The science of radio astronomy focuses on the observation and study of celestial objects by reading their radio waves. The 5 meter radio-telescope is able to observe different radio sources using a C-band LNB. This re...The science of radio astronomy focuses on the observation and study of celestial objects by reading their radio waves. The 5 meter radio-telescope is able to observe different radio sources using a C-band LNB. This research was essentially focused on Crab Nebula, also known as Taurus A. The study led to interesting observations, which were validated numerically using various scientific computing software. The radio waves emitted by Taurus A are readable by the RTL-SDR, a software defined radio receiver. This device is capable of reading radio frequencies in the range of 0.5 MHZ to 1700 MHZ.展开更多
General situation of the protection of radio astronomy frequency in China is introduced in this paper. The organization that is responsible for the management of radio frequencies in China, then the environment of int...General situation of the protection of radio astronomy frequency in China is introduced in this paper. The organization that is responsible for the management of radio frequencies in China, then the environment of international cooperation are briefly described in the first two section. The situation of the protection of radio astronomy frequency we met, and what we have done and ever achieved so far are followed to show a geneneral scene of radio environment for radio astronomy in China.展开更多
In 2019,the Event Horizon Telescope(EHT)released the first-ever image of a black hole event horizon.Astronomers are now aiming for higher angular resolutions of distant targets,like black holes,to understand more abou...In 2019,the Event Horizon Telescope(EHT)released the first-ever image of a black hole event horizon.Astronomers are now aiming for higher angular resolutions of distant targets,like black holes,to understand more about the fundamental laws of gravity that govern our universe.To achieve this higher resolution and increased sensitivity,larger radio telescopes are needed to operate at higher frequencies and in larger quantities.Projects like the next-generation Very Large Array(ngVLA)and the Square-Kilometer Array(SKA)require building hundreds of telescopes with diameters greater than 10 ms over the next decade.This has a twofold effect.Radio telescope surfaces need to be more accurate to operate at higher frequencies,and the logistics involved in maintaining a radio telescope need to be simplified to support them properly in large quantities.Both of these problems can be solved with improved methods for surface metrology that are faster and more accurate with a higher resolution.This leads to faster and more accurate panel alignment and,therefore,a more productive observatory.In this paper,we present the use of binocular fringe projection profilometry as a solution to this problem and demonstrate it by aligning two panels on a 3-m radio telescope dish.The measurement takes only 10 min and directly delivers feedback on the tip,tilt,and piston of each panel to create the ideal reflector shape.展开更多
Radio Frequency System on Chip(RFSo C)offers great potential for implementing a complete next generation signal processing system on a single board for radio astronomy.We designed a pulsar digital backend system based...Radio Frequency System on Chip(RFSo C)offers great potential for implementing a complete next generation signal processing system on a single board for radio astronomy.We designed a pulsar digital backend system based on the ZCU111 board.The system uses RFSo C technology to implement digitization,channelization,correlation and high-speed data transmission in the Xilinx ZU28 DR device.We have evaluated the performance of the eight 12-bit RF-ADCs,which are integrated in RFSo C,with the maximum sampling rate of 4.096 GSPS.The RF-ADC sampling frequency,channel bandwidth and time resolution can be configured dynamically in our designed system.To verify the system performance,we deployed the RFSo C board on the Nanshan 26 m radio telescope and observed the pulsar signal with a frequency resolution of 1 MHz and time resolution of 64μs.In the observation test,we obtained pulsar profiles with high signal-to-noise ratio and accurately searched the DM values.The experimental results show that the performance of RF-ADCs,FPGA and CPU cores in RFSo C is sufficient for radio astronomy signal processing applications.展开更多
The Five-hundred-meter Aperture Spherical radio Telescope(FAST)was launched on 2016 September 25.From early 2017,we began to use the FAST wideband receiver,which was designed,constructed and installed on the FAST in G...The Five-hundred-meter Aperture Spherical radio Telescope(FAST)was launched on 2016 September 25.From early 2017,we began to use the FAST wideband receiver,which was designed,constructed and installed on the FAST in Guizhou,China.The front end of the receiver is composed an uncooled Quad Ridge Flared Horn feed(QRFH)with the frequency range of 270 to 1620 MHz,and a cryostat operating at 10 K.We have cooperated with the Institute of Automation of the Chinese Academy of Sciences to develop the China Reconfigurable ANalog-digital backEnd(CRANE).The system covers the 3 GHz operating band of FAST.The hardware part of the backend includes an Analog Front-end Board,a wideband high precision Analog Digital Converter,and a FAST Digital Back-end.Analog circuit boards,field programmable gate arrays,and control computers form a set of hardware,software,and firmware platforms to achieve flexible bandwidth requirements through parameter changes.It is also suitable for the versatility of different astronomical observations,and can meet specific requirements.This paper briefly introduces the hardware and software of CRANE,as well as some observations of the system.展开更多
This study presents a general outline of the Qitai radio telescope(QTT)project.Qitai,the site of the telescope,is a county of Xinjiang Uygur Autonomous Region of China,located in the east Tianshan Mountains at an elev...This study presents a general outline of the Qitai radio telescope(QTT)project.Qitai,the site of the telescope,is a county of Xinjiang Uygur Autonomous Region of China,located in the east Tianshan Mountains at an elevation of about 1800 m.The QTT is a fully steerable,Gregorian-type telescope with a standard parabolic main reflector of 110 m diameter.The QTT has adopted an umbrella support,homology-symmetric lightweight design.The main reflector is active so that the deformation caused by gravity can be corrected.The structural design aims to ultimately allow high-sensitivity observations from 150 MHz up to115 GHz.To satisfy the requirements for early scientific goals,the QTTwill be equipped with ultra-wideband receivers and large field-of-view multi-beam receivers.A multi-function signal-processing system based on RFSo C and GPU processor chips will be developed.These will enable the QTT to operate in pulsar,spectral line,continuum and Very Long Baseline Interferometer(VLBI)observing modes.Electromagnetic compatibility(EMC)and radio frequency interference(RFI)control techniques are adopted throughout the system design.The QTT will form a world-class observational platform for the detection of lowfrequency(nano Hertz)gravitational waves through pulsar timing array(PTA)techniques,pulsar surveys,the discovery of binary black-hole systems,and exploring dark matter and the origin of life in the universe.The QTT will also play an important role in improving the Chinese and international VLBI networks,allowing high-sensitivity and high-resolution observations of the nuclei of distant galaxies and gravitational lensing systems.Deep astrometric observations will also contribute to improving the accuracy of the celestial reference frame.Potentially,the QTT will be able to support future space activities such as planetary exploration in the solar system and to contribute to the search for extraterrestrial intelligence.展开更多
With aperture synthesis(AS)technique,a number of small antennas can be assembled to form a large telescope whose spatial resolution is determined by the distance of two farthest antennas instead of the diameter of a s...With aperture synthesis(AS)technique,a number of small antennas can be assembled to form a large telescope whose spatial resolution is determined by the distance of two farthest antennas instead of the diameter of a single-dish antenna.In contrast from a direct imaging system,an AS telescope captures the Fourier coefficients of a spatial object,and then implement inverse Fourier transform to reconstruct the spatial image.Due to the limited number of antennas,the Fourier coefficients are extremely sparse in practice,resulting in a very blurry image.To remove/reduce blur,“CLEAN”deconvolution has been widely used in the literature.However,it was initially designed for a point source.For an extended source,like the Sun,its efficiency is unsatisfactory.In this study,a deep neural network,referring to Generative Adversarial Network(GAN),is proposed for solar image deconvolution.The experimental results demonstrate that the proposed model is markedly better than traditional CLEAN on solar images.The main purpose of this work is visual inspection instead of quantitative scientific computation.We believe that this will also help scientists to better understand solar phenomena with high quality images.展开更多
The Tianlai Cylinder Pathfinder is a radio interferometer array designed to test techniques for 21 cm intensity mapping in the post-reionization Universe,with the ultimate aim of mapping the large scale structure and ...The Tianlai Cylinder Pathfinder is a radio interferometer array designed to test techniques for 21 cm intensity mapping in the post-reionization Universe,with the ultimate aim of mapping the large scale structure and measuring cosmological parameters such as the dark energy equation of state.Each of its three parallel cylinder reflectors is oriented in the north-south direction,and the array has a large field of view.As the Earth rotates,the northern sky is observed by drift scanning.The array is located in Hongliuxia,a radio-quiet site in Xinjiang,and saw its first light in September 2016.In this first data analysis paper for the Tianlai cylinder array,we discuss the sub-system qualification tests,and present basic system performance obtained from preliminary analysis of the commissioning observations during 2016-2018.We show typical interferometric visibility data,from which we derive the actual beam profile in the east-west direction and the frequency band-pass response.We describe also the calibration process to determine the complex gains for the array elements,either using bright astronomical point sources,or an artificial on site calibrator source,and discuss the instrument response stability,crucial for transit interferometry.Based on this analysis,we find a system temperature of about 90 K,and we also estimate the sensitivity of the array.展开更多
The Square Kilometre Array(SKA)project consists of delivering two largest radio telescope arrays being built by the SKA Observatory(SKAO),which is an intergovernmental organization bringing together nations from aroun...The Square Kilometre Array(SKA)project consists of delivering two largest radio telescope arrays being built by the SKA Observatory(SKAO),which is an intergovernmental organization bringing together nations from around the world with China being one of the major member countries.The computing resources needed to process,distribute,curate and use the vast amount of data that will be generated by the SKA telescopes are too large for the SKAO to manage on its own.To address this challenge,the SKAO is working with the international community to create a shared,distributed data,computing and networking capability called the SKA Regional Centre Alliance.In this model,the SKAO will be supported by a global network of SKA Regional Centres(SRCs)distributed around the world in its member countries to build an end-to-end science data system that will provide astronomers with high-quality science products.SRCs undertake deep processing,scientific analysis,and long-term storage of the SKA data,as well as user support.China has been actively participating in and promoting the construction of SRCs.This paper introduces the international cooperation and ongoing prototyping of the global SRC network,the basis for the construction of the China SRC and describes in detail the progress of the China SRC prototype.The paper also presents examples of scientific applications of SKA precursor and pathfinder telescopes performed using resources from the China SRC prototype.Finally,the future prospects of the China SRC are presented.展开更多
FAST is the largest single-dish radio telescope in the world.The characteristics of FAST are presented and analyzed in the context of the parameter space to show how FAST science achievements are affected.We summarize...FAST is the largest single-dish radio telescope in the world.The characteristics of FAST are presented and analyzed in the context of the parameter space to show how FAST science achievements are affected.We summarize the scientific achievements of FAST and discuss its future science based on the new parts of the parameter space that can be explored by FAST.展开更多
文摘The science of radio astronomy focuses on the observation and study of celestial objects by reading their radio waves. The 5 meter radio-telescope is able to observe different radio sources using a C-band LNB. This research was essentially focused on Crab Nebula, also known as Taurus A. The study led to interesting observations, which were validated numerically using various scientific computing software. The radio waves emitted by Taurus A are readable by the RTL-SDR, a software defined radio receiver. This device is capable of reading radio frequencies in the range of 0.5 MHZ to 1700 MHZ.
文摘General situation of the protection of radio astronomy frequency in China is introduced in this paper. The organization that is responsible for the management of radio frequencies in China, then the environment of international cooperation are briefly described in the first two section. The situation of the protection of radio astronomy frequency we met, and what we have done and ever achieved so far are followed to show a geneneral scene of radio environment for radio astronomy in China.
基金funded by the National Science Foundation(NSF)Award 2009384.
文摘In 2019,the Event Horizon Telescope(EHT)released the first-ever image of a black hole event horizon.Astronomers are now aiming for higher angular resolutions of distant targets,like black holes,to understand more about the fundamental laws of gravity that govern our universe.To achieve this higher resolution and increased sensitivity,larger radio telescopes are needed to operate at higher frequencies and in larger quantities.Projects like the next-generation Very Large Array(ngVLA)and the Square-Kilometer Array(SKA)require building hundreds of telescopes with diameters greater than 10 ms over the next decade.This has a twofold effect.Radio telescope surfaces need to be more accurate to operate at higher frequencies,and the logistics involved in maintaining a radio telescope need to be simplified to support them properly in large quantities.Both of these problems can be solved with improved methods for surface metrology that are faster and more accurate with a higher resolution.This leads to faster and more accurate panel alignment and,therefore,a more productive observatory.In this paper,we present the use of binocular fringe projection profilometry as a solution to this problem and demonstrate it by aligning two panels on a 3-m radio telescope dish.The measurement takes only 10 min and directly delivers feedback on the tip,tilt,and piston of each panel to create the ideal reflector shape.
基金supported by the National Natural Science Foundation of China(Grant No.12073067)the program of the Light in China’s Western Region(2019-XBQNXZ-B-018)the Youth Innovation Promotion Association of CAS(2021059)。
文摘Radio Frequency System on Chip(RFSo C)offers great potential for implementing a complete next generation signal processing system on a single board for radio astronomy.We designed a pulsar digital backend system based on the ZCU111 board.The system uses RFSo C technology to implement digitization,channelization,correlation and high-speed data transmission in the Xilinx ZU28 DR device.We have evaluated the performance of the eight 12-bit RF-ADCs,which are integrated in RFSo C,with the maximum sampling rate of 4.096 GSPS.The RF-ADC sampling frequency,channel bandwidth and time resolution can be configured dynamically in our designed system.To verify the system performance,we deployed the RFSo C board on the Nanshan 26 m radio telescope and observed the pulsar signal with a frequency resolution of 1 MHz and time resolution of 64μs.In the observation test,we obtained pulsar profiles with high signal-to-noise ratio and accurately searched the DM values.The experimental results show that the performance of RF-ADCs,FPGA and CPU cores in RFSo C is sufficient for radio astronomy signal processing applications.
文摘The Five-hundred-meter Aperture Spherical radio Telescope(FAST)was launched on 2016 September 25.From early 2017,we began to use the FAST wideband receiver,which was designed,constructed and installed on the FAST in Guizhou,China.The front end of the receiver is composed an uncooled Quad Ridge Flared Horn feed(QRFH)with the frequency range of 270 to 1620 MHz,and a cryostat operating at 10 K.We have cooperated with the Institute of Automation of the Chinese Academy of Sciences to develop the China Reconfigurable ANalog-digital backEnd(CRANE).The system covers the 3 GHz operating band of FAST.The hardware part of the backend includes an Analog Front-end Board,a wideband high precision Analog Digital Converter,and a FAST Digital Back-end.Analog circuit boards,field programmable gate arrays,and control computers form a set of hardware,software,and firmware platforms to achieve flexible bandwidth requirements through parameter changes.It is also suitable for the versatility of different astronomical observations,and can meet specific requirements.This paper briefly introduces the hardware and software of CRANE,as well as some observations of the system.
基金supported by the National Key Research and Development Program of China(Grant Nos.2021YFC2203501,2021YFC2203502,2021YFC2203503,and 2021YFC2203600)the National Natural Science Foundation of China(Grant Nos.12173077,11873082,11803080,and 12003062)+3 种基金the Scientific Instrument Developing Project of the Chinese Academy of Sciences(Grant No.PTYQ2022YZZD01)the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instrumentsbudgeted from the Ministry of Finance of China and Administrated by the Chinese Academy of Sciencesthe Chinese Academy of Sciences“Light of West China”Program(Grant No.2021-XBQNXZ-030)。
文摘This study presents a general outline of the Qitai radio telescope(QTT)project.Qitai,the site of the telescope,is a county of Xinjiang Uygur Autonomous Region of China,located in the east Tianshan Mountains at an elevation of about 1800 m.The QTT is a fully steerable,Gregorian-type telescope with a standard parabolic main reflector of 110 m diameter.The QTT has adopted an umbrella support,homology-symmetric lightweight design.The main reflector is active so that the deformation caused by gravity can be corrected.The structural design aims to ultimately allow high-sensitivity observations from 150 MHz up to115 GHz.To satisfy the requirements for early scientific goals,the QTTwill be equipped with ultra-wideband receivers and large field-of-view multi-beam receivers.A multi-function signal-processing system based on RFSo C and GPU processor chips will be developed.These will enable the QTT to operate in pulsar,spectral line,continuum and Very Long Baseline Interferometer(VLBI)observing modes.Electromagnetic compatibility(EMC)and radio frequency interference(RFI)control techniques are adopted throughout the system design.The QTT will form a world-class observational platform for the detection of lowfrequency(nano Hertz)gravitational waves through pulsar timing array(PTA)techniques,pulsar surveys,the discovery of binary black-hole systems,and exploring dark matter and the origin of life in the universe.The QTT will also play an important role in improving the Chinese and international VLBI networks,allowing high-sensitivity and high-resolution observations of the nuclei of distant galaxies and gravitational lensing systems.Deep astrometric observations will also contribute to improving the accuracy of the celestial reference frame.Potentially,the QTT will be able to support future space activities such as planetary exploration in the solar system and to contribute to the search for extraterrestrial intelligence.
基金the National Natural Science Foundation of China(NSFC)(Grant Nos.61572461,61811530282,61872429,11790301 and 11790305).
文摘With aperture synthesis(AS)technique,a number of small antennas can be assembled to form a large telescope whose spatial resolution is determined by the distance of two farthest antennas instead of the diameter of a single-dish antenna.In contrast from a direct imaging system,an AS telescope captures the Fourier coefficients of a spatial object,and then implement inverse Fourier transform to reconstruct the spatial image.Due to the limited number of antennas,the Fourier coefficients are extremely sparse in practice,resulting in a very blurry image.To remove/reduce blur,“CLEAN”deconvolution has been widely used in the literature.However,it was initially designed for a point source.For an extended source,like the Sun,its efficiency is unsatisfactory.In this study,a deep neural network,referring to Generative Adversarial Network(GAN),is proposed for solar image deconvolution.The experimental results demonstrate that the proposed model is markedly better than traditional CLEAN on solar images.The main purpose of this work is visual inspection instead of quantitative scientific computation.We believe that this will also help scientists to better understand solar phenomena with high quality images.
基金support of the Astronomical Technology Center of National Astronomical Observatories of China(NAOC)support of Ministry of Science and Technology(MOST)(Grant No.2012AA121701)+10 种基金supported by MOST(Grant Nos.2016YFE0100300,and 2018YFE0120800)the National Natural Science Foundation of China(NSFC)(Grant Nos.11633004,11473044,and 11653003)the Chinese Academy of Sciences(CAS)(Grant No.QYZDJ-SSW-SLH017)support of the NSFC-CAS Joint Fund of Astronomy(Grant No.U1631118)partially supported by the National Key R&D Program(Grant No.2017YFA0402603)the CAS Interdisciplinary Innovation Team(Grant No.JCTD-2019-05)support of NSFC(Grant No.U1501501)the Tianhe-1 supercomputerpartially supported by the US National Science Foundation(NSF)Award(Grant No.AST-1616554)partial support from Centre National de la Recherche Scientifique(CNRS)via IN2P3&INSU,Observatoire de ParisIrfu/CEA。
文摘The Tianlai Cylinder Pathfinder is a radio interferometer array designed to test techniques for 21 cm intensity mapping in the post-reionization Universe,with the ultimate aim of mapping the large scale structure and measuring cosmological parameters such as the dark energy equation of state.Each of its three parallel cylinder reflectors is oriented in the north-south direction,and the array has a large field of view.As the Earth rotates,the northern sky is observed by drift scanning.The array is located in Hongliuxia,a radio-quiet site in Xinjiang,and saw its first light in September 2016.In this first data analysis paper for the Tianlai cylinder array,we discuss the sub-system qualification tests,and present basic system performance obtained from preliminary analysis of the commissioning observations during 2016-2018.We show typical interferometric visibility data,from which we derive the actual beam profile in the east-west direction and the frequency band-pass response.We describe also the calibration process to determine the complex gains for the array elements,either using bright astronomical point sources,or an artificial on site calibrator source,and discuss the instrument response stability,crucial for transit interferometry.Based on this analysis,we find a system temperature of about 90 K,and we also estimate the sensitivity of the array.
基金supported by the National Key R&D Program of China(Grant No.2018YFA0404603)Chinese Academy of Sciences International Partner Program(Grant No.114231KYSB20170003)+2 种基金National Natural Science Foundation of China(Grant No.12041301)Youth Innovation Promotion AssociationChinese Academy of Sciences(Grant Nos.201664,and2021258)。
文摘The Square Kilometre Array(SKA)project consists of delivering two largest radio telescope arrays being built by the SKA Observatory(SKAO),which is an intergovernmental organization bringing together nations from around the world with China being one of the major member countries.The computing resources needed to process,distribute,curate and use the vast amount of data that will be generated by the SKA telescopes are too large for the SKAO to manage on its own.To address this challenge,the SKAO is working with the international community to create a shared,distributed data,computing and networking capability called the SKA Regional Centre Alliance.In this model,the SKAO will be supported by a global network of SKA Regional Centres(SRCs)distributed around the world in its member countries to build an end-to-end science data system that will provide astronomers with high-quality science products.SRCs undertake deep processing,scientific analysis,and long-term storage of the SKA data,as well as user support.China has been actively participating in and promoting the construction of SRCs.This paper introduces the international cooperation and ongoing prototyping of the global SRC network,the basis for the construction of the China SRC and describes in detail the progress of the China SRC prototype.The paper also presents examples of scientific applications of SKA precursor and pathfinder telescopes performed using resources from the China SRC prototype.Finally,the future prospects of the China SRC are presented.
基金supported by the National Key R&D Programof China no.2018YFE0202900L.Qian is supported by the Youth Innovation Promotion Association of CAS(ID 2018075)+4 种基金R.Yao is supported by the Youth Innovation Promotion Association of CAS(ID 2017080)J.H.Sun is supported by the Youth Innovation Promotion Association of CAS(ID2016059)J.L.Xu is supported by the Youth Innovation Promotion Association of CAS(ID 2019058)Z.C.Pan is supported by the CAS“Light ofWest China”ProgramP.Jiang is supported by the Youth Innovation Promotion Association of CAS(ID 2013039)。
文摘FAST is the largest single-dish radio telescope in the world.The characteristics of FAST are presented and analyzed in the context of the parameter space to show how FAST science achievements are affected.We summarize the scientific achievements of FAST and discuss its future science based on the new parts of the parameter space that can be explored by FAST.