The Breakthrough Listen Search for Intelligent Life: Public Data, Formats, Reduction and Archiving (1906.07391v3)

Abstract: Breakthrough Listen is the most comprehensive and sensitive search for extraterrestrial intelligence (SETI) to date, employing a collection of international observational facilities including both radio and optical telescopes. During the first three years of the Listen program, thousands of targets have been observed with the Green Bank Telescope (GBT), Parkes Telescope and Automated Planet Finder. At GBT and Parkes, observations have been performed ranging from 700 MHz to 26 GHz, with raw data volumes averaging over 1PB / day. A pseudo-real time software spectroscopy suite is used to produce multi-resolution spectrograms amounting to approximately 400 GB hr^-1 GHz^-1 beam^-1. For certain targets, raw baseband voltage data is also preserved. Observations with the Automated Planet Finder produce both 2-dimensional and 1-dimensional high resolution (R~10^5) echelle spectral data. Although the primary purpose of Listen data acquisition is for SETI, a range of secondary science has also been performed with these data, including studies of fast radio bursts. Other current and potential research topics include spectral line studies, searches for certain kinds of dark matter, probes of interstellar scattering, pulsar searches, radio transient searches and investigations of stellar activity. Listen data are also being used in the development of algorithms, including machine learning approaches to modulation scheme classification and outlier detection, that have wide applicability not just for astronomical research but for a broad range of science and engineering. In this paper, we describe the hardware and software pipeline used for collection, reduction, archival, and public dissemination of Listen data. We describe the data formats and tools, and present Breakthrough Listen Data Release 1.0 (BLDR 1.0), a defined set of publicly-available raw and reduced data totalling 1 PB.

The Breakthrough Listen Search for Intelligent Life

The paper "The Breakthrough Listen Search for Intelligent Life: Public Data, Formats, Reduction and Archiving" discusses the methodologies and strategies employed by Breakthrough Listen (BL), the most comprehensive and sensitive search for extraterrestrial intelligence (SETI) initiative to date. This paper outlines the technical framework for data collection, reduction, and archival processes pivotal to the BL initiative, which utilizes state-of-the-art facilities including the Green Bank Telescope (GBT), Parkes Telescope, and Automated Planet Finder (APF).

Data Collection and Observational Strategy

The BL team has developed a robust observational strategy to search for technosignatures, which are potential indicators of extraterrestrial technology. This strategy encompasses radio and optical observations across diverse targets, ranging from nearby stars and galaxies to solar system objects.

In radio astronomy, BL employs single-dish telescopes to observe both radio and optical wavelengths. Specifically, the GBT and Parkes Telescope are instrumental in capturing vast data volumes, with data rates exceeding 1 PB/day. The core of the radio search strategy revolves around systematic observations in the L-, S-, C-, and X-band frequencies. The GBT's backend consists of numerous compute nodes optimized for handling extensive data streams through graphics processing units (GPUs). These nodes channel the raw data into multiple spectrograms with varying resolutions tailored for distinct astrophysical analyses.

Similarly, optical observations with the APF utilize echelle spectrometers to produce high-resolution spectra of the target stars. These observations aim to identify artificial laser emissions indicative of extraterrestrial civilizations.

Data Reduction and Archiving

The paper details the sophisticated data reduction pipeline, which converts raw voltages into spectrograms facilitating SETI and secondary scientific analyses. The reductions are performed using GPU-accelerated codes such as gpuspec and rawspec, yielding products in filterbank format for subsequent analysis. Filterbank files offer multi-resolution spectrograms suitable for various research pursuits, including narrow-band searches for technosignatures and pulsar studies.

To ensure accessibility and usability, data are further transformed into Hierarchical Data Format (HDF5), a format providing enhanced compressibility and data management capabilities. The BL initiative has avowed commitment to public transparency by releasing Breakthrough Listen Data Release 1.0 (BLDR 1.0), a collection of over 1 PB of raw and reduced data.

Challenges and Instrumental Artifacts

Managing the colossal data volume underpins significant challenges, such as dealing with radio frequency interference (RFI) and instrumental effects affecting data integrity. The paper addresses specific issues, including analog filtering, dropped blocks, and data saturation, which necessitate meticulous calibration techniques. Nonetheless, leveraging cutting-edge technology, BL orchestrates a sophisticated data pipeline designed to maximize signal detection probability while mitigating noise and artifacts.

Implications and Future Prospects

The methodology outlined in this paper implicates a substantial step forward in the search for extraterrestrial life. The breadth of observations and the comprehensiveness of data archival offer extensive research potential beyond SETI. For instance, the archived data is being utilized in studies of fast radio bursts (FRBs) and spectral line studies. Moreover, the initiative's open-data policy fosters collaborative opportunities across scientific domains.

Future developments in AI and machine learning are anticipated to further augment the analytical capabilities of SETI research. Algorithmic advancements could refine modulation schemes and bolster outlier detection, thus amplifying the efficacy of signal classification endeavors.

In conclusion, the Breakthrough Listen initiative represents a landmark in astronomical science, systematically ushering the search for life beyond Earth into a new era characterized by transparency and interdisciplinary collaboration. As archived data continue to grow, the potential for emergent discoveries beckons, paving the way for profound contributions to our understanding of the universe.