Hubble image of the spiral galaxy NGC 1068. Credit: NASA/ESA/A. van der Hoeven
For the first time, an international team of scientists have found evidence of high-energy neutrino emission from NGC 1068, also known as Messier 77, an active galaxy in the constellation Cetus and one of the most familiar and well-studied galaxies to date. First spotted in 1780, this galaxy, located 47 million light-years away from us, can be observed with large binoculars. The results were published in Science, and shared in an online scientific webinar that gathered experts, journalists, and scientists from around the globe.
The IceCube Neutrino Observatory reported the first observation of a high-energy astrophysical neutrino source in 2018. The source, TXS 0506+056, is a known blazar located off the left shoulder of the Orion constellation and 4 billion light-years away.
“One neutrino can single out a source. But only an observation with multiple neutrinos will reveal the obscured core of the most energetic cosmic objects,” says Francis Halzen, a professor of physics at the University of Wisconsin–Madison and principal investigator of IceCube. He adds, “IceCube has accumulated some 80 neutrinos of teraelectronvolt energy from NGC 1068, which are not yet enough to answer all our questions, but they definitely are the next big step towards the realization of neutrino astronomy.”
Unlike light, neutrinos can escape in large numbers from extremely dense environments in the universe and reach Earth largely undisturbed by matter and the electromagnetic fields that permeate extragalactic space. Although scientists envisioned neutrino astronomy more than 60 years ago, the weak interaction of neutrinos with matter and radiation makes their detection extremely difficult. Neutrinos could be key to our queries about the workings of the most extreme objects in the cosmos.
A winterover standing in front of the IceCube Lab at the South Pole, with auroras and Milky Way overhead. Credit: Josh Veitch-Michaelis, IceCube/NSF
NGC 1068 is an active galaxy—a Seyfert II type in particular—seen from Earth at an angle that obscures its central region where the black hole is located. In a Seyfert II galaxy, a torus of nuclear dust obscuresmost of the high-energy radiation produced by the dense mass of gas and particles that slowly spiral inward toward the center of the galaxy.
“Recent models of the black hole environments in these objects suggest that gas, dust, and radiation should block the gamma rays that would otherwise accompany the neutrinos,” says Hans Niederhausen, a postdoctoral associate at Michigan State University. “This neutrino detection from the core of NGC 1068 will improve our understanding of the environments around supermassive black holes.”
NGC 1068 could become a standard candle for future neutrino telescopes, according to Theo Glauch, a postdoctoral associate at the Technical University of Munich (TUM), in Germany.
“It is already a very well-studied object for astronomers, and neutrinos will allow us to see this galaxy in a totally different way. A new view will certainly bring new insights,” says Glauch.With the neutrino measurements of TXS 0506+056 and NGC 1068, IceCube is one step closer to answering the century-old question of the origin of cosmic rays. Additionally, these results imply that there may be many more similar objects in the universe yet to be identified. “The unveiling of the obscured universe has just started, and neutrinos are set to lead a new era of discovery in astronomy,” says Elisa Resconi, a professor of physics at TUM.
“It is great news for the future of our field,” says Marek Kowalski, an IceCube collaborator and senior scientist at Deutsches Elektronen-Synchrotron, in Germany. “It means that with a new generation of more sensitive detectors there will be much to discover. The future IceCube-Gen2 observatory could not only detect many more of these extreme particle accelerators but would also allow their study at even higher energies. It’s as if IceCube handed us a map to a treasure trove.”
“Evidence for neutrino emission from the nearby active galaxy NGC 1068,” The IceCube Collaboration: R. Abbasi et al., Science 378, 6619 (2022), DOI:10.1126/science.abg3395 / arXiv:2211.09972
Frank Calaprice in Campo Imperatore, Gran Sasso, during a summer school. Credits: Borexino Collaboration
Prof. Emeritus Frank Paul Calaprice, Princeton University, has been awarded the prestigious Bethe prize for 2023.
“For pioneering work on large-scale ultra-low-background detectors, specifically Borexino, measuring the complete spectroscopy of solar neutrinos, culminating in observation of CNO neutrinos, thus experimentally proving operation of all the nuclear-energy driving reactions of stellar evolution.”
Frank Calaprice earned his Ph.D. from UC Berkeley in 1967 and joined Princeton faculty in 1970. In early 1990’s Frank started working on Borexino with Gianpaolo Bellini, Raju Raghavan, Jay Benziger, and Franz von Feilitzsch. Borexino aimed for the first time to search for sub-MeV solar neutrinos with a massive liquid scintillator at the Gran Sasso Laboratory, Italy. The main goal for Borexino was the measurement of the so-called 7Be solar neutrinos. At that time this was a great challenge. An extreme radio-purity better than 10-16 g/g for uranium and thorium was required. To face this challenge Frank and collaborators designed and built the Counting Test Facility (CTF). The CTF was a 4-ton liquid scintillator detector viewed by 100 8-inch photomultipliers inside a muon veto made of 1 kton of high purity water. The CTF was successful and paved the way for Borexino. Construction started in 1998. Borexino used 1 kton of pseudocumene viewed by 2212 8-inch photomultipliers inside a 14 meters in diameter stainless steel vessel. The ultra-high radio-purity 280 tons liquid scintillator was contained by a 125 mm thick nylon vessel. Borexino took data from May 2007 until October 2021. The radio-purity achieved by Borexino was much better than expected at the level of 10-18 g/g. This outstanding achievement allowed for the first time the measurement of sub-MeV solar neutrinos including pep and pp neutrinos besides 7Be, boosting our understanding of the interior of the sun. In 2020, Borexino observed CNO neutrinos. The CNO cycle, predicted by Bethe, makes only about 1% of the energy produced by the sun. Yet, in more massive stars it is the dominant source of energy. For the first time this energy source has been probed experimentally. CNO neutrinos are also a unique probe for the sun’s metallicity. Metallicity is a key input in the theory which describes the sun. Therefore, understanding experimentally the sun’s metallicity is crucial. The first attempt in this direction has been carried out by Borexino with CNO neutrinos.
Frank played a crucial role in the design and construction of the Borexino detector. In addition to much more he was deeply involved in the purification strategy, where he contributed with many important ideas. His role and involvement in the measurement of CNO neutrinos has been crucial. His recognition with a Bethe prize is quite appropriate, considering that Borexino has probed the basis of energy production in the sun through the pp-chain and the CNO cycle. Furthermore, the technology developed in the framework of Borexino is at the root of next-generation experiments which search for rare events, such as dark matter and neutrinoless double beta decay. In the last two decades Frank gave important contributions to direct search for dark matter through DarkSide-50 and SABRE both at the Gran Sasso Laboratory.
Stavros Katsanevas, born in Athens in 1953, died on 27 November 2022. He is known as a tireless proponent of astroparticle physics in all his functions, whether as deputy director of the French IN2P3, director of the APC in Paris or director of the EGO in Pisa. He has promoted the European and global coordination of astroparticle physics for decades and is rightly described as one of the founding fathers of this modern field of research.
Stavros Katsanevas was the initiator of several European scientific projects in the field of astroparticle physics. With the support of the European Commission, he founded ASPERA I+II, followed by the AstroParticle Physics European Consortium (ApPEC), which entered a new era in 2012 under the name APPEC. Stavros was the first Chair of the General Assembly of APPEC from 2012-2014. He has always been an indispensable member, a driving force and a mainstay of all APPEC activities. He played a central role in defining a global strategy of astroparticle physics and its road-mapping. He always paid special attention to interdisciplinary science around astroparticle physics, and to projects combining art and science to engage the public in the history, culture and bright future of science.
Stavros Katsanevas was animated by an inexhaustible desire to contribute to the progress of science by serving, stimulating and enlivening the community. This was a passion for which he lived and from which he let nothing deter him. His participation in APPEC was instrumental in bringing astroparticle physics to the attention of Europe and the world. A physicist and colleague with boundless and inexhaustible enthusiasm and great scientific culture, steeped in philosophy, literature and poetry, a humanist and universalist, Stavros was also a friend to many of us.
With extraordinary courage, Stavros fought his illness for years with such dignity and energy that he seemed invincible. Deep sadness gripped us when we received the news that Stavros left us on 27 November 2022 and that he will now share his inspirations on scientific knowledge elsewhere. But we are sure that he will convince and inspire there as well. APPEC and astroparticle physics owe a lot to Stavros and we ourselves have always felt comfortable and inspired around him. This is a great gift and we will miss him as a colleague and as a friend.
In summer 2022, the Cherenkov Telescope Array Observatory (CTAO) released the layouts that define the geographical position of the elements that will compose the two CTAO arrays, including the telescopes, calibration systems and atmospheric characterization devices. The distribution considers the approved number of telescopes within the so-called Alpha Configuration: 13 telescopes (four Large-Sized Telescopes, LST, and nine Medium-Sized Telescopes, MST) distributed over an area of ~0.5 km2 for the CTAO Northern Array at La Palma, Spain; and 51 telescopes (14 MSTs and 37 Small-Sized Telescopes, SSTs) over a ~3 km2 surface for the CTAO Southern Array in the Atacama Desert, Chile.
These coordinates are the result of a meticulous optimization to reach the most outstanding scientific performance. The optimization was led by the CTAO Project Scientist, Roberta Zanin, in close collaboration with the Cherenkov Telescope Array Consortium (CTAC) Physics Groups that supported the process.
“The defined layout ensures that the CTAO will have 5 to 10 times better sensitivity than any current instrument. Small modifications may occur based on local geophysical constraints and other factors, but any shift would be limited to prevent a significant difference in terms of performance,” says Roberta Zanin. “With such unprecedented sensitivity, we will guarantee transformational science.”
Layout of the CTAO Northern Array on La Palma, Spain (left) and the CTAO Southern Array in the Atacama Desert, Chile (right). Credits: CTAO and CTAC.
The Alpha Configuration and its geographical positions will be used in the coming Construction Phase of the Observatory, which will initiate once the CTAO transitions its legal status from the current gGmbH (under German law) to a European Research Infrastructure Consortium or ERIC (under European law).
In May 2022, the CTAO’s Board of Governmental Representatives (BGR) submitted the formal request to the European Commission to establish the CTAO ERIC. This request, known as the “Step 2” application, included the final version of all the required documentation with the approval of the future CTAO ERIC member countries, as their formal commitment to build and support the Observatory throughout its lifetime.
“The CTAO gGmbH was charged with two main goals: On the one hand, preparing for construction and, on the other hand, achieving the formation of the ERIC. With this submission, the preparatory phase has concluded. Our hope is that the European Commission ratifies the ERIC before the end of 2023,” explains Federico Ferrini, Managing Director of the CTAO gGmbH, who also comments: “Everything is in order from the managerial point of view to start the construction as soon as the formal conditions are satisfied.”
The European Commission is currently revising the documentation to prepare its final decision. The establishment of the CTAO ERIC, one of biggest milestones in the lifetime of the Observatory, is expected to take place in the first half of 2023. The launch of the CTAO ERIC marks the official start of the construction of the CTAO, the first ground-based gamma-ray observatory and the world’s most powerful instrument to detect this high-energy radiation. And with the data open to all, for the first time, exciting advances in the way we see the Universe are just around the corner!
The second JENAS, Joint ECFA (European Committee for Future Accelerators) – NuPECC (Nuclear Physics European Collaboration Committee) – APPEC (AstroParticle Physics European Consortium) Seminar was held in May 2022 in the auditorium of CSIC in Madrid: see https://indico.cern.ch/event/1040535/. For three days members of the European astroparticle, nuclear and particle physics communities presented their overlapping challenges and strategies. The symposium offered both senior and junior scientists of the three communities as well as representatives of the relevant funding agencies the opportunity to get a taste of each other’s activities. For many of the more than 160 participants, it was their first on-site attendance at a conference after more than two years of the Covid pandemic. The aim of the JENA symposium series is to achieve a comprehensive assessment of overlapping research topics in order to explore more efficiently our understanding of both the smallest and largest structures in nature.
The symposium started with overview talks on research highlights and strategies of the three individual research fields. A major part of the symposium concerned the progress and plans of the six joint projects that have emerged since the first JENAS in 2019: dark matter (iDMEu initiative); gravitational waves for fundamental physics; machine-learning optimised design of experiments; nuclear physics at the LHC; storage rings to search for charged-particle electric dipole moments; and synergies between the LHC and future electron–ion collider experiments. All these projects are open networks in which new interested people can participate at any time (contact points see under http://nupecc.org/jenaa/?display=eois). The discussions on these joint projects were complemented by a poster session where young scientists presented details of these activities.
Members of the astroparticle, nuclear and particle physics communities met in Madrid (CSIC) in May 2022 for the second JENAS Symposium.
R&D of detectors, Big Data computing and applications of Artificial Intelligence in the analysis and design of detectors and telescopes are just a few examples of developments that are important for our research and that were discussed at the meeting. Overview talks and round-table discussions on organizational matters related to education, outreach, open science and transfer of knowledge, provided lively debates between the participants. In addition, first results of surveys on diversity and the recognition of individual achievements in medium-size and large collaborations were presented and discussed. For the latter, a joint APPEC–ECFA–NuPECC working group has presented an aggregation of best practices already in place. A major finding is that many collaborations have already addressed this topic thoroughly. However, they are encouraged to further monitor progress and consider introducing more of the best practices that were identified.
The physics presented at the seminar, especially in the context of future large-scale global research facilities such as the FAIR accelerator complex, the HL-LHC or the Einstein Telescope, which always deal with cross-cutting issues, requires concerted action not only among scientists but also with the relevant funding agencies. One day of the seminar was dedicated to presentations and closed discussions with representatives of the European funding agencies and the European Commission. They were asked to assess whether appropriate funding programmes and organisational structures could be created to exploit synergies between the research fields to enable a more efficient use of resources. The recommendations made and feedback received from the seminar participants and the funding agencies will be very thoroughly considered and in particular the third JENA seminar in about three years will be very carefully planned and coordinated with the three communities and the funding agencies at an early stage.
The excellent organization and hospitality of the local organizers in Madrid, led by Maria Jose Garcia Borge, largely contributed to the success and the enjoyable atmosphere of JENAS 2022.
Andreas Haungs, KIT (APPEC chair)
Karl Jakobs, U Freiburg (ECFA chair)
Marek Lewitowicz, GANIL (NuPECC chair)
On 18th and 19th of July 2022 a hybrid meeting of the APPEC General Assembly took place in Vienna, Austria. At this occasion we could welcome two new APPEC members: The Austrian Academy of Sciences (ÖAW), represented in the GA by Josef Pradler and the National Academy of Sciences of Ukraine (NASU), with Fedor Danevich as new GA member. Josef Pradler and Fedor Danevich reported about current activities in astroparticle physics in their countries. Please find a summary of these reports below.
Austria
Florian Reindl – scientist from HEPHY and co-initiator of iDMEU, Andreas Haungs – APPEC Chair, Jochen Schieck – director of HEPHY, and Josef Pradler – representative of Austria in the GA, at the General Assembly in Vienna.
Credits: K. Link/ APPEC
Astroparticle physics activities in Austria consist of longstanding engagements in cosmic ray physics (FERMI, CTA, H.E.S.S.) by the University of Innsbruck and more recent growing investments in the experimental and theoretical exploration of dark matter in Vienna, e.g. in the frame of the JENAA EoI iDMEU.
In particular, the Vienna Institute of High Energy Physics (HEPHY) by the Austrian Academy of Sciences is involved in the CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) and COSINUS (Cryogenic Observatory for SIgnals seen in Next-generation Underground Searches) dark matter direct detection experiments. Their focus is on sub-GeV mass dark matter particles and a test of the DAMA/LIBRA signal claim, respectively. Both operate at the LNGS (Laboratori Nazionali del Gran Sasso). A comparatively smaller involvement in neutrino physics happens through the participation in the NUCLEUS experiment. HEPHY is Austria’s largest center for particle physics in Austria and the Austrian Academy of Sciences is the official signatory of the APPEC association document.
The experimental dark matter program is supplemented by various theory groups in Graz and Vienna and it includes the current and future ERC-funded efforts in stellar dynamics (ArcheoDyn), cosmology (COSMO-SIMS), and theory of particle dark matter (NLO-DM).
Austria’s major funding organisation for fundamental research is the Austrian Science Fund FWF. In addition, there is the Austrian Research an Promotion Agency (FFG) for industrial research and development in Austria. The participation in major research infrastructures such as CTA and CERN is enabled through by the Federal Ministry for Education, Science and Research.
Ukraine
Andreas Haungs – APPEC Chair, and Fedor Danevich – Ukrainian representative, after signing the APPEC MoU.
Credits: K. Link/ APPEC
There are several groups in Ukraine working in different experimental and theoretical activities in the field of astroparticle physics.
Two groups from the Main Astronomical Observatory of the National Academy of Sciences of Ukraine (NASU) use astronomical big data to study dynamical mechanisms of accretion in galactic nuclei, stability, accretion, and tidal disruption near supermassive black holes, to analyse the matter distribution in large-scale structures, estimate virial masses in different galaxy systems, to study properties of the matter and non-zero magnetic fields in voids and search for hypothetical particles.
In 2015 several Ukrainian institutions joined the CTA Consortium. Besides, the scientists participate in the LISA, THESEUS and ATHENA projects.
Restrictions on the parameters of dark-matter-candidate particles, search for astrophysical signal of light-sterile neutrinos decays, limit on the mass of light fermionic-dark-matter particles were set by a group of the Bogolyubov Institute for Theoretical Physics of the NASU. Gravity theories, dark matter, extension of the Standard Model are subjects of the researchers from the I.I. Mechnykov National University (Odessa). Dark matter and dark energy on astrophysical and cosmological scales are the directions of activity of the group from the Ivan Franko National University of Lviv.
Experimentalists from the Taras Shevchenko National University of Kyiv participate in the Hyper-Kamiokande and DUNE collaborations.
The principal scientific goal of the Lepton Physics Department of the Institute for Nuclear Sciences of NASU (INR NASU) is search for rare or hypothetical processes in nuclear and particle physics. The group participates in the CUPID collaboration aiming at search for neutrinoless double-beta decay of 100Mo. R&Ds for the project are carried out in the framework of the CUPID-Mo, CROSS and BINGO projects. The INR NASU is also a member of the Borexino collaboration. Recently the group joined the RES-NOVA project to develop PbWO4 based bolometers for neutrino detection from astrophysical sources. A group from the Kharkiv Institute of Physics and Technology of NASU carried out a deep purification of the archaeological lead samples, while the PbWO4 crystal scintillators were grown by the Institute of Scintillation Materials of NASU.
Participation in APPEC will be definitely the very suitable and reliable basis for Ukrainian scientists to participate in the research in the field in Europe.
NuPECC, the Nuclear Physics European Collaboration Committee, calls for inuput for the NuPECC Long Range Plan 2024. Please find below a message from the NuPECC LRP2024 Steering Committee and note that it explicitly mentioned that synergies with astroparticle physics are being considered.
“NuPECC is launching the process of creating a new Long Range Plan (LRP) for Nuclear Physics in Europe, identifying opportunities and priorities for nuclear science in Europe, with the aim of publishing the document in 2024. The previous Long Range Plan can be found at http://nupecc.org/pub/lrp17/lrp2017.pdf and an assessment of its implementation at http://nupecc.org/2017_LRP_Assessment_of_Implementation_final.pdf.
With the intention of strengthening the bottom-up approach that has always played an important role in its LRPs, NuPECC is opening a call for inputs to the next LRP in form of short (5 page) documents describing the view of collaborations, experiments, or communities on the key topics for the next 10 years to be included in the upcoming LRP. We also solicit new ideas going beyond the topics considered in the LRP 2017 or exploring synergies with the particle physics and astroparticle physics communities and considering new developments such as gravitational waves and multi-messenger astronomy. Contributions related to novel applications in cross disciplinary fields are also welcome.
The call will be open until 1 Oct 2022. Details concerning the submission procedure and the format of inputs can be found at the submission site https://indico.ph.tum.de/e/LRP2024-input .”
Marek Lewitowicz
on behalf of the NuPECC LRP2024 Steering Committee
Scientists met at KIT to work on the next-generation dark matter detector.
Credits: Joachim Wolf/ KIT
Scientists from the leading dark matter experiments came together in June at the Karlsruhe Institute of Technology, joining forces to design and build a future dark matter detector within the XLZD consortium. The XENON and LUX-ZEPLIN collaborations currently each operate some of the most sensitive experiments ever built to detect rare particle interactions, such as those expected from dark matter or neutrinos. The DARWIN collaboration, uniting XENON and new members, is planning a next-generation observatory for rare-event searches based on the liquid-xenon technique. These collaborations came together to jointly work on the next-generation experiment, which is expected to take data later in this decade.
At the meeting in Karlsruhe, the scientists discussed how this experiment can be realized together. The project is expected to make dramatic advances for our understanding of dark matter, the dominant form of matter in the universe. The same experiment will also advance our understanding of how our Sun creates its energy through the study of neutrinos that directly come from the core of our star. Further discoveries may be made through the study of rare nuclear decays. “I am thrilled about the enormous potential of this detector” says Prof. Laura Baudis from the University of Zurich. “With one
experiment, we will simultaneously learn about dark matter, neutrinos, our Sun, nuclear physics, particle physics, and even cosmology”. Prof. Hugh Lippincott from the University of Santa Barbara added: “Here we have the best teams in the search for dark matter joining forces, to get to the bottom of this cosmic riddle. We are motivated to do the science, and this meeting has made it clear that we also have the necessary expertise to build this observatory in the coming years.”
A recent whitepaper outlining the science case was signed by over 600 scientists from 150 institutions in 28 countries, underlining the international scope and support of the project. “We had signed a Memorandum of Understanding already in 2021”, says Prof. Kathrin Valerius from KIT, “and this meeting was a great success. It allowed us to further solidify our joint scientific work that we had so far only been able to do remotely over the past year.”
The XII symposium of the Einstein Telescope (ET) took place in Budapest, at the Hungarian Academy of Sciences, on the 7th – 8th of June. The ET scientific community met in Budapest for a crucial step in the long Einstein Telescope journey: the formal establishment of the ET Collaboration.
More than 400 scientists, out of more than 1200 members of the Collaboration, participated in the meeting in person or remotely. The ET members discussed the status of the experiment, the technical challenges, the scientific case, and the scientific and technical progresses made by each of the ET boards. The ET Project Directorate presented the perspective from the funding agencies. Finally, the approved INFRA-DEV Horizon EU project, for supporting the preparation phase of the experiment, and the INFRA-TECH Horizon EU proposal, recently submitted to Brussels for supporting technological R&D activities, were introduced to the whole Collaboration.
During the meeting in Budapest, the ET Collaboration Board (CB) was constituted, temporary chaired by Dr. H. Lueck (AEI), composed of the representatives from each of the 79 research units from 13 countries. During the first CB meeting, the ET Collaboration discussed the recently created ET bylaws that will govern the future of the experiment and initiated procedures to set up the required Collaboration committees. In addition, interim ET Spokesperson (Michele Punturo, INFN) and Deputy Spokesperson (Harald Lueck) figures were identified.
With the birth of the ET Collaboration, this symposium marks a milestone on the long journey of the Einstein Telescope endeavour.
XENONnT researchers assemblying one of the two PMT arrays (front) and working on the TPC (back)
Credit: XENONnT Collaboration
XENONnT detector at LNGS.
Credit: XENONnT Collaboration
On July 22nd during the IDM 2022 Conference (https://indico.cern.ch/event/922783/) held in Vienna, the XENONnT Collaboration announced its first results on Electron Recoils events.
The XENONnT detector at the Gran Sasso Laboratory in Italy replaces the previous one, XENON1T. XENONnT aimed not only to enlarge the detector mass (5.9 t active volume from 2 t) but improve significantly the background identification and rejection exploiting new techniques and an active neutron veto. Details on the detector can be found here: XENON Collaboration, JCAP 11 (2020) 031.
XENONnT took the first science data over 97.1 days, from July 6 to November 10, 2021.
The Electron Recoils (ER) events measurement has allowed XENONnT to probe the excess observed by XENON1T at 2.3 keV (ER energy). XENONnT has reached an unprecedented low level of radon of order 2 μBq/kg. The low background achieved allows XENONnT to use rare signal, such as the double-electron capture on 124Xe, as validation tool. The first data has allowed XENONnT to probe that the detector is performing well, to cancel the excess at low energy, which was due to 3H, and to probe the neutrino magnetic moment with unprecedented sensitivity to 6.3×10-12 μB.
