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  • richardmitnick 12:27 pm on July 10, 2021 Permalink | Reply
    Tags: "LHAASO's Measurement of Crab Nebula Brightness Yields New UHE Gamma-ray Standard", Chinese Academy of Sciences [中国科学院] (CN), The Crab Nebula Supernova Remnant, Čerenkov astronomy   

    From Chinese Academy of Sciences [中国科学院] (CN) : “LHAASO’s Measurement of Crab Nebula Brightness Yields New UHE Gamma-ray Standard” 

    From Chinese Academy of Sciences [中国科学院] (CN)

    Jul 08, 2021
    LIU Jia

    The Chinese Large High Altitude Air Shower Observatory-Institute of High Energy Physics (CN)-Chinese Academy of Sciences [中国科学院](CN), one of China’s key national science and technology infrastructure facilities, has accurately measured the brightness over 3.5 orders of magnitude of the standard candle in high-energy astronomy, thus calibrating a new standard for ultra-high-energy (UHE) gamma-ray sources. The standard candle is the famous Crab Nebula, which evolved from the “guest star” recorded by the imperial astronomers of China’s Song Dynasty [below].

    LHAASO has also discovered a photon with an energy of 1.1 PeV (1 PeV = one quadrillion electronvolts), indicating the presence of an extremely powerful electron accelerator—about one-tenth the size of the solar system—located in the core region of the Crab Nebula. The accelerator can energize electrons to a level 20,000 times greater than what CERN’s Large Electron–Positron Collider (LEP) can ever achieve, thus approaching the absolute theoretical limit posed by classical electrodynamics and ideal magnetohydrodynamics.

    Results will be published in Science on July 8. The LHAASO International Collaboration, which is led by the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences, completed this study.

    The Crab Nebula is 6,500 light-years from Earth. It was born in a bright supernova explosion in AD 1054. It is the first supernova remnant identified by modern astronomy with a clear historical record. The nebula harbors an energetic pulsar with a period of 30 milliseconds. The fast-rotating magnetosphere of the pulsar drives a powerful wind composed of electron-positron pairs moving at nearly the speed of light. The electrons/positrons in the pulsar wind further accelerate to higher energies once the wind encounters the ambient medium. The nebula is produced by the radiation of the accelerated electrons/positrons.

    The Crab Nebula is one of the few sources that has been measured in all energy bands, i.e., radio, infrared, optical, ultraviolet, X-ray and gamma-ray. Its spectrum has been extensively studied for decades by many observers. As a bright and stable high-energy source, the Crab Nebula is regarded as the standard candle for many different energy bands. In this capacity, it serves as a reference for the measurement of other sources.

    LHAASO has measured the spectrum of the Crab Nebula at the highest-energy end, covering the broad range 0.0005-1.1 PeV. It has confirmed measurements from the past several decades. It has also achieved an accurate measurement in the UHE band (0.3-1.1 PeV) for the first time, thus calibrating the brightness of the standard candle over such an unprecedented energy range.

    Among the 12 UHE gamma-ray sources discovered previously by LHAASO, the Crab Nebula was identified as one of two sources capable of emitting PeV photons, and is the only source with a definite astrophysical counterpart. The measured 1.1 PeV photon provides direct evidence for the acceleration of 2.3 PeV electrons in the source. Such an energy is about 20,000 times the maximum achievable energy of the most powerful man-made electron accelerator, the LEP, which is the predecessor of the LHC. Since high energy electrons suffer strong energy loss in a magnetic field, the accelerator in the Crab Nebula must operate at an incredibly high efficiency to balance the huge energy loss. According to the LHAASO measurement, its acceleration efficiency can reach 15% of the theoretical upper limit, thus surpassing that of the supernova blast wave by a factor of 1,000. This poses challenges to the standard paradigm of electron acceleration in high-energy astrophysics. An in-depth analysis and discussion of this topic are detailed in the current paper in Science.

    LHAASO is a major national scientific and technological infrastructure facility focusing on cosmic ray observation and research. It is located at 4,410 meters above sea level on Mt. Haizi in Daocheng County, Sichuan Province and covers an area of about 1.36 km^2. It is composed of 5,195 electromagnetic particle detectors and 1,188 Muon detectors located in the square-kilometer complex array, a 78,000 m^2 water Čerenkov detector array, and 18 wide-field-of-view Čerenkov telescopes. Using these four techniques, LHAASO will be able to measure air showers generated by cosmic rays or gamma rays omnidirectionally with multiple variables simultaneously.

    Basic information about the incident particles, such as arrival direction, type and energy, can be measured through the reconstruction of the showers. The newly published discovery demonstrates that LHAASO is capable of cross-checking measurements using multiple detection techniques, thus insuring reliable and accurate results. LHAASO will be completed this month and put into operation. With an expectation of detecting 1-2 photons with energies around 1 PeV from the Crab Nebula every year, the puzzle of the cosmic PeV electron accelerator will be unraveled in the coming years.

    2
    Historical records of the guest star in 1054 (Image by Institute of High Energy Physics (CN))

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Chinese Academy of Sciences [中国科学院] (CN) is the linchpin of China’s drive to explore and harness high technology and the natural sciences for the benefit of China and the world. Comprising a comprehensive research and development network, a merit-based learned society and a system of higher education, CAS brings together scientists and engineers from China and around the world to address both theoretical and applied problems using world-class scientific and management approaches.

    Since its founding, CAS has fulfilled multiple roles — as a national team and a locomotive driving national technological innovation, a pioneer in supporting nationwide S&T development, a think tank delivering S&T advice and a community for training young S&T talent.

    Now, as it responds to a nationwide call to put innovation at the heart of China’s development, CAS has further defined its development strategy by emphasizing greater reliance on democratic management, openness and talent in the promotion of innovative research. With the adoption of its Innovation 2020 programme in 2011, the academy has committed to delivering breakthrough science and technology, higher caliber talent and superior scientific advice. As part of the programme, CAS has also requested that each of its institutes define its “strategic niche” — based on an overall analysis of the scientific progress and trends in their own fields both in China and abroad — in order to deploy resources more efficiently and innovate more collectively.

    As it builds on its proud record, CAS aims for a bright future as one of the world’s top S&T research and development organizations.

     
  • richardmitnick 1:51 pm on July 7, 2021 Permalink | Reply
    Tags: "Researchers Discover Origin of Near Ultraviolet and Visible Absorption Characteristics of Ti: sapphire Laser Crystals", , , Chinese Academy of Sciences [中国科学院] (CN), ,   

    From Chinese Academy of Sciences [中国科学院] (CN) : “Researchers Discover Origin of Near Ultraviolet and Visible Absorption Characteristics of Ti: sapphire Laser Crystals” 

    From Chinese Academy of Sciences [中国科学院] (CN)

    1
    Fig. 1. (a) The supercell structure of Al2O3, (b) the interstitial Ti3+, Al vacancy and substitutional Ti3+ models, and their transformation process, (c) the line-contact Ti3+-Ti3+ ion pair model, (d) the face-contact Ti3+-Ti3+ ion pair model, (e) the point-contact Ti4+-Ti3+ ion pair model (Al vacancy is considered as the charge compensation mechanism of Ti4+). (Image by SIOM)

    Recently, a research group from the Shanghai Institute of Optics and Fine Mechanics (SIOM) of the Chinese Academy of Sciences (CAS) carried out a theoretical research on the origin of Ti: sapphire laser crystal in near ultraviolet and visible regions using the first principles method based on density functional theory. Related research results have been published in Materials Today Communications on June 4.

    Ti: sapphire, also known as Ti-doped α-Al2O3 single crystal, is a very important laser crystal material. At present, it is also one of the key materials in a class of super-intense, ultrafast, and tunable laser devices. Since the laser properties of it was reported in 1982, the origin of some suspicious absorption phenomena in the optical absorption band of Ti: sapphire has been one of the focuses of attention and research.

    According to the wavelength distribution, these questionable absorption bands can be roughly divided into three regions: the near ultraviolet absorption band with a peak at 390 nm, the visible absorption band with multi-peak configuration and small bumps, and the residual infrared absorption band overlapped with the laser emission band.

    In this study, the researchers performed a systematic theoretical study on the suspicious absorption phenomenon of Ti: sapphire in near ultraviolet and visible regions.

    Through the analysis of the crystal structure of alumina and the calculation of the electronic and optical properties of the possible single Ti doping defect models and Ti ion pair defect models in Ti: sapphire, they pointed out that when there is an Al vacancy near the interstitial Ti3+, the interstitial Ti3+ will enter the Al vacancy through structural relaxation, and finally form defect equivalent to the substitutional Ti3+.

    The charge transfer transition of substitutional Ti3+ ion’s 3d electron from Ti 3d orbital to Al 3s3p orbital is the main reason for the near ultraviolet absorption band, and the calculated absorption spectra are in good agreement with the experimental spectra.

    Moreover, the multi-peak configuration and bumps of the visible absorption band are mainly caused by the contribution of the line-contact Ti3+-Ti3+, face-contact Ti3+-Ti3+, and point-contact Ti4+-Ti3+ ion pairs.

    In addition, the researchers provided a more comprehensive understanding of the multi-peak configuration and bumps of visible absorption bands from the perspective of ligand field theory and thermal activation.

    This study not only reveals the origin of the suspicious absorption characteristics in Ti-doped Al2O3 crystal but also provides ideas for the study of defects and properties of similar transition metal ions doped oxides having corundum structure.

    This work was supported by the Strategic Priority Research Program of CAS, the National Key R&D Program of China, the National Natural Science Foundation of China, etc.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Chinese Academy of Sciences [中国科学院] (CN) is the linchpin of China’s drive to explore and harness high technology and the natural sciences for the benefit of China and the world. Comprising a comprehensive research and development network, a merit-based learned society and a system of higher education, CAS brings together scientists and engineers from China and around the world to address both theoretical and applied problems using world-class scientific and management approaches.

    Since its founding, CAS has fulfilled multiple roles — as a national team and a locomotive driving national technological innovation, a pioneer in supporting nationwide S&T development, a think tank delivering S&T advice and a community for training young S&T talent.

    Now, as it responds to a nationwide call to put innovation at the heart of China’s development, CAS has further defined its development strategy by emphasizing greater reliance on democratic management, openness and talent in the promotion of innovative research. With the adoption of its Innovation 2020 programme in 2011, the academy has committed to delivering breakthrough science and technology, higher caliber talent and superior scientific advice. As part of the programme, CAS has also requested that each of its institutes define its “strategic niche” — based on an overall analysis of the scientific progress and trends in their own fields both in China and abroad — in order to deploy resources more efficiently and innovate more collectively.

    As it builds on its proud record, CAS aims for a bright future as one of the world’s top S&T research and development organizations.

     
  • richardmitnick 9:57 pm on June 30, 2021 Permalink | Reply
    Tags: "A fast-expanding Type Ia supernova exploded in NGC 474 study finds", , , , Chinese Academy of Sciences [中国科学院] (CN), , , Xinglong Observatory [兴隆观测站] (CN)   

    From Xinglong Observatory [兴隆观测站] (CN) via phys.org : “A fast-expanding Type Ia supernova exploded in NGC 474, study finds” 

    LAMOST telescope located in Xinglong Station, Hebei Province, China.

    From Xinglong Observatory [兴隆观测站] (CN)

    Chinese Academy of Sciences [中国科学院] (CN)

    via

    phys.org

    June 30, 2021
    Tomasz Nowakowski

    1
    The left panel shows a color image which is synthesized from observations in gr bands obtained by the CFHT
    before the discovery of SN 2017fgc. The red circle marks the position of SN 2017fgc and the gas bridge can be clearly seen here. The right panel shows a color image synthesized from TNT observations in the gri bands after the explosion of SN 2017fgc, and the SN is marked with a red circle while the reference stars are labeled by numbers. Credit: Zeng et al., 2021.


    Using ground-based facilities, astronomers from China and elsewhere have conducted extensive optical photometric and spectroscopic observations of the supernova SN 2017fgc, which exploded in the galaxy NGC 474. Results of the study, published June 23, indicate that this explosion is a fast-expanding Type Ia supernova.

    Type Ia supernovae (SN Ia) are found in binary systems in which one of the stars is a white dwarf. Stellar explosions of this type are important for the scientific community, as they offer essential clues into the evolution of stars and galaxies.

    SN 2017fgc was detected on July 9, 2017 by the Distance Less Than 40 Mpc (DLT40) survey. Further studies of SN 2017fgc classified it as a normal supernova of Type Ia and found that it exploded in the nearby shell galaxy NGC 474 at a distance of some 96.2 million light years.

    Now, new observations of SN 2017fgc conducted by a team of astronomers led by Xiangyun Zeng of the Xinjiang Astronomical Observatory in China, shed more light on the properties of this SN. The team used a set of various observatories for their study, including the 0.8 m Tsinghua NAOC telescope (TNT).

    2
    Tsinghua NAOC telescope (TNT)

    The researchers monitored SN 2017fgc from 12 days before to around 389 days after its maximum brightness. The observations found that the SN has an absolute peak magnitude of about −19.32 mag and a post-peak decline at a level of 1.05 mag. Its peak luminosity was measured to be approximately 13.2 tredecillion erg/s, what indicates a synthesized nickel mass of about 0.51 solar masses.

    The spectral evolution of SN 2017fgc suggests that it is a high-velocity (HV) SN Ia. It was noted that it has a maximum-light Si II velocity of about 15,000 km/s and a post-peak velocity gradient at a level of some 120 km/s/d. Moreover, the light curve and color curve evolution of SN 2017fgc turned out to be similar to those of other fast-expanding HV SNe Ia such as SN 2002bo and SN 2006X.

    However, the study found that SN 2017fgc is located far away (about 61,600 light years) from the center of its host galaxy, while HV SNe Ia usually explode near the center of their hosts.

    “It seems that SN 2017fgc is an outlier and does not follow this trend of HV SNe Ia. However, closer inspection of the host galaxy NGC 474 reveals that it is a massive lenticular galaxy that experienced a merger ∼ 2 Gyr ago. (…) We speculate that SN 2017fgc could be ejected from the inner part of the companion galaxy NGC 470 during the merger that took place at ∼2 Gyr ago, or formed as a result of some cold gas remaining in the companion disk,” the astronomers write.

    They added that more observations, focused on the host environment of SN 2017fgc, are needed to confirm this assumption.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Chinese Academy of Sciences-National Astronomical Observatories Xinglong Observatory Station, located in Xinglong Station, Hebei Province, China.

    The Xinglong Observatory [兴隆观测站] (CN) of the National Astronomical Observatories, Chinese Academy of Sciences (NAOC) (IAU code: 327, coordinates: 40°23′39′′ N, 117°34′30′′ E) was founded in 1968. At present, it is one of most primary observing stations of NAOC. As the largest optical astronomical observatory site in the continent of Asia, it has 9 telescopes with effective aperture larger than 50 cm. These are the Guo Shoujing Telescope, also called the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), the 2.16-m Telescope, a 1.26-m optical & near-infrared telescope, a 1-m Alt-Az telescope, an 85-cm telescope (NAOC-Beijing Normal University Telescope, NBT), an 80-cm telescope (Tsinghua University-NAOC Telescope, TNT), a 60-cm telescope, a 50-cm telescope and a 60/90-cm Schmidt telescope.

    The average altitude of the Xinglong Observatory is about 900 m. The Xinglong Observatory is located at the south of the main peak of the Yanshan Mountains, in the Xinglong County, Hebei Province, which lies about 120 km (about 2 hours’ drive) to the northeast of Beijing. A shuttle bus runs between NAOC campus and Xinglong Observatory every Tuesday and Friday. The mean and media seeing values of the Xinglong Observatory are 1.9′′ and 1.7′′, respectively. On average, there are 117 photometric nights and 230 observable nights per year based on the data of 2007-2014. Most of the time, the wind speed is less than 4 m/s (the mean value is 2 m/s), and the sky brightness is about 21.1 mag arcsec2 in V band at the zenith.

    Each year, more than a hundred astronomers use the telescopes of the Xinglong Observatory to perform the observations for the studies on Galactic sciences (stellar parameters, extinction measurements, Galactic structures, exoplanets, etc.) and extragalactic sciences (including nearby galaxies, AGNs, high-redshift quasars), as well as time-domain astronomy (supernovae, gamma-ray bursts, stellar tidal disruption events, and different types of variable stars). In recent years, besides the basic daily maintenance of the telescopes, new techniques and methods have been explored by the engineers and technicians of the Xinglong Observatory to improve the efficiency of observations. Meanwhile, the Xinglong Observatory is also a National populscience and education base of China for training students from graduate schools, colleges, high schools and other education institutes throughout China, and it has hosted a number of international workshops and summer schools.

    The Chinese Academy of Sciences [中国科学院] (CN) is the linchpin of China’s drive to explore and harness high technology and the natural sciences for the benefit of China and the world. Comprising a comprehensive research and development network, a merit-based learned society and a system of higher education, CAS brings together scientists and engineers from China and around the world to address both theoretical and applied problems using world-class scientific and management approaches.

    Since its founding, CAS has fulfilled multiple roles — as a national team and a locomotive driving national technological innovation, a pioneer in supporting nationwide S&T development, a think tank delivering S&T advice and a community for training young S&T talent.

    Now, as it responds to a nationwide call to put innovation at the heart of China’s development, CAS has further defined its development strategy by emphasizing greater reliance on democratic management, openness and talent in the promotion of innovative research. With the adoption of its Innovation 2020 programme in 2011, the academy has committed to delivering breakthrough science and technology, higher caliber talent and superior scientific advice. As part of the programme, CAS has also requested that each of its institutes define its “strategic niche” — based on an overall analysis of the scientific progress and trends in their own fields both in China and abroad — in order to deploy resources more efficiently and innovate more collectively.

    As it builds on its proud record, CAS aims for a bright future as one of the world’s top S&T research and development organizations.

     
  • richardmitnick 9:15 pm on June 1, 2021 Permalink | Reply
    Tags: "Study Reveals Diverse Magnetic Fields in Solar-type Star Forming Cores", Analysis of the gas velocity gradient revealed that the kinematics due to gas accretion flows onto the parental filament could have altered the magnetic field configuration., , , , Chinese Academy of Sciences [中国科学院] (CN), , The observations were conducted as a part of a large international program called B-fields In STar-forming Region Observations (BISTRO).   

    From Chinese Academy of Sciences [中国科学院] (CN): “Study Reveals Diverse Magnetic Fields in Solar-type Star Forming Cores” 

    From Chinese Academy of Sciences [中国科学院] (CN)

    Jun 01, 2021
    LI Yuan

    1
    Fig. 1 Core-scale magnetic fields (red segments) inferred using high-resolution and sensitive dust emission polarization observations using JCMT. The Solar-type star forming cores fragmented out of B213 filament are shown. Credit: Eswaraiah Chakali, et al. 2021.

    Magnetic fields are ubiquitous throughout our Milky Way Galaxy and play a crucial role in all dynamics of interstellar medium. However, questions like how solar-type stars form out of magnetized molecular clouds, whether the role of magnetic fields changes at various scales and densities of molecular clouds, and what factors can change the morphology of magnetic fields in low-mass dense cores still remain unclear.

    A new study led by Dr. Eswaraiah Chakali from Prof. LI Di’s research group at the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) has partially answered these questions. The study reveals the diverse magnetic field morphologies in solar-type star forming cores in the Taurus B213 region.

    This study was published in The Astrophysical Journal Letters on May 10.

    The researchers used high-resolution and sensitive 850-micron dust emission polarization data acquired by the James Clerk Maxwell Telescope (JCMT) using the SCUBA-2 camera along with the POL-2 polarimeter.

    The observations were conducted as a part of a large international program called B-fields In STar-forming Region Observations (BISTRO).

    “Although formed out of the same filamentary cloud, Taurus/B213, among the three dense cores having more polarization measurements, only one remembers the relatively uniform large-scale magnetic field threading the parental cloud,” said Dr. Eswaraiah Chakali, lead author of the study.

    This is in contrast to expectations based on the theory that magnetic fields regulate star formation. If a large-scale magnetic field dominates throughout cloud accumulation, core collapse and star formation, the mean position angle of the magnetic field should be similar across various spatial scales.

    Further analysis of the gas velocity gradient revealed that the kinematics due to gas accretion flows onto the parental filament could have altered the magnetic field configuration.

    “Even in the presence of substantial magnetic flux, local physical conditions can significantly affect magnetic field morphology and their role in star formation,” said Prof. LI Di, co-corresponding author of the study.

    “Our current observations represent one of the deepest sub-millimeter polarimetry images ever taken using a single dish telescope toward a Galactic region,” said Prof. QIU Keping of Nanjing University [南京大學] (CN), co-PI of the BISTRO project and a coauthor of the study.

    2
    Fig. 2 Large-scale, uniform magnetic field morphology of Taurus/B213 region, inferred based on multi-wavelength polarization data. The extent of Fig. 1 is marked with a white box. Credit: Eswaraiah Chakali, et al. 2021

    Prof. LI Di also highlighted “more comprehensive analyses, in combination with Planck data and stellar polarimetry, may give more insights into the evolution of magnetic fields in this stereotypical low-mass star-forming region.”

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Chinese Academy of Sciences [中国科学院] (CN) is the linchpin of China’s drive to explore and harness high technology and the natural sciences for the benefit of China and the world. Comprising a comprehensive research and development network, a merit-based learned society and a system of higher education, CAS brings together scientists and engineers from China and around the world to address both theoretical and applied problems using world-class scientific and management approaches.

    Since its founding, CAS has fulfilled multiple roles — as a national team and a locomotive driving national technological innovation, a pioneer in supporting nationwide S&T development, a think tank delivering S&T advice and a community for training young S&T talent.

    Now, as it responds to a nationwide call to put innovation at the heart of China’s development, CAS has further defined its development strategy by emphasizing greater reliance on democratic management, openness and talent in the promotion of innovative research. With the adoption of its Innovation 2020 programme in 2011, the academy has committed to delivering breakthrough science and technology, higher caliber talent and superior scientific advice. As part of the programme, CAS has also requested that each of its institutes define its “strategic niche” — based on an overall analysis of the scientific progress and trends in their own fields both in China and abroad — in order to deploy resources more efficiently and innovate more collectively.

    As it builds on its proud record, CAS aims for a bright future as one of the world’s top S&T research and development organizations.

     
  • richardmitnick 8:47 pm on June 1, 2021 Permalink | Reply
    Tags: "FAST Is Promising in Interplanetary Scintillation Observation", Chinese Academy of Sciences [中国科学院] (CN), Ground-based IPS observations can be used to study the solar wind and forecast space weather., IPS-interplanetary scintillation: the radio signal from a distant compact radio source is scattered by the density inhomogeneities of the solar wind., Scientists obtained the solar wind model-fitting parameters within 20 s.   

    From Chinese Academy of Sciences [中国科学院] (CN): “FAST Is Promising in Interplanetary Scintillation Observation” 

    From Chinese Academy of Sciences [中国科学院] (CN)

    Jun 01, 2021
    LI Yuan

    The radio signal from a distant compact radio source is scattered by the density inhomogeneities of the solar wind, and consequently a random diffraction pattern is observed on the Earth.

    This phenomenon is called interplanetary scintillation (IPS). Ground-based IPS observations can be used to study the solar wind and forecast space weather.

    1
    Fig. 1 Scheme of IPS phenomenon. Image by J. A. González-Esparza et al., 2004.

    Based on the Five-hundred-meter Aperture Spherical radio Telescope (FAST) and its ultra-wideband (UWB) receiver, a research team led by Prof. PENG Bo from National Astronomical Observatories of Chinese Academy of Sciences (NAOC) observed some 3C sources to analyze the solar wind through interplanetary scintillation.

    The study was published online in MNRAS on May 20, 2021.

    “This development is novel and of benefit to the wider astrophysical community,” said the anonymous referee.

    From 2016 to 2018, some distinctive observations of IPS sources like 3C 286 and 3C 279 were accomplished with FAST. Due to the wide frequency coverage of the ultra-wideband (UWB) receiver (270-1620MHz), one can use both single-frequency and dual-frequency analyses to determine the projected velocity of the solar wind simultaneously.

    Based on the extraordinary sensitivity of FAST, Ph.D. Candidate LIU Lijia, the first author of the study, obtained the solar wind model-fitting parameters within 20 s. The observing time was at least reduced by an order of magnitude compared to other radio telescopes.

    For the first time, the four fitting parameters and errors of the solar wind can be obtained at the same time, with the radio frequency interference (RFI) mitigation strategy and an optimized model-fitting method developed by the researchers.

    “FAST is promising to play a unique role in IPS study,” said Prof. PENG Bo, the corresponding author of the study.

    2
    Fig. 2 The model-fitting example of source 3C 286 with SSSF analysis mode. (Image by Liu et al., 2021)

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Chinese Academy of Sciences [中国科学院] (CN) is the linchpin of China’s drive to explore and harness high technology and the natural sciences for the benefit of China and the world. Comprising a comprehensive research and development network, a merit-based learned society and a system of higher education, CAS brings together scientists and engineers from China and around the world to address both theoretical and applied problems using world-class scientific and management approaches.

    Since its founding, CAS has fulfilled multiple roles — as a national team and a locomotive driving national technological innovation, a pioneer in supporting nationwide S&T development, a think tank delivering S&T advice and a community for training young S&T talent.

    Now, as it responds to a nationwide call to put innovation at the heart of China’s development, CAS has further defined its development strategy by emphasizing greater reliance on democratic management, openness and talent in the promotion of innovative research. With the adoption of its Innovation 2020 programme in 2011, the academy has committed to delivering breakthrough science and technology, higher caliber talent and superior scientific advice. As part of the programme, CAS has also requested that each of its institutes define its “strategic niche” — based on an overall analysis of the scientific progress and trends in their own fields both in China and abroad — in order to deploy resources more efficiently and innovate more collectively.

    As it builds on its proud record, CAS aims for a bright future as one of the world’s top S&T research and development organizations.

     
  • richardmitnick 12:15 pm on May 18, 2021 Permalink | Reply
    Tags: "Observatory discovers a dozen PeVatrons and photons exceeding 1 PeV launches ultra-high-energy gamma astronomy era", China's Large High Altitude Air Shower Observatory -LHAASO, Chinese Academy of Sciences [中国科学院] (CN),   

    From Chinese Academy of Sciences [中国科学院] (CN): “LHAASO Discovers a Dozen PeVatrons and Photons Exceeding 1 PeV and Launches Ultra-high-energy Gamma Astronomy Era” 

    From Chinese Academy of Sciences [中国科学院] (CN)

    May 17, 2021
    LIU Jia

    China’s Large High Altitude Air Shower Observatory (LHAASO)—one of the country’s key national science and technology infrastructure facilities—has found a dozen ultra-high-energy (UHE) cosmic accelerators within the Milky Way. It has also detected photons with energies exceeding 1 peta-electron-volt (quadrillion electron-volts or PeV), including one at 1.4 PeV. The latter is the highest energy photon ever observed.

    These findings overturn the traditional understanding of the Milky Way and open up an era of UHE gamma astronomy. These observations will prompt people to rethink the mechanism by which high-energy particles are generated and propagated in the Milky Way, and will encourage people to explore more deeply violent celestial phenomena and their physical processes as well as test basic physical laws under extreme conditions.

    These discoveries are published in the journal Nature on May 17. The LHAASO International Collaboration, which is led by the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences, completed this study.

    The LHAASO Observatory is still under construction. The cosmic accelerators—known as PeVatrons since they accelerate particles to the PeV range—and PeV photons were discovered using the first half of the detection array, which was finished at the end of 2019 and operated for 11 months in 2020.

    Photons with energies exceeding 1 PeV were detected in a very active star-forming region in the constellation Cygnus. LHAASO also detected 12 stable gamma ray sources with energies up to about 1 PeV and significances of the photon signals seven standard deviations greater than the surrounding background. These sources are located at positions in our galaxy that can be measured with an accuracy better than 0.3°. They are the brightest Milky Way gamma ray sources in LHAASO’s field of view.

    Although the accumulated data from the first 11 months of operation only allowed people to observe those sources, all of them emit so-called UHE photons, i.e., gamma rays above 0.1 PeV. The results show that the Milky Way is full of PeVatrons, while the largest accelerator on Earth (LHC at CERN) can only accelerate particles to 0.01 PeV. Scientists have already determined that cosmic ray accelerators in the Milky Way have an energy limit. Until now, the predicted limit was around 0.1 PeV, thus leading to a natural cut-off of the gamma-ray spectrum above that.

    But LHAASO’s discovery has increased this “limit,” since the spectra of most sources are not truncated. These findings launch an era for UHE gamma astronomic observation. They show that non-thermal radiation celestials, such as young massive star clusters, supernova remnants, pulsar wind nebulas and so on—represented by Cygnus star-forming regions and the Crab nebula—are the best candidates for finding UHE cosmic rays in the Milky Way.

    Through UHE gamma astronomy, a century-old mystery-—the origin of cosmic rays—may soon be solved. LHAASO will prompt scientists to rethink the mechanisms of high energy cosmic ray acceleration and propagation in the Milky Way. It will also allow scientists to explore extreme astrophysical phenomena and their corresponding processes, thus enabling examination of the basic laws of physics under extreme conditions.

    Extended Materials:

    LHAASO and Its Core Scientific Goals

    LHAASO is a major national scientific and technological infrastructure facility focusing on cosmic ray observation and research. It is located 4,410 meters above sea level on Mt. Haizi in Daocheng County, Sichuan Province. When construction is completed in 2021, LHAASO’s particle detector arrays will comprise 5,195 electromagnetic particle detectors and 1,188 Muon detectors located in the square-kilometer complex array (KM2A), a 78,000 m2 water Čerenkov detector array (WCDA), and 18 wide-field-of-view Čerenkov telescopes (WFCTA). Using these four detection techniques, LHAASO will be able to measure cosmic rays omnidirectionally with multiple variables simultaneously. The arrays will cover an area of about 1.36 km2.

    LHAASO’s core scientific goal is to explore the origin of high-energy cosmic rays and study related physics such as the evolution of the universe, the motion and interaction of high-energy astronomical celestials, and the nature of dark matter. LHAASO will extensively survey the universe (especially the Milky Way) for gamma ray sources. It will precisely measure their energy spectra over a broad range—from less than 1 TeV (trillion electron-volts or tera-electron-volts) to more than 1 PeV. It will also measure the components of diffused cosmic rays and their spectra at even higher energies, thus revealing the laws of the generation, acceleration and propagation of cosmic rays, as part of the exploration of new physics frontiers.

    PeVatrons and PeV Photons

    The signal of UHE photons around PeVatrons is so weak that just one or two photons at PeV energy can be detected using 1 km^2 of detectors per year even when focusing on the Crab Nebula, known as the “standard candle for gamma astronomy.” What’s worse, those one or two photons are submerged in tens of thousands of ordinary cosmic rays. The 1,188 muon detectors in LHAASO’s KM2A are designed to select photon-like signals, making LHAASO the most sensitive UHE gamma ray detector in the world. With its unprecedented sensitivity, in just 11 months, the half-sized KM2A detected one photon around 1 PeV from the Crab Nebula. In addition, KM2A found 12 similar sources in the Milky Way, all of which emit UHE photons and extend their spectra continuously into the vicinity of 1 PeV. Even more important, KM2A has detected a photon with energy of 1.4 PeV—the highest ever recorded. It is clear that LHAASO’s scientific discoveries represent a milestone in identifying the origin of cosmic rays. To be specific, LHAASO’s scientific breakthroughs fall into the following three areas:

    1) Revealing the ubiquity of cosmic accelerators capable of accelerating particles to energies exceeding 1 PeV in the Milky Way. All the gamma ray sources that LHAASO has effectively observed radiate photons in the UHE range above 0.1 PeV, indicating that the energy of the parent particles radiating these gamma rays must exceed 1 PeV. As a matter of convention, these sources must have significances of photon signals five standard deviations greater than the surrounding background. The observed energy spectrum of these gamma rays has not truncated above 0.1 peV, demonstrating that there is no acceleration limit below PeV in the galactic accelerators.

    This observation violates the prevailing theoretical model. According to current theory, cosmic rays with energies in the PeV range can produce gamma rays of 0.1 PeV by interacting with surrounding gases in the accelerating region. Detecting gamma rays with energies greater than 0.1 PeV is an important way to find and verify PeV cosmic ray sources. Since previous international mainstream detectors work below this energy level, the existence of PeV cosmic ray accelerators had not been solidly confirmed before. But now LHAASO has revealed a large number of PeV cosmic acceleration sources in the Milky Way, all of which are candidates for being UHE cosmic ray generators. This is a crucial step toward determining the origin of cosmic rays.

    2) Beginning an era of “UHE gamma astronomy.” In 1989, an experimental group at the Whipple Observatory in Arizona successfully discovered the first object emitting gamma radiation above 0.1 TeV, marking the onset of the era of “very-high-energy” gamma astronomy.

    University of Arizona Veritas Four Čerenkov telescopes A novel gamma ray telescope under construction at the CfA Fred Lawrence Whipple Observatory (US), Mount Hopkins, Arizona (US), altitude 2,606 m 8,550 ft. A large project known as the Čerenkov Telescope Array, composed of hundreds of similar telescopes to be situated at Roque de los Muchachos Observatory [Instituto de Astrofísica de Canarias ](ES) in the Canary Islands and Chile at European Southern Observatory Cerro Paranal(EU) site. The telescope on Mount Hopkins will be fitted with a prototype high-speed camera, assembled at the University of Wisconsin–Madison (US) and capable of taking pictures at a billion frames per second. Credit: Vladimir Vassiliev.

    Over the next 30 years, more than 200 “very-high-energy” gamma ray sources were discovered. However, the first object emitting UHE gamma radiation was not detected until 2019. Surprisingly, by using a partly complete array for less than a year, LHAASO has already boosted the number of UHE gamma ray sources to 12.

    With the completion of LHAASO and the continuous accumulation of data, we can anticipate to find an unexplored “UHE universe” full of surprising phenomena. It is well known that background radiation from the Big Bang is so pervasive it can absorb gamma rays with energies greater than 1 PeV. Even if gamma rays were produced beyond the Milky Way, we wouldn’t be able to detect them. This makes LHAASO’s observational window so special.

    3) Photons with energies greater than 1 PeV were first detected from the Cygnus region and the Crab Nebula. The detection of PeV photons is a milestone in gamma astronomy. It fulfills the dream of the gamma astronomy community and has long been a strong driving force in the development of research instruments in the field. In fact, one of the main reasons for the explosion of gamma astronomy in the 1980s was the challenge of the PeV photon limit. The star-forming region in the direction of Cygnus is the brightest area in the northern territory of the Milky Way, with a large number of massive star clusters. Massive stars live only on the order of one million years, so the clusters contain enormous stars in the process of birth and death, with a complex strong shock environment. They are ideal “particle astrophysics laboratories,” i.e., places for accelerating cosmic rays.

    The first PeV photons found by LHAASO were from the star-forming region of the constellation Cygnus, making this area the best candidate for exploring the origin of UHE cosmic rays. Therefore, much attention has turned to LHAASO and multi-wavelength observation of this region, which could offer a potential breakthrough in solving the “mystery of the century.”

    Extensive observational studies of the Crab Nebula over the years have made the celestial body almost the only standard gamma ray source with a clear emission mechanism. Indeed, precise spectrum measurements across 22 orders of magnitude clearly reveal the signature of an electron accelerator. However, the UHE spectra measured by LHAASO, especially photons at PeV energy, seriously challenge this “standard model” of high-energy astrophysics and even the more fundamental theory of electron acceleration.

    Technology Innovations

    LHAASO has developed and/or improved: 1) clock synchronization technology over long distances that ensures timing synchronization accuracy to the sub-nanosecond level for each detector in the array; 2) multiple parallel event trigger algorithms and their realization, with the help of high-speed front-end signal digitization, high-speed data transmission and large on-site computing clusters; and advanced detection technologies include 3) silicon photo multipliers (SiPM) and 4) ultra-large photocathode micro-channel plate photomultiplier tubes (MCP-PMT). They are being employed at LHAASO on a large scale for the first time. They have greatly improved the spatial resolution of photon measurements and lowered the detection energy threshold. These features allow detectors to achieve unprecedented sensitivity in exploring the deep universe at a wide energy range. LHAASO provides an attractive experimental platform for conducting interdisciplinary research in frontier sciences such as atmosphere, high-altitude environment and space weather. It will also serve as a base for international cooperation on high-level scientific research projects.

    History of Cosmic Ray Research in China

    Cosmic ray research in China has experienced three stages. LHAASO represents the third generation of high-altitude cosmic ray observatories. High-altitude experiments are a means of making full use of the atmosphere as a detector medium. In this way, scientists can observe cosmic rays on the ground, where the size of the detector can be much larger than in a space-borne detector outside the atmosphere. This is the only way to observe cosmic rays at very high energy.

    In 1954, China’s first cosmic ray laboratory was built on Mt. Luoxue in Dongchuan, Yunnan Province, at 3,180 meters above sea level. In 1989, the Sino-Japanese cosmic ray experiment ASg was built at an altitude of 4,300 meters above sea level at Yangbajing, Tibet Autonomous Region.

    In 2006, the joint Sino-Italian ARGO-YBJ experiment was built at the same site.

    In 2009, at the Xiangshan Science Forum in Beijing, Professor CAO Zhen proposed to build a large-scale composite detection array (i.e., LHAASO) in a high-altitude area. The LHAASO project was approved in 2015 and construction began in 2017. By April 2019, construction was 25% complete and scientific operation had begun. By January 2020, an additional 25% had been completed and put into operation. In December of the same year, 75% of the facility had been completed. The entire facility will be completed in 2021. LHAASO has already become one of the world’s leading UHE gamma detection facilities, and will operate for a long time. With it, scientists will be able to study the origin of cosmic rays from many aspects.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Chinese Academy of Sciences [中国科学院] (CN) is the linchpin of China’s drive to explore and harness high technology and the natural sciences for the benefit of China and the world. Comprising a comprehensive research and development network, a merit-based learned society and a system of higher education, CAS brings together scientists and engineers from China and around the world to address both theoretical and applied problems using world-class scientific and management approaches.

    Since its founding, CAS has fulfilled multiple roles — as a national team and a locomotive driving national technological innovation, a pioneer in supporting nationwide S&T development, a think tank delivering S&T advice and a community for training young S&T talent.

    Now, as it responds to a nationwide call to put innovation at the heart of China’s development, CAS has further defined its development strategy by emphasizing greater reliance on democratic management, openness and talent in the promotion of innovative research. With the adoption of its Innovation 2020 programme in 2011, the academy has committed to delivering breakthrough science and technology, higher caliber talent and superior scientific advice. As part of the programme, CAS has also requested that each of its institutes define its “strategic niche” — based on an overall analysis of the scientific progress and trends in their own fields both in China and abroad — in order to deploy resources more efficiently and innovate more collectively.

    As it builds on its proud record, CAS aims for a bright future as one of the world’s top S&T research and development organizations.

     
  • richardmitnick 10:53 pm on May 12, 2021 Permalink | Reply
    Tags: "Excitation spectral microscopy integrates multi-target imaging and quantitative biosensing", Chinese Academy of Sciences [中国科学院] (CN),   

    From University of California- Berkeley (US) and From Chinese Academy of Sciences [中国科学院] (CN) via phys.org : “Excitation spectral microscopy integrates multi-target imaging and quantitative biosensing” 

    From University of California-Berkeley (US)

    and

    From Chinese Academy of Sciences [中国科学院] (CN)

    via

    phys.org

    May 12, 2021

    1
    a, Schematic of the setup. Full-frame spectral micrographs are obtained by the synchronized fast modulation of the excitation wavelength in consecutive frames. P, polarizer; L, lens; F, bandpass filter; DM, dichroic mirror. b, Unmixed images of 6 subcellular targets in a live COS-7 cell with 8 excitation wavelengths. LipidSpot 488: lipid droplets (LDs), SYBR Green: mitochondrial DNA, Mito-PhiYFP: mitochondrial matrix, WGA-CF532: cell membrane, LysoBrite Orange: lysosomes, tdTomato-ER3: ER. c, Reference excitation spectra of the 6 fluorophores, separately measured on the setup using singly labeled samples. d, Mito-pHRed absolute pH maps of the mitochondrial matrix in a live HeLa cell, before (top) and after (bottom) 120 s treatment with 20 μM CCCP. e, Color-coded FRET maps for a macromolecular crowding sensor, for two live COS-7 cells before (left), ~10 s after (center), and ~25 s after (right) 150% hypertonic treatment. f, Unmixed images of color-coded Mito-pHRed absolute pH map, mOrange2-Parkin, PhiYFP-LC3, and LAMP1-Clover for two Parkin-expressing live HeLa cells after the application of 20 μM CCCP for 4 h. g, Zoom-in of the white box in (f) Credit: Kun Chen, Rui Yan, Limin Xiang, and Ke Xu.

    The multiplexing capability of fluorescence microscopy is severely limited by the broad fluorescence spectral width. Spectral imaging offers potential solutions, yet typical approaches to disperse the local emission spectra notably impede the attainable throughput and place substantial constraints on temporal resolution. Tunable bandpass filters provide a possibility to scan through the emission wavelength in the wide field. However, applying narrow bandpasses to the fluorescence emission results in inefficient use of the scarce signal.

    In a new paper published in Light: Science & Applications, a team of scientists, led by Professor Ke Xu from College of Chemistry, University of California, Berkeley(US) have demonstrated that using a single, fixed fluorescence emission detection band, through frame-synchronized fast scanning of the excitation wavelength from a white lamp via an acousto-optic tunable filter (AOTF), up to 6 subcellular targets, labeled by common fluorophores of substantial spectral overlap, can be simultaneously imaged in live cells with low (~1%) crosstalk and high temporal resolution (down to ~10 ms).

    The demonstrated capability to quantify the abundances of different fluorophores in the same sample through unmixing the excitation spectra next enabled them to devise novel, quantitative imaging schemes for both bi-state and FRET (Förster resonance energy transfer) fluorescent biosensors in live cells. They thus achieved full-frame high sensitivities and spatiotemporal resolutions in quantifying the mitochondrial matrix pH and the intracellular macromolecular crowding. They thus unveiled significant spatial heterogeneities in both parameters, including spontaneous sudden jumps in the mitochondrial matrix pH accompanied by dramatic mitochondrial shape changes. They further demonstrated, for the first time, the multiplexing of absolute pH imaging with three additional target organelles/proteins to elucidate the complex, Parkin-mediated mitophagy pathway.

    “The potential extension of our approach to even more fluorophores may be achieved by further increasing the number of excitation wavelengths or integrating emission dispersion. Whereas in this work we focused on a facile system based on a lamp-operated epifluorescence microscope, the fast multi-fluorophore and quantitative biosensor imaging capabilities we demonstrated here should be readily extendable to other systems, including light-sheet fluorescence microscopy and structured illumination microscopy” the scientists commented.

    Together, these results “unveil the exceptional opportunities excitation spectral microscopy provides for highly multiplexed fluorescence imaging. The prospect of acquiring fast spectral images in the wide-field without the need for fluorescence dispersion or the care for the spectral response of the detector offers tremendous potential,” the scientists conclude.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Chinese Academy of Sciences [中国科学院] (CN) is the linchpin of China’s drive to explore and harness high technology and the natural sciences for the benefit of China and the world. Comprising a comprehensive research and development network, a merit-based learned society and a system of higher education, CAS brings together scientists and engineers from China and around the world to address both theoretical and applied problems using world-class scientific and management approaches.

    Since its founding, CAS has fulfilled multiple roles — as a national team and a locomotive driving national technological innovation, a pioneer in supporting nationwide S&T development, a think tank delivering S&T advice and a community for training young S&T talent.

    Now, as it responds to a nationwide call to put innovation at the heart of China’s development, CAS has further defined its development strategy by emphasizing greater reliance on democratic management, openness and talent in the promotion of innovative research. With the adoption of its Innovation 2020 programme in 2011, the academy has committed to delivering breakthrough science and technology, higher caliber talent and superior scientific advice. As part of the programme, CAS has also requested that each of its institutes define its “strategic niche” — based on an overall analysis of the scientific progress and trends in their own fields both in China and abroad — in order to deploy resources more efficiently and innovate more collectively.

    As it builds on its proud record, CAS aims for a bright future as one of the world’s top S&T research and development organizations.

    The University of California-Berkeley (US) is a public land-grant research university in Berkeley, California. Established in 1868 as the state’s first land-grant university, it was the first campus of the University of California (US) system and a founding member of the Association of American Universities (US). Its 14 colleges and schools offer over 350 degree programs and enroll some 31,000 undergraduate and 12,000 graduate students. Berkeley is ranked among the world’s top universities by major educational publications.

    Berkeley hosts many leading research institutes, including the Mathematical Sciences Research Institute and the Space Sciences Laboratory. It founded and maintains close relationships with three national laboratories at DOE’s Lawrence Berkeley National Laboratory(US), DOE’s Lawrence Livermore National Laboratory(US) and DOE’s Los Alamos National Lab(US), and has played a prominent role in many scientific advances, from the Manhattan Project and the discovery of 16 chemical elements to breakthroughs in computer science and genomics. Berkeley is also known for student activism and the Free Speech Movement of the 1960s.

    Berkeley alumni and faculty count among their ranks 110 Nobel laureates (34 alumni), 25 Turing Award winners (11 alumni), 14 Fields Medalists, 28 Wolf Prize winners, 103 MacArthur “Genius Grant” recipients, 30 Pulitzer Prize winners, and 19 Academy Award winners. The university has produced seven heads of state or government; five chief justices, including Chief Justice of the United States Earl Warren; 21 cabinet-level officials; 11 governors; and 25 living billionaires. It is also a leading producer of Fulbright Scholars, MacArthur Fellows, and Marshall Scholars. Berkeley alumni, widely recognized for their entrepreneurship, have founded many notable companies.

    Berkeley’s athletic teams compete in Division I of the NCAA, primarily in the Pac-12 Conference, and are collectively known as the California Golden Bears. The university’s teams have won 107 national championships, and its students and alumni have won 207 Olympic medals.

    Made possible by President Lincoln’s signing of the Morrill Act in 1862, the University of California was founded in 1868 as the state’s first land-grant university by inheriting certain assets and objectives of the private College of California and the public Agricultural, Mining, and Mechanical Arts College. Although this process is often incorrectly mistaken for a merger, the Organic Act created a “completely new institution” and did not actually merge the two precursor entities into the new university. The Organic Act states that the “University shall have for its design, to provide instruction and thorough and complete education in all departments of science, literature and art, industrial and professional pursuits, and general education, and also special courses of instruction in preparation for the professions”.

    Ten faculty members and 40 students made up the fledgling university when it opened in Oakland in 1869. Frederick H. Billings, a trustee of the College of California, suggested that a new campus site north of Oakland be named in honor of Anglo-Irish philosopher George Berkeley. The university began admitting women the following year. In 1870, Henry Durant, founder of the College of California, became its first president. With the completion of North and South Halls in 1873, the university relocated to its Berkeley location with 167 male and 22 female students.

    Beginning in 1891, Phoebe Apperson Hearst made several large gifts to Berkeley, funding a number of programs and new buildings and sponsoring, in 1898, an international competition in Antwerp, Belgium, where French architect Émile Bénard submitted the winning design for a campus master plan.

    20th century

    In 1905, the University Farm was established near Sacramento, ultimately becoming the University of California, Davis. In 1919, Los Angeles State Normal School became the southern branch of the University, which ultimately became the University of California, Los Angeles. By 1920s, the number of campus buildings had grown substantially and included twenty structures designed by architect John Galen Howard.

    In 1917, one of the nation’s first ROTC programs was established at Berkeley and its School of Military Aeronautics began training pilots, including Gen. Jimmy Doolittle. Berkeley ROTC alumni include former Secretary of Defense Robert McNamara and Army Chief of Staff Frederick C. Weyand as well as 16 other generals. In 1926, future fleet admiral Chester W. Nimitz established the first Naval ROTC unit at Berkeley.

    In the 1930s, Ernest Lawrence helped establish the Radiation Laboratory (now DOE’s Lawrence Berkeley National Laboratory (US)) and invented the cyclotron, which won him the Nobel physics prize in 1939. Using the cyclotron, Berkeley professors and Berkeley Lab researchers went on to discover 16 chemical elements—more than any other university in the world. In particular, during World War II and following Glenn Seaborg’s then-secret discovery of plutonium, Ernest Orlando Lawrence’s Radiation Laboratory began to contract with the U.S. Army to develop the atomic bomb. Physics professor J. Robert Oppenheimer was named scientific head of the Manhattan Project in 1942. Along with the Lawrence Berkeley National Laboratory, Berkeley founded and was then a partner in managing two other labs, Los Alamos National Laboratory (1943) and Lawrence Livermore National Laboratory (1952).

    By 1942, the American Council on Education ranked Berkeley second only to Harvard University (US) in the number of distinguished departments.

    In 1952, the University of California reorganized itself into a system of semi-autonomous campuses, with each campus given its own chancellor, and Clark Kerr became Berkeley’s first Chancellor, while Sproul remained in place as the President of the University of California.

    Berkeley gained a worldwide reputation for political activism in the 1960s. In 1964, the Free Speech Movement organized student resistance to the university’s restrictions on political activities on campus—most conspicuously, student activities related to the Civil Rights Movement. The arrest in Sproul Plaza of Jack Weinberg, a recent Berkeley alumnus and chair of Campus CORE, in October 1964, prompted a series of student-led acts of formal remonstrance and civil disobedience that ultimately gave rise to the Free Speech Movement, which movement would prevail and serve as precedent for student opposition to America’s involvement in the Vietnam War.

    In 1982, the Mathematical Sciences Research Institute (MSRI) was established on campus with support from the National Science Foundation and at the request of three Berkeley mathematicians — Shiing-Shen Chern, Calvin Moore and Isadore M. Singer. The institute is now widely regarded as a leading center for collaborative mathematical research, drawing thousands of visiting researchers from around the world each year.

    21st century

    In the current century, Berkeley has become less politically active and more focused on entrepreneurship and fundraising, especially for STEM disciplines.

    Modern Berkeley students are less politically radical, with a greater percentage of moderates and conservatives than in the 1960s and 70s. Democrats outnumber Republicans on the faculty by a ratio of 9:1. On the whole, Democrats outnumber Republicans on American university campuses by a ratio of 10:1.

    In 2007, the Energy Biosciences Institute was established with funding from BP and Stanley Hall, a research facility and headquarters for the California Institute for Quantitative Biosciences, opened. The next few years saw the dedication of the Center for Biomedical and Health Sciences, funded by a lead gift from billionaire Li Ka-shing; the opening of Sutardja Dai Hall, home of the Center for Information Technology Research in the Interest of Society; and the unveiling of Blum Hall, housing the Blum Center for Developing Economies. Supported by a grant from alumnus James Simons, the Simons Institute for the Theory of Computing was established in 2012. In 2014, Berkeley and its sister campus, Univerity of California-San Fransisco (US), established the Innovative Genomics Institute, and, in 2020, an anonymous donor pledged $252 million to help fund a new center for computing and data science.

    Since 2000, Berkeley alumni and faculty have received 40 Nobel Prizes, behind only Harvard and MIT among US universities; five Turing Awards, behind only Massachusetts Institute of Technology (US) and Stanford; and five Fields Medals, second only to Princeton University (US). According to PitchBook, Berkeley ranks second, just behind Stanford University, in producing VC-backed entrepreneurs.

    UC Berkeley Seal

     
  • richardmitnick 11:08 am on May 6, 2021 Permalink | Reply
    Tags: "FAST detects 3D spin-velocity alignment in a pulsar", , , , Chinese Academy of Sciences [中国科学院] (CN),   

    From Chinese Academy of Sciences [中国科学院] (CN): “FAST detects 3D spin-velocity alignment in a pulsar” 

    From Chinese Academy of Sciences [中国科学院] (CN)

    1
    Illustration of supernova remnant S147 and pulsar J0538+2817. National Astronomical Observatories Xinglong Observatory [兴隆观测站] (CN).

    Pulsars – another name for fast-spinning neutron stars – originate from the imploded cores of massive dying stars through supernova explosion.

    Dame Susan Jocelyn Bell Burnell, discovered pulsars with radio astronomy. Jocelyn Bell at the Mullard Radio Astronomy Observatory, University of Cambridge(UK), taken for the Daily Herald newspaper in 1968. Denied the Nobel.

    Now, more than 50 years after the discovery of pulsars and confirmation of their association with supernova explosions, the origin of the initial spin and velocity of pulsars is finally beginning to be understood.

    Based on observations from the Five-hundred-meter Aperture Spherical radio Telescope (FAST), Dr. YAO Jumei, member of a team led by Dr. LI Di from National Astronomical Observatories Xinglong Observatory [兴隆观测站] (NAOC) (CN) of Chinese Academy of Sciences [中国科学院](CN) , found the first evidence for three-dimensional (3D) spin-velocity alignment in pulsars.

    The study was published in Nature Astronomy on May 6. It also marks the beginning of in-depth pulsar research with FAST.

    For decades, scientists have found observational evidence for spin-velocity alignment in young pulsars. The relationship thus revealed between pulsars’ spin axis and spatial velocity vectors, however, has largely been restricted to a 2D sky plane perpendicular to the line of sight, due to the hardship in constraining radial velocity.

    Focusing on PSR J0538+2817 in the supernova remnant (SNR) S147 and through the scintillation technique, Dr. YAO obtained its radial location with respect to the SNR boundary and its radial velocity for the first time. “Then we got the 3D velocity by combining the transverse velocity measured by Very Long Baseline Interferometers,” said Dr. YAO. The polarization analysis resulted in the direction of the 3D spin axis. The best fit angle between these two vectors was found to be about 10 degrees, which is the first such measurement in 3D.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Chinese Academy of Sciences [中国科学院] (CN) is the linchpin of China’s drive to explore and harness high technology and the natural sciences for the benefit of China and the world. Comprising a comprehensive research and development network, a merit-based learned society and a system of higher education, CAS brings together scientists and engineers from China and around the world to address both theoretical and applied problems using world-class scientific and management approaches.

    Since its founding, CAS has fulfilled multiple roles — as a national team and a locomotive driving national technological innovation, a pioneer in supporting nationwide S&T development, a think tank delivering S&T advice and a community for training young S&T talent.

    Now, as it responds to a nationwide call to put innovation at the heart of China’s development, CAS has further defined its development strategy by emphasizing greater reliance on democratic management, openness and talent in the promotion of innovative research. With the adoption of its Innovation 2020 programme in 2011, the academy has committed to delivering breakthrough science and technology, higher caliber talent and superior scientific advice. As part of the programme, CAS has also requested that each of its institutes define its “strategic niche” — based on an overall analysis of the scientific progress and trends in their own fields both in China and abroad — in order to deploy resources more efficiently and innovate more collectively.

    As it builds on its proud record, CAS aims for a bright future as one of the world’s top S&T research and development organizations.

     
  • richardmitnick 9:48 am on May 4, 2021 Permalink | Reply
    Tags: "Physicists Just Found The Lightest Known Form of Uranium And It Has Unique Behaviors", , , Chinese Academy of Sciences [中国科学院] (CN), ,   

    From Heavy Ion Research Facility in Lanzhou China at Chinese Academy of Sciences [中国科学院] (CN) via Science Alert (AU) : “Physicists Just Found The Lightest Known Form of Uranium And It Has Unique Behaviors” 

    From Chinese Academy of Sciences [中国科学院] (CN)

    via

    ScienceAlert

    Science Alert (AU)

    4 MAY 2021
    MARA JOHNSON-GROH

    1
    Credit: IncrediVFX/iStock/Getty Images.

    Scientists have discovered a new type of uranium that is the lightest ever known. The discovery could reveal more about a weird alpha particle that gets ejected from certain radioactive elements as they decay.

    The newfound uranium, called uranium-214, is an isotope, or a variant of the element, with 30 more neutrons than protons, one fewer neutron than the next-lightest known uranium isotope.

    2
    Credit: APS/Carin Cain

    Because neutrons have mass, uranium-214 is much lighter than more common uranium isotopes, including uranium-235, which is used in nuclear reactors and has 51 extra neutrons.

    This newfound isotope isn’t just lighter than others, but it also showed unique behaviors during its decay. As such, the new findings will help scientists better understand a radioactive decay process known as alpha decay, in which an atomic nucleus loses a group of two protons and two neutrons – collectively called an alpha particle.

    Though scientists know that alpha decay results in the ejection of this alpha particle, after a century of study, they still don’t know the exact details of how the alpha particle is formed before it gets ejected.

    The researchers created the new uranium isotope at the Heavy Ion Research Facility in Lanzhou, China. There, they shone a beam of argon at a target made of tungsten inside a machine called a gas-filled recoil separator – in this case the Spectrometer for Heavy Atoms and Nuclear Structure, or SHANS. By shining a laser at the tungsten, the researchers effectively added protons and neutrons to the material to create uranium.

    The new uranium-214 isotope had a half-life of just half a millisecond, meaning that’s the amount of time it takes for half of the radioactive sample to decay. The most common isotope of uranium – called uranium-238 – has a half-life of about 4.5 billion years, which is about the age of Earth.

    By carefully watching how the isotopes decayed, the scientists were able to study the strong nuclear force – one of the four fundamental forces that hold matter together – acting on the alpha particle parts – the neutrons and protons – on the surface of the uranium.

    They found that the proton and neutron in each alpha particle interacted much more strongly than in isotopes and other elements with similar numbers of protons and neutrons that have been previously studied.

    This is likely due to the specific number of neutrons inside the nucleus of uranium-214, the researchers said. The new isotope has 122 neutrons, nearing the “magic neutron number” of 126, which is especially stable due to the configuration of the neutrons in complete sets, or shells.

    With this configuration, it is easier for scientists to calculate the strong force interaction between the protons and neutrons. That makes these isotopes particularly interesting to scientists, since studying these interactions can reveal features related to nuclear structure and decay process, said study lead author Zhiyuan Zhang, physicist at the Chinese Academy of Sciences [中国科学院](CN).

    The scientists suspect that this proton-neutron interaction could be even stronger heavier radioactive elements such as isotopes of plutonium and neptunium. These elements have a few more protons, and the configuration of their orbits suggests they could have even stronger interactions than the uranium isotopes.

    The scientists would like to study other elemental isotopes near the magic neutron number; however, since such elements have even shorter half-lives, even more sensitive detectors and more powerful beams will be needed.

    The new findings were published April 14 in the journal Physical Review Letters.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Chinese Academy of Sciences [中国科学院] (CN) is the linchpin of China’s drive to explore and harness high technology and the natural sciences for the benefit of China and the world. Comprising a comprehensive research and development network, a merit-based learned society and a system of higher education, CAS brings together scientists and engineers from China and around the world to address both theoretical and applied problems using world-class scientific and management approaches.

    Since its founding, CAS has fulfilled multiple roles — as a national team and a locomotive driving national technological innovation, a pioneer in supporting nationwide S&T development, a think tank delivering S&T advice and a community for training young S&T talent.

    Now, as it responds to a nationwide call to put innovation at the heart of China’s development, CAS has further defined its development strategy by emphasizing greater reliance on democratic management, openness and talent in the promotion of innovative research. With the adoption of its Innovation 2020 programme in 2011, the academy has committed to delivering breakthrough science and technology, higher caliber talent and superior scientific advice. As part of the programme, CAS has also requested that each of its institutes define its “strategic niche” — based on an overall analysis of the scientific progress and trends in their own fields both in China and abroad — in order to deploy resources more efficiently and innovate more collectively.

    As it builds on its proud record, CAS aims for a bright future as one of the world’s top S&T research and development organizations.

     
  • richardmitnick 1:33 pm on January 28, 2021 Permalink | Reply
    Tags: "Dalian Coherent Light Source Reveals Origin of Interstellar Medium S2", , , Chinese Academy of Sciences [中国科学院] (CN), CS2 is believed to be the most important molecule in comet nuclei; interstellar dust; or ice cores., Studying the creation and evolution of sulfur-containing compounds in outer space is essential for understanding interstellar chemistry.   

    From Chinese Academy of Sciences [中国科学院] (CN): “Dalian Coherent Light Source Reveals Origin of Interstellar Medium S2” 

    From Chinese Academy of Sciences [中国科学院] (CN)

    Jan 28, 2021
    LI Yuan, Editor

    1
    Researchers directly observed the C + S2 channel in CS2 photodissociation. Credit: LI Zhenxing.

    Studying the creation and evolution of sulfur-containing compounds in outer space is essential for understanding interstellar chemistry. CS2 is believed to be the most important molecule in comet nuclei, interstellar dust, or ice cores. It could produce CS and S2 fragments after photodissociation.

    The International Ultraviolet Explorer satellite only observed the emission spectra of CS and S2, not that of CS2. The photodissociation mechanism of CS2 molecules remains unclear, and S2 fragments have not been experimentally observed before.

    2
    ESA/NASA/UK International Ultraviolet Explorer (IUE).

    Recently, a team led by Prof. YUAN Kaijun from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), in cooperation with Prof. WANG Xing’an’s group from the University of Science and Technology of China, observed the C+S2 product channel from CS2 photodissociation for the first time using a home-made Time-Sliced Velocity Map Ion Imaging (TS-VMI) experimental setup based on the Dalian Coherent Light Source (DCLS).

    1
    Chinese Academy of Sciences Dalian Coherent Light Source (DCLS)

    The study, published in Journal of Physical Chemistry Letters on Jan. 11, provided direct experimental evidence for the origin of the interstellar medium S2 fragments observed previously.

    The researchers investigated the two-photon ultraviolet (UV) and one-photon vacuum ultraviolet (VUV) photodissociation dynamics of CS2 molecules via the VUV free-electron laser (FEL) at DCLS.

    They directly observed the C + S2 product channel from CS2 photodissociation and obtained images of the electronically ground/excited states of S2 products with vibrational excitation. The electronically-excited states of the central atom of the CS2 molecule played an important role in the isomerization and photodissociation processes.

    This research demonstrated that interstellar medium S2 fragments could be directly generated from CS2 photodissociation.

    “Given the similarity of OCS studied in our previous works and CS2 in this work, we believe that the central-atom elimination channel is more general than expected in the photodissociation of triatomic molecules,” said Prof. YUAN.

    This work was supported by the Chemical Dynamics Research Center, the National Natural Science Foundation of China, and the Key Technology Team of CAS.

    See the full article here .

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    The Chinese Academy of Sciences [中国科学院] (CN) is the linchpin of China’s drive to explore and harness high technology and the natural sciences for the benefit of China and the world. Comprising a comprehensive research and development network, a merit-based learned society and a system of higher education, CAS brings together scientists and engineers from China and around the world to address both theoretical and applied problems using world-class scientific and management approaches.

    Since its founding, CAS has fulfilled multiple roles — as a national team and a locomotive driving national technological innovation, a pioneer in supporting nationwide S&T development, a think tank delivering S&T advice and a community for training young S&T talent.

    Now, as it responds to a nationwide call to put innovation at the heart of China’s development, CAS has further defined its development strategy by emphasizing greater reliance on democratic management, openness and talent in the promotion of innovative research. With the adoption of its Innovation 2020 programme in 2011, the academy has committed to delivering breakthrough science and technology, higher caliber talent and superior scientific advice. As part of the programme, CAS has also requested that each of its institutes define its “strategic niche” — based on an overall analysis of the scientific progress and trends in their own fields both in China and abroad — in order to deploy resources more efficiently and innovate more collectively.

    As it builds on its proud record, CAS aims for a bright future as one of the world’s top S&T research and development organizations.

     
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