiev; K. Egberts; S. Einecke; J. -P. Ernenwein; K. Feijen; G. Fichet de Clairfontaine; Miroslav Filipovic; G. Fontaine; M. Fübling; S. Funk; S. Gabici; Y. A. Gallant; S. Ghafourizadeh; null et al

doi:10.1051/0004-6361/202245776

Detection of extended γ-ray emission around the Geminga pulsar with H.E.S.S.

F. Aharonian, F. Ait Benkhali. F., J. Aschersleben, H. Ashkar, M. Backes, V. Barbosa Martins, R. Batzofin, Y. Becherini, D. Berge, K. Bernlöhr, B. Bi, M. Böttcher, C. Boisson, J. Bolmont, J. Borowska, M. Bouyahiaoui, F. Bradascio, R. Brose, F. Brun, B. BrunoT. Bulik, C. Burger-Scheidlin, F. Cangemi, S. Caroff, S. Casanova, J. Celic, M. Cerruti, P. Chambery, T. Chand, S. Chandra, A. Chen, J. Chibueze, O. Chibueze, G. Cotter, J. Damascene Mbarubucyeye, J. Devin, A. Djannati-Ataï, A. Dmytriiev, K. Egberts, S. Einecke, J. -P. Ernenwein, K. Feijen, G. Fichet de Clairfontaine, Miroslav Filipovic, G. Fontaine, M. Fübling, S. Funk, S. Gabici, Y. A. Gallant, S. Ghafourizadeh, et al

Western Sydney University

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

Abstract

Geminga is an enigmatic radio-quiet γ-ray pulsar located at a mere 250 pc distance from Earth. Extended very-high-energy γ-ray emission around the pulsar was discovered by Milagro and later confirmed by HAWC, which are both water Cherenkov detector-based experiments. However, evidence for the Geminga pulsar wind nebula in gamma rays has long evaded detection by imaging atmospheric Cherenkov telescopes (IACTs) despite targeted observations. The detection of γ-ray emission on angular scales ≳2° poses a considerable challenge for the background estimation in IACT data analysis. With recent developments in understanding the complementary background estimation techniques of water Cherenkov and atmospheric Cherenkov instruments, the H.E.S.S. IACT array can now confirm the detection of highly extended γ-ray emission around the Geminga pulsar with a radius of at least 3° in the energy range 0.5-40 TeV. We find no indications for statistically significant asymmetries or energy-dependent morphology. A flux normalisation of (2.8 ± 0.7)×10-12 cm-2 s-1 TeV-1 at 1 TeV is obtained within a 1° radius region around the pulsar. To investigate the particle transport within the halo of energetic leptons around the pulsar, we fitted an electron diffusion model to the data. The normalisation of the diffusion coefficient obtained of D0 = 7.6-1.2+1.5×1027 cm2 s-1, at an electron energy of 100 TeV, is compatible with values previously reported for the pulsar halo around Geminga, which is considerably below the Galactic average.

Original language	English
Article number	A148
Number of pages	14
Journal	Astronomy and Astrophysics
Volume	673
DOIs	https://doi.org/10.1051/0004-6361/202245776
Publication status	Published - 1 May 2023

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Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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10.1051/0004-6361/202245776

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Aharonian, F., Ait Benkhali. F., F., Aschersleben, J., Ashkar, H., Backes, M., Barbosa Martins, V., Batzofin, R., Becherini, Y., Berge, D., Bernlöhr, K., Bi, B., Böttcher, M., Boisson, C., Bolmont, J., Borowska, J., Bouyahiaoui, M., Bradascio, F., Brose, R., Brun, F., ... et al (2023). Detection of extended γ-ray emission around the Geminga pulsar with H.E.S.S. Astronomy and Astrophysics, 673, Article A148. https://doi.org/10.1051/0004-6361/202245776

@article{b219e2660bd94470bfe8b0e641b35cc8,

title = "Detection of extended γ-ray emission around the Geminga pulsar with H.E.S.S.",

abstract = "Geminga is an enigmatic radio-quiet γ-ray pulsar located at a mere 250 pc distance from Earth. Extended very-high-energy γ-ray emission around the pulsar was discovered by Milagro and later confirmed by HAWC, which are both water Cherenkov detector-based experiments. However, evidence for the Geminga pulsar wind nebula in gamma rays has long evaded detection by imaging atmospheric Cherenkov telescopes (IACTs) despite targeted observations. The detection of γ-ray emission on angular scales ≳2° poses a considerable challenge for the background estimation in IACT data analysis. With recent developments in understanding the complementary background estimation techniques of water Cherenkov and atmospheric Cherenkov instruments, the H.E.S.S. IACT array can now confirm the detection of highly extended γ-ray emission around the Geminga pulsar with a radius of at least 3° in the energy range 0.5-40 TeV. We find no indications for statistically significant asymmetries or energy-dependent morphology. A flux normalisation of (2.8 ± 0.7)×10-12 cm-2 s-1 TeV-1 at 1 TeV is obtained within a 1° radius region around the pulsar. To investigate the particle transport within the halo of energetic leptons around the pulsar, we fitted an electron diffusion model to the data. The normalisation of the diffusion coefficient obtained of D0 = 7.6-1.2+1.5×1027 cm2 s-1, at an electron energy of 100 TeV, is compatible with values previously reported for the pulsar halo around Geminga, which is considerably below the Galactic average.",

author = "F. Aharonian and {Ait Benkhali. F.}, F. and J. Aschersleben and H. Ashkar and M. Backes and {Barbosa Martins}, V. and R. Batzofin and Y. Becherini and D. Berge and K. Bernl{\"o}hr and B. Bi and M. B{\"o}ttcher and C. Boisson and J. Bolmont and J. Borowska and M. Bouyahiaoui and F. Bradascio and R. Brose and F. Brun and B. Bruno and T. Bulik and C. Burger-Scheidlin and F. Cangemi and S. Caroff and S. Casanova and J. Celic and M. Cerruti and P. Chambery and T. Chand and S. Chandra and A. Chen and J. Chibueze and O. Chibueze and G. Cotter and {Damascene Mbarubucyeye}, J. and J. Devin and A. Djannati-Ata{\"i} and A. Dmytriiev and K. Egberts and S. Einecke and Ernenwein, {J. -P.} and K. Feijen and {Fichet de Clairfontaine}, G. and Miroslav Filipovic and G. Fontaine and M. F{\"u}bling and S. Funk and S. Gabici and Gallant, {Y. A.} and S. Ghafourizadeh and {et al}",

year = "2023",

month = may,

day = "1",

doi = "10.1051/0004-6361/202245776",

language = "English",

volume = "673",

journal = "Astronomy and Astrophysics",

issn = "0004-6361",

publisher = "EDP Sciences",

}

Aharonian, F, Ait Benkhali. F., F, Aschersleben, J, Ashkar, H, Backes, M, Barbosa Martins, V, Batzofin, R, Becherini, Y, Berge, D, Bernlöhr, K, Bi, B, Böttcher, M, Boisson, C, Bolmont, J, Borowska, J, Bouyahiaoui, M, Bradascio, F, Brose, R, Brun, F, Bruno, B, Bulik, T, Burger-Scheidlin, C, Cangemi, F, Caroff, S, Casanova, S, Celic, J, Cerruti, M, Chambery, P, Chand, T, Chandra, S, Chen, A, Chibueze, J, Chibueze, O, Cotter, G, Damascene Mbarubucyeye, J, Devin, J, Djannati-Ataï, A, Dmytriiev, A, Egberts, K, Einecke, S, Ernenwein, J-P, Feijen, K, Fichet de Clairfontaine, G, Filipovic, M, Fontaine, G, Fübling, M, Funk, S, Gabici, S, Gallant, YA, Ghafourizadeh, S & et al 2023, 'Detection of extended γ-ray emission around the Geminga pulsar with H.E.S.S.', Astronomy and Astrophysics, vol. 673, A148. https://doi.org/10.1051/0004-6361/202245776

TY - JOUR

T1 - Detection of extended γ-ray emission around the Geminga pulsar with H.E.S.S.

AU - Aharonian, F.

AU - Ait Benkhali. F., F.

AU - Aschersleben, J.

AU - Ashkar, H.

AU - Backes, M.

AU - Barbosa Martins, V.

AU - Batzofin, R.

AU - Becherini, Y.

AU - Berge, D.

AU - Bernlöhr, K.

AU - Bi, B.

AU - Böttcher, M.

AU - Boisson, C.

AU - Bolmont, J.

AU - Borowska, J.

AU - Bouyahiaoui, M.

AU - Bradascio, F.

AU - Brose, R.

AU - Brun, F.

AU - Bruno, B.

AU - Bulik, T.

AU - Burger-Scheidlin, C.

AU - Cangemi, F.

AU - Caroff, S.

AU - Casanova, S.

AU - Celic, J.

AU - Cerruti, M.

AU - Chambery, P.

AU - Chand, T.

AU - Chandra, S.

AU - Chen, A.

AU - Chibueze, J.

AU - Chibueze, O.

AU - Cotter, G.

AU - Damascene Mbarubucyeye, J.

AU - Devin, J.

AU - Djannati-Ataï, A.

AU - Dmytriiev, A.

AU - Egberts, K.

AU - Einecke, S.

AU - Ernenwein, J. -P.

AU - Feijen, K.

AU - Fichet de Clairfontaine, G.

AU - Filipovic, Miroslav

AU - Fontaine, G.

AU - Fübling, M.

AU - Funk, S.

AU - Gabici, S.

AU - Gallant, Y. A.

AU - Ghafourizadeh, S.

AU - et al, null

PY - 2023/5/1

Y1 - 2023/5/1

N2 - Geminga is an enigmatic radio-quiet γ-ray pulsar located at a mere 250 pc distance from Earth. Extended very-high-energy γ-ray emission around the pulsar was discovered by Milagro and later confirmed by HAWC, which are both water Cherenkov detector-based experiments. However, evidence for the Geminga pulsar wind nebula in gamma rays has long evaded detection by imaging atmospheric Cherenkov telescopes (IACTs) despite targeted observations. The detection of γ-ray emission on angular scales ≳2° poses a considerable challenge for the background estimation in IACT data analysis. With recent developments in understanding the complementary background estimation techniques of water Cherenkov and atmospheric Cherenkov instruments, the H.E.S.S. IACT array can now confirm the detection of highly extended γ-ray emission around the Geminga pulsar with a radius of at least 3° in the energy range 0.5-40 TeV. We find no indications for statistically significant asymmetries or energy-dependent morphology. A flux normalisation of (2.8 ± 0.7)×10-12 cm-2 s-1 TeV-1 at 1 TeV is obtained within a 1° radius region around the pulsar. To investigate the particle transport within the halo of energetic leptons around the pulsar, we fitted an electron diffusion model to the data. The normalisation of the diffusion coefficient obtained of D0 = 7.6-1.2+1.5×1027 cm2 s-1, at an electron energy of 100 TeV, is compatible with values previously reported for the pulsar halo around Geminga, which is considerably below the Galactic average.

AB - Geminga is an enigmatic radio-quiet γ-ray pulsar located at a mere 250 pc distance from Earth. Extended very-high-energy γ-ray emission around the pulsar was discovered by Milagro and later confirmed by HAWC, which are both water Cherenkov detector-based experiments. However, evidence for the Geminga pulsar wind nebula in gamma rays has long evaded detection by imaging atmospheric Cherenkov telescopes (IACTs) despite targeted observations. The detection of γ-ray emission on angular scales ≳2° poses a considerable challenge for the background estimation in IACT data analysis. With recent developments in understanding the complementary background estimation techniques of water Cherenkov and atmospheric Cherenkov instruments, the H.E.S.S. IACT array can now confirm the detection of highly extended γ-ray emission around the Geminga pulsar with a radius of at least 3° in the energy range 0.5-40 TeV. We find no indications for statistically significant asymmetries or energy-dependent morphology. A flux normalisation of (2.8 ± 0.7)×10-12 cm-2 s-1 TeV-1 at 1 TeV is obtained within a 1° radius region around the pulsar. To investigate the particle transport within the halo of energetic leptons around the pulsar, we fitted an electron diffusion model to the data. The normalisation of the diffusion coefficient obtained of D0 = 7.6-1.2+1.5×1027 cm2 s-1, at an electron energy of 100 TeV, is compatible with values previously reported for the pulsar halo around Geminga, which is considerably below the Galactic average.

UR - https://hdl.handle.net/1959.7/uws:74306

U2 - 10.1051/0004-6361/202245776

DO - 10.1051/0004-6361/202245776

M3 - Article

SN - 0004-6361

VL - 673

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

M1 - A148

ER -

Detection of extended γ-ray emission around the Geminga pulsar with H.E.S.S.

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