Jun 5, 2023 04:27 PM
https://www.universetoday.com/161714/ast...milky-way/
EXCERPT: . . . a rotating beacon near Galactic Center (GC) is considered a promising technosignature to SETI researchers. For an advanced species, such a beacon would provide a means for communicating with the entire galaxy without the need for direct contact. For species dying to know if they are alone in the Universe but not so eager as to advertise their location, a beacon is doubly attractive because it would also allow some anonymity to be maintained. As Suresh told Universe Today via email:
“From a game theory perspective, the core of the Milky Way is a likely “Schelling point” by which different alien worlds may establish communication without prior contact. For instance, intelligent aliens may choose to transmit beacons toward the center of the Milky Way to reach a maximum number of targets. Equivalently, such aliens may also transmit directly away from the center of the Milky Way, knowing that societies like ours will look towards the core of the galaxy.”
For their search, the team employed a fast folding algorithm (FFA), an open-source machine learning software designed to detect periodic events within time series data. They first tested this algorithm on known pulsars, successfully detecting the expected periodic emissions. They then consulted datasets obtained by the 100-meter Green Bank Telescope (GBT) – part of the Breakthrough Listen’s network – on a region at the center of the Milky Way during a 4.5-hour observing period. This region measures 50 light-years in diameter and encompasses over half a million stars.
Unlike pulsars, which emit signals across a broad range of radio frequencies, BLIPSS narrowed its search to look for regularly-spaced sequences of pulses (11 to 100 seconds apart) across a signal range of a few kilohertz – similar to radar communications. “Unfortunately, our searches did not reveal any pulsating signals that may be of extraterrestrial origin,” said Suresh. “Our results suggest that from the nearly 600,000 stars surveyed at the center of our galaxy, beacons with repetition rates between 11 to 100 seconds were either off or too faint to be detected during our observations.”
While their search did not turn up any clear indications of periodic radio signals, it accomplished several firsts. Before BLISS, radio SETI was primarily dedicated to looking for continuous signals, whereas a galactic beacon would rely on pulsed radio bursts. The search conducted by Suresh and his colleagues is the first-ever comprehensive, in-depth search for these signals. It is also the first time that FFA algorithms have been used to mine data for possible indications of pulsed signals.
In addition, the methodology employed by Suresh and his colleagues was novel in its combination of narrow bandwidths with periodic patterns that could be technosignatures. And by searching for timed sequences in a specific frequency range, this unprecedented survey has established constraints that future studies can build on... (MORE - missing details)
EXCERPT: . . . a rotating beacon near Galactic Center (GC) is considered a promising technosignature to SETI researchers. For an advanced species, such a beacon would provide a means for communicating with the entire galaxy without the need for direct contact. For species dying to know if they are alone in the Universe but not so eager as to advertise their location, a beacon is doubly attractive because it would also allow some anonymity to be maintained. As Suresh told Universe Today via email:
“From a game theory perspective, the core of the Milky Way is a likely “Schelling point” by which different alien worlds may establish communication without prior contact. For instance, intelligent aliens may choose to transmit beacons toward the center of the Milky Way to reach a maximum number of targets. Equivalently, such aliens may also transmit directly away from the center of the Milky Way, knowing that societies like ours will look towards the core of the galaxy.”
For their search, the team employed a fast folding algorithm (FFA), an open-source machine learning software designed to detect periodic events within time series data. They first tested this algorithm on known pulsars, successfully detecting the expected periodic emissions. They then consulted datasets obtained by the 100-meter Green Bank Telescope (GBT) – part of the Breakthrough Listen’s network – on a region at the center of the Milky Way during a 4.5-hour observing period. This region measures 50 light-years in diameter and encompasses over half a million stars.
Unlike pulsars, which emit signals across a broad range of radio frequencies, BLIPSS narrowed its search to look for regularly-spaced sequences of pulses (11 to 100 seconds apart) across a signal range of a few kilohertz – similar to radar communications. “Unfortunately, our searches did not reveal any pulsating signals that may be of extraterrestrial origin,” said Suresh. “Our results suggest that from the nearly 600,000 stars surveyed at the center of our galaxy, beacons with repetition rates between 11 to 100 seconds were either off or too faint to be detected during our observations.”
While their search did not turn up any clear indications of periodic radio signals, it accomplished several firsts. Before BLISS, radio SETI was primarily dedicated to looking for continuous signals, whereas a galactic beacon would rely on pulsed radio bursts. The search conducted by Suresh and his colleagues is the first-ever comprehensive, in-depth search for these signals. It is also the first time that FFA algorithms have been used to mine data for possible indications of pulsed signals.
In addition, the methodology employed by Suresh and his colleagues was novel in its combination of narrow bandwidths with periodic patterns that could be technosignatures. And by searching for timed sequences in a specific frequency range, this unprecedented survey has established constraints that future studies can build on... (MORE - missing details)