Radio astronomers analyzing archival information from the Green Bank survey found 51 new pulsars.
They had been obscured by extraneous factors.
It is quite common for astronomical databases to “hide” faint pulsation signals among interstellar noise.
By analyzing legacy survey information and applying more powerful algorithms, scientists managed to detect the weak radio pulses that had been overlooked in previous analyses.
This complete re-analysis increases the census of our local stars with the identification of a rapid millisecond pulsar in a binary star system.
Re-evaluating legacy survey data with new algorithms
Astronomers store petabytes of observational data collected by ground-based radio telescopes in digital form for future analysis.
First-time survey reduction software may miss faint or intermittent pulsars due to computational limitations or severe radio frequency interference.
Past Green Bank Telescope observations are being reanalyzed to measure the effectiveness of existing filtering methods on legacy survey data through a data reprocessing process.
The novel digital signal processing method can filter out terrestrial interference patterns to reveal faint signals from space.
This is how reanalysis of legacy files makes new discoveries possible without the additional costs of observing time across competitive facilities.
Detection of weak radio pulses in crowded sky surveys
Pulsar emissions travel up to thousands of light-years across the galaxy as very weak electromagnetic signals.
Free electrons in the interstellar medium distort the calculation of pulse timing, making it difficult to locate fast-spinning or distant neutrons.
Use of dispersion measure corrections helped to filter out the galactic background noise from the telescope data files.
Weak signals detected many radio pulses repeating themselves in the selected sky regions.
Detection of weak periodic impulses makes old and noisy databases useful for neutron star detection.
The discovery of 51 new pulsars in the North Celestial Cap
The systematic scanning process helped to find 51 different rotating neutron stars that could not be made out during the original scan.
This additional list brings the total number of known signal sources in the Green Bank North Celestial Cap survey close to one thousand.
The sources listed have different rotation characteristics, ranging from slow to fast millisecond rotation.
This additional list provides samples to study the distribution of the neutron stars in our Milky Way galaxy.
Census updating enables astrophysicists to figure out the actual number of radio pulsars in the galactic neighborhood.
A fast millisecond pulsar in a binary system
Among the discoveries made include a very fast pulsar with a rotation speed of just 3.2 milliseconds.
This fast-spinning pulsar exists within a binary system in which it revolves around its partner.
Through the gravitational effects of binary systems, neutrons are accelerated to very high speeds due to mass transfer.
Accurate measurements of the revolving path mean the mass of the two objects can be measured, according to arXiv.
Fast binary pulsars give us clues about the process by which the angular momentum of dead stars is recycled from their companion stars.
Developing new automated searches in radio astronomy
The discovery of multiple pulsars in older datasets proves just how much can be achieved with modern computer technology when applied to older archives.
Astronomers will use machine learning searches in future all-sky surveys to discover even more elusive stars.
The use of automated algorithms helps minimize human error and increases the speed of discovery of extreme phenomena.
Improvement in the technology to apply to future searches means that that older data archives will continue to prove their scientific worth for decades to come.
Opening up older telescopic data archives suggests that many more scientific discoveries will soon come to light.
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