The universe is full of explosive events – for example, when stars detonate or are torn apart near black holes. Very rarely, about once every hundred years, such events can be observed with the naked eye in the night sky. In antiquity, they were understood as signs from the gods; today, such events are used in astrophysics as precision measurement probes to determine the laws of nature and components of the universe that are responsible for the movement of entire galaxies, for example. This requires powerful telescopes that can detect such events even in distant galaxies.
New wide-field telescope observes the universe with unprecedented sensitivity
The Vera Rubin Observatory (VRO) recently put a new wide-field telescope into operation at the peak of Cerra Pachon in Chile, at an altitude of 2,682 metres. With a diameter of 8.4 metres, the telescope surveys the universe with unprecedented sensitivity. Now, the enormous amounts of data collected by this telescope from the most distant regions of the cosmos are being made available to the scientific community in real time. This is done via five access nodes – one of which is the AMPEL platform. AMPEL has been developed since 2019 by the Experimental Astroparticle Physics and Cosmology Group (EAT) at the Department of Physics at Humboldt-Universität Berlin (HU) to classify measurement data and make it manageable for researchers. The platform is hosted at the computing facility of the DESY research centre in Zeuthen, Germany.
Research platform provides the most accurate classification of data
‘The new telescope will for the first time allow us to accurately observe tens of thousands of exploding stars occurring during billions of years throughout the expansion of the Universe. This data will allow us not only to map out how the universe has evolved, but will directly constrain properties of dark matter and dark energy, two mysterious energy sources which dominate the evolution of the universe today,’ says Dr Jakob Nordin, who heads the project at HU. ‘The pure scale of the data volumes has forced us to create new analysis tools. This is where AMPEL comes from – a platform that allows scientists to encode their scientific ideas as analysis schema.’ The automated classification of measurement data enables researchers to filter out specific data on the events they need for their research. Tests show that AMPEL provides the most accurate classification compared to other access points.
The processing of the data and its use by scientists worldwide poses particular challenges. This is because the telescope's camera is so sensitive that it reports millions of light signals every night. ‘Most alerts we receive from the VRO are due to the normal variability of stars, while some herald the birth of something unique,’ says Dr Jakob van Santen at DESY. ‘So we had to build and program the platform in such a way that it combines both flexibility and processing power, while upholding the scientific standards of reproducibility.’
HU astrophysicists use new light measurements from the universe to study neutrinos and gravitational waves
In addition to developing the research platform for processing the EAT group at the Department of Physics and at DESY will also maintain it in the future. Furthermore, the astrophysicists will use the data for their own research, specifically for studying neutrinos. Neutrinos are electrically neutral particles that have recently also been used as cosmic messenger particles. ‘Thanks to the neutrinos detected by IceCube observatory in the Antarctic, we can now view sources of high energy particle acceleration’, says Professor Marek Kowalski, head of the EAT group at HU Berlin and Lead Scientist at DESY. ‘AMPEL allows us to compare data-streams from IceCube and VRO in real-time. As neutrinos can travel through large lengths of space, we need observatories with the depth of VRO to allow us to search for the optical counterpart. What is special is that we can use the same methods to search for the sources of gravitational waves.’
It remains to be seen whether this new telescope will actually reveal unexpected events in the universe. ‘History shows that with every new generation of telescopes, previously unknown phenomena appear as we can search the Universe for more distant and rare events,’ says Jakob Nordin. ‘Who knows what we will find this time.’