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Despite several decades of multi-wavelength and multi-messenger spectral observations, Gamma-Ray Bursts (GRBs) remain one of the big mysteries of modern astrophysics. Polarization measurements are essential to gain a more clear and complete picture of the emission processes at work in these extremely powerful transient events. In this regard, a first generation of dedicated gamma-ray polarimeters, POLAR and GAP, were launched into space in the last decade. After 6 months of operation, the POLAR mission detected 55 GRBs, among which 14 have been analyzed in detail, reporting a low polarization degree and a hint of a temporal evolution of the polarization angle. Starting early 2024 and based on the legacy of the POLAR results, the POLAR-2 instrument will aim to provide a catalog of high quality measurements of the energy and temporal evolution of the GRB polarization thanks to its large and efficient polarimeter. Several spectrometer modules will additionally allow to perform joint spectral and polarization analyzes. The mission is foreseen to make high precision polarization measurements of about 50 GRBs every year on board of the China Space Station (CSS). The technical design of the polarimeter modules will be discussed in detail, as well as the expected scientific performances based on the first results of the developed prototype modules., Proceeding from the 37th International Cosmic Ray Conference (ICRC2021), 9 pages, 5 figures

Despite over 50 years of Gamma-Ray Burst (GRB) observations many open questions remain about their nature and the environments in which the emission takes place. Polarization measurements of the GRB prompt emission have long been theorized to be able to answer most of these questions. The POLAR detector was a dedicated GRB polarimeter developed by a Swiss, Chinese and Polish collaboration. The instrument was launched, together with the second Chinese Space Lab, the Tiangong-2, in September 2016 after which it took 6 months of scientific data. During this period POLAR detected 55 GRBs as well as several pulsars. From the analysis of the GRB polarization catalog we see that the prompt emission is lowly polarized or fully unpolarized. There is, however, the caveat that within single pulses there are strong hints of an evolving polarization angle which washes out the polarization degree in the time integrated analysis. Building on the success of the POLAR mission, the POLAR-2 instrument is currently under development. POLAR-2 is a Swiss, Chinese, Polish and German collaboration and was recently approved for launch in 2024. Thanks to its large sensitivity POLAR-2 will produce polarization measurements of at least 50 GRBs per year with a precision equal or higher than the best results published by POLAR. POLAR-2 thereby aims to make the prompt polarization a standard observable and produce catalogs of the gamma-ray polarization of GRBs. Here we will present an overview of the POLAR mission and all its scientific measurement results. Additionally, we will present an overview of the future POLAR-2 mission, and how it will answer some of the questions raised by the POLAR results., Presented at the 37th International Cosmic Ray Conference (ICRC 2021)

Despite over 50 years of research, many open questions remain about the origin and nature of GRBs. Polarization measurements of the prompt emission of these extreme phenomena have long been thought to be the key to answering a range of these questions. The POLAR detector was designed to produce the first set of detailed and reliable polarization measurements in an energy range of approximately 50-500 keV. During late 2016 and early 2017, POLAR detected a total of 55 GRBs. Analysis results of 5 of these GRBs have been reported in the past. The results were found to be consistent with a low or unpolarized flux. However, previous reports by other collaborations found high levels of polarization. We study the polarization for all the 14 GRBs observed by POLAR for which statistically robust inferences are possible. Additionally, time-resolved polarization studies are performed on GRBs with sufficient apparent flux. A publicly available polarization analysis tool, developed within the 3ML framework, was used to produce statistically robust results. The method allows to combine spectral and polarimetric data from POLAR with spectral data from the Fermi GBM and Swift-BAT to jointly model the spectral and polarimetric parameters. The time integrated analysis finds all results to be compatible with a low or zero polarization with the caveat that, when time-resolved analysis is possible within individual pulses, we observe moderate polarization with a rapidly changing polarization angle. Thus, time-integrated polarization results, while pointing to lower polarization are potentially an artifact of summing over the changing polarization signal and thus, washing out the true moderate polarization. Therefore, we caution against over interpretation of any time-integrated results and encourage one to wait for more detailed polarization measurements from forthcoming missions such as POLAR-2 and LEAP., Comment: 43 pages, 78 figures, Accepted for publication in A&A

14 pages, 8 figures. The paper has been accepted by Research in Astronomy and Astrophysics (RAA), Rapid response and short time latency are very important for Time Domain Astronomy, such as the observations of Gamma-ray Bursts (GRBs) and electromagnetic (EM) counterparts of gravitational waves (GWs). Based on near real-time Fermi/GBM data, we developed a low-latency pipeline to automatically calculate the temporal and spectral properties of GRBs. With this pipeline, some important parameters can be obtained, such as T and fluence, within ∼ 20 min after the GRB trigger. For ∼ 90% of GRBs, T and fluence are consistent with the GBM catalog results within 2σ errors. This pipeline has been used by the Gamma-ray Bursts Polarimeter (POLAR) and the Insight Hard X-ray Modulation Telescope (Insight-HXMT) to follow up the bursts of interest. For GRB 170817A, the first EM counterpart of GW events detected by Fermi/GBM and INTEGRAL/SPI-ACS, the pipeline gave T and spectral information 21 min after the GBM trigger, providing important information for POLAR and Insight-HXMT observations. © 2018 National Astronomical Observatories, CAS and IOP Publishing Ltd.., We thank the anonymous reviewer for helpful comments and suggestions. This work is supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB23040400), the National Natural Science Foundation of China (Grant Nos. 11403026, 11503028 and 11673023) and the National Basic Research Program of China (973 program, Grant No. 2014CB845800). BBZ acknowledges support from the National Thousand Young Talents programof China. We gratefully acknowledge support from the collaboration team of POLAR, a project funded by China National Space Administration (CNSA), the Chinese Academy of Sciences (CAS) and the University of Geneva (UNIGE). The authors would also like to thank Jing Jin, Jinlu Qu, Xiaobo Li, Youli Tuo, Zijian Li, Mingyu Ge, Jinyuan Liao, Guangcheng Xiao, Yue Huang and Chengkui Li for their suggestions on data analysis and the revision of this paper.

POLAR is a compact space-borne detector designed to perform reliable measurements of the polarization for transient sources like Gamma-Ray Bursts in the energy range 50-500keV. The instrument works based on the Compton Scattering principle with the plastic scintillators as the main detection material along with the multi-anode photomultiplier tube. POLAR has been launched successfully onboard the Chinese space laboratory TG-2 on 15th September, 2016. In order to reliably reconstruct the polarization information a highly detailed understanding of the instrument is required for both data analysis and Monte Carlo studies. For this purpose a full study of the in-orbit performance was performed in order to obtain the instrument calibration parameters such as noise, pedestal, gain nonlinearity of the electronics, threshold, crosstalk and gain, as well as the effect of temperature on the above parameters. Furthermore the relationship between gain and high voltage of the multi-anode photomultiplier tube has been studied and the errors on all measurement values are presented. Finally the typical systematic error on polarization measurements of Gamma-Ray Bursts due to the measurement error of the calibration parameters are estimated using Monte Carlo simulations., Comment: 43 pages, 30 figures, 1 table; Preprint accepted by NIMA

POLAR is a dedicated Compton scattering polarimeter to detect Gamma-Ray Bursts (GRBs) in the energy range of about 50 to 500 keV, which was launched on-board the Chinese space laboratory Tiangong-2 (TG2) on Sep 15, 2016. Since then, POLAR has detected 55 GRBs jointly with other telescopes as of Apr 1, 2017. Meanwhile, more GRBs detected by POLAR only will be revealed as the burst search and identification program gets more sophisticated to deal with the complicated background. After subtracting the non-observation period due to varies reasons in the commissioning phase, the effective observation time is about 3180 hours, thus the GRB detection rate of POLAR is estimated to be about 150 GRBs/year, demonstrating that POLAR is one of the most sensitive GRB detectors in operation. Thanks to the high sensitivity, large FOV (about 1/2 of the all-sky) and unique capability of polarization measurement, POLAR is a very important detector in the search for high-energy electromagnetic counterpart for Gravitational Wave Bursts (GWB), High Energy Neutrinos (HEN) and Fast Radio Bursts (FRB). In this paper, we summarized the GRB observation by POLAR, including GRB search and identification, joint observation and Gamma-ray Coordinates Network (GCN) alerts, data analysis, GRB catalogues and so on.

In this study, UPLC-MS/MS was adopted to determine the contents of five ephedrine alkaloids (Norephedrine, Norpseudoephedrine, Ephedrine, Pseudoephedrine, Methylephedrine) in plasma and urine in rats after the combined administration of Ephedrae Herba-Gypsum Fibrosum and calculate relevant pharmacokinetic parameters, in order to discuss the effect of the combined administration of Ephedrae Herba-Gypsum Fibrosum on plasma pharmacokinetics and urinary excretion characteristics. According to the results, after being combined with Gypsum, the five ephedrine alkaloids showed similar pharmacokinetic changes, such as shortened t(max), accelerated absorption rate, but reduced AUC(0-t) and V(z)/F, which may be related to the increase in urine excretion. Besides, Gypsum was added to enhance C(max) of Pseudoephedrine and prolong MRT(0-t) of Methylephedrine, so as to enhance the anti-asthmatic effect of Ephedrae Herba and resist the toxic effect of Norephedrine and Ephedrine. This study proved the scientific compatibility of Ephedrae Herba-Gypsum Fibrosum and provided a reference for studies on the prescription compatibility regularity and relevant practices.

Five kinds of Ephedra alkaloids (NME, NMP, E, PE and ME) in Ephedrae Herba extracts and Ephedrae Herba-Atractylodis Macrocephalae Rhizoma herbal pair extracts of plasma pharmacokinetic and tissue distribution study in rats were carried out, to discuss the changes of Ephedrae Herba compatibility with Atractylodis Macrocephalae Rhizoma before and afterHPLC- MS method was used and the condition was as flollows: ZORBAX SB-C18 column (100 mm x 2.1 mm, 3.5 µm), column temperature of 35 °C, mobile phase of ACE-0.1% formic solution in gradient elution mode, flow rate at 0.4 mL/min; MRM positive ion detection mode.The distribution trends of Ephedra alkaloids were changing in plasma and tissues of rats after Ephedrae Herba compati- bility with Atractylodis Macrocephalae Rhizoma.Ephedrae Herba compatibility with Atractylodis Macrocephalae Rhizoma may increase drug efficacy and reduce the toxicity of Ephedra alkaloids at the same time.