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GRB 221009A is the brightest gamma-ray burst ever detected since the discovery of this kind of energetic explosions. However, an accurate measurement of the prompt emission properties of this burst is very challenging due to its exceptional brightness. With joint observations of \textit{Insight}-HXMT and GECAM-C, we made an unprecedentedly accurate measurement of the emission during the first $\sim$1800 s of GRB 221009A, including its precursor, main emission (ME, which dominates the burst in flux), flaring emission and early afterglow, in the hard X-ray to soft gamma-ray band from $\sim$ 10 keV to $\sim$ 6 MeV. Based on the GECAM-C unsaturated data of the ME, we measure a record-breaking isotropic equivalent energy ($E_{\rm iso}$) of $\bf \sim 1.5 \times 10^{55}$ erg, which is about eight times the total rest-mass energy of the Sun. The early afterglow data require a significant jet break between 650 s and 1100 s, most likely at $\sim950$ s from the afterglow starting time $T_{AG}$, which corresponds to a jet opening angle of $\sim {0.7^\circ} \ (\eta_\gamma n)^{1/8}$, where $n$ is the ambient medium density in units of $\rm cm^{-3}$ and $\eta_\gamma$ is the ratio between $\gamma$-ray energy and afterglow kinetic energy. The beaming-corrected total $\gamma$-ray energy $E_{\gamma}$ is $\sim 1.15 \times10^{51} \ (\eta_\gamma n)^{1/4}$ erg, which is typical for long GRBs. These results suggest that this GRB may have a special central engine, which could launch and collimate a very narrowly beamed jet with an ordinary energy budget, leading to exceptionally luminous gamma-ray radiation per unit solid angle. Alternatively, more GRBs might have such a narrow and bright beam, which are missed by an unfavorable viewing angle or have been detected without distance measurement., Comment: Submitted to National Science Review. This paper is under press embargo, contact the corresponding author for details

We have performed a spectral-timing analysis on the black hole X-ray binary MAXI J1535--571 during its 2017 outburst, with the aim of exploring the evolution of the inner accretion flow geometry. X-ray reverberation lags are observed in the hard-intermediate state (HIMS) and soft-intermediate state (SIMS) of the outburst. During the HIMS, the characteristic frequency of the reverberation lags $\nu_0$ (the frequency at which the soft lag turns to zero in the lag-frequency spectra) increases when the spectrum softens. This reflects a reduction of the spatial distance between the corona and accretion disc, when assuming the measured time lags are associated with the light travel time. We also find a strong correlation between $\nu_0$ and type-C Quasi Periodic Oscillation (QPO) centroid frequency $\nu_{QPO}$, which can be well explained by the Lense-Thirring (L-T) precession model under a truncated disk geometry. Despite the degeneracy in the spectral modellings, our results suggest that the accretion disc is largely truncated in the low hard state (LHS), and moves inward as the spectrum softens. Combine the spectral modelling results with the $\nu_0$ - $\nu_{QPO}$ evolution, we are inclined to believe that this source probably have a truncated disk geometry in the hard state.

Particle morphology can affect the performance of an electrostatic precipitator air–liquid interface (ESP-ALI) cell exposure system and the resulting cell toxicity. In this study, three types of monodisperse aerosols – spherical sucrose particles, nonspherical align soot aggregates, and nanosilver aggregates/agglomerates – were selected to evaluate the collection efficiency at flow rates ranging from 0.3 to 1.5 lpm. To quantify the particle morphology, the fractal dimensions (Df) of the tested aerosols were characterized. The penetration of fine particles (dp = 100–250 nm) under different operating conditions was correlated with a characteristic exponential curve using the dimensionless drift velocity (Vc/Vavg,r) as the scaling parameter. For nanoparticles (NPs, dp nm) with different particle morphologies, the particle penetrations in the ESP-ALI were similar, but their diffusion losses were not negligible. In contrast, for fine particles, the collection efficiency of soot nanoaggregates (Df = 2.29) was higher than that of spherical sucrose particles. This difference might be due to the simultaneous influences of the electric field-induced and flow field-induced alignment. Furthermore, based on Zhibin and Guoquan’s Deutsch model, a quadratic equation was applied to fit the experimental data and to predict the performance of the ESP-ALI.

Recent studies have reported gene therapy as an alternative treatment for canine’s cancer. Fifty-three samples from canine patients were obtained and the expression of MHC classes I and II and CD-markers in tumour cells, subpopulations of tumour-infiltrating lymphocytes (TILs), peripheral blood lymphocytes (PBLs) through flow cytometry and tumour cell cytokines were examined through real-time reverse transcription polymerase chain reaction. These data were compared by using Biomarker Patterns Software. Mammary gland tumours (MGTs) showed low MHC I expression that can be correlated with tumour malignancy, with cut-off values of 72.58% (MGT, [Formula: see text]% and non-MGT, [Formula: see text]%). IL-8, showing a positive correlation with angiogenesis, expression in MGTs was significantly high and IL-12 expression in complex and tubulopapillary carcinomas were significantly lower than that in healthy mammary gland cells ([Formula: see text]). PBLs of dogs with MGTs had fewer T cells, particularly T helper cells, and B cells and more non-T, non-B cells, particularly malignant MGTs, than did PBLs of healthy dogs. Among all surface markers and cytokines detected, high CD3 TIL was significantly correlated with a more favourable prognosis. Cytokines, such as IL-8, -12, and -15, can be the indicators of therapeutic targets because of their specific expression patterns in specific MGT subtypes.

Additional file 2: Table S1. Antimicrobial resistance profiles of the 144 E. coli, 66 Enterobacter spp., 110 K. pneumoniae and 43 Enterococcus spp. isolates from the feces of giant pandas in China. Table S2 The location, sex and age of the sampled giant pandas. Table S3 MIC breakpoints for Enterobacterales and Enterococcus spp. according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Table S4 Primers, expected product sizes and annealing temperatures in the amplification of antimicrobial resistance genes.

The milestone of GW 170817-GRB 170817A-AT 2017gfo has shown that gravitational wave (GW) is produced during the merger of neutron star-neutron star/black hole and that in electromagnetic (EM) wave a gamma-ray burst (GRB) and a kilonovae (KN) are generated in sequence after the merger. Observationally, however, EM property during a merger is still unclear. Here we report a peculiar precursor in a KN-associated long GRB 211211A. The duration of the precursor is $\sim$ 0.2 s, and the waiting time between the precursor and the main emission (ME) of the burst is $\sim$ 1 s, which is about the same as the time interval between GW 170817 and GRB 170817A. Quasi-Periodic Oscillations (QPO) with frequency $\sim$22 Hz (at $>5\sigma$ significance) are found throughout the precursor, the first detection of periodic signals from any {\it bona fide} GRBs. This indicates most likely that a magnetar participated in the merger, and the precursor might be produced due to a catastrophic flare accompanying with torsional or crustal oscillations of the magnetar. The strong seed magnetic field of $\sim 10^{14-15}$ G at the surface of the magnetar may also account for the prolonged duration of GRB 211211A. However, it is a challenge to reconcile the rather short lifetime of a magnetar \cite{kaspi2017magnetars} with the rather long spiraling time of a binary neutron star system only by gravitational wave radiation before merger., Comment: 37 pages, 14 figures

Vehicle emissions are an important source of particulate matter (PM) in urban areas and have well-known adverse health effects on human health. Oxidative potential (OP) is used as a quantification metric for indexing PM toxicity. In this study, by using a liquid spot sampler (LSS) and the dithiothreitol (DTT) assay, the diurnal OP variation was assessed at a ground-level urban monitoring station. Besides, since the monitoring station was adjacent to the main road, the correlation between OP and traffic volume was also evaluated. PM components, including metals, water-soluble inorganic aerosols (WSIAs), black carbon (BC), and polycyclic aromatic hydrocarbons (PAHs), were also simultaneously monitored. The daytime and evening mean ± std volume-normalized OP (OPv) were 0.46 ± 0.27 and 0.48 ± 0.26 nmol/min/m3, and exhibited good correlations with PM1.0 and BC; however, these concentrations were only weakly correlated with mass-normalized OP (OPm). The mean ± std OPm was higher in the daytime (41.3 ± 13.8 pmol/min/μg) than in the evening (36.1 ± 11.5 pmol/min/μg). According to the PMF analysis, traffic emissions dominated the diurnal OP contribution. Organic matter and individual metals associated with non-exhaust traffic emissions, such as Mn, Fe, and Cu, contributed substantially to OP. Diurnal variations of PAH concentrations suggest that photochemical reactions could enhance OP, highlighting the importance of atmospheric aging on PM toxicity.

Additional file 1: Figure S1. Details of collected samples of three different age groups of GPs. Figure S2a. The abundance of different antibiotic families in fecal samples of 60 GPs. Figure S3. The abundance (%) of top 30 ARGs in each sample of three different age groups of GPs. Figure S4. An average abundance of approximately 20 genera in fecal samples of 60 GPs. Figure S5. Abundance of the top three bacteria at the genus level in three different groups of GPs juvenile, adult, and geriatric. Figure S6. The network analysis of 84 genera with an average abundance of ≥ 0.01% based on the Pearson coefficient of correlation. Figure S7. Quantitative analysis of the proteome of the gut microbiota of captive GPs. Figure S8. The increasing and decreasing level of Escherichia and Streptococcus in three different groups (juvenile, adult, and geriatric) of GPs and the significant difference of abundance of these genera among these groups. Figure S9. (A) Biosynthesis of Antibiotic and (B) Resistant Pathway.

Additional file 4: Figure S2b. The abundance of 570 ARGs ranged from 0.0001 to 3.6%. Highlighted area indicating top most abundant ARGs.

The Hard X-ray Modulation Telescope (HXMT) named Insight is China's first X-ray astronomical satellite. The Low Energy X-ray Telescope (LE) is one of its main payloads onboard. The detectors of LE adopt swept charge device CCD236 with L-shaped transfer electrodes. Charges in detection area are read out continuously along specific paths, which leads to a time response distribution of photons readout time. We designed a long exposure readout mode to measure the time response distribution. In this mode, CCD236 firstly performs exposure without readout, then all charges generated in preceding exposure phase are read out completely. Through analysis of the photons readout time in this mode, we obtained the probability distribution of photons readout time.

In order to fully utilize the freshwater and improve urban water environment, the feasibility studies of tidal sluice construction have been carried out in recent years. The key problem is sediment siltation at the reach downstream the gate. Based on measured data of sedimentation under existing tidal sluices of estuaries, this paper analyzes characteristics and strength of siltation downstream tidal sluices in different regions of China, and evaluates sedimentation of tidal sluices according to reduction of river cross section, reduction of discharge capacity and watercourse length downstream tidal sluices; analyzes overall sediment deposition of watercourse downstream tidal sluices, sediment deposition and sediment thickness of some river reaches. The analysis shows that the longer the watercourse downstream tidal sluices, the greater the total volume of sediment deposition; annual average sediment deposition in each kilometer is 40~186,000 m3 according to overall sedimentation of watercourse downstream tidal sluices; back-silting intensity is the largest within the first year after tidal sluice built, annual sediment thickness is about 1.1m, decreases gradually and tends to be stable. Width of watercourse downstream tidal sluices involved in this paper are among 100~250m and influence of watercourse width on sediment deposition needs to be further analyzed.

High-power pulsed magnetron sputtering (HiPIMS) can produce high density and high adhesion coatings due to the high ionization. However, industrial application of HiPIMS is limited because of the unstable discharge and small deposition rate. A cylindrical cathode, developed on the basis of hollow cathode effect, can improve the discharge stability. With the development of electromagnetic systems, the plasma transport is improved, and thus increasing the deposition rate significantly. However, the introduction of electromagnetic system leads the strong discharge and large etching area on the target to be incompatibly controlled. In this work, the distribution of the tangential and longitudinal magnetic field on the target surface are improved by adding external magnets, and their effects on the plasma discharge are studied. By optimizing the magnets, the tangential magnetic field on the target surface becomes stronger and more uniform. Meanwhile, the peak of the longitudinal magnetic field increases from 73 to 96 mT and the peak location expands to two-sides of the cathode. The simulation result shows that the target etching area described by the proportion of the target area with the tangential magnetic field intensity higher than 40 mT increases from 51% to 67%, and the HiPIMS discharge studied by the particle in cell/Monte Carlo collision (PIC/MCC) method and plasma global model shows that the ion current and spectral intensity are significantly enhanced, exhibiting a doubled Cr density of 2.6 × 1020 m–3 and an increased ionization from 90% to 92.1%. The practical Ar/Cr HiPIMS discharge is carried out separately with the original and optimized cylindrical cathode, and the results reveal that the brightness of plasma glow, the target current and the etching area all increase after the improvement. Furthermore, the ion current and the optical emission spectrum suggest that the flux of ions arriving at the substrate is approximately doubled, which means that an about doubled deposition rate of the optimized cathode is achievable.

Phase-II Project of Deep Water Channel Construction of Yangtze River(2014-2015), including the Yi-Zheng Segment, enables the water depth of Yangtze River Channel between Nanjing and Nantong arrive 12.5 meters. This thesis analyzes the sedimentation movement of Yi-Zheng Segment with mathematical model, makes prediction of the sediment's strength and space-time distribution. The simulation results indicate that the yearly dredging quantity of 1998 and 2010, two typical hydrological years, are 1.528 million m3 and 0.499 million m3 separately. The main maintenance months are October, November and December during the dry season, while the main maintenance parts are the channel from Dadaohe to Majiakou, the channel from Majiakou to Qibaidu, the channel from Qibaidu to Longmenkou in the right branch of Shiyezhou. These results could be helped to provide support of later dredging operation for keeping deep water Channel of Yi-Zheng Segment.

High-power impulse magnetron sputtering (HiPIMS) is a new magnetron sputtering technique which can produce high-density plasmas with a high ionization rate and prepare coatings with a good performance such as large density and high adhesion. To obtain stable discharge and universal materials’ ionization rates, a cylindrical cathode is proposed based on the hollow cathode effect. However, the unusual plasma transport results in a large loss of ions and a low deposition rate. To solve these problems, an expanding electromagnetic field is proposed to control the plasma transport in this work. The particle in cell/Monte Carlo collision (PIC/MCC) method and the plasma diffusion model are used to simulate the plasma transport in and out of the cylindrical cathode with different currents in the electromagnetic coils, respectively. The simulation results reveal that different electromagnetic fields can achieve different plasma density distributions, resulting in different accumulated positions and different diffusion paths. When the coil current is positive, the resistance to axial motion of electrons is small but the resistance to radial motion is large, so that the hollow cathode effect is weakened and the plasma beam tends to output uniformly. When the coil current is negative, the resistance to axial motion of electrons is large but the resistance to radial motion is small, so that the hollow cathode effect is enhanced and the plasma tends to gather on the central axis and then diffuses outward. To verify the simulation results, Ar/Cr HiPIMS discharge experiments are carried out with the cylindrical cathode in a homemade vacuum system. The experiment results indicate that the threshold voltage, the plasma flow shape, the optical emission spectrum (OES) intensity, and the deposition distribution are determined by the electromagnetic coil current. The variation tendency is in coincidence with the prediction of the simulation. Consequently, by adding an expanding electromagnetic field, the plasma discharge in the cylindrical cathode can be easily controlled and the deposition rate is greatly enhanced. This electromagnetic control strategy not only realizes the enhancement and effective control of plasma, but also improves the homogeneity and the deposition rate of the coatings, thus laying a foundation for the industrial application of HiPIMS.

This paper focuses on the fusion method of visible image and infrared image, making in-depth discussion on the existing algorithms and proposes a novel method on the fusion rules. The image is firstly decomposed into low-frequency and high-frequency coefficients by NSCT and the characteristics of visible image and infrared image are then taken into account to finish the fusion. Finally, the quality of the fused image by different algorithms is compared with several existing criterions. MATLAB is employed to finish the simulation and the results will demonstrate this algorithm can improve the quality of the fused image effectively and the features in the image won’t be missing

This article discusses Castanea resources in the Dandong region of China. These resources include Dandong Chestnut, Japanese Chestnut (Castanea crenata Sieb. et Zucc.), Korean Chestnut and Chinese Chestnut (C. mollissima Bl.). Dandong is the most northerly region of chestnut cultivation in China. The climate is cold and the chestnut is easily frozen. Through years of investigation and experimentation, we have developed a series of solutions that not only do no harm to the environment and consumers, but also keep the taste and the nutrition of chestnut. These solutions are Regional Layout, Ecological Chestnut Orchards, Cultivation of Improved Varieties, Normalized Management and Ecological Pest Control.

By Floquet-Bloch theory, the electric and magnetic fields are the summation of an infinite number of space harmonics, where the harmonics include forward and backward propagated harmonics. In this paper, the distribution of space harmonics are analyzed at the Bragg condition in grating structure of dielectric waveguides.

With the development of 3D technology, converting 2D videos available into 3D videos has been an important way to gain 3D contents. In the conversion, a crucial step is how to obtain a more accurate depth map. This paper proposes a method for depth extraction based on color and geometric information of the original image. Firstly, we generate a qualitative depth map by SVM and classify image scenes into three categories. Then depending on geometric information, a geometric depth map can be generated by vanishing lines detection and gradient plane assignment. At last, we blend two depth maps to get a final depth map, which has more widely application and improves accuracy of depth better.

Spatial recognition is one of neural functions of rat's hippocampus. Head direction cells, grid cells and place cells play a major role in this function. Information about direction, distance, and location is integrated in the grid cells. Place cells receive information from grid cell firing and construct representation of the spatial environment of the brain. This representation is demonstrated to the foundation of the cognitive map. Spatial representations in the hippocampus emerge and develop as rat pups first begin to explore their environment outside of the nest and develop with age. This paper reviews and discusses the basis of neural functions including their biological properties, development process, modeling work and some applications based on this mechanism in agents.

Dark energy is a fundamental constituent of our universe, its status in the cosmological field equation should be equivalent to that of gravity. Here we construct a dark energy and matter gravity coupling (DEMC) model of cosmology in a way that dark energy and gravity are introduced into the cosmological field equation in parallel with each other from the beginning. The DEMC universe possesses a composite symmetry from global Galileo invariance and local Lorentz invariance. The observed evolution of the universe expansion rate at redshift z>1 is in tension with the standard LCDM model, but can be well predicted by the DEMC model from measurements of only nearby epochs. The so far most precise measured expansion rate at high z is quite a bit slower than the expectations from LCDM, but remarkably consistent with that from DEMC. It is hoped that the DEMC scenario can also help to solve other existing challenges to cosmology: large scale anomalies in CMB maps and large structures up to about 10^3 Mpc of a quasar group. The DEMC universe is a well defined mechanical system. From measurements we can quantitatively evaluate its total rest energy, present absolute radius and expanding speed., 9 pages, 4 figures

We present a model-independent determination of the curvature parameter $\Omega_k$ by using the Hubble parameter $H(z)$ and angular diameter distance $D_A(z)$ from the recent baryon acoustic oscillation (BAO) measurements. Each $H(z)$ and $D_A(z)$ pair from a BAO measurement can constrain a curvature parameter. The accuracy of the curvature measurement improves with increased redshift of $H(z)$ and $D_A(z)$ data. By using the $H(z)$ and $D_A(z)$ pair derived from BAO Lyman $\alpha$ forest measurement at $z=2.36$, the $\Omega_k$ is confined to be -0.05$\pm$0.06, which is consistent with the curvature $-0.037^{+0.044}_{-0.042}$ constrained by the nine-year WMAP data only. Considering future BAO meausurements, at least one order of magnitude improvement of this curvature measurement could be expected., Comment: 5 pages, 3 figures. Accepted for publication in ApJL

We show that large-voltage and high-temperature pinch plasma columns can generate hard x-ray and γ-ray flashes with energy spectra and spectral evolution characteristics consistent with those observed in γ-ray bursts.

The quasar PKS0528+134 was observed to flare by the energetic gamma-ray experiment (EGRET) gamma-ray telescope on the Compton gamma-ray observatory during the viewing period 213 (VP213). The Compton telescope data from VP213 have been reanalyzed by using the direct demodulation method, Images of the source are obtained at energies above 3 MeV and the time variability in the energy range 10-30 MeV is consistent with the result of EGRET. There is no spectral break at energies above 3 MeV during the flare.

The acceleration of the cosmic expansion revealed by supernova observations indicates that the present universe is dominated by repulsive dark energy. It is natural that the coupling between the dark energy and the attractive gravity has to be taken into account in studying the evolution of our universe. Here we induce a dynamic equation of universe evolution based on the cosmological principal, gravity-dark energy coupling, and energy conservation. The solutions of this dynamic equation provide a specific picture of cosmic evolution, which is well compatible with current observed evolution histories of both Hubble parameter H(z) and equation of state parameter w(z) of dark energy. In this picture, the already observed universe has undergone through three epochs - the epoch of equilibrium between gravity and dark energy at cosmological redshifts z>1, the phase transition epoch at z between about 0.5 and 1, and the present acceleration epoch starting from z~0.5. The expected matter-dominated deceleration epoch has not been seen yet, which requires future deep observations to look back upon more early universe., 12 pages, 4 figures

In cosmic microwave background (CMB) experiments, foreground-cleaned temperature maps are still contaminated by the residual dipole due to uncertainties of the Doppler dipole direction and microwave radiometer sidelobe. To obtain reliable CMB maps, such contamination has to be carefully removed from observed data. We have previously built a software package for map-making, residual dipole-contamination removal, and power spectrum estimation from the Wilkinson Microwave Anisotropy Probe (WMAP) raw data. This software has now been significantly improved. With the improved software, we obtain a negative result of CMB quadrupole detection with the WMAP raw data, which is -3.2+-3.5 uK^2 from the seven-year WMAP (WMAP7) data. This result is evidently incompatible with ~1000 uK^2 expected from the standard cosmological model LCDM. The completely missing of CMB quadrupole poses a serious challenge to the standard model and sets a strong constraint on possible models of cosmology. Due to the importance of this result for understanding the origin and early evolution of our universe, the software codes we used are opened for public checking., 15 pages, 5 figures. The final version to be published in Chin Sci Bull

Modulation imaging method on the basis of direct restoration technique, which we developed for analyzing space γ-ray data, can produce images with fine angular resolution over a wide field by means of a simple collimated telescope. This method can be used for conducting deep-sky, high-resolution, low-energy γ-ray surveys on board satellites and for making simultaneous space multi-wavelength observations.

The discovery of accelerated cosmic expansion implies that, in addition to the attractive gravity of matter, there exists in our universe some other form of energy (dark energy or cosmological constant) producing a repulsive force. The natural interpretation of dark energy is the vacuum energy. However, the density of vacuum energy expected by the quantum field theory is 120 orders of magnitude larger than what is allowed by cosmological observations, which is called the cosmological constant problem and remains one of the most significant unsolved problems in fundamental physics. Here we show that the huge discrepancy can be resolved by assuming that our universe is an attraction-repulsion coupled system with energy conservation, and that the pre-inflation vacuum is in equilibrium between attraction and repulsion (in flat Minkowski spacetime, not de Sitter or anti de Sitter). The attraction-repulsion coupling picture can also easily explain why both kinds of energy in our universe have similar magnitude today, and avoid singularity problems in general relativity and cosmology., 8 pages, 1 figure

To reliably detect the cosmic microwave background (CMB) anisotropy is of great importance in understanding the birth and evolution of the Universe. One of the difficulties in CMB experiments is the domination of measured CMB anisotropy maps by the Doppler dipole moment from the motion of the antenna relative to the CMB. For each measured temperature the expected dipole component has to be calculated separately and then subtracted from the data. A small error in dipole direction, antenna pointing direction, sidelobe pickup contamination, and/or timing synchronism, can raise significant deviation in the dipole cleaned CMB temperature. After a full-sky observational scan, the accumulated deviations will be structured with a pattern closely correlated to the observation pattern with artificial anisotropies on large scales, including artificial quadrupole, octopole etc in the final CMB map. Such scan-induced anisotropies on large scales can be predicted by the true dipole moment and observational scan scheme. Indeed, the expected scan-induced quadrupole pattern of the WMAP mission is perfectly in agreement with the published WMAP quadrupole. With the scan strategy of the Planck mission, we predict that scan-induced anisotropies will also produce an artificially aligned quadrupole. The scan-induced anisotropy is a common problem for all sweep missions and, like the foreground emissions, has to be removed from observed maps. Without doing so, CMB maps from COBE, WMAP, and Planck as well, are not reliable for studying the CMB anisotropy., Comment: Accepted for publication in ApJ

In this paper we propose to use the method of iterative calculation to solve directly the imaging equation for image recovery. The same method can be applied to the recovery of one-dimensional spectra. During the iteration suitable constraints are applied to effect nonlinear control over the process. The use of fitting technique in the treatment of the imaging equation suppresses noise and raises sensitivity. Analyses of both Monte Carlo samples and actual high-energy astronomical data showed that the direct method is more sensitive and having greater resolving power than the traditional method, is capable of revealing simultaneously both diffuse and discrete structures in the target object and can be used on data of lower statistical quality. In principle, the direct method can be used in all types of image and spectrum recovery in other fields.

The electron-positron annihilation process in accreting binary systems, typically Cygnus X-3, was investigated. Our Monte Carlo calculation shows that, under certain conditions such systems can emit a rather narrow annihilation line, whose flux and width depend on the intensity of the emitted γ photons, the state, size and temperature distribution of the X-ray halo, and the density and distribution of the electrons in the disk. We also discussed the possibility of observing the line by current experiments including the OSSE detector on board the GRO satellite.

The cosmic microwave background (CMB) temperature maps from the Wilkinson Microwave Anisotropy Probe (WMAP) are of great importance for cosmology. In previous work we had developed a pipeline for map-making independently of the WMAP team. The new maps produced from the WMAP raw data by our pipeline are notably different to the official ones, and the power spectrum as well as the best-fit cosmological parameters are significantly different too. What's more, by revealing the inconsistency between the WMAP raw data and their official map, we had pointed out that there must exist an unexpected problem in the WMAP team's pipeline. In this work, we find that the trouble comes from the inaccuracy of antenna pointing direction caused by a systematical time drift between the attitude data and the science data in the WMAP raw time-order data (TOD). The CMB quadrupole in the WMAP release can be exactly generated from a differential dipole field which is completely determined by the spacecraft velocity and the antenna directions without using any CMB signal. After correcting the WMAP team's error, the CMB quadrupole component disappears. Therefore, the released WMAP CMB quadrupole is almost completely artificial and the real quadrupole of the CMB anisotropy should be near zero. Our finding is important for understanding the early universe., v1: 6 pages, 2 figures. v2: 9 pages, 3 figures, a time drift between the attitude data and the science data in the WMAP TOD is revealed as the reason for producing the inconsistency in WMAP release, figure 3 is added to show the effect of different offsets.

The Doppler dipole signal dominates the cosmic microwave background (CMB) anisotropy maps obtained by the Wilkinson Microwave Anisotropy Probe (WMAP) mission, and plays a key role throughout the data processing. Previously, we discovered a timing asynchronism of -25.6ms between the timestamps of the spacecraft attitude and radiometer output in the original raw WMAP time-ordered data (TOD), which, if not corrected in following data processing, would generate an artificial quadrupole component (l=2) in recovered CMB maps (Liu, Xiong & Li 2010). Recently, Roukema (2010b) proves that there does exist a timing-offset-induced error corresponding to about -25.6ms in the WMAP calibrated TOD by studying the fluctuation variance per pixel in the temperature map recovered from the TOD as a function of assumed timing-offset. Here, we find evidence directly in the WMAP TOD for such an uncorrected timing error, possibly occurred in calculating the Doppler dipole signal during the WMAP team's TOD data processing. The amplitude is highly significant and is consistent with previous work. We also show that the uncorrected timing-offset can lead the WMAP CMB quadrupole to be substantially overestimated., Accepted for publication in MNRAS Lett

The cosmic microwave background (CMB) temperature maps published by the Wilkinson Microwave Anisotropy Probe (WMAP) team are found to be inconsistent with the differential time-ordered data (TOD), from which the maps are reconstructed. The inconsistency indicates that there is a serious problem in the map making routine of the WMAP team, and it is necessary to reprocess the WMAP data. We develop a self-consistent software package of map-making and power spectrum estimation independently of the WMAP team. Our software passes a variety of tests. New CMB maps are then reconstructed, which are significantly different from the official WMAP maps. In the new maps, the inconsistency disappeared, along with the hitherto unexplained high level alignment between the CMB quadrupole and octopole components detected in released WMAP maps. An improved CMB cross-power spectrum is then derived from the new maps which better agrees with that of BOOMRANG. Two important results are hence obtained: the CMB quadrupole drops to nearly zero, and the power in multiple moment range between 200 and 675 decreases on average by about 13%, causing the best-fit cosmological parameters to change considerably, e.g., the total matter density increases from 0.26 up to 0.32 and the dark energy density decreases from 0.74 down to 0.68. These new parameters match with improved accuracy those of other independent experiments. Our results indicate that there is still room for significant revision in the cosmological model parameters., Submitted to MNRAS. In the revised version (v3) we make foreground reduction with the same technique WMAP team used and add the results of reconstructing the sky maps with the WMAP default flagging and our software

We have investigated the outbursts of IGR J17473-2721. We analyzed all available observations carried out by RXTE on IGR J17473-2721 during its later outburst and as well all the available SWIFT/BAT data. The flux of the latter outburst rose in ~ one month and then kept roughly constant for the following ~ two months. During this time period, the source was in a low/hard state. The source moved to a high/soft state within the following three days, accompanied by the occurrence of an additional outburst at soft X-rays and the end of the preceding outburst in hard X-rays. During the decay of this soft outburst, the source went back to a low/hard state within 6 days, with a luminosity 4 times lower than the first transition. This shows a full cycle of the hysteresis in transition between the hard and the soft states. The fact that the flux remained roughly constant for ~ two months at times prior to the spectral transition to a high/soft state might be regarded as the result of balancing the evaporation of the inner disk and the inward accretion flow, in a model in which the state transition is determined by the mass flow rate. Such a balance might be broken via an additional mass flow accreting onto the inner disk, which lightens the extra soft outburst and causes the state transition. However, the possibility of an origin of the emission from the jet during this time period cannot be excluded. The spectral analysis suggests an inclined XRB system for IGR J17473-2721. Such a long-lived preceding low/hard state makes IGR J17473-2721 resemble the behavior of outbursts seen in black hole X-ray binaries like GX 339-4., A&A in press

A gamma-ray map of the Galaxy in 40–50 MeV reveals, besides the three sources known at higher energies, four additional sources with intensities comparable to that of the Crab.

Sky temperature map of the cosmic microwave background (CMB) is one of the premier probes of cosmology. To minimize instrumentally induced systematic errors, CMB anisotropy experiments measure temperature differences across the sky using paires of horn antennas with a fixed separation angle, temperature maps are recovered from temperature differences obtained in sky survey through a map-making procedure. The instrument noise, inhomogeneities of the sky coverage and sky temperature inevitably produce statistical and systematical errors in recovered temperature maps. We show in this paper that observation-dependent noise and systematic temperature distortion contained in released Wilkinson Microwave Anisotropy Probe (WMAP) CMB maps are remarkable. These errors can contribute to large-scale anomalies detected in WMAP maps and distort the angular power spectrum as well. It is needed to remake temperature maps from original WMAP differential data with modified map-making procedure to avoid observation-dependent noise and systematic distortion in recovered maps., 23 pages, 15 figures, submitted to ApJ

In a previous paper [1] we obtained statistically significant evidence for a 39-ms period in the COS-B data of 30–5000 MeV gamma rays in the direction of PSR 1951 + 32. Most of the gamma photons from PSR 1951 + 32 are pulsed and concentrated in a narrow interval of phase. We have examined the partical distribution of gamma ray intensity in the region around the pulsar and estimated the integrated flux to be 4.1 × 10 −7 ph cm −2 s −1 above 100 MeV and 8.2 × 10 −8 ph cm −2 s −1 above 300 MeV.

We present here the result of the hard X spectrum of Cyg X-1 in the 20–200 keV range obtained with a balloon-borne CsI-NaI phoswich telescope launched at Xianhe Balloon Facilities on 1985 Sept 22. The X luminosity in 10–200 keV is estimated to be (1.07 ± 0.08) × 1037 erg/s, which indicates that Cyg X-1 may not be in the normal low state at that time.

We have re-analyzed Einstein Observatory data on CTB 80 using phase folding method. Significant pulsation was found in both the HRI and IPC data with similar phase diagrams at periods near those predicted by the radio observations. An acceleration in PSR 1951+32 during the period October 1979–April 1980 is indicated.

We calculated the absorption of gamma rays of Cygnus X — 3 by the ambient X — ray photons through photon-photon pair production and inverse Compton scattering. Differences in the gamma ray spectrum between the X — ray high state and low state indicate the presence of this absorption.

We report on an RXTE/PCA observation of Aql X-1 during its outburst in March 1997 in which, immediately following a Type-I burst, the broad-band 2-10 keV flux decreased by about 10% and the kilohertz QPO frequency decreased from 813+-3 Hz to 776+-4 Hz. This change in kHz QPO frequency is much larger than expected from a simple extrapolation of a frequency-flux correlation established using data before the burst. Meanwhile a very low frequency noise (VLFN) component in the broad-band FFT power spectra with a fractional root-mean-square (rms) amplitude of 1.2% before the burst ceased to exist after the burst. All these changes were accompanied by a change in the energy spectral shape. If we characterize the energy spectra with a model composed of two blackbody (BB) components and a power law component, almost all the decrease in flux was in the two BB components. We attribute the two BB components to the contributions from a region very near the neutron star or even the neutron star itself and from the accretion disk, respectively., Comment: 12 pages with 4 figures, accepted for publication in ApJ Letters, typos corrected and references updated

Systematic variations of average observational characteristics and correlation properties between different parameters of gamma-ray bursts (GRBs) with time from 1991 April to 1994 September are revealed. It is hard to explain the observed long-term variability by variations of experimental conditions. The variability of GRB properties with the time scale of months to years, together with the similarity between GRBs, solar hard X-ray flares and terrestrial gamma-ray flashes, may indicate an origin of GRBs, at least partly, within the heliosphere. Large-voltage and high-temperature pinch plasma columns produced by disruptive electrical discharges in the outer heliosphere can generate hard X-ray and gamma-ray flashes with energy spectra and spectral evolution characters consistent with that observed in GRBs., Comment: LaTex, epsfig. 20 pages, 17 figures, replace to correct the definition of Epk and revise Figs 12-15

High resolution reconstruction of complicated objects from incomplete and noisy data can be achieved by solving observational modulation equations or correlated modulation equations iteratively under physical constraints. Simulations and experiments show that wide field and high resolution images of space hard X-rays and soft γ-rays can be obtained by scan observation of a collimated non-position-sensitive detector.

In virture of the eigenvalue equations of operators, the entangled states' completeness relation is proved from that of the coherent states, and the integral values of non-symmetric projective operators of entangled states are obtained.

The coordinate state vector 〈f(x)| is expressed with 〈x| in virtue of particle number states and the eigen equations of coordinate operator functions，accordingly we can convert non-symmetric projective operators into symmetric，the integrations over non-symmetric projective operators are obtained by the completeness relation of coordinate eigenstates.

The hard X-ray phoswich telescope, HAPI-1, is described. It was designed for making observations on board high-flying balloons. The telescope comprises a 145 cm 2 primary crystal of 5 cm thick Cs I(T1), effectively shielded over the lower 2π steradians by a 5 cm thick NaI(T1) crystal and has a field of view of approximately 4° HWHM determined by a graded shield and a collimator. The scintillation pulses originating in CsI and NaI crystals are distinguished by pulse shape discrimination. All sub-systems of the telescope are described. The Crab pulsar was obsserved by HAPI-1 in a balloon flight on 1984 May 23 in the energy range 20 to 200 keV and the observed result is presented.

Results on cosmic gamma rays have been taken with data, available for the first time, on the distribution of molecular hydrogen over a significant region of the Galactic plane, to study the distribution of cosmic rays in the Galaxy. It is found that there is strong evidence for a lower cosmic-ray intensity in the outer Galaxy, suggestive of a Galactic origin for the particles.

New date on the distribution of molecular hydrogen in the first and second quadrants allow a detailed analysis of the relationship between the column density of gas (in all major forms) and the intensity of cosmic gamma-rays in the Galaxy. It is concluded that most of the features observed in the gamma-ray map can be explained in terms of cosmic-ray interactions with the gas in the ISM, with molecular hydrogen playing an important role. The cosmic-ray intensity in the important production regions appears to be roughly independent of galactocentric distance, R, for l:65-100 deg and to fall off slowly with R for l:100-180 deg.