Collection

zero Useful+1

zero

Dark matter particle detection satellite

Exploration satellite with the widest observation energy range and the best energy resolution in the world

This entry is made by Compilation and application of scientific encyclopedia entries of "Science Popularization China" to examine.

Dark Matter Particle Explorer (DAMPE) is Chinese Academy of Sciences space science Strategic leading science and technology project One of the first four scientific experiment satellites approved for development in China, it is a dark matter particle detection satellite with the widest observation range and the best energy resolution in the world.

DAMPE is a Space telescope , payload mass 1410 kg, it can detect high energy Gamma ray , electronic and cosmic rays 。 It consists of a plastic Scintillation detector , silicon micro strip, tungsten plate, electromagnetic energy meter and Neutron detector form. The main scientific goal of DAMPE is to measure the ratio of positive and negative electrons in cosmic rays with higher energy and better resolution to find out possible dark matter signals. It also has great potential to deepen human understanding of the origin and propagation mechanism of high-energy cosmic rays Gamma ray There are new discoveries in astronomy.^[1]

At 8:12 on December 17, 2015 Jiuquan Satellite Launch Center use Long March 2D The dark matter particle detection satellite Wukong was successfully launched. It has the advantages of high energy resolution, large measurement energy range and strong background suppression ability, which will raise China's dark matter detection to a new level.^[2]

Zijinshan Observatory of the Chinese Academy of Sciences reported on December 29, 2016 that the dark matter particle detection satellite "Wukong" frequently recorded data from Supermassive black hole Gamma ray burst of CTA 102. This is the first observation result released by the dark matter satellite research team on the Self Defense Satellite. The phenomenon observed by Wukong indicates that the black hole CTA 102 is experiencing a new round of activity.^[3]

Chinese name: Dark matter particle detection satellite
Foreign name: DArk Matter Particle Explorer, DAMPE^[4]
Alias: name of a fictitious monkey with supernatural powers^[5]
Country: China
Chief scientist: Constant progression

Payload: 1410 kg
Launch time: 8:12 on December 17, 2015
Launch site: Jiuquan Satellite Launch Center
Launch a rocket: Long March 2D
Status: China's first scientific satellite series

catalog

Satellite Introduction

Announce

edit

Dark matter particle detection satellite (5 sheets)

The "Dark Matter Particle Detection Satellite" program belongs to Chinese Academy of Sciences The "Strategic Leading Science and Technology Project of Space Science" was funded by the Dark Matter and Space Astronomy Research Department of Zijinshan Observatory, Chinese Academy of Sciences University of Science and Technology of China 、 Chinese Academy of Sciences Institute of Modern Physics and Institute of High Energy Physics, Chinese Academy of Sciences And other cooperative research and development.^[6]

Wukong is a dark matter particle detection satellite with the widest observation range and the best energy resolution in the world, surpassing all similar detectors in the world. It will carry out high-energy electron and high-energy gamma ray detection missions in space, explore the evidence of the existence of dark matter, and study the characteristics and spatial distribution of dark matter.

Satellite composition

Announce

edit

Main purpose: to find Dark matter particles The study of dark matter characteristics and spatial distribution laws, the exploration of the origin of cosmic rays and the observation of high-energy gamma rays are expected to bring new major breakthroughs in physics and astronomy.^[7]

Main skills: measure the energy, direction and charge of high-energy particles, and identify the types of particles.

Main components: plastic flash array detector (PSD), silicon array detector (STK), electromagnetic calorimeter (BGO) Neutron detector 。

PSD is used as anti coincidence and consists of two layers of plastic scintillator strips; STK consists of six track bilayers, each consisting of two single-sided silicon strips placed in an orthogonal manner; There are three layers of tungsten plates with thickness of 1cm, 2mm and 2mm respectively, which are inserted in front of the second, third and fourth layers of silicon micro strips for photon conversion; BGO has 14 layers, 22 in each layer, and two adjacent layers are arranged orthogonally to measure the energy of rays; Neutron detector Add to the bottom of the calorimeter. BGO calorimeter And STK total about 33 radiation lengths, is the deepest calorimeter in space.^[1]

Neutron detector

Respective roles:

Plastic Scintillator detector : Distinguish charge. When electrons and photons come in, they are different.

Si array detector: measure the direction and charge of cosmic rays.

BGO calorimeter : The most important is to measure the energy of cosmic rays.

Neutron detector : Distinguish between protons and electrons.

At the same time, the size of the shower produced by different energies is also different.

DAMPE can detect electrons with unprecedented sensitivity and energy range, photon and cosmic rays （ proton and Heavy ion ）。 For electrons and photons, the detection range is 5GeV-10TeV, and the energy resolution at 800GeV is 1%. For cosmic rays, the detection range is 100GeV-100TeV energy region, and the energy resolution at 800GeV is better than 40%. For electrons and photons, Geometric factor Is about 0.3 mSR, and about 0.2 mSR for cosmic rays. The angular resolution of 100 GeV is 0.1 °.^[1]

Scientific objectives

Announce

edit

One is the indirect detection of dark matter, which is also the most important; The second is to find the origin of cosmic rays; The third is gamma ray astrophysics.^[8]

Detection principle

Announce

edit

name of a fictitious monkey with supernatural powers (6 sheets)

1. What are high-energy cosmic rays?

It refers to the energy from the universe Charged particle flow , 1912 by Germany Scientist Victor Hans found that. He made an ionization chamber to measure the ionization degree (the number of charged particles in the air) in the air. At the same time, other scientists also made ionization chambers. Hans' innovation is that he put the ionization chamber on the hot air balloon, so that before release, the ground ionization degree can be measured, and after release, the ionization degree at different altitudes can be measured. Hans' measurement results show that the higher the altitude, the greater the ionization degree.

This shows that charged particles are not generated by the earth, otherwise they will not be farther away from the ground and the ionization degree will be higher. In other words, charged particles will be produced in the space and hit the earth again.

After the generation of cosmic rays, there is a certain probability that they will escape from the Milky Way and go to the space in the process of propagation in the Milky Way, so that the energy of cosmic rays will become lower and lower. But in fact, the energy of cosmic rays is relatively stable. This is because there is a source of cosmic rays. The source of cosmic rays is generally believed to be the explosion of supernovae. When a supernova explodes, it will throw its own high-energy particles, such as hydrogen and helium nuclei, into the galactic space at a very high speed.

2. Why is it possible to detect dark matter by measuring high-energy cosmic rays?

The source of cosmic rays is generally believed to be the supernova explosion. If dark matter exists, the cosmic rays generated when dark matter annihilates become an additional source of cosmic rays. At this time, the detected cosmic rays will be different from the standard model, and the extra part may come from the annihilation or decay of dark matter, Is the indirect detection of dark matter. from The nobel prize in physics The dark matter particle detection satellite AMS-2 in the AMS project hosted by Ding Zhaozhong, the winner, is based on this principle. China's dark matter particle detection satellite is also a cosmic ray detector, which is to use this kind of mechanism to detect dark matter.^[8]

Performance and structure

Announce

edit

Structure diagram (2 sheets)

Space exploration cosmic ray mainly measures the charge, energy and incident direction of cosmic ray particles, and the measured charge includes the size, positive and negative of the charge. The measurement of positive and negative charges is the most difficult, which can only be realized with the help of magnetic field. Magnetic spectrometer can measure the deflection of cosmic ray in its magnetic field, and then determine the charge of incident cosmic ray. Magnetic spectrometer is expensive, and the only detector still operating in space is AMS-02. The three detectors Fermi LAT, CALET and DAMPE all use calorimeters to measure the energy of cosmic rays without measuring the positive and negative charges. DAMPE, or "Wukong", is the first space high-energy particle detector in China. After the global naming campaign, it was finally named "Wukong", which means to use the dazzling Wukong in Journey to the West to find evidence of the existence of dark matter that is difficult to detect. "Wukong" was launched on February 17, 2015, which is the world's widest observation energy band and the best energy resolution Space probe Its observation energy segment is the International Space Station Alpha magnetic spectrometer The energy resolution is more than 3 times higher than that of similar international detectors. On orbit operation status is stable, and a large amount of data is continuously obtained. DAMPE is mainly developed in China with the participation of Switzerland and Italy. DAMPE mainly detects electronic cosmic rays, high-energy gamma rays and nuclide cosmic rays up to Pe V. It has three advantages: high energy resolution, large measuring energy range and strong background suppression ability. The design indexes are shown in Table 1. The performance advantage of DAMPE is closely related to its structural design. The detector of the dark matter particle detection satellite consists of four parts: plastic flash array detector, silicon array detector BGO calorimeter as well as Neutron detector 。

The main function of plastic flash array detector is to measure the charge of incident cosmic rays to distinguish different nuclides, and also to distinguish high-energy electrons and gamma rays. When energetic charged particles pass through plastic scintillators, they lose energy through ionization and emission of radiation (photons). The deposited energy is converted into fluorescence Photomultiplier tube It is converted into an electrical signal and read out after being put on the access stage. The plastic flash array detector is mainly developed by Lanzhou Institute of Modern Physics. The main function of silicon array detector is to measure the direction and charge of incident cosmic ray particles. Silicon array detector consists of 6 layers Silicon micro strip detector It is stacked up and down. At the same time, there is a tungsten plate between layers 1/2, 2/3 and 3/4 respectively. High energy photons are converted into positron negative pairs with a high probability when passing through the tungsten plate. So the signals of photons and electrons in the calorimeter are consistent. If no signal of charged particles is recorded in the first layer, but the signal is recorded in the lower layers, the incident particles are gamma rays. The silicon array detector is jointly developed by the Institute of High Energy Physics, Chinese Academy of Sciences, the University of Geneva, Perugia University and other institutions. BGO calorimeter It is the core component of the detector. Its function is to measure the energy of cosmic ray particles and distinguish between electrons and protons in cosmic rays. BGO crystal is a colorless and transparent pure inorganic scintillator without activator, which is commonly used in nuclear physics experiments. The BGO crystal used by the dark matter particle detection satellite is composed of Shanghai Silicate Research Institute Specially designed and developed. The data readout system of the BGO calorimeter has up to 80000 electronic signal channels (that is, the entire detector has 80000 electronic signal outputs; moreover, it is very difficult to arrange these 80000 electronic signal channels within a small range of 1 m3).^[2]

Neutron detector It measures the secondary neutrons produced by cosmic ray particles in the upper three layers of the detector. High energy electrons are mainly electromagnetic showers, which produce a small number of neutrons, but protons and other nuclides also produce hadron showers, which produce a large number of high energy neutrons. According to this effect, electrons and protons of cosmic rays can be further distinguished. The neutron detector is mainly composed of Zijinshan Observatory, Chinese Academy of Sciences Responsible for development.^[2]

advantage

Announce

edit

Compared with other international dark matter detection satellites, it has three significant advantages.

First, the energy of cosmic rays that can be measured is very high, 104 GeV can be measured; Second, the energy resolution is high, which can reach about 1%, and the measurement is relatively accurate; Third, the background of energy measurement is relatively low, that is, the ability to distinguish electrons from protons is very strong.^[8]

R&D background

Announce

edit

Astronomical observations show that the most important component in the universe is dark substance And dark energy. Dark matter accounts for 25% of the universe, and dark energy accounts for 70%. Generally, ordinary matter observed only accounts for 5% of the universe's mass. Previously, he found that some high-energy electrons of unknown origin may be Dark matter particles Evidence of annihilation.

In order to further trace dark matter, Constant progression The scientific research team of the Ministry of Science and Technology of the People's Republic of China and the Chinese Academy of Sciences proposed the plan of developing a "dark matter particle detection satellite", which was supported by the Ministry of Science and Technology of the People's Republic of China and the Chinese Academy of Sciences. According to Chang Jin, it is not easy to find dark matter in the vast universe. The traditional method is to use large detectors. For example, it was developed by Professor Ding Zhaozhong, the Nobel Prize winner Alpha magnetic spectrometer 2 The detector weighs 7 tons. However, the "dark matter particle detection satellite" being developed in China is cheap and light, and hopes to make a breakthrough in the field of dark matter detection.

More than 95% of the universe

Dark matter and dark energy account for more than 95% of the universe Law of universal gravitation It is confirmed to exist, but has never been directly observed. The detection of dark matter particles is the most competitive research field in the international scientific frontier. Countries around the world, including China, are preparing or implementing a number of dark matter detection experimental projects, whose research results may bring major breakthroughs in the field of basic science.

It is reported that Wukong consists of four payloads, namely plastic flash array detector, silicon array detector, BGO energy device and Neutron detector 。 All detectors and electronic equipment are installed in a space of 1 cubic meter, which is more technically difficult than all China's high energy detection equipment.

The dark matter satellites launched this time are all developed and produced by the Chinese Academy of Sciences. The project was approved in 2011 with a cost of US $100 million, which is far lower than similar detectors abroad. The satellite will operate in orbit for more than three years, and the first batch of scientific achievements is expected to be released in six months to one year.

For emission Long March 2D from China Aerospace Science and Technology Corporation Belonging to Shanghai Aerospace Technology Research Institute Grasping the general development, this is Long March Series Launch Vehicle The 221st flight of.

Director of National Space Science Center, Chinese Academy of Sciences Wu Ji He said that the successful launch and in orbit operation of the dark matter particle detection satellite will hopefully promote Chinese scientists to make major breakthroughs in the field of dark matter detection, which is of great significance for promoting the innovative development of China's space science.

In addition to dark matter satellites, China's science satellite series will also launch quantum science experiment satellites, Shijian 10 recoverable science experiment satellites Hard X-ray modulation telescope satellite 。

Mysterious dark matter

News background: What kind of magical existence is dark matter?

Mysterious dark matter

Xinhua News Agency, Jiuquan, December 17 (Reporter Wu Jingjing, Yu Fei, Yu Xiaojie) How hot is dark matter? Even Sheldon, the leading character in the popular American TV series The Big Bang Theory, has turned to studying dark matter.

How was dark matter discovered? In the early 1930s, California Institute of Technology Astrophysicists Zweiki The first discovery is that the visible matter in the universe is far from enough to connect the universe. If there were not a mysterious and invisible matter, the galaxy would have disintegrated.

Scientists call this invisible mysterious matter "dark matter". By the 1970s, various astronomical observations, such as Disk galaxy Rotation curve Galaxy cluster X-ray observation Gravitational lens All of them show the existence of dark matter. But until now, no definite dark matter signal has been detected.

The concept of dark matter was proposed by Swiss astronomer Fritz Zwick. When he was studying Coma galaxy cluster, he found that the total mass of the galaxy cluster calculated according to the Virial theorem was far greater than the mass of the galaxy cluster calculated according to the luminosity. He speculated that there was a large amount of non luminous matter in the galaxy cluster, which was called dark matter. In the 1970s, American astronomer Vera Rubin and others measured and found the rotation curve of the galaxy (that is, the relationship between the speed of the matter in the galaxy rotating around the center and the distance to the center), and found that the rotation speed at the large radius was far greater than the theoretical expectation given by the luminous matter. If the theory of gravity is correct, it is necessary to introduce invisible matter to provide greater gravity to bind the matter at such a high speed. Although the exact physical properties of dark matter particles still need further research, it is generally believed that dark matter particles have the following properties: electrically neutral, large mass (much heavier than protons), long life (significantly longer than the life of the universe 13.7 billion years), and normal Gravitational interaction 。 Dark matter particles have no electromagnetic interaction and strong interaction, but may have Weak interaction 。 None of the known particles meet these properties, which means that the study of dark matter particles is likely to bring about a revolutionary breakthrough in physics.

Although scientists do not know what dark matter is made of, they still have some understanding of it by observing how it affects ordinary matter and simulating its gravitational effect:

——Dark matter and dark energy account for more than 95% of the universe, and dark matter accounts for 26.8%. Dark matter does not emit light, emit electromagnetic waves, and participate in electromagnetic interaction. It cannot be directly "seen" by any optical or electromagnetic observation equipment.

——Dark matter is difficult to detect because of its low density, fast speed and difficulty in capturing. Scientists estimate that dark matter particles move at a speed of 220 kilometers per second, which is Type 56 semi-automatic rifle 300 times the velocity of the bullet.

——Dark matter should come from the Big Bang. At a certain time in the early universe, the temperature of the universe was very high, and the energy of particles was very strong. They collided violently. Under this interaction, various substances, including dark matter, were produced.

——The structure of the universe is related to dark matter. Because dark matter does not act on itself and other matter except gravity, it is the primary type of matter that promotes the expansion of the universe to form a specific structure under its own gravity. Dark matter sowed the seeds of the cosmic filamentary structure, and then visible matter gathered on some gravitational points established by dark matter, and finally formed galaxies.

——Dark matter is indispensable to life. Without the gravitational effect of dark matter, our Milky Way will never collapse and form in the expansion process after the Big Bang. In that case, there is neither the sun nor the earth, nor you and I

Wu Ji, director of the National Space Science Center of the Chinese Academy of Sciences, said that since humans do not understand dark matter, they have no choice but to call it "dark". Once they discover what they are, and with the deepening of research, the newly discovered particles will have many names. "Dark" is only a phased name, which fully reflects that human beings have not yet understood it.

Scientists have been waiting for decades to find dark matter. Through a series of experiments and observations, scientists may be one step away from solving the cosmic mystery of dark matter.

At present, there are mainly three dark matter detection schemes: direct detection, indirect detection and collider detection. Direct detection seeks for signals generated by collisions between dark matter particles and nucleons. This kind of experiment is usually carried out in the underground laboratory because it needs to shield the influence of charged particles in the atmosphere. Its advantage is that it can be carried out on the ground, and the cost is low. China has the world's deepest underground laboratory - Jinping Underground Laboratory, so China has also made great achievements in the field of direct detection of dark matter. Tsinghua University and Shanghai Jiaotong University Independent dark matter direct detection experiment project. Collider detection is mainly to find High-energy particle Non conservation process of energy and momentum caused by dark matter particles that cannot be detected by the detector due to collision. Such detection is carried out on large high-energy colliders, which are expensive and technically difficult. Indirect detection is mainly to study and detect ordinary particles produced by the annihilation of dark matter particles in the Milky Way Galaxy, and the signal turns into various "excess" or "bulge" in the cosmic ray spectrum. Because of the shielding effect of the atmosphere on cosmic rays, such experiments need to be launched Space probe Explore in the atmosphere. The Fermi Large Area Telescope (Fermi LAT) is an international space science satellite in operation, Alpha magnetic spectrometer 2 AMS-02, CALET and China's dark matter particle detection satellite DAMPE.^[2]

R&D history

Announce

edit

Successful launch

Wukong launches

At 8:12 on December 17, 2015 Jiuquan Satellite Launch Center use Long March 2D Ding successfully launched the dark matter particle detection satellite Wukong, and the satellite successfully entered the scheduled transfer orbit. The successful launch mission marks an important step forward in China's space science research.

"Wukong" goes on the shoulder Space The mission of finding the evidence of the existence of dark matter has a "golden eye". Its observation energy range and energy resolution are better than other similar detectors in the world. It can be said to be "powerful" and is expected to bring a major breakthrough in the forefront of physics.

Dark matter and dark energy are called by scientists as "two dark clouds enveloping physics in the 21st century". China and other countries around the world have begun to prepare or implement several dark matter detection experimental projects, and their research results may bring about major breakthroughs in the field of basic science.^[9]

Officially named

The public naming activity of dark matter particle detection satellite was initiated by People's Network and National Space Science Center, Chinese Academy of Sciences , Zijinshan Observatory of Chinese Academy of Sciences and co sponsored by, since the launch at the end of September, a total of 32517 valid name schemes have been received. On the basis of data statistics, approved by the Chinese Academy of Sciences after voting by expert judges, on the afternoon of December 16, 2015, National Space Science Center, Chinese Academy of Sciences The dark matter particle detection satellite was officially named "Wukong".^[5]

Wukong Satellite

Naming the dark matter particle detection satellite "Wukong" is in line with the practice of naming scientific satellites in mythical images, such as the U.S Apollo Ulysses in Europe, Chinese Jade Hare Etc. In this way, the traditional culture can be used to improve the scientific literacy of the public in China, and attract young people to love science and explore the unknown.^[10] Wukong is a Chinese classic《 Journey to the West 》The name of the Great Sage of Zhongqitian, "Wu" means understanding, and "Wukong" means understanding and exploring space; On the other hand, Wukong's fiery eyes, like the detectors of the dark matter particle detection satellite, can identify the traces of dark matter in the vast space.

Establish a scientific team

From October 29 to 31, 2015, the 4th Dark Matter Detection Satellite (DAMPE) Seminar hosted by Zijinshan Observatory, Chinese Academy of Sciences was held in Nanjing. From the main development units of DAMPE, Zijinshan Observatory of Chinese Academy of Sciences, Institute of High Energy Physics, Institute of Modern Physics, National Space Science Center and University of Science and Technology of China And international cooperation units University of Geneva Italian National Institute of Nuclear Physics Perugia University 、 Barry University 、 University of Salento as well as Massachusetts Institute of Technology More than 50 experts and scholars from other units attended the meeting.^[11]

During the workshop, Constant progression It was officially announced that the Scientific Cooperation Group of Dark Matter Particle Detection Satellite was established. Under the organization of DAMPE scientific application system, the scientific cooperation group is responsible for the calibration, reconstruction and physical analysis of DAMPE detector operation and experimental data. The Cooperation Group has elected the Organizational Committee (IB) and the Executive Committee (EB), which consists of the Operation Group, the Software Group, the Technical Group, the Physical Analysis Group and the Scientific Advisory Group. At the end of the meeting, the scientific application system also discussed and determined the research and development status and division of labor of DAMPESW software, which laid a foundation for data processing and analysis after the successful launch of the satellite and the implementation of scientific objectives.

Complete beam experiment

December 2012, by University of Science and Technology of China The first sample of the DAMPE particle detection spectrometer developed by the State Key Laboratory of Detection and Nuclear Electronics is in the European Centre for Nuclear Research (CERN) conducted beam test and calibration experiments for 20 days. The beam experiment of the identification part of the DAMPE spectrometer at CERN is an indispensable part of the development of the whole dark matter particle detection satellite. Its successful completion has verified that the software and hardware functions of the DAMPE spectrometer are complete and correct, the system works reliably, the scientific detection data is reliable, and the performance reaches the standard; It also provides a basis for the analysis of physical data of normal flying parts in orbit, and ensures the credibility of future scientific achievements.^[4]^[12]

Complete test on orbit delivery

On March 17, 2016, the first dark matter particle detection satellite of China's space science series, "Wukong", successfully completed the three-month in orbit test mission and successfully delivered it to the user unit.

After three months of in orbit testing, the four major scientific loads of the satellite - plastic flash array detector, silicon array detector BGO calorimeter The function and performance of the neutron detector and the neutron detector are stable, all the instructions injected to the satellite are correctly executed, the satellite ground link is smooth, all the established test items have been completed, and the technical indicators of the satellite have met or exceeded the expectations.

Current situation abroad

Direct detection measures the recoil signal of the nucleus after the collision between dark matter particles and the nucleus. Nuclear recoil signals are generally obtained by measuring phonon, light and charge signals. Many experiments have been carried out internationally, such as Xenon, CoGeNT, CDMS, DAMA Etc.^[13]

Successfully received data

Announce

edit

Chinese Academy of Sciences Kashi Station, the China Remote Sensing Satellite Earth Station affiliated to Remote Sensing and Digital Earth, successfully tracked and received the first orbit X-band downlink data of China's first dark matter particle detection satellite "Wukong" at 8:45 on December 20. By 8:52, the mission data was received, recorded and transmitted to National Space Science Center, Chinese Academy of Sciences 。 This successful reception marks the official opening of the data transmission link between Wukong and the ground station.

At 17:55 on December 24, 2015, the dark matter particle detection satellite "Wukong", the first star of China's science satellite series, was successfully launched in Jiuquan. On the seventh day after the successful launch, the first batch of scientific data was successfully transmitted to the space science mission hall of the National Space Science Center of the Chinese Academy of Sciences after the satellite platform test, the payload manager power on test, and the science detector high-voltage power on test.

The data received shows that the four major scientific loads of the dark matter satellite: plastic flash array detector, silicon array detector BGO calorimeter The counting rate of high-energy electrons and gamma rays detected by the neutron detector is consistent with that predicted on the ground, indicating that the payload of the dark matter satellite has started to work normally.

Since the dark matter satellite received the first frame of data transmission on December 20, 2015, the satellite ground support system has received 494 tracks of data in total, received about 2.4TB of original data files in total, generated 41 categories of scientific data products, totaling 110606, and the total number of data products is about 5.5TB. As of March 17, 2016, the dark matter satellites have been in orbit for 92 days, with 460 million detected High-energy particle , completed the scanning of two-thirds of the sky area.

Advantages of DAMPE

Announce

edit

The dark matter particle detection satellite is China's first space astronomy satellite. It has strong international competitiveness in indirect detection of dark matter, greatly improving the level of dark matter detection in China. DAMPE has three main scientific objectives: indirect detection of dark matter, cosmic ray physics and gamma ray astronomy. DAMPE was launched on February 17, 2015. On orbit operation is stable, and a large amount of data has been obtained. DAMPE can accurately measure the energy spectrum of cosmic ray positrons and negatives, and is expected to completely measure the "beyond" truncation behavior. The origin of the "excess" of cosmic ray positron and negative electron includes two types of models: dark matter model and astrophysical process model. The predicted truncation behavior of "excess" is significantly different. The existing data can not effectively distinguish the two types of models because it only covers the relatively low energy segment. DAMPE is expected to accurately measure the energy spectrum at the "beyond" cutoff and distinguish the origin model. In addition, DAMPE will also obtain the energy spectrum of 1~10 Te V electron cosmic rays in space for the first time, and discover or limit adjacent high-energy electron ray sources. DAMPE is expected to make a breakthrough in the search of gamma ray line spectrum due to its excellent energy resolution. Because for the line spectrum structure, the signal is easily submerged in the background noise if the energy resolution is poor. In high energy resolution data, it will appear as a very "sharp" structure. Therefore, the higher the energy resolution, the more likely it is to find the line spectrum structure in the data. DAMPE can measure nuclear cosmic rays up to 100 Te V. The measured energy band of ground cosmic ray experiment is high, and it is difficult to accurately distinguish various components of cosmic ray. DAMPE can realize the connection of ground detection and space detection in energy spectrum, and can distinguish cosmic ray components.^[2]

Observation results

Announce

edit

Supermassive black hole It is a kind of celestial body widely existing in the universe. Its mass is hundreds of thousands to tens of billions of times that of the sun. Almost every major galaxy, including the center of the Milky Way where human beings live, has at least one such black hole. Some Giant black hole It has existed since the very early days of the universe. How they form, evolve and react on galaxies is still an unsolved mystery. But it is not impossible for human beings to study these huge "cosmic monsters".

Scientists have found that some Supermassive black hole Instead of being silent all the time, they will eat and drink with impunity: the materials they devour will gather to form an accretion disk and generate a powerful jet, making the black hole appear extremely bright. This kind of celestial body is also called Active galactic nucleus They are the key to solving the mystery of black holes.

CTA 102 is a famous active galactic nucleus. It was first discovered in 1963. Its black hole has a mass about 850 million times that of the sun and is about 8 billion light years away from the solar system. According to scientific records, the last time CTA 102 was more intense was in 2012.

The dark matter particle detection satellite "Wukong" launched by China at the end of 2015 is mainly aimed at exploring the dark matter in the universe and cosmic "monsters" like black holes through space observation of cosmic rays and gamma rays. Purple mountain observatory According to the dark matter satellite team, since October, Wukong has frequently captured gamma ray radiation from CTA 102. Especially after November 23, Wukong recorded a significantly enhanced gamma ray burst, which peaked on December 16. The highest recorded photon energy is about 62 billion electron volts, equivalent to 66 times the equivalent energy of stationary protons.

This observation result is also confirmed by other equipment. Purple mountain observatory The 1-meter Near Earth Object Survey Telescope also observed this round of explosion of CTA 102. According to the telescope records, the brightness of CTA 102 continued to increase between June 18 and December 20.

"CTA 102 is the first 'goblin' captured by 'Wukong', and we will continue to monitor its activities. It is believed that with the help of 'Wukong''s golden eye, more 'cosmic goblins' can be' captured 'in the future, providing powerful help for humans to understand the universe." said Xu Zunlei, a member of the dark matter satellite project team.^[3]

Over the past year, Wukong has sent back 1.9 billion particle data. Among them, the number of high-energy electrons between 5GeV and 10TeV has exceeded 1 million.^[14]

On November 30, 2017, the international authoritative academic journal Nature published online that the dark matter particle detection satellite "Wukong" had sufficient data to confirm that an abnormal wave of electronic cosmic rays was measured in space. This wave has never been observed before, which means that Chinese scientists have made a groundbreaking discovery and may be related to dark matter.^[15] On November 1, 2022, it was learned from the dark matter satellite "Wukong" team that, based on the "Wukong" data, scientific researchers have recently mapped the specific energy spectrum of boron/carbon and boron/oxygen cosmic ray particles with the highest energy band so far, and found a new structure of the energy spectrum. This latest result shows that the propagation of high-energy particles in the universe may be slower than expected.^[16]

Novice on the road

Growth task Getting Started with Editing Edit Rule Edit by myself

I have questions

Content query Online Service Official post bar Feedback

Complaints and suggestions

Report bad information Failed to appeal through entries Complaint of infringement information Blocking query and unblocking

Jinggong Network Anbei No. 1100000200001