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Welcome to the webpages of H.E.S.S., one of the leading observatories studying very high energy (VHE) gamma-ray astrophysics. To learn more about H.E.S.S. and the high energy universe, or to view pictures from the telescopes and the site in Namibia visit the About H.E.S.S. section.

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For older news see our News Archive

Detection of VHE gamma-ray emission from GRB190829A
Sep. 24, 2019

Gamma-ray bursts (GRB), known from the 1960's, are burst of gamma rays of extragalactic origin, which appear randomly on the sky at a rate of about one per day, and whose prompt emission is know to last from a few seconds to a few minutes. They are subsequently followed by a afterglow phase, fading progressively during up to a few months. Short GRBs appear to be associated with coalescence of neutron stars, a theory which is now supported by the detection of gravitational waves GW170817 associated with a gamma ray burst on august 17th, 2017. Long GRBs, on the other hand, are most likely produced during the gravitational collapse of giant stars, which can lead to the formation of a black hole or a neutron star. This hypothesis was in particular strongly supported by the observation in 2003 of GRBs in coincidence with supernova (of type Ib/c).

Gamma-ray burst are one of the few types of astrophysical objects that could potentially accelerate particles up to extreme energies (1019 electronvolts), and thus unveil the mystery of Ultra High Energy Cosmic Rays (UHECRs). Until very recently, high energy photons up to about 100 gigaelectronvolts (GeV) from GRBs were deteced by the Fermi-LAT space observatory. In January 2019 the MAGIC ground-based gamma-ray experiment announced the detection of >300 GeV gamma rays from GRB190114C [ATEL #12390] and H.E.S.S. announced the detection of VHE emission from another burst (GRB180720B) at the 1st CTA Symposium in May 2019.

On August 30, 2019 H.E.S.S. reported the detection of very-high energy emission associated with the afterglow phase of the GRB190829A in an Astronomer's Telegram. Gamma-ray emission was detected more than 4 hours after the burst, which will bring new constrains on the models of particle acceleration and radiation, and shed a new light on these extreme objects.

Original announcement: http://www.astronomerstelegram.org/?read=13052

Astronomy and Astrophysics journal highlights HESS results
Feb. 4, 2019

The Astronomy and Astrophysics journal has chosen a HESS paper as an A&A Highlight; selected by A&A Editors as particularly interesting papers.

The pulsar wind nebula HESS J1825-137 was one of the first sources detected by HESS in the Galactic Plane and the first to show strong energy-dependent morphology.

Combining data over more than ten years of HESS observations into a deep exposure on the region enabled detailed spectral and morphological analysis of the nebula. By characterising the extent of the gamma-ray emission in a set of independent energy bands, the changing size was used to test the mechanism of particle transport within the nebula. A spatially resolved spectral analysis into more than 40 regions enabled a spectral map of the nebula to be made.

The A&A Highlight text can be found here: https://www.aanda.org/2019-highlights/1617 The paper can be downloaded from the preprint server: https://arxiv.org/abs/1810.12676

HESS operations to be extended beyond 2019
Jan 30, 2019

Major step for the HESS experiment and ground-based gamma-ray astronomy in general:

In the current context of emerging multi-messenger, multi-wavelength astronomy, the HESS Steering Committee evaluated the possible options for the future of HESS during its meeting on January 28th, 2019. After careful analysis of the proposed strategy for the upcoming years, the Steering Committee unanimously voted in favour of the extension of HESS operations for an initial duration of 3 years. The corresponding extension agreement is currently being finalized between the relevant parties. As part of the strategy towards improved efficiency and faster response to transient phenomena, the camera of the large telescope will be replaced by a brand new, state-of-the-art camera as designed for the upcoming Cherenkov Telescope Array (CTA). This way, HESS will be preparing for the future CTA era while continuing to deliver exciting and excellent science.

The Passing of Professor Sergio Colafrancesco.
Oct 4, 2018

It is with great sadness that the H.E.S.S. Collaboration announces the passing of Professor Sergio Colafrancesco. He passed away on Sunday, 30 September 2018, following a battle with cancer.

The H.E.S.S. Collaboration offers its deepest condolences to the family, friends and colleagues of Prof. Colafrancesco.

He was the DST-NRF Square Kilometre Array (SKA) Research Chair in Radio Astronomy in the School of Physics at the University of the Witwatersrand, Johannesburg, South Africa. His appointment heralded the beginning of distinguished research activity in multiwavelength and multi-messenger astronomy and astrophysics at Wits University, with the establishment of a very active H.E.S.S. group.

Prof. Colafrancesco's SKA Chair is of local and international significance. It was established to contribute to the understanding of the structure, origin and evolution of the Universe and of its sub-structures, from the smallest galaxies to the largest galaxy clusters.

Prof. Colafrancesco was involved in a number of ground-breaking projects that showcased the country's leadership and competitiveness in science. He was a highly cited, internationally recognised expert in cosmology and astrophysics and a leading driver of progress in multi-wavelength and multi-messenger astronmoy and astrophysics in South Africa.

The South African Institute of Physics has conveyed its condolences, adding that Colafrancesco made tremendous contributions to the development of radio and gamma-ray astronomy in South Africa and further afield on the African continent.

Born in Italy, Colafrancesco joined Wits in August 2011 from the University of Rome where he was a professor of astrophysics. Prior to that, he was a senior scientist with the Italian Institute for Astrophysics. He obtained his PhD in Astronomy at the University of Padua, Italy.

Details of his memorial service will be shared once available.

H.E.S.S. Collaboration releases first public test data in open FITS format
Sep 11, 2018

Today, the H.E.S.S. Collaboration has, for the first time, released a small subset of its archival data in Flexible Image Transport System (FITS) format, an open file format widely used in astronomy. The release consists of event lists and instrument response functions for observations of various well-known gamma-ray sources (the Crab nebula, PKS 2155-304, MSH 15-52, RX J1713.7-3946) as well as observations of empty fields for background modeling. It is compliant to the open format specifications developed in view of the upcoming CTA Observatory. The release is meant to support the development of open-source science tools for high-level analysis of gamma-ray data by providing access to "real" gamma-ray data in the appropriate format for the first time.

Links to the data, release notes document, data format specification, tutorials how to analyse the data and more information can be found at https://www.mpi-hd.mpg.de/hfm/HESS/pages/dl3-dr1/

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