ترغب بنشر مسار تعليمي؟ اضغط هنا

Analysis of solar gamma rays and solar neutrons detected on March 7th and September 25th of 2011 by Ground Level Neutron Telescopes, SEDA-FIB and FERMI-LAT

66   0   0.0 ( 0 )
 نشر من قبل Yasushi Muraki
 تاريخ النشر 2017
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

At the 33rd ICRC, we reported the possible detection of solar gamma rays by a ground level detector and later re-examined this event. On March 7, 2011, the solar neutron telescope (SNT) located at Mt. Sierra Negra, Mexico (4,600 m) observed enhancements of the counting rate from 19:49 to 20:02 UT and from 20:50 to 21:01 UT. The statistical significance was 9.7sigma and 8.5sigma, respectively. This paper discusses the possibility of using this mountain detector to detect solar gamma rays. In association with this event, the solar neutron detector SEDA-FIB onboard the International Space Station has also detected solar neutrons with a statistical significance of 7.5sigma. The FERMI-LAT detector also observed high-energy gamma rays from this flare with a statistical significance of 6.7sigma. We thus attempted to make a unified model to explain this data. In this paper, we report on another candidate for solar gamma rays detected on September 25th, 2011 by the SNT located in Tibet (4,300 m) from 04:37 to 04:47 UT with a statistical significance of 8.0sigma (by the Li-Ma method).

قيم البحث

اقرأ أيضاً

The SEDA-FIB is a detector designed to measure solar neutrons. This solar neutron detector was operated onboard the ISS on July 16, 2009 and March 31, 2018. Eighteen large solar flares were later observed by the GOES satellite in solar active region 12673 that appeared on September 4 and lasted until September 10, 2017, with intensity higher than > M2. In nine of those solar flares, the SEDA-FIB detected clear signals of solar neutrons, along with five minor excesses. Among these events, we focus on two associated with the flares of X2.2 (SOL2017-09-06) and X8.2 (SOL2017-09-10) that share a common feature: a process of accelerating electrons into high energies as clearly recorded by the FERMI-GBM detector. These events may provide us with useful information to elucidate the ion acceleration process. The X8.2 event was a limb flare that proved adequate for fixing the parameters needed to explain the process of particle acceleration into high energies. According to our analysis, the electron acceleration process may possibly be explained by the shock acceleration model. However, we found that it would be difficult to explain the simultaneous acceleration of ions with electrons, unless the ions were preheated prior to their rapid acceleration.
The Fermi-Large Area Telescope (LAT) detection of the X8.2 GOES class solar flare of 2017 September 10 provides for the first time observations of a long duration high-energy gamma-ray flare associated with a Ground Level Enhancement (GLE). The >100 MeV emission from this flare lasted for more than 12 hours covering both the impulsive and extended phase. We present the localization of the gamma-ray emission and find that it is consistent with the active region (AR) from which the flare occurred over a period lasting more than 6 hours contrary to what was found for the 2012 March 7 flares. The temporal variation of the proton index inferred from the gamma-ray data seems to suggest two phases in acceleration of the proton population. Based on timing arguments we interpret the second phase to be tied to the acceleration mechanism powering the GLE, believed to be particle acceleration at a coronal shock driven by the CME.
The Fermi Large Area Telescope (LAT) is a powerful pulsar detector, as demonstrated by the over one hundred objects in its second catalog of pulsars. Pass 8 is a new reconstruction and event selection strategy developed by the Fermi-LAT collaboration . Due to the increased acceptance at low energy, Pass 8 improves the pulsation detection sensitivity. Ten new pulsars rise above the 5 sigma threshold and are presented in this work, as well as one previously seen with the former Pass 7 reconstruction. More than 60$%$ of the known pulsars with spin-down power ($dot{E}$) greater than $10^{36}$ erg/s show pulsations in gamma-rays, as seen with the Fermi Large Area Telescope. Many non-detections of these energetic pulsars are thought to be a consequence of a high background level, or a large distance leading to a flux below the sensitivity limit of the instrument. The gamma-ray beams of the others probably miss the Earth. The new Pass 8 data now allows the detection of gamma ray pulsations from three of these high spin-down pulsars, PSRs J1828$-$1101, J1831$-$0952 and J1837$-$0604, as well as three others with $dot{E}$ $ge 10^{35}$ erg/s. We report on their properties and we discuss the reasons for their detection with Pass 8.
The Fermi Large Area Telescope (LAT) is the most sensitive instrument ever deployed in space for observing gamma-ray emission >100 MeV. This sensitivity has enabled the LAT to detect gamma-ray emission from the Sun during quiescent periods from pions produced by cosmic-ray protons interacting in the solar atmosphere and from cosmic-ray electrons interacting with solar optical photons. The LAT has detected high-energy gamma-ray emission associated with GOES M-class and X-class X-ray flares accompanied by coronal mass ejections and solar energetic particle events. In a number of cases, LAT has detected gamma rays with energies up to several hundreds of MeV during the impulsive phase and gamma rays up to GeV energies sustained for several hours after the impulsive phase. This presentation focuses on observations in the impulsive emission phase in solar flares, including the modest GOES M2-class flare at SOL2010-06-12T0057 and more recent detections, such as the bright X-class flares of March 2012.
In the solar flare observed on June 3, 2012, high energy gamma-rays and neutrons were observed. The event includes a remarkable feature of a high neutron/gamma-ratio in the secondary particles. We have examined whether this high n/$gamma$-ratio can b e explained by simulation. As a result of simulations using the GEANT4 program, the high n/$gamma$-ratio may be reproduced for the case that helium and other heavy ions were dominantly accelerated in the flare.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا