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Possible γ-ray emission of radio intermediate AGN Ⅲ Zw 2.and its implication on the evolution of jets in AGNs

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Research in Astronomy and Astrophysics 2010年第8期10卷 707-712页

作者： liang chen Jin-Ming {2. Jin Zhang Hong-Tao Liu national astronomical {2./yunnan observatory Chinese Academy of Sciences Kunming 650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China Graduate University of chinese Academy of Sciences Beijing 100049 China College of Physics and Electronic Engineering Guangxi Teachers Education University Nanning 530001 China

AGNs with hard γ-ray emission identified so far are radio-loud. Ⅲ Zw 2.is a radio intermediate AGN with a relativistic jet. We study its spectral energy distribution （SED） and find that the broad band emissions are dominated by the nonthermal emissions from the jet. We model its SED through a synchrotron ＋ inverse Compton （IC） model. The results show that the IC component of Ⅲ Zw 2.peaks at a few MeV, and the flux density drops rapidly at higher energy with photon index F 3.3 above 0.1 GeV. The predicted flux is slightly over the sensitivity of Fermi/LAT, but it was not included in the first Fermi/LAT AGN catalog. The reason for this may be： 1） that the IC peak is low and the spectrum is very steep above 0.1 GeV, 2. that Ⅲ Zw 2.is in the low state during the period of the Fermi/LAT operation. We also find that Ⅲ Zw 2.follows similar jet processes as those in γ-ray AGNs, e.g., the relation between jet power and radiation power, which is called the blazar sequence. We suggest that Ⅲ Zw 2.may be a young source at an earlier stage of jet activity.

关键词： galaxies active -- galaxies Seyfert- galaxies jets -- radiation mechanisms non-thermal

The connection between radio and γ-ray emission in Fermi/LAT blazars

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Research in Astronomy and Astrophysics 2012年第11期12卷 1475-1485页

作者： Xu-liang Fan Jin-Ming bai Hong-Tao Liu liang chen Neng-Hui Liao national astronomical {2. / yunnan observatory Chinese Academy of SciencesKunming 650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy ofSciences Kunming 650011 China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoriesChinese Academy of Sciences Shanghai 200030 China Graduate University of chinese Acaciemy of Sciences Beijing 100049 China

We collect the second Large Area Telescope AGN catalog （2.AC） and Monitor of Jets in AGN with VLBA Equipment （MOJAVE） quasi-simultaneous data to investigate the radio-γ connection of blazars. The cross sample contains 166 sources. The statistical analysis based on this sample confirms positive correlations between these two bands, but the correlations become weaker as the γ-ray energy increases. The statistical results between various parameters show negative correla- tions of γ-ray photon spectral index with γ-ray loudness for both Flat Spectrum Radio Quasars （FSRQs） and BL Lacertae objects, positive correlations of γ-ray variability index with the γ-ray loudness for FSRQs, a negative correlation of the γ-ray variabil- ity index with the γ-ray photon spectral index for FSRQs, and negative correlations of γ-ray photon spectral index with γ-ray luminosity for FSRQs. These results suggest that the γ-ray variability may be due to changes inside the γ-ray emission region like the injected power, rather than changes in the photon density of the external radiation fields, and the variability amplitude tends to be larger as the γ-rays are closer to the high energy peak of the spectral energy distribution （SED）. No correlation of variabil- ity index found for BL Lacertae objects implies that variability behavior may differ below and above the peak energy.

关键词： BL Lacertae objects general -- galaxies: jets -- quasars general -- radio continuum galaxies -- gamma rays observations

Is BZB J1450+52.1 the most distant gamma-ray BL Lacertae object?

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Research in Astronomy and Astrophysics 2015年第3期15卷 313-326页

作者： Neng-Hui Liao Jin-Ming bai Jian-Guo Wang Hong-Tao Liu Jiu-Jia Zhang Ning Jiang Zun-Li Yuan liang {2. yunnan observatories Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences University of chinese Academy of Sciences Key Laboratory for Research in Galaxies and Cosmology University of Science and Technology of China Chinese Academy of Sciences Department of Astronomy University of Science and Technology of China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy of Sciences

BL Lacertae （BL Lac） objects at high redshifts （z ≥ 2. are rarely detected. Through careful analysis of its Sloan Digital Sky Survey spectrum, BZB J1450＋52.1 is confirmed to be a high-z BL Lac object with z ≥ 2.471 by identifying the Lyα 12.6 and CIV 1548/1550 absorption lines. This indicates that BZB J1450＋52.1 is the most distant BL Lac object discovered to date. Careful analysis of the five-year Fermi-LAT data of 2.GL J1451.0＋5159 shows that its γ-ray emission is robust with a confidence level of 6.2. at 1-3 GeV and 6.7σ at 3-10 GeV. This analysis with the five-year data overcomes confusion with its bright neighbor, which is a problem when analyzing the two-year data. In addition, 2.GL J 1451.0＋5159 is confirmed to be associated with BZB J1450＋52.1 using the five-year data. The analysis of multiwavelength data, from radio to γ-ray energies, indicates that BZB J1450＋52.1 is an intermediate synchrotron peaked （ISP） source. Its multiwavelength properties are consistent with distributions of other ISP sources at lower redshifts in the second Fermi-LAT AGN catalog. The pure synchrotron self-Compton （SSC） model seems to be disfavored, but the scattering of weak external emission plus the SSC process can provide a satisfactory description of the broadband emission.

关键词： galaxies active -- BL Lacertae objects individual (BZB J1450+52.1)-- gamma rays galaxies -- radiation mechanisms non-thermal

astronomical Site Monitoring System at Lijiang observatory

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Research in Astronomy and Astrophysics 2020年第9期20卷 291-308页

作者： Yu-Xin Xin Jin-Ming bai Bao-Li Lun Yu-Feng Fan Chuan-Jun Wang Xiao-Wei Liu Xiao Guang Yu Kai Ye Teng-Fei Song liang Chang Shou-Sheng He Jji-Rong Mao liang Xu Ding-Rong Xiong Xi-liang Zhang Jian-Guo Wang Xu Ding Hai-cheng Feng Xiang-Kun Liu Yang Huang Bing-Qiu chen yunnan observatories Chinese Academy of SciencesKunming 650216China University of chinese Academy of Sciences Beijing 100049China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China Center for astronomical Mega-Sciences Chinese Academy of SciencesBeijing 100101China South-Western Institute for Astronomy Research Yunnan UiversityKunming 650500China

We installed two sets of astronomical Site Monitoring Systems(ASMSs)at Lijiang observatory(GMG),for the running of the 2.4-meter Lijiang optical telescope(LJT)and the 1.6-meter Multi-channel Photometric Survey Telescope(Mephisto).The Mephisto is under *** ASMS has been running on robotic mode since *** core instruments:Cloud Sensor,All-Sky Camera and AutonomousDIMM that are developed by our group,together with the commercial Meteorological Station and Sky Quality Meter,are combined into the astronomical optical site monitoring *** new Cloud Sensor's Cloud-Clear Relationship is presented for the first time,which is used to calculate the All-Sky cloud *** designed the Autonomous-DIMM located on a tower,with the same height as *** seeing data have been observed for a full ***'s data for the year 2.19 are also analysed in detail,which are valuable to observers.

关键词： astronomical Site Monitoring System Lijiang observatory Cloud Sensor Autonomous-DIMM

Data reduction and calibration of the FMG onboard ASO-S

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Research in Astronomy and Astrophysics 2019年第11期19卷 63-78页

作者： Jiang-Tao Su Xian-Yong bai Jie chen Jing-Jing Guo Suo Liu Xiao-Fan Wang Hai-Qing Xu Xiao Yang Yong-{2. Song Yuan-Yong Deng Kai-Fan Ji Lei Deng Yu Huang Hui Li Wei-Qun Gan Key Laboratory of Solar Activity National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China yunnan observatories Chinese Academy of SciencesKunming 650216China Innovation Academy for Microsatellites of chinese Academy of Sciences Shanghai 201203China Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210008China

The Full-disk vector Magneto Graph(FMG)instrument will carry out polarization observations at one wavelength position of the Fe I 532..179?spectral *** paper describes how to choose this single wavelength position,the relevant data-processing and the magnetic field calibrations based on the measured polarization signals at one single wavelength *** is found that solar radial Doppler velocity,which can cause the spectral line to shift,is a disadvantageous factor for the linear calibration at one wavelength *** at two symmetric wavelength positions may significantly reduce the wavelength shift effect(~75%),but simulations show that such polarization signals located at the solar limbs(e.g.,beyond the longitude range of±30°)are not free from the effect *** future work,we plan to apply machine learning techniques to calibrate vector magnetic fields,or employ full Stokes parameter profile inversion techniques to obtain accurate vector magnetic fields,in order to complement the linear calibration at the single wavelength position.

关键词： Sun photosphere-Sun magnetic fields-Sun calibration

Site testing campaign for the Large Optical/infrared Telescope of china:overview

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Research in Astronomy and Astrophysics 2020年第6期20卷 81-95页

作者： Lu Feng Jin-Xin Hao Zi-Huang Cao Jin-Min bai Ji Yang Xu Zhou Yong-Qiang Yao Jin-liang Hou Yong-Heng Zhao Yu Liu Teng-Fei Song Li-Yong Liu Jia Yin Hua-Lin {2. Chong Pei Ali Esamdin Lu Ma Chun-Hai bai Peng Wei Jing Xu Guang-Xin Pu Guo-Jie Feng Xuan Zhang liang Ming Abudusaimaitijiang Yisikandee Jian-Rong Shi Jian Li Yuan Tian Zheng Wang Xia Wang Xiao-Jun Jiang Jian-Feng Wang Jian-Feng Tian Yan-Jie Xue Jian-Sheng {2. Jing-Yao Hu Zhi-Xia Shen Yun-Ying Jiang national astronomical {2. Chinese Academy of SciencesBeijing 100101China yunnan observatories Chinese Academy of SciencesKunming 650216China Xinjiang astronomical observatory Chinese Academy of SciencesUrumqi 830011China Shanghai astronomical observatory Chinese Academy of SciencesShanghai 200030China Nanjing Institute of astronomical Optics&Technology Chinese Academy of SciencesNanjing 210042China Purple Mountain observatory Chinese Academy of SciencesNanjing 210033China University of chinese Academy of Sciences Beijing 100049China

The Large Optical/infrared Telescope(LOT)is a ground-based 12.m diameter optical/infrared telescope which is proposed to be built in the western part of china in the next *** on satellite remote sensing data,along with geographical,logistical and political considerations,three candidate sites were chosen for ground-based astronomical performance *** sites include:Ali in Tibet,Dao{2.g in Sichuan and Muztagh-ata in *** until now,all three sites have continuously collected data for two *** this paper,we will introduce this site testing campaign,and present its monitoring results obtained during the period between March 2.17 and March 2.19.

关键词： techniques telescope-site testing

Lijiang 2.4-meter Telescope and its instruments

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Research in Astronomy and Astrophysics 2019年第10期19卷 95-108页

作者： Chuan-Jun Wang Jin-Ming bai Yu-Feng Fan Ji-Rong Mao liang Chang Yu-Xin Xin Ju-Jia Zhang Bao-Li Lun Jian-Guo Wang Xi-liang Zhang Mei Ying Kai-Xing Lu Xiao-Li Wang Kai-Fan Ji Ding-Rong Xiong Xiao-Guang Yu Xu Ding Kai Ye Li-Feng Xing Wei-Min Yi liang Xu Xiang-Ming Zheng Yuan-Jie Feng Shou-Sheng He Xue-Li Wang Zhong Liu Dong chen Jun Xu Song-Nian Qin Rui-Long Zhang Hui-Song Tan Zhi Li Ke Lou Jian Li Wei-Wei Liu yunnan observatories Chinese Academy of SciencesKunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650216 China Center for astronomical Mega-Science Chinese Academy of Sciences Beijing 100101 China University of chinese Academy of Sciences Beijing 100049 China Astrophysics Center of Guangzhou University Guangzhou 510006China

The Lijiang 2.4-meter Telescope(LJT), the largest common-purpose optical telescope in china,has been available to the worldwide astronomical community since 2.08. It is located at the Gaomeigu site,Lijiang {2.(LJO), in the southwest of china. The site has very good observational *** its 10-year operation, several instruments have been equipped on the LJT. Astronomers can perform both photometric and spectral observations. The main scientific goals of LJT include recording photometric and spectral evolution of supernovae, reverberation mapping of active galactic nuclei, investigating the physical properties of binary stars and near-earth objects(comets and asteroids), and identification of exoplanets and all kinds of transients. Until now, the masses of 41 high accretion rate black holes have been measured, and more than 168 supernovae have been identified by the LJT. More than 190 papers related to the LJT have been published. In this paper, the general observation conditions of the Gaomeigu site is introduced at first. Then, the structure of the LJT is described in detail, including the optical, mechanical, motion and control system. The specification of all the instruments and some detailed parameters of the YFOSC is also presented. Finally, some important scientific results and future expectations are summarized.

关键词： telescopes Lijiang 2.4-m Telescope-instrumentation photometers-instrumentation spectrographs

Site-testing at Muztagh-ata site Ⅰ:ground meteorology and sky brightness

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Research in Astronomy and Astrophysics 2020年第6期20卷 162-174页

作者： Jing Xu Ali Esamdin Jin-Xin Hao Jin-Min bai Ji Yang Xu Zhou Yong-Qiang Yao Jin-liang Hou Guang-Xin Pu Guo-Jie Feng Chun-Hai bai Peng Wei Shu-Guo Ma Abudusaimaitijiang Yisikandee Le-Tian Wang Xuan Zhang liang Ming Lu Ma Jin-Zhong Liu Zi-Huang Cao Yong-Heng Zhao Lu Feng Jian-Rong Shi Hua-Lin chen Chong Pei Xiao-Jun Jiang Jian-Feng Wang Jian-Feng Tian Yan-Jie Xue Jing-Yao Hu Yun-Ying Jiang Xinjiang astronomical observatory Chinese Academy of SciencesUrumqi 830011China University of chinese Academy of Sciences Beijing 100049China national astronomical {2. Chinese Academy of SciencesBeijing 100101China yunnan observatories Chinese Academy of SciencesKunming 650000China Purple Mountain observatory Chinese Academy of SciencesNanjing 210008 China Shanghai astronomical observatory Chinese Academy of SciencesShanghai 200030China Nanjing Institute of astronomical Optics&Technology Chinese Academy of SciencesNanjing 210008China

Site-testing is crucial for achieving the goal of scientific research and analysis of meteorological and optical observing conditions,one of the associated basic *** one of three potential sites to host the 12.meter Large Optical/infrared Telescope(LOT),the Muztagh-ata site,which is located on the Pamir Plateau in Xinjiang,in west china,began its site-testing task in the spring of *** this paper,we firstly start with an introduction to the site and then present a statistical analysis of the ground-level meteorological properties such as air temperature,barometric pressure,relative humidity,and wind speed and direction,recorded by an automatic weather station with standard meteorological sensors for a two-year *** also show the monitoring results of sky brightness during this period.

关键词： site testing meteorological condition optical observing

Evidence for particle acceleration approaching PeV energies in the W51 complex

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Science Bulletin 2024年第18期69卷 2833-2841页

作者： LHAASO Collaboration Zhen Cao F.Aharonian Axikegu Y.X.bai Y.W.Bao D.Bastieri X.J.Bi Y.J.Bi W.Bian A.V.Bukevich Q.Cao W.Y.Cao Zhe Cao J.Chang J.F.Chang A.M.chen E.S.chen H.X.chen liang chen Lin chen Long chen M.J.chen M.L.chen Q.H.chen S.chen S.H.chen S.Z.chen T.L.chen Y.chen N.cheng Y.D.cheng M.Y.Cui S.W.Cui X.H.Cui Y.D.Cui B.Z.Dai H.L.Dai Z.G.Dai Danzengluobu X.Q.Dong K.K.Duan J.H.Fan Y.Z.Fan J.Fang J.H.Fang K.Fang C.F.Feng H.Feng L.Feng S.H.Feng X.T.Feng Y.Feng Y.L.Feng S.Gabici B.Gao C.D.Gao Q.Gao W.Gao W.K.Gao M.M.Ge L.S.Geng G.Giacinti G.H.Gong Q.B.Gou M.H.Gu F.L.Guo X.L.Guo Y.Q.Guo Y.Y.Guo Y.A.Han M.Hasan H.H.He H.N.He J.Y.He Y.He Y.K.Hor B.W.Hou C.Hou X.Hou H.B.Hu Q.Hu S.C.Hu D.H.Huang T.Q.Huang W.J.Huang X.T.Huang X.Y.Huang Y.Huang X.L.Ji H.Y.Jia K.Jia K.Jiang X.W.Jiang Z.J.Jiang M.Jin M.M.Kang I.Karpikov D.Kuleshov K.Kurinov B.B.Li C.M.Li cheng Li Cong Li D.Li F.Li H.B.Li H.C.Li Jian Li Jie Li K.Li S.D.Li W.L.Li W.L.Li X.R.Li Xin Li Y.Z.Li Zhe Li Zhuo Li E.W.liang Y.F.liang S.J.Lin B.Liu C.Liu D.Liu D.B.Liu H.Liu H.D.Liu J.Liu J.L.Liu M.Y.Liu R.Y.Liu S.M.Liu W.Liu Y.Liu Y.N.Liu Q.Luo Y.Luo H.K.Lv B.Q.Ma L.L.Ma X.H.Ma J.R.Mao Z.Min W.Mitthumsiri H.J.Mu Y.C.Nan A.Neronov L.J.Ou P.Pattarakijwanich Z.Y.Pei J.C.Qi M.Y.Qi B.Q.Qiao J.J.Qin A.Raza D.Ruffolo A.Sáiz M.Saeed D.Semikoz L.Shao O.Shchegolev X.D.Sheng F.W.Shu H.C.Song Yu.V.Stenkin V.Stepanov Y.Su D.X.Sun Q.N.Sun X.N.Sun Z.B.Sun J.Takata P.H.T.Tam Q.W.Tang R.Tang Z.B.Tang W.W.Tian C.Wang C.B.Wang G.W.Wang H.G.Wang H.H.Wang J.C.Wang Kai Wang Kai Wang L.P.Wang L.Y.Wang P.H.Wang R.Wang W.Wang X.G.Wang X.Y.Wang Y.Wang Y.D.Wang Y.J.Wang Z.H.Wang Z.X.Wang Zhen Wang Zheng Wang D.M.Wei J.J.Wei Y.J.Wei T.Wen C.Y.Wu H.R.Wu Q.W.Wu S.Wu X.F.Wu Y.S.Wu S.Q.Xi J.Xia G.M.Xiang D.X.Xiao G.Xiao Y.L.Xin Y.Xing D.R.Xiong Z.Xiong D.L.Xu R.F.Xu R.X.Xu W.L.Xu L.Xue D.H.Yan J.Z.Yan T.Yan C.W.Yang C.Y.Yang F.Yang F.F.Yang L.L.Yang M.J.Yang R.Z.Yang W.X.Yang Y.H.Yao Z.G.Yao L.Q.Yin N.Yin X.H.You Z.Y.You Y.H.Yu Q.Yuan H.Yue H.D.Zeng T.X.Zeng W.Zeng M.Zha B.B.Zhang F.Zhang H.Zhang 不详 Key Laboratory of Particle Astrophysics&Experimental Physics Division&Computing Center Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of chinese Academy of Sciences Beijing 100049China TIANFU Cosmic Ray Research Center ChengduChina Dublin Institute for Advanced Studies 31 Fitzwilliam Place2 DublinIreland Max-Planck-Institut for Nuclear Physics P.O.Box 103980Heidelberg 69029Germany School of Physical Science and Technology&School of Information Science and Technology Southwest Jiaotong UniversityChengdu 610031China School of Astronomy and Space Science Nanjing UniversityNanjing 210023China Center for Astrophysics Guangzhou UniversityGuangzhou 510006China Tsung-Dao Lee Institute&School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Institute for Nuclear Research of Russian Academy of Sciences Moscow 117312Russia Hebei Normal University Shijiazhuang 050024China University of Science and Technology of china Hefei 230026China State Key Laboratory of Particle Detection and Electronics China Key Laboratory of Dark Matter and Space Astronomy&Key Laboratory of Radio Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China Research Center for astronomical Computing Zhejiang LaboratoryHangzhou 311121China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy of SciencesShanghai 200030China School of Physics and Astronomy Yunnan UniversityKunming 650091China Key Laboratory of Cosmic Rays(Tibet University) Ministry of EducationLhasa 850000China national astronomical {2. Chinese Academy of SciencesBeijing 100101China School of Physics and Astronomy(Zhuhai)&School of Physics(Guangzhou)&Sino-French Institute of Nuclear Engineering and Technology(Zhuhai) Sun Yat-sen UniversityZhuhai 519000&Guangzhou 510275GuangdongChina Institute of Frontier and Interdisciplinary Science Shandong UniversityQingdao 266237China APC UniversitéParis Cité

Theγ-ray emission from the W51 complex is widely acknowledged to be attributed to the interaction between the cosmic rays(CRs)accelerated by the shock of supernova remnant(SNR)W51C and the dense molecular clouds in the adjacent star-forming region,***,the maximum acceleration capability of W51C for CRs remains *** on observations conducted with the Large High Altitude Air Shower observatory(LHAASO),we report a significant detection ofγrays emanating from the W51 complex,with energies from 2.to 2.0 *** LHAASO measurements,for the first time,extend theγ-ray emission from the W51 complex beyond 100 TeV and reveal a significant spectrum bending at tens of *** combining the"π^(0)-decay bump"featured data from Fermi-LAT,the broadbandγ-ray spectrum of the W51 region can be well-characterized by a simple pp-collision *** observed spectral bending feature suggests an exponential cutoff at~400 TeV or a power-law break at~2.0 TeV in the CR proton spectrum,most likely providing the first evidence of SNRs serving as CR accelerators approaching the PeV ***,two young star clusters within W51B could also be theoretically viable to produce the most energeticγrays observed by *** findings strongly support the presence of extreme CR accelerators within the W51 complex and provide new insights into the origin of Galactic CRs.

关键词： UHE c-ray Cosmic rays SNR W51C Star clusters