https://www.um.edu.mt/library/oar/handle/123456789/16098 2026-10-22T14:44:18Z 2026-10-22T14:44:18Z Davenport, James R. A. Sheikh, Sofia Z. Farah, Wael Nilipour, Andy Cabrales, Bárbara Croft, Steve Pollak, Alexander W. Siemion, Andrew P. V. https://www.um.edu.mt/library/oar/handle/123456789/150250 2026-10-20T07:44:24Z 2023-01-01T00:00:00Z

Title: Real-time technosignature strategies with SN 2023ixf Authors: Davenport, James R. A.; Sheikh, Sofia Z.; Farah, Wael; Nilipour, Andy; Cabrales, Bárbara; Croft, Steve; Pollak, Alexander W.; Siemion, Andrew P. V. Abstract: Several technosignature techniques focus on historic events such as SN 1987A as the basis to search for coordinated signal broadcasts from extraterrestrial agents. The recently discovered SN 2023ixf in the spiral galaxy M101 is the nearest Type II supernova in over a decade, and will serve as an important benchmark event. Here we review the potential for SN 2023ixf to advance ongoing techonsignature searches, particularly signal-synchronization techniques such as the “SETI Ellipsoid” that identifies over time stars that could transmit signals after observing a supernovae event. We find that more than 100 stars within 100 pc are already close to intersecting this SETI Ellipsoid, providing numerous targets for real-time monitoring within ∼3° of SN 2023ixf. We are commencing a radio technosignature monitoring campaign of these targets with the Allen Telescope Array and the Green Bank Telescope.

2023-01-01T00:00:00Z Wandia, Kelvin Garrett, Michael A. Radcliffe, Jack F. Garrington, Simon T. Fawcett, James Gajjar, Vishal MacMahon, David H. E. Varenius, Eskil Campbell, Robert M. Paragi, Zsolt Siemion, Andrew P. V. https://www.um.edu.mt/library/oar/handle/123456789/150036 2026-10-14T13:57:52Z 2023-01-01T00:00:00Z

Title: An interferometric SETI observation of Kepler-111 b Authors: Wandia, Kelvin; Garrett, Michael A.; Radcliffe, Jack F.; Garrington, Simon T.; Fawcett, James; Gajjar, Vishal; MacMahon, David H. E.; Varenius, Eskil; Campbell, Robert M.; Paragi, Zsolt; Siemion, Andrew P. V. Abstract: The application of very long baseline interferometry (VLBI) to the search for extraterrestrial intelligence (SETI) has been limited to date, despite the technique offering many advantages over traditional single-dish SETI observations. In order to further develop interferometry for SETI, we used the European VLBI network (EVN) at 21 cm to observe potential secondary phase calibrators in the Kepler field. Unfortunately, no secondary calibrators were detected. However, a VLBA primary calibrator in the field, J1926+4441, offset only ~1.88 arcmin from a nearby exoplanet Kepler-111 b, was correlated with high temporal (0.25s) and spectral (16384×488Hz channels) resolution. During the analysis of the high-resolution data, we identified a spectral feature that was present in both the auto and cross-correlation data with a central frequency of 1420.424 ± 0.0002 MHz and a width of 0.25 MHz. We demonstrate that the feature in the cross-correlations is an artefact in the data, associated with a significant increase in each telescope's noise figure due to the presence of H I in the beam. This would typically go unnoticed in data correlated with standard spectral resolution. We flag (excluded from the subsequent analysis) these channels and phase rotate the data to the location of Kepler-111 b aided by the Gaia catalogue and search for signals with SNR>7 . At the time of our observations, we detect no transmitters with an equivalent isotropically radiated power ≳4 × 1015 W.

2023-01-01T00:00:00Z Nilipour, Andy Davenport, James R. A. Croft, Steve Siemion, Andrew P. V. https://www.um.edu.mt/library/oar/handle/123456789/149872 2026-10-08T13:41:27Z 2023-01-01T00:00:00Z

Title: Signal synchronization strategies and time domain SETI with Gaia DR3 Authors: Nilipour, Andy; Davenport, James R. A.; Croft, Steve; Siemion, Andrew P. V. Abstract: Spatiotemporal techniques for signal coordination with actively transmitting extraterrestrial civilizations, without the need for prior communication, can constrain technosignature searches to a significantly smaller coordinate space. With the variable star catalog from Gaia Data Release 3, we explore two related signaling strategies: the SETI Ellipsoid, and that proposed by Seto, which are both based on the synchronization of transmissions with a conspicuous astrophysical event. This data set contains more than 10 million variable star candidates with light curves from the first three years of Gaia’s operational phase, between 2014 and 2017. Using four different historical supernovae as source events, we find that less than 0.01% of stars in the sample have crossing times, the times at which we would expect to receive synchronized signals on Earth, within the date range of available Gaia observations. For these stars, we present a framework for technosignature analysis that searches for modulations in the variability parameters by splitting the stellar light curve at the crossing time.

2023-01-01T00:00:00Z Acharyya, Atreya Adams, Colin Archer, A. Bangale, Priyadarshini Batista, Pedro Benbow, Wystan Brill, Aryeh Capasso, Massimo Errando, Manel Falcone, Abraham Feng, Qi Finley, J. P. Foote, Juniper Fortson, Lucy Furniss, Amy Griffin, S. Hanlon, William Hanna, David Hervet, Olivier Hinrichs, Claire Hoang, J. Holder, Jamie Humensky, Thomas Jin, Weidong Kaaret, Philip Kertzman, M. Kherlakian, M. Kieda, David Kleiner, Tobias K. Korzoun, Nikolas Kumar, Sajan Lang, M.J. Lundy, Matthew Maier, Gernot McGrath, C. E. Millard, Matthew Miller, H. R. Millis, J. Mooney, Connor Moriarty, Patrick Mukherjee, Reshmi O’Brien, Stephan Ong, Rene Pohl, Martin Pueschel, Elisa Quinn, John Ragan, Ken Reynolds, P. T. Ribeiro, Deivid Roache, E. Ryan, James Sadeh, Iftach Saha, Lab Santander, Marcos Sembroski, G. H. Shang, Ruo-Yu Tak, D. Talluri, A. K. Tucci, J. V. Vazquez, N. Williams, David A. Wong, Samantha Woo, Jooyun DeBoer, David Isaacson, Howard de Pater, I. Price, D. C. Siemion, Andrew P. V. https://www.um.edu.mt/library/oar/handle/123456789/148646 2026-08-25T07:44:26Z 2023-01-01T00:00:00Z

Title: A VERITAS/breakthrough listen search for optical technosignatures Authors: Acharyya, Atreya; Adams, Colin; Archer, A.; Bangale, Priyadarshini; Batista, Pedro; Benbow, Wystan; Brill, Aryeh; Capasso, Massimo; Errando, Manel; Falcone, Abraham; Feng, Qi; Finley, J. P.; Foote, Juniper; Fortson, Lucy; Furniss, Amy; Griffin, S.; Hanlon, William; Hanna, David; Hervet, Olivier; Hinrichs, Claire; Hoang, J.; Holder, Jamie; Humensky, Thomas; Jin, Weidong; Kaaret, Philip; Kertzman, M.; Kherlakian, M.; Kieda, David; Kleiner, Tobias K.; Korzoun, Nikolas; Kumar, Sajan; Lang, M.J.; Lundy, Matthew; Maier, Gernot; McGrath, C. E.; Millard, Matthew; Miller, H. R.; Millis, J.; Mooney, Connor; Moriarty, Patrick; Mukherjee, Reshmi; O’Brien, Stephan; Ong, Rene; Pohl, Martin; Pueschel, Elisa; Quinn, John; Ragan, Ken; Reynolds, P. T.; Ribeiro, Deivid; Roache, E.; Ryan, James; Sadeh, Iftach; Saha, Lab; Santander, Marcos; Sembroski, G. H.; Shang, Ruo-Yu; Tak, D.; Talluri, A. K.; Tucci, J. V.; Vazquez, N.; Williams, David A.; Wong, Samantha; Woo, Jooyun; DeBoer, David; Isaacson, Howard; de Pater, I.; Price, D. C.; Siemion, Andrew P. V. Abstract: The Breakthrough Listen Initiative is conducting a program using multiple telescopes around the world to search for “technosignatures”: artificial transmitters of extraterrestrial origin from beyond our solar system. The Very Energetic Radiation Imaging Telescope Array System (VERITAS) Collaboration joined this program in 2018 and provides the capability to search for one particular technosignature: optical pulses of a few nanoseconds in duration detectable over interstellar distances. We report here on the analysis and results of dedicated VERITAS observations of Breakthrough Listen targets conducted in 2019 and 2020 and of archival VERITAS data collected since 2012. Thirty hours of dedicated observations of 136 targets and 249 archival observations of 140 targets were analyzed and did not reveal any signals consistent with a technosignature. The results are used to place limits on the fraction of stars hosting transmitting civilizations. We also discuss the minimum pulse sensitivity of our observations and present VERITAS observations of CALIOP: a space-based pulsed laser on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations. The detection of these pulses with VERITAS, using the analysis techniques developed for our technosignature search, allows a test of our analysis efficiency and serves as an important proof of principle.

2023-01-01T00:00:00Z