Vietnam is the co-author of a new discovery about astronomical astronomy

After 7 years of operation, VATLY cosmic ray laboratory (Vietnam - Auger training laboratory) with members is Prof. Pierre Darriulat - one of the best physicists in the world in the past 30 years, TS Vo Van Thuan - Former Director of the Institute of Nuclear Science and Technology and 6 other young scientists have achieved very proud successes, making Vietnam a co-author of new discoveries of energetic particles. High quality in the universe. This result was published in Science magazine on November 9, 2007.

On November 9, 2007, Pierre Auger Observatory scientists announced that strong active galaxies (AGNs) are suitable candidates for the source of the highest energy cosmic rays coming to the Left. land. Thanks to the use of the world's largest cosmic ray observatory, Pierre Auger, in Argentina, the collective of scientists from 17 countries has found that the sources of the highest energy particles are unevenly distributed. in the sky. The results of the Auger Observatory show the link between the origin of these particles and the positions of nearby galaxies with a strong active center. The results of this study were published in Science magazine issue 318 on November 9, 2007.

Under the direction of the late Prof. Nguyen Dinh Tu, Auger-Vietnam group was established in 1995 at the Institute of Nuclear Science and Technology (Vietnam Atomic Energy Institute, Ministry of Science and Technology). Then, with the help of Prof. Pierre Darriulat, Cosmic Ray Laboratory was built in 2001, with short name is VATLY (Vietnam-Auger Training Laboratory). VATLY is a member of the Pierre Auger project, currently participating in joint studies of this international project. The laboratory consists of a group of graduate students who are responsible for analyzing and processing the recorded scientific data at the Auger Observatory. Currently, modern media allows easy access to data from most reputable observatories, laboratories around the world or from space stations, creating favorable conditions. for developing countries to jointly implement scientific research. This is also VATLY's method of operation and the practice on the measurement system installed in Hanoi to train and help students understand the method of scientific experiment and data processing.

Scientists believe that the energetic galactic centers (AGNs) powered by ultra-heavy black holes are swallowing a large amount of material around it. For a long time, AGN is considered a place that can accelerate particles to high energy. They swallow gas, dust, and other materials from the galaxy that contain them, and at the same time spray particles and energy. Most galaxies have black holes at their center, but only some galaxies have a strong active nucleus. The exact mechanism that answers the question of how AGNs can accelerate particles to energies 100 million times greater than the energy achieved on the world's most powerful particle accelerators remains a mystery. . Talking about this event, Professor James Cronin, University of Chicago (Nobel Prize in physics in 1980), who joined Prof. Alan Watson, Leeds University to start the Pierre Auger Observatory, said: 'We has made a big step in solving the mystery of nature, the source of the highest energy cosmic rays, first discovered by French physicist Pierre Auger in 1938 . We found distribution of ultra high-energy cosmic rays over half of the heterogeneous southern sky. This is a fundamental finding. The period of astronomical cosmic rays is coming. In the next few years, our data will allow us to pinpoint the source of these cosmic rays and how they can accelerate particles to such a high energy. '

Cosmic rays are protons and atomic nuclei that move in the universe at nearly the speed of light. When these particles collide with the Earth's upper atmosphere, they create a class of secondary particles, called atmospheric showers, that can spread over an area of ​​about 40 km2 or more when reaching the ground. . The Pierre Auger Observatory recognizes cosmic rays by a network of 1,600 stations that record secondary particles spaced 1.5 km apart spread over an area of ​​3,000 km2. Twenty-four telescopes have been specially designed to recognize the radiation of fluorescent light generated by atmospheric showers. The combination of particle recognition and fluorescent telescopes has created the best tool ever in cosmic ray research. The Pierre Auger Observatory has recorded nearly one million cosmic rays, but only a few of them with the highest energy can be attached to their source with reliable accuracy. Until now, scientists of Auger Observatory have recorded 81 cosmic rays with energy on 4x1019 electron volts (also written as 40 EVs). This is the number of cosmic rays with the highest energy of over 40 EV recorded so far compared to other observatories. At this ultra-high energy level, the cosmic ray's error of direction is only a few degrees, allowing scientists to determine where the source is emitted. Further selection, the Auger Observatory has discovered 27 events with the highest energy, greater than 57 Eels, not coming from all directions evenly. Comparing these events with the location of 381 AGNs, scientists found that most of these events correspond very well to the location of AGNs in some nearby galaxies, such as galaxies. Centaurus A. According to scientists, most galaxies have black holes of a few million to several billion times the mass of the Sun at their centers. The black hole at the center of our galaxy (often called the Milky Way) has about 3 million times the mass of the Sun but it is not an AGN. It is thought that galaxies containing AGN are galaxies that have ever collided with other galaxies or experienced some major material fluctuations within the last few hundred million years.

Astronomical cosmic rays are a complex science. Low-energy cosmic rays cannot provide reliable information about where the source emitted because of the propagation of the rays in the galaxy and the intergalactic magnetic fields. deviate from the original. In contrast, most of the high-energy particles reaching the Earth in the direction of the source emit them due to very little influence by the magnetic field. Unfortunately, they come to Earth with a very sparse frequency, averaging about 1 particle per 1 km2 in a century. This leads to the need for a huge observatory to be able to record a significant amount of high-energy particles. At the size of the Auger Observatory, about 30 of the highest energy events have been recorded each year.

Pierre Auger Observatory in the Southern Hemisphere was constructed on March 17, 1999 on Mendoza Plateau, Argentina. After a period of installation and testing of measuring stations, scientific data collection was started in January 2004. The observatory is named after French scientist Pierre Victor Auger (1899-1993), who first observed high-energy cosmic rays in 1938. The project was organized by 40 organizations in 17 countries. now, about 50 million USD has been spent on construction of the Southern Hemisphere observatory. Over the next few years, a second observatory will be built in the Northern Hemisphere to comprehensively observe the sky. There are more than 370 researchers and engineers participating in this scientific experiment. Besides the 5 member countries of the G7, there are also a number of members of developing countries. Most other members are in Europe and America. In particular, there is only one Asian member country, Vietnam with the cosmic ray physics group under the Institute of Nuclear Science and Technology.

Since operating the VATLY Cosmic Ray Laboratory in 5.2001 up to now, Auger Vietnam has been continuously funded by the Ministry of Science and Technology to fund basic scientific research and support to participate in international cooperation. bilateral exchange. After nearly 7 years of VATLY's operation, there has been a doctoral thesis and 5 master's theses protected with high quality, published 3 scientific works in international journals and co-authors in 4 articles of the Auger International Scientific Society published in international scientific journals, not to mention many reports at scientific conferences and articles in domestic scientific journals. VATLY graduate students were involved in the measurement and analysis of scientific data provided by Pierre Auger International Project. Professor James Cronin, Prof. Alan Watson and some leading experts of Project Auger have visited Vietnam many times to exchange science, guide and help Auger Vietnam team to integrate into the international scientific community. VATLY also receives the support and support of many scientists and international organizations such as CERN, World Lab, Vietnam Meetings Association and the French National Center for Scientific Research (CNRS).

● Vietnam is the only Asian member participating in the Pierre Auger Project, with 8 participants (out of 370 participants in this Project).
● VATLY group consists of 8 members (in alphabetical order): Pham Ngoc Diep, Pham Ngoc Dong, Pham Thi Tuyet Nhung, Pierre Darriulat, Nguyen Thi Thao, Dang Quang Thieu, Vo Van Thuan and Nguyen Thi Van.
● In the work just published in Science, the Institute of Nuclear Science and Technology and young colleagues of Auger Vietnam group have been recognized as co-authors of this important scientific discovery.
● A presentation (presented in French and Vietnamese) titled 'Listening to the Universe from Hanoi' will be held at the French Cultural Center (24 Trang Tien, Hanoi) at 18:00 on December 19. 2007 aims to introduce VATLY and the research activities of Auger Vietnam

According to information from VATLY and Auger-Vietnam VAT Physics Laboratory Training Laboratory