36 research outputs found
A 1.1 to 1.9 GHz SETI Survey of the Kepler Field: I. A Search for Narrow-band Emission from Select Targets
We present a targeted search for narrow-band (< 5 Hz) drifting sinusoidal
radio emission from 86 stars in the Kepler field hosting confirmed or candidate
exoplanets. Radio emission less than 5 Hz in spectral extent is currently known
to only arise from artificial sources. The stars searched were chosen based on
the properties of their putative exoplanets, including stars hosting candidates
with 380 K > T_eq > 230 K, stars with 5 or more detected candidates or stars
with a super-Earth (R_p 50 day orbit. Baseband voltage data
across the entire band between 1.1 and 1.9 GHz were recorded at the Robert C.
Byrd Green Bank Telescope between Feb--Apr 2011 and subsequently searched
offline. No signals of extraterrestrial origin were found. We estimate that
fewer than ~1% of transiting exoplanet systems host technological civilizations
that are radio loud in narrow-band emission between 1-2 GHz at an equivalent
isotropically radiated power (EIRP) of ~1.5 x 10^21 erg s^-1, approximately
eight times the peak EIRP of the Arecibo Planetary Radar, and we limit the the
number of 1-2 GHz narrow-band-radio-loud Kardashev type II civilizations in the
Milky Way to be < 10^-6 M_solar^-1. Here we describe our observations, data
reduction procedures and results.Comment: Accepted to the Astrophysical Journa
New SETI Sky Surveys for Radio Pulses
Berkeley conducts 7 SETI programs at IR, visible and radio wavelengths. Here
we review two of the newest efforts, Astropulse and Fly's Eye.
A variety of possible sources of microsecond to millisecond radio pulses have
been suggested in the last several decades, among them such exotic events as
evaporating primordial black holes, hyper-flares from neutron stars, emissions
from cosmic strings or perhaps extraterrestrial civilizations, but to-date few
searches have been conducted capable of detecting them.
We are carrying out two searches in hopes of finding and characterizing these
mu-s to ms time scale dispersed radio pulses. These two observing programs are
orthogonal in search space; the Allen Telescope Array's (ATA) "Fly's Eye"
experiment observes a 100 square degree field by pointing each 6m ATA antenna
in a different direction; by contrast, the Astropulse sky survey at Arecibo is
extremely sensitive but has 1/3,000 of the instantaneous sky coverage.
Astropulse's multibeam data is transferred via the internet to the computers of
millions of volunteers. These computers perform a coherent de-dispersion
analysis faster than the fastest available supercomputers and allow us to
resolve pulses as short as 400 ns. Overall, the Astropulse survey will be 30
times more sensitive than the best previous searches. Analysis of results from
Astropulse is at a very early stage.
The Fly's Eye was successfully installed at the ATA in December of 2007, and
to-date approximately 450 hours of observation has been performed. We have
detected three pulsars and six giant pulses from the Crab pulsar in our
diagnostic pointing data. We have not yet detected any other convincing bursts
of astronomical origin in our survey data. (Abridged)Comment: 9 pages, 6 figures, Accepted to Acta Astronautica "Special Issue:
Life Signatures
The Breakthrough Listen Search for Intelligent Life: A 3.95-8.00 GHz Search for Radio Technosignatures in the Restricted Earth Transit Zone
We report on a search for artificial narrowband signals of 20 stars within
the restricted Earth Transit Zone as a part of the ten-year Breakthrough Listen
(BL) search for extraterrestrial intelligence. The restricted Earth Transit
Zone is the region of the sky from which an observer would see the Earth
transit the Sun with an impact parameter of less than 0.5. This region of the
sky is geometrically unique, providing a potential way for an extraterrestrial
intelligence to discover the Solar System. The targets were nearby (7-143 pc)
and the search covered an electromagnetic frequency range of 3.95-8.00 GHz. We
used the Robert C. Byrd Green Bank Telescope to perform these observations with
the standard BL data recorder. We searched these data for artificial narrowband
(Hz) signals with Doppler drift rates of Hz s. We found
one set of potential candidate signals on the target HIP 109656 which was then
found to be consistent with known properties of anthropogenic radio frequency
interference. We find no evidence for radio technosignatures from
extraterrestrial intelligence in our observations. The observing campaign
achieved a minimum detectable flux which would have allowed detections of
emissions that were to times as powerful as the signaling
capability of the Arecibo radar transmitter, for the nearest and furthest stars
respectively. We conclude that at least of the systems in the restricted
Earth Transit Zone within 150 pc do not possess the type of transmitters
searched in this survey. To our knowledge, this is the first targeted search
for extraterrestrial intelligence of the restricted Earth Transit Zone. All
data used in this paper are publicly available via the Breakthrough Listen
Public Data Archive (http://seti.berkeley.edu/bldr2).Comment: 17 pages, 8 figures, submitted to Ap
No bursts detected from FRB121102 in two 5-hour observing campaigns with the Robert C. Byrd Green Bank Telescope
Here, we report non-detection of radio bursts from Fast Radio Burst FRB
121102 during two 5-hour observation sessions on the Robert C. Byrd 100-m Green
Bank Telescope in West Virginia, USA, on December 11, 2017, and January 12,
2018. In addition, we report non-detection during an abutting 10-hour
observation with the Kunming 40-m telescope in China, which commenced UTC 10:00
January 12, 2018. These are among the longest published contiguous observations
of FRB 121102, and support the notion that FRB 121102 bursts are episodic.
These observations were part of a simultaneous optical and radio monitoring
campaign with the the Caltech HIgh- speed Multi-color CamERA (CHIMERA)
instrument on the Hale 5.1-m telescope.Comment: 1 table, Submitted to RN of AA
Current and Nascent SETI Instruments
Here we describe our ongoing efforts to develop high-performance and
sensitive instrumentation for use in the search for extra-terrestrial
intelligence (SETI). These efforts include our recently deployed Search for
Extraterrestrial Emissions from Nearby Developed Intelligent Populations
Spectrometer (SERENDIP V.v) and two instruments currently under development;
the Heterogeneous Radio SETI Spectrometer (HRSS) for SETI observations in the
radio spectrum and the Optical SETI Fast Photometer (OSFP) for SETI
observations in the optical band. We will discuss the basic SERENDIP V.v
instrument design and initial analysis methodology, along with instrument
architectures and observation strategies for OSFP and HRSS. In addition, we
will demonstrate how these instruments may be built using low-cost, modular
components and programmed and operated by students using common languages, e.g.
ANSI C.Comment: 12 pages, 5 figures, Original version appears as Chapter 2 in "The
Proceedings of SETI Sessions at the 2010 Astrobiology Science Conference:
Communication with Extraterrestrial Intelligence (CETI)," Douglas A. Vakoch,
Edito
Status of the UC-Berkeley SETI Efforts
We summarize radio and optical SETI programs based at the University of
California, Berkeley. The SEVENDIP optical pulse search looks for ns time scale
pulses at visible wavelengths using an automated 30 inch telescope. The ongoing
SERENDIP V.v sky survey searches for radio signals at the 300 meter Arecibo
Observatory. The currently installed configuration supports 128 million
channels over a 200 MHz bandwidth with ~1.6 Hz spectral resolution. SETI@home
uses the desktop computers of volunteers to analyze over 160 TB of data at
taken at Arecibo looking for two types of continuous wave signals and two types
of pulsed signals. A version to be released this summer adds autocorrelation
analysis to look for complex wave forms that have been repeated (and overlayed)
after a short delay. SETI@home will soon be processing data of Kepler exoplanet
systems collected at the GBT. The Astropulse project is the first SETI search
for s time scale dispersed pulses in the radio spectrum. We recently
reobserved 114 sky locations where microsecond pulses were detected. This data
is in process of being transferred to Berkeley for analysis.Comment: 8 pages, including 1 figure. Presented at SPIE Conf. 8152, San Diego,
CA, Aug 25, 201
Breakthrough Listen follow-up of the reported transient signal observed at the Arecibo Telescope in the direction of Ross 128
We undertook observations with the Green Bank Telescope, simultaneously with the 300 m telescope in Arecibo, as a follow-up of a possible flare of radio emission from Ross 128. We report here the non-detections from the GBT observations in C band (4–8 GHz), as well as non-detections in archival data at L band (1.1–1.9 GHz). We suggest that a likely scenario is that the emission comes from one or more satellites passing through the same region of the sky
A 4-8 GHz Galactic Center Search for Periodic Technosignatures
Radio searches for extraterrestrial intelligence have mainly targeted the
discovery of narrowband continuous-wave beacons and artificially dispersed
broadband bursts. Periodic pulse trains, in comparison to the above
technosignature morphologies, offer an energetically efficient means of
interstellar transmission. A rotating beacon at the Galactic Center (GC), in
particular, would be highly advantageous for galaxy-wide communications. Here,
we present blipss, a CPU-based open-source software that uses a fast folding
algorithm (FFA) to uncover channel-wide periodic signals in radio dynamic
spectra. Running blipss on 4.5 hours of 4-8 GHz data gathered with the Robert
C. Byrd Green Bank Telescope, we searched the central 6' of our Galaxy for
kHz-wide signals with periods between 11-100 s and duty cycles ()
between 10-50%. Our searches, to our knowledge, constitute the first FFA
exploration for periodic alien technosignatures. We report a non-detection of
channel-wide periodic signals in our data. Thus, we constrain the abundance of
4-8 GHz extraterrestrial transmitters of kHz-wide periodic pulsed signals to
fewer than one in about 600,000 stars at the GC above a 7 equivalent
isotropic radiated power of W at . From an astrophysics standpoint, blipss, with its utilization of a
per-channel FFA, can enable the discovery of signals with exotic radio
frequency sweeps departing from the standard cold plasma dispersion law.Comment: 20 pages, 11 figures, published in AJ, in press
(http://seti.berkeley.edu/blipss/