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Correcting for the solar wind in pulsar timing observations: the role of simultaneous and low-frequency observations

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Research in Astronomy and Astrophysics 2017年第10期17卷 33-40页

作者： Ze-Xi Niu george hobbs Jing-Bo Wang Shi Dai Department of Astronomy Beijing Normal University Australia Telescope National Facility CSIRO Xinjiang Astronomical Observatory Chinese Academy of Sciences Key Laboratory of Radio Astronomy Chinese Academy of Sciences

The primary goal of pulsar timing array projects is to detect ultra-low-frequency gravitational waves. Pulsar data sets are affected by numerous noise processes including varying dispersive delays in the interstellar medium and from the solar wind. The solar wind can lead to rapidly changing variations that, with existing telescopes, can be hard to measure and then remove. In this paper we study the possibility of using a low frequency telescope to aid in such correction for the Parkes Pulsar Timing Array （PPTA） and also discuss whether the ultra-wide-bandwidth receiver for the FAST telescope is sufficient to model solar wind variations. Our key result is that a single wide-bandwidth receiver can be used to model and remove the effect of the solar wind. However, for pulsars that pass close to the Sun such as PSR J1022＋ 1022, the solar wind is so variable that observations at two telescopes separated by a day are insufficient to correct the solar wind effect.

关键词： stars: pulsars -- gravitational waves

Ultra-wide Bandwidth Observations of 19 Pulsars with Parkes Telescope

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Research in Astronomy and Astrophysics 2022年第8期22卷 6-22页

作者： Zu-Rong Zhou Jing-Bo Wang Na Wang george hobbs Shuang-Qiang Wang Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqiXinjiang 830011China University of Chinese Academy of Sciences 19A Yuquan RoadBeijing 100049China Xinjiang Key Laboratory of Radio Astrophysics 150 Science1-StreetUrumqiXinjiang 830011China Key Lab of Radio Astronomy Chinese Academy of SciencesBeijing 100101China CSIRO Astronomy and Space Science PO Box 76EppingNSW 1710Australia CAS Key Laboratory of FAST NAOCChinese Academy of SciencesBeijing 100101China

Flux densities are basic observation parameters to describe *** the most updated pulsar catalog,24%of the listed radio pulsars have no flux density measurement at any ***,we report the first flux density measurements,spectral indices,pulse profiles,and correlations of the spectral index with pulsar parameters for 19 pulsars employing the Ultra-Wideband Low receiver system installed on the Parkes radio *** results for spectral indices of 17 pulsars are in the range between-0.6 *** polarization profiles of thirteen pulsars are *** is a moderate correlation between the spectral index and spin *** most pulsars detected,the signal-to-noise ratio of pulse profile is not high,so DM,Faraday rotation measure,and polarization cannot be determined ***-nine pulsars were not detected in our *** discuss the possible explanations for why these pulsars were not detected.

关键词： (stars:)pulsars:general stars:neutron methods:data analysis

The role of FAST in pulsar timing arrays

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Research in Astronomy and Astrophysics 2019年第2期19卷 39-54页

作者： george hobbs Shi Dai Richard N.Manchester Ryan M.Shannon Matthew Kerr Ke-Jia Lee Ren-Xin Xu CSIRO Astronomy and Space Science Department of Astronomy School of Physics Peking University Kavli Institute for Astronomy and Astrophysics Peking University Max-Planck-Institut für Radioastronomie

The Five-hundred-meter Aperture Spherical radio Telescope(FAST) will become one of the world-leading telescopes for pulsar timing array(PTA) research. The primary goals for PTAs are to detect(and subsequently study) ultra-low-frequency gravitational waves, to develop a pulsar-based time standard and to improve solar system planetary ephemerides. FAST will have the sensitivity to observe known pulsars with significantly improved signal-to-noise ratios and will discover a large number of currently unknown pulsars. We describe how FAST will contribute to PTA research and show that jitter-and timing-noise will be the limiting noise processes for FAST data sets. Jitter noise will limit the timing precision achievable over data spans of a few years while timing noise will limit the precision achievable over many years.

关键词： stars:pulsars gravitational waves

Wide-bandwidth drift-scan pulsar surveys of globular clusters:application to early science observations with FAST

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Research in Astronomy and Astrophysics 2016年第10期16卷 11-20页

作者： Lei Zhang george hobbs Di Li Duncan Lorimer Jie Zhang Meng Yu You-Ling Yue Pei Wang Zhi-Chen Pan Shi Dai School of Physics and Space Science China West Normal University National Astronomical Observatories Chinese Academy of Sciences Australia Telescope National Facility CSIRO Key Laboratory of Radio Astronomy Chinese Academy of Sciences Department of Physics and Astronomy White HallWest Virginia University National Radio Astronomy Observatory Green Bank Observatory

The Five-hundred-meter Aperture Spherical Telescope （FAST） will begin its early-science oper- ations during 2016. Drift-scan pulsar surveys will be carried out during this period using an ultra-wide-band receiver system （covering - 270 to 1620 MHz）. We describe a method for accounting for the changes in the telescope beam shape and the pulsar parameters when searching for pulsars over such a wide bandwidth. We applied this method to simulated data sets of pulsars in globular clusters that are visible to FAST and found that a representative observation would have a sensitivity of -40 ply. Our results showed that a sin- gle drift-scan （lasting less than a minute） is likely to find at least one pulsar for observations of four globular clusters. Repeated observations will increase the likely number of detections. We found that pulsars in - 16 clusters are likely to be found if the data from 100 drift-scan observations of each cluster are incoherently combined.

关键词： pulsars -- drift-scan pulsar surveys -- globular clusters

Flux density measurements for 32 pulsars in the 20 cm observing band

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Research in Astronomy and Astrophysics 2019年第7期19卷 143-150页

作者： Yan-Wei Xie Jing-Bo Wang george hobbs Jane Kaczmarek Di Li Jie Zhang Shi Dai Andrew Cameron Lei Zhang Chen-Chen Miao Mao Yuan Shen Wang Song-Bo Zhang Heng Xui Ren-Xin Xu School of Physics and Space Science China West Normal UniversityNanchong 637002China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Key Laboratory of Radio Astronomy Chinese Academy of SciencesUrumqi 830011China CSIRO Astronomy and Space Science PO Box 76EppingNSW 1710Australia CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China College of Physics and Electronic Engineering Qilu Normal UniversityJinan 250014China Astronomy Department Cornell UniversityIthacaNY 14853USA Purple Mountain Observatory Chinese Academy of SciencesNanjing 21000& China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China Department of Astronomy School of PhysicsPeking UniversityBeijing 100871China

Flux densities are fundamental observational parameters that describe a *** the current pulsar catalogue,27% of the listed radio pulsars have no flux density measurement in the 20 cm observing ***,we present the first such measurements for 32 pulsars observed employing the Parkes radio *** have used both archival and new observations to make these *** schemes exist for measuring flux densities and we show how the measured flux densities vary between these methods and how the presence of radio-frequency interference will bias the flux density measurements.

关键词： methods data analysis-pulsars general

The first pulsar discovered by FAST

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Science China(Physics,Mechanics & Astronomy) 2019年第5期62卷 71-74页

作者： Lei Qian ZhiChen Pan Di Li george hobbs WeiWei Zhu Pei Wang ZhiJie Liu YouLing Yue Yan Zhu HongFei Liu DongJun Yu JingHai Sun Peng Jiang GaoFeng Pan Hui Li HengQian Gan Rui Yao XiaoYao Xie Fernando Camilo Andrew Cameron Lei Zhang Shen Wang FAST Collaboration CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China Commonwealth Scientific and Industrial Research Organization Australia Telescope National FacilitySydney 2122Australia Key Laboratory of Information and Computing Science Guizhou Normal UniversityGuiyang 550001China South African Radio Astronomy Observatory Observatory 7925South Africa 不详

To assist with the commissioning [1] of the Five-hundredmeter Aperture Spherical radio Telescope (FAST), we performed a pulsar search, with the primary goal of developing and testing the pulsar data acquisition and processing pipelines. We tested and used three pipelines, two (Pl and P2 hereafter) searched for the periodic signature of pulsars whereas the other one was used to search for bright single pulses (P3 hereafter).

关键词： pulsar Telescope

Gravitational wave astronomy: the current status

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Science China(Physics,Mechanics & Astronomy) 2015年第12期58卷 3-43页

作者： BLAIR David JU Li ZHAO ChunNong WEN LinQing CHU Qi FANG Qi CAI RongGen GAO JiangRui LIN XueChun LIU Dong WU Ling-An ZHU ZongHong REITZE David H. ARAI Koji ZHANG Fan FLAMINIO Raffaele ZHU XingJiang hobbs george MANCHESTER Richard N. SHANNON Ryan M. BACCIGALUPI Carlo GAO Wei XU Peng BIAN Xing CAO ZhouJian CHANG ZiJing DONG Peng GONG XueFei HUANG ShuangLin JU Peng LUO ZiRen QIANG Li'E TANG WenLin WAN XiaoYun WANG Yue XU ShengNian ZANG YunLong ZHANG HaiPeng LAU Yun-Kau NI Wei-Tou School of Physics The University of Western Australia State Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences The School of Physics & Electronic Engineering Shanxi University Laboratory of All-Solid-State Light Sources Institute of Semiconductors Chinese Academy of Science State Key Laboratroy of Modern Optical Instrumentation Department of Optical Engineering Zhejiang University Laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Gravitational Wave and Cosmology Laboratory Department of Astronomy Beijing Normal University LIGO Laboratory California Institute of Technology Department of Physics University of Florida Department of Physics West Virginia University National Astronomical Observatory of Japan CSIRO Astronomy and Space Science International Centre for Radio Astronomy Research Curtin University SISSA Astrophysics Sector Institute of Applied Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences University of Chinese Academy of Sciences Morningside Center of Mathematics Chinese Academy of Sciences State Key Laboratory of Scientific and Engineering Computing Academy of Mathematics and Systems ScienceChinese Academy of Sciences Department of Mathematics Henan University Department of Mathematics Capital Normal University Department of Geophysics College of the Geology Engineering and Geomatics Chang'an University QUEST Centre of Quantum Engineering and Space-Time Research Leibniz Universitt Hannover Max-Planck-Institut für Gravitationsphysik(Albert Einstein Institut) Aerospace Flight Dynamics Laboratory Beijing Aerospace Control Center Qian Xuesen Laboratory of Launch Vehicle Technology Center for Gravitation and Cosmology Department of Physics Tsing Hua University

In the centenary year of Einstein's General Theory of Relativity, this paper reviews the current status of gravitational wave astronomy across a spectrum which stretches from attohertz to kilohertz frequencies. Sect. 1 of this paper reviews the historical development of gravitational wave astronomy from Einstein's first prediction to our current understanding the spectrum. It is shown that detection of signals in the audio frequency spectrum can be expected very soon, and that a north-south pair of next generation detectors would provide large scientific benefits. Sect. 2 reviews the theory of gravitational waves and the principles of detection using laser interferometry. The state of the art Advanced LIGO detectors are then described. These detectors have a high chance of detecting the first events in the near future. Sect. 3 reviews the KAGRA detector currently under development in Japan,which will be the first laser interferometer detector to use cryogenic test masses. Sect. 4 of this paper reviews gravitational wave detection in the nanohertz frequency band using the technique of pulsar timing. Sect. 5 reviews the status of gravitational wave detection in the attohertz frequency band, detectable in the polarisation of the cosmic microwave background, and discusses the prospects for detection of primordial waves from the big bang. The techniques described in sects. 1–5 have already placed significant limits on the strength of gravitational wave sources. Sects. 6 and 7 review ambitious plans for future space based gravitational wave detectors in the millihertz frequency band. Sect. 6 presents a roadmap for development of space based gravitational wave detectors by China while sect. 7 discusses a key enabling technology for space interferometry known as time delay interferometry.

关键词： gravitational waves ground based detectors pulsar timing spaced based detectors CMB

帕博利珠单抗单用或与放疗联用治疗转移性非小细胞肺癌:两个随机试验的汇总分析

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中华肿瘤防治杂志 2021年第24期28卷 1841-1850页

作者：陈大卫(翻译) 于金明(校对) Willemijn S M E Theelen Vivek Verma Brian P hobbs Heike M U Peulen Joachim G J V Aerts Idris Bahce Anna Larissa N Niemeijer Joe Y Chang Patricia M de Groot Quynh-Nhu Nguyen Nathan I Comeaux george R Simon Ferdinandos Skoulidis Steven H Lin Kewen He Roshal Patel John Heymach Paul Baas James W Welsh 山东省肿瘤防治研究院(山东省肿瘤医院) 山东第一医科大学(山东省医学科学院)山东济南250117 不详 Department of Radiation Oncology The University of Texas M D Anderson Cancer CenterHoustonTX 77030USA

背景放疗可以提高整个机体对免疫治疗的应答。在Ⅱ期PEMBRO-RT研究和Ⅰ/Ⅱ期MDACC研究中,患有转移性非小细胞肺癌(NSCLC)的患者被随机分配入组,接受免疫治疗(帕博利珠单抗)+放疗联合疗法,或免疫治疗单一疗法。当上述2个研究单独分析时,... 详细信息

背景放疗可以提高整个机体对免疫治疗的应答。在Ⅱ期PEMBRO-RT研究和Ⅰ/Ⅱ期MDACC研究中,患有转移性非小细胞肺癌(NSCLC)的患者被随机分配入组,接受免疫治疗(帕博利珠单抗)+放疗联合疗法,或免疫治疗单一疗法。当上述2个研究单独分析时,联合疗法组显示出潜在获益。由于每个研究的样本量较小,缓解率和结局并未显示出统计学意义,然而却有显著的临床获益。因此,本研究进行汇总分析,来判断放疗是否会改善转移性NSCLC患者的免疫治疗应答。方法PEMBRO-RT和MDACC研究纳入标准:患者年龄≥18岁,患有转移性NSCLC,且有≥1处未经放疗照射的病灶,以便进行射野外应答监测。PEMBRO-RT研究纳入曾接受过化疗患者,MDACC研究纳入曾接受过治疗或新诊断患者。2个研究中的患者均未接受过免疫治疗。在PEMBRO-RT研究中患者被等比例随机分配入组,并根据吸烟状态进行分层(分为<10年组和≥10年组)。MDACC研究的患者根据放疗计划可行性被等比例随机分配入2个受试组。由于联合治疗组的干预本质,每个研究中的放疗均不适用盲法。在2个研究中,不论是否进行放疗,均静脉滴入帕博利珠单抗(每3周200 mg)。在PEMBRO-RT研究中,在放疗(24 Gy 3次分割照射)结束后1周给予第1剂帕博利珠单抗。在MDACC研究中,在第1次放疗(50 Gy 4次分割照射或45 Gy 15次分割照射)同时给予帕博利珠单抗。仅检测未经照射病灶的应答。本研究的终点为最佳射野外(远隔)应答率(ARR)、最佳射野外疾病控制率(ACR)、12周时ARR、12周时ACR、无进展生存期(PFS)和总生存期(OS)。2个研究的意向治疗(ITT)人群均纳入分析。PEMBRO-RT研究(NCT02492568)和MDACC研究(NCT02444741)均在***上注册。发现纳入148例患者,76例接受帕博利珠单抗治疗,72例接受帕博利珠单抗+放疗治疗。所有患者随访时间中位数为33个月[四分位距(IQR):32.4~33.6]。148例患者中124例(84%)组织学特征为非鳞癌,111例(75%)患者曾经接受过化疗。组间没有基线特征差异,包括PD-L1表达状态和转移灶体积。最常见的照射部位为肺转移灶(39%,28/72)、胸腔内淋巴结(21%,15/72)和非原发灶(17%,12/72)。帕博利珠单抗组和联合治疗组的最佳ARR分别为19.7%(15/76)和41.7%(30/72),OR=2.96,95%CI:1.42~6.20,P=0.0039;最佳ACR分别为43.4%(33/76)和65.3%(47/72),OR=2.51,95%CI:1.28~4.91,P=0.0071;PFS中位数分别为4.4(IQR:2.9~5.9)和9.0个月(IQR:6.8~11.2),HR=0.67,95%CI:0.45~0.99,P=0.045;OS中位数分别为8.7(IQR:6.4~11.0)和19.2个月(IQR:14.6~23.8),OR=0.67,95%CI:0.54~0.84,P=0.0004。在汇总分析中没有发现新的安全问题。解读帕博利珠单抗免疫疗法+放疗显著提高转移性NSCLC患者的应答和改善治疗结局。这些结果需要在三期临床试验中进行验证。

关键词：帕博利珠单抗非小细胞肺癌放疗汇总分析

Performance and calibration of quark/gluon-jet taggers using 140 fb^(-1) of pp collisions at √s=13 TeV with the ATLAS detector

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Chinese Physics C 2024年第2期48卷 1-25页

作者： G. Aad B. Abbott K. Abeling N.J. Abicht S.H. Abidi A. Aboulhorma H. Abramowicz H. Abreu Y. Abulaiti B.S. Acharya C. Adam Bourdarios L. Adamczyk S.V. Addepalli M.J. Addison J. Adelman A. Adiguzel T. Adye A.A. Affolder Y. Afik M.N. Agaras J. Agarwala A. Aggarwal C. Agheorghiesei A. Ahmad F. Ahmadov W.S. Ahmed S. Ahuja X. Ai G. Aielli A. Aikot M. Ait Tamlihat B. Aitbenchikh I. Aizenberg M. Akbiyik T.P.A. Åkesson A.V. Akimov D. Akiyama N.N. Akolkar K. Al Khoury G.L. Alberghi J. Albert P. Albicocco G.L. Albouy S. Alderweireldt M. Aleksa I.N. Aleksandrov C. Alexa T. Alexopoulos F. Alfonsi M. Algren M. Alhroob B. Ali H.M.J. Ali S. Ali S.W. Alibocus M. Aliev G. Alimonti W. Alkakhi C. Allaire B.M.M. Allbrooke J.F. Allen C.A. Allendes Flores P.P. Allport A. Aloisio F. Alonso C. Alpigiani M. Alvarez Estevez A. Alvarez Fernandez M. Alves Cardoso M.G. Alviggi M. Aly Y. Amaral Coutinho A. Ambler C. Amelung M. Amerl C.G. Ames D. Amidei S.P. Amor Dos Santos K.R. Amos V. Ananiev C. Anastopoulos T. Andeen J.K. Anders S.Y. Andrean A. Andreazza S. Angelidakis A. Angerami A.V. Anisenkov A. Annovi C. Antel M.T. Anthony E. Antipov M. Antonelli F. Anulli M. Aoki T. Aoki J.A. Aparisi Pozo M.A. Aparo L. Aperio Bella C. Appelt A. Apyan N. Aranzabal S.J. Arbiol Val C. Arcangeletti A.T.H. Arce E. Arena J-F. Arguin S. Argyropoulos J.-H. Arling O. Arnaez H. Arnold G. Artoni H. Asada K. Asai S. Asai N.A. Asbah J. Assahsah K. Assamagan R. Astalos S. Atashi R.J. Atkin M. Atkinson H. Atmani P.A. Atmasiddha K. Augsten S. Auricchio A.D. Auriol V.A. Austrup G. Avolio K. Axiotis G. Azuelos D. Babal H. Bachacou K. Bachas A. Bachiu F. Backman A. Badea P. Bagnaia M. Bahmani A.J. Bailey V.R. Bailey J.T. Baines L. Baines O.K. Baker E. Bakos D. Bakshi Gupta V. Balakrishnan R. Balasubramanian E.M. Baldin P. Balek E. Ballabene F. Balli L.M. Baltes W.K. Balunas J. Balz E. Banas M. Bandieramonte A. Bandyopadhyay S. Bansal L. Barak M. Barakat E.L. Barberio D. Barberis M. Barbero M.Z. Barel K.N. Barends T. Barillari M-S. Barisits T. Barklow P. Baron D.A. Baron Mo The ATLAS Collaboration

The identification of jets originating from quarks and gluons,often referred to as quark/gluon tagging,plays an important role in various analyses performed at the Large Hadron Collider,as Standard Model measurements and searches for new particles decaying to quarks often rely on suppressing a large gluon-induced *** paper describes the measurement of the efficiencies of quark/gluon taggers developed within the ATLAS Collaboration,using √s=13 TeV proton–proton collision data with an integrated luminosity of 140 fb^(-1) collected by the ATLAS *** taggers with high performances in rejecting jets from gluon over jets from quarks are studied:one tagger is based on requirements on the number of inner-detector tracks associated with the jet,and the other combines several jet substructure observables using a boosted decision tree.A method is established to determine the quark/gluon fraction in data,by using quark/gluon-enriched subsamples defined by the jet *** in tagging efficiency between data and simulation are provided for jets with transverse momentum between 500 GeV and 2 TeV and for multiple tagger working points.

关键词： ATLAS JET QUARK GLUON TAGGING