How many new objects are there in the Milky Way? Researchers have made new discoveries.
Recently, Zhang Xiang, assistant researcher at the Shanghai Astronomical Observatory of the Chinese Academy of Sciences, and her Australian collaborator Dr. Hurley-Walker from the International Radio Astronomy Research Center of Curtin University, analyzed the observation data of the SKA pilot telescope and found a radio transient source with unusually slow periodic radiation. The research team believes that the radio transient source may be an ultra-long-period magnetar or a white dwarf with a super-strong magnetic field. The results of the research were published online in the Journal Of Nature on Jan. 27.
This discovery opens a new window for the search for low-frequency temporary sources. Zhang Xiang explained that since this is the first detection of long-period temporary sources in the silver road surface region, if more temporary sources with similar characteristics can continue to be detected and their physical properties can be revealed, it means that there is a class of long-period stars with super magnetic fields in the Milky Way, which is conducive to a comprehensive understanding of the evolution and death of stars.
That's how SKA explores the world
The International Big Science Program and the Big Science Project have become an important global public product in the field of scientific and technological innovation in the world and an important cooperation platform for enhancing the innovation ability of the country.
Square Kilometre Array (SKA) as an international large-scale scientific engineering project, is the world's largest comprehensive aperture radio telescope built and operated by a multinational joint venture around the world, which integrates the performance of large field of view, high sensitivity, high resolution, wide frequency range and so on, and is named because of the total receiving area of about "1 square kilometer". Located in the radio quiet area of South Africa and 8 southern African countries and Australia, the station has started construction in 2021, which is also the largest radio telescope ever built by mankind, and will be about 50 times more sensitive and about 10,000 times faster than the current largest radio telescope array JVLA.
In 2019, as a founding member, the mainland signed the Convention on the Establishment of the Square Kilometre Array Observatory, according to which it officially became a member of the SKA Observatory since June 26 last year.
Such large-scale scientific installation projects are essential to helping scientists discover results.
Wu Xiangping, academician of the Chinese Academy of Sciences and chief scientist of China SKA, once introduced that SKA is the most advanced radio telescope of the next generation, and scientific research goals include how to form the first generation of luminous objects in the universe, pulsar search and gravitational theory test, galaxy formation and evolution, dark energy properties, cosmic magnetic field, gravitational nature, life molecules and extraterrestrial civilizations, etc. Any breakthrough in any of these issues will be a major change in natural science.
"Unlike astronomers in ancient times, which usually detected at night, with these telescopes, we now basically don't have to work night shifts." Zhang Xiang told the first financial reporter that because the telescope is basically operated by computers, the telescope is also constantly taking various photos at night to accumulate data, and these data will be transmitted to the nearby supercomputing center, after the first wave of processing, it will be transmitted to other centers around the world through similar submarine optical cables, which is convenient for local scientists to process these data.
Gold leaf/photo
In this result, the second author of the paper, Zhang Xiang of the Shanghai Astronomical Observatory, mainly undertook the polarization calibration and polarization data analysis in this work, and produced three key images in the paper.
She introduced that due to the huge amount of raw data in the project, the amount of data generated by the data processing intermediate process is larger (more than 10 million image files), the data processing process is complex, and the data processing software has extremely high requirements for the access input and output (IO) bandwidth, data IO bandwidth, high concurrent tasks and high parallelization processing of the computing cluster.
Based on the above-mentioned characteristics and extremely high requirements of SKA polarization data processing, Shanghai Observatory, as a full member of MWA, has carried out a series of scientific research on SKA's key scientific goals by using the self-developed prototype of the China SKA Regional Center and the international SKA scientific team.
It is worth noting that in this research work, the prototype of the SKA Regional Center in China undertook the calculation and storage of part of the MWA data of the project, participated in the processing of wideband polarization data, completed the analysis of partially polarized images, and completed other data processing tasks together with the computing equipment of the SKA Regional Center in Australia.
China SKA Regional Center Prototype Gold Leaf /Photo
An Tao, a researcher at the Shanghai Observatory and the head of the prototype of the China SKA Regional Center, introduced that the prototype of the SKA Regional Center in China has been one of the top ten astronomical scientific and technological progress in China for two consecutive years since its completion in November 2019, and has been recognized by SKAO (Square Kilometer Array Observatory) as the "first SKA Regional Center Prototype in the World", which will provide computing resources and technical support for the large-scale sky survey project of the SKA Pilot Telescope in the future, helping SKA scientists around the world to produce more original results.
The role of the pilot device
The result of this discovery is the SKA Low Frequency Telescope's pilot device MWA (Murchison Widefield Array), the Murchison Radio Observatory (MRO) in Western Australia. As a full member, the Shanghai Astronomical Observatory participated in the phase II operation of the MWA and obtained relevant data and scientific resources.
As a pilot project for the SKA Low Frequency Telescope, MWA will explore scientific research in the areas of cosmic reionization, Hanoi and extragalactics surveys, time-domain astrophysics, and the sun and the ionosphere
"MWA has a sky survey observation model, which is a kind of scanning observation, and the data of these observations accumulates and scientists can do further data mining." Zhang Xiang said that it was through studying these data that they discovered a dense temporary source with unusually slow periodic radiation.
The tentative appearance originated in early 2018, and its burst period is about 18 minutes, which is 9 times longer than the longest known pulsar burst period. Neither the long-period nor the high polarization of the low-frequency band of the transient source can be explained by the theoretical model and observational characteristics of a known pulsar, thus ruling out the possibility that it is an ordinary pulsar. "We think it's more likely to be a Magnetar or a white dwarf with a super-strong magnetic field."
"We are conducting a systematic search to discover more stars of this type and build a large sample for statistical studies to fill in the gaps in magnetometric research." Zhang Xiang said.