scholarly journals Detection of a flaring blazar coincident with an IceCube high-energy neutrino

2019 ◽  
Vol 207 ◽  
pp. 02001
Author(s):  
Anna Franckowiak
Keyword(s):  
Gamma Ray ◽  
Spectral Energy Distribution ◽  
Neutrino Flux ◽  
High Energy ◽  
Spectral Energy ◽  
Large Area ◽  
High Energy Neutrino ◽  
Energy Neutrino ◽  
Radio Wavelength ◽  
First Time

In September 22, 2017, IceCube released a public alert announcing the detection of a 290 TeV neutrino track event with an angular uncertainty of one square degree (90% containment). A multi-messenger follow-up campaign was initiated resulting in the detection of a GeV gamma-ray flare by the Fermi Large Area Telescope positionally consistent with the location of the known Bl Lac object, TXS 0506+056 , located only 0.1 degrees from the best-fit neutrino position. The probability of finding a GeV gamma-ray flare in coincidence with a high-energy neutrino event assuming a correlation of the neutrino flux with the gamma-ray energy flux in the energy band between 1 and 100 GeV was calculated to be 3σ (after trials correction). Following the detection of the flaring blazar the imaging air Cherenkov telescope MAGIC detected the source for the first time in the > 100 GeV gamma-ray band. The activity of the source was confirmed in X-ray, optical and radio wavelength. Several groups have developed lepto-hadronic models which succeed to explain the multi-messenger spectral energy distribution.

scholarly journals Extreme and high synchrotron peak blazars beyond 4FGL: The 2BIGB γ-ray catalogue

2020 ◽  
Vol 493 (2) ◽  
pp. 2438-2451
Author(s):  
B Arsioli ◽  
Y-L Chang ◽  
B Musiimenta
Keyword(s):  
Gamma Ray ◽  
Spectral Energy Distribution ◽  
Broad Band ◽  
High Energy ◽  
Spectral Energy ◽  
Large Area ◽  
Data Repositories ◽  
Total Contribution ◽  
Public Data ◽  
Γ Ray

ABSTRACT This paper presents the results of a γ-ray likelihood analysis over all the extreme and high synchrotron peak blazars (EHSP and HSP) from the 3HSP catalogue. We investigate 2013 multifrequency positions under the eyes of Fermi Large Area Telescope, considering 11 yr of observations in the energy range between 500 MeV and 500 GeV, which results in 1160 γ-ray signatures detected down to the TS=9 threshold. The detections include 235 additional sources concerning the Fermi Large Area Telescope Fourth Source Catalog (4FGL), all confirmed via high-energy TS (Test Statistic) maps, and represent an improvement of ∼25 per cent for the number of EHSP and HSP currently described in γ-rays. We build the γ-ray spectral energy distribution (SED) for all the 1160 2BIGB sources, plot the corresponding γ-ray logN−logS, and measure their total contribution to the extragalactic gamma-ray background, which reaches up to ∼33 per cent at 100 GeV. Also, we show that the γ-ray detectability improves according to the synchrotron peak flux as represented by the figure of merit parameter, and note that the search for TeV peaked blazars may benefit from considering HSP and EHSP as a whole, instead of EHSPs only. The 2BIGB acronym stands for ‘Second Brazil-ICRANet Gamma-ray Blazars’ catalogue, and all the broad-band models and SED data points will be available on public data repositories (OpenUniverse, GitHub, and Brazilian Science Data Center-BSDC).

scholarly journals Testing high energy neutrino emission from the Fermi Gamma-ray Space Telescope Large Area Telescope (4LAC) sources.

2021 ◽  
Author(s):  
Antonio Galván ◽  
Nissim Fraija ◽  
Edilberto Aguilar-Ruiz ◽  
Jagdish C. Joshi ◽  
Jose Antonio de Diego Onsurbe ◽  
...  
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Neutrino Emission ◽  
Large Area ◽  
High Energy Neutrino ◽  
Space Telescope ◽  
Energy Neutrino

scholarly journals Neutrino emission from the direction of the blazar TXS 0506+056 prior to the IceCube-170922A alert

Science ◽  
2018 ◽  
Vol 361 (6398) ◽  
pp. 147-151 ◽  
Author(s):  
◽  
Mark Aartsen ◽  
Markus Ackermann ◽  
Jenni Adams ◽  
Juan Antonio Aguilar ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Neutrino Flux ◽  
High Energy ◽  
Time Variable ◽  
Neutrino Emission ◽  
High Energy Neutrino ◽  
Excess Emission ◽  
Energy Neutrino ◽  
Variable Flux ◽  
Astrophysical Neutrino

A high-energy neutrino event detected by IceCube on 22 September 2017 was coincident in direction and time with a gamma-ray flare from the blazar TXS 0506+056. Prompted by this association, we investigated 9.5 years of IceCube neutrino observations to search for excess emission at the position of the blazar. We found an excess of high-energy neutrino events, with respect to atmospheric backgrounds, at that position between September 2014 and March 2015. Allowing for time-variable flux, this constitutes 3.5σ evidence for neutrino emission from the direction of TXS 0506+056, independent of and prior to the 2017 flaring episode. This suggests that blazars are identifiable sources of the high-energy astrophysical neutrino flux.

scholarly journals Fermi LAT detection of the supernova remnant SN 1006 revisited: The southwest limb

2019 ◽  
Vol 71 (4) ◽  
Author(s):  
Yi Xing ◽  
Zhongxiang Wang ◽  
Xiao Zhang ◽  
Yang Chen
Keyword(s):  
Supernova Remnant ◽  
Gamma Ray ◽  
Spectral Energy Distribution ◽  
High Energy ◽  
Spectral Energy ◽  
Large Area ◽  
Significance Level ◽  
Very High Energy ◽  
Γ Ray ◽  
Energy Emissions

Abstract The data from the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope have recently been updated. Thus we re-analyze the LAT data for the supernova remnant (SNR) SN 1006. Two parts of γ-ray emission from the region are clearly resolved, which correspond to the northeast (NE) and southwest (SW) limbs of the SNR. The former has been detected in the previous LAT data (Xing et al. 2016, ApJ, 823, 44), but the latter is newly detected in this work. The detections of the two limbs are at a ∼4σ significance level, and the spectral results for the NE limb are consistent with those obtained in previous detection analyses. We construct the broadband spectral energy distribution (SED) for the SW limb. Different scenarios are considered for its SED in γ-ray energies. We conclude that, very similarly in the case of the NE limb, the high-energy and very high-energy emissions from the SW limb is likely dominated by the leptonic process, in which high-energy electrons accelerated from the shell region of the SNR inverse-Compton scatter background photons to γ-rays.

scholarly journals Flaring Rate Distribution of Gamma-Ray Blazars and Implications for High-Energy Neutrino Emission

2019 ◽  
Author(s):  
Kenji Yoshida ◽  
Maria Petropoulou ◽  
Meg Urry ◽  
Paolo Coppi ◽  
Charles Bailyn ◽  
...  
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Neutrino Emission ◽  
High Energy Neutrino ◽  
Rate Distribution ◽  
Energy Neutrino

scholarly journals Searching for Optical Counterparts to High-Energy Neutrino Sources with the Zwicky Transient Facility

2019 ◽  
Vol 207 ◽  
pp. 03001 ◽  
Author(s):  
Ludwig Rauch
Keyword(s):  
Active Galactic Nuclei ◽  
Gamma Ray ◽  
Galactic Nuclei ◽  
High Energy ◽  
Correlation Study ◽  
High Energy Neutrino ◽  
Energy Neutrino ◽  
Ice Cube ◽  
Sky Survey ◽  
High Cadence

The IceCube neutrino observatory has discovered a flux of extragalactic neutrinos. However, the origin of these neutrinos is still unknown. Among the possible candidates are Gamma-Ray Bursts (GRBs), Core-Collapse Supernovae (SNe), Active Galactic Nuclei (AGN) and Tidal Disruption Events (TDEs) - all are accompanied by a characteristic optical counterpart. The goal of this study is thus to identify the neutrino sources by detecting their optical counterparts with the Zwicky Transient Facility (ZTF). ZTF features a high cadence northern-sky survey enabling realtime correlation of optical transients with high-energy neutrino candidates. In this talk I will highlight the multimessenger potential of ZTF for an online neutrino correlation study with Ice- Cube.

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