Related papers: Solar Cycle Variation of Sustained Gamma Ray Emiss…
The sustained gamma ray emission (SGRE) from the Sun is one of the fascinating high energy phenomena closely related to the acceleration of protons to energies >300 MeV. Here we report on the solar cycle variation of SGRE events based on…
Solar Cycle (SC) 24 was the weakest in the space age, yet it produced many sustained gamma ray emission (SGRE) events from the Sun. Solar cycle (SC) 25, which is a bit stronger than SC 24 observed only a handful of SGRE events over the…
We characterize and provide a catalog of thirty >100 MeV sustained gamma-ray emission (SGRE) events observed by Fermi LAT. These events are temporally and spectrally distinct from the associated solar flares. Their spectra are consistent…
We report on the 2024 September 9 sustained gamma ray emission (SGRE) event observed by the Large Area Telescope (LAT) onboard the Fermi satellite. The event was associated with a backside solar eruption observed by multiple spacecraft such…
We report on the linear relationship between the durations of two types of electromagnetic emissions associated with shocks driven by coronal mass ejections: sustained gamma-ray emission (SGRE) and interplanetary type II radio bursts. The…
The sustained gamma-ray emission (SGRE) events from the Sun are associated with an ultrafast (2000 km/s or greater) halo coronal mass ejection (CME) and a type II radio burst in the decameter-hectometric (DH) wavelengths. The SGRE duration…
We considered 18 solar flares observed between June 2010 and July 2012, in which high energy >100 MeV {\gamma}-emission was registered by the Large Area Telescope (LAT) aboard FermiGRO. We examined for these {\gamma}-events soft X-ray…
Ground Level Enhancement (GLE) in large solar energetic particle (SEP) events is indicative of protons accelerated to GeV energies. Almost all GLE events are associated with sustained gamma-ray emission (SGRE) from the Sun because the…
We report on the 2015 June 25 sustained gamma-ray emission (SGRE) event associated with a halo coronal mass ejection and a type II radio burst in the decameter-hectometric (DH) wavelengths. The duration and ending frequency of the type II…
We present the detections of 19 solar flares detected in high-energy gamma rays (above 100 MeV) with the Fermi Large Area Telescope (LAT) during its first four years of operation. Interestingly, all flares are associated with fairly fast…
We have statistically analyzed 379 radio-loud (RL) CMEs and their associated flares during the period 1996 - 2019 covering both solar cycles (SC) 23 and 24. We classified them into two sets of populations based on the observation period: i)…
We summarize observations of around a thousand solar energetic particle (SEP) events since 1967 that include ~25 MeV protons, made by various near-Earth spacecraft (IMPs 4, 5, 7, 8, ISEE 3, SOHO), that encompass Solar Cycle 20 to the…
We present a multi-spacecraft analysis of the 2024 July 16 Long-Duration Gamma-Ray Flare (LDGRF) detected by the Large Area Telescope on the Fermi satellite. The measured >100 MeV $\gamma$-ray emission persisted for over seven hours after…
The sustained gamma-ray emission (SGRE) from the Sun is a prolonged enhancement of >100 MeV gamma-ray emission that extends beyond the flare impulsive phase.The origin of the >300 MeV protons resulting in SGRE is debated, both flares and…
During its first six years of operation, the Fermi Large Area Telescope (LAT) has detected >30 MeV gamma-ray emission from more than 40 solar flares, nearly a factor of 10 more than those detected by EGRET. These include detections of…
We report on a study of all major solar eruptions that occurred on the front-side of the Sun during the rise to peak phase of cycle 24 (first 62 months) in order to understand the key factors affecting the occurrence of large solar…
Since the launch of the Fermi Gamma-ray Space Telescope on June 11, 2008, 55 gamma-ray bursts (GRBs) have been observed at coordinates that fall within 66^\circ of the Fermi Large Area Telescope (LAT) boresight with precise localizations…
Two scenarios have been proposed to account for sustained $\ge 30$\,MeV gamma-ray emission in solar flares: (1) prolonged particle acceleration/trapping involving large-scale magnetic loops at the flare site, and (2) precipitation of…
We present a search for intraday transient gamma-ray signals using 15.4 years of the Fermi Large Area Telescope data. The search is based on a recently developed variable-size sliding-time-window (VSSTW) analysis and aimed at studying…
It has recently been shown that the spatially and temporally extended gamma-ray emission in solar eruptions are caused by greater than 300 MeV protons precipitating on the Sun from shocks driven by coronal mass ejections (CMEs). The…