Chapter 4
Cherenkov Telescopes for Optical SETI
Patrizia A. Caraveo
Abstract Using Cherenkov telescopes to search for optical signals from interstellar
civilizations is a clever way to exploit the vast Cherenkov mirrors and their ultrafast
cameras. Such searches could be done in parallel with the telescope routine operations
without hampering the gamma-ray data collection.
4.1 A Visionary Common Start
High-energy gamma-ray astrophysics and the search for Interstellar communications
have common roots since they have been proposed over 60 years ago by Philip
Morrison and Giovanni Cocconi, two visionary scientists who dared to explore new
fields.
4.1.1 The Beginning of High-Energy Astrophysics
At the time, cosmic rays represented the frontier of particle physics since studying
cosmic ray interactions unveiled new particles. Cosmic rays were studied both
directly, through devices capable of tracing their interactions such as stacks of photographic plates brought at high altitude or bubble-chambers on ground laboratories,
and indirectly through the air showers they created upon their interactions with the
atmosphere’ atoms [1]. During such cascade process, the number of secondary particles, carrying a fraction of the incoming particle energy, is rapidly increasing until
the multiplication process stops and the shower dies out. Indeed, only the showers
produced by the highest energy particles can reach the ground where the secondary
particles can be detected using arrays of counters. Although the cosmic nature of
the particles’ flux was accepted, its origin was far from clear as discussed, e.g., by
P. A. Caraveo (B)
IASF-INAF Via A.Corti 12, 20133 Milan, Italy
e-mail: patrizia.caraveo@inaf.it
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
S. Montebugnoli and A. Melis (eds.), The Search for ExtraTerrestrial Intelligence,
Springer Proceedings in Physics 260, https://doi.org/10.1007/978-3-030-63806-1_4
21
Cherenkov Telescopes for Optical SETI
Patrizia A. Caraveo
Abstract Using Cherenkov telescopes to search for optical signals from interstellar
civilizations is a clever way to exploit the vast Cherenkov mirrors and their ultrafast
cameras. Such searches could be done in parallel with the telescope routine operations
without hampering the gamma-ray data collection.
4.1 A Visionary Common Start
High-energy gamma-ray astrophysics and the search for Interstellar communications
have common roots since they have been proposed over 60 years ago by Philip
Morrison and Giovanni Cocconi, two visionary scientists who dared to explore new
fields.
4.1.1 The Beginning of High-Energy Astrophysics
At the time, cosmic rays represented the frontier of particle physics since studying
cosmic ray interactions unveiled new particles. Cosmic rays were studied both
directly, through devices capable of tracing their interactions such as stacks of photographic plates brought at high altitude or bubble-chambers on ground laboratories,
and indirectly through the air showers they created upon their interactions with the
atmosphere’ atoms [1]. During such cascade process, the number of secondary particles, carrying a fraction of the incoming particle energy, is rapidly increasing until
the multiplication process stops and the shower dies out. Indeed, only the showers
produced by the highest energy particles can reach the ground where the secondary
particles can be detected using arrays of counters. Although the cosmic nature of
the particles’ flux was accepted, its origin was far from clear as discussed, e.g., by
P. A. Caraveo (B)
IASF-INAF Via A.Corti 12, 20133 Milan, Italy
e-mail: patrizia.caraveo@inaf.it
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
S. Montebugnoli and A. Melis (eds.), The Search for ExtraTerrestrial Intelligence,
Springer Proceedings in Physics 260, https://doi.org/10.1007/978-3-030-63806-1_4
21