The observations with Swift X-ray telescope （XRT） challenge the conventional gamma-ray burst model in many aspects. The XRT light curves are generally composed of four consecutive segments, i.e., a steep decay segme...The observations with Swift X-ray telescope （XRT） challenge the conventional gamma-ray burst model in many aspects. The XRT light curves are generally composed of four consecutive segments, i.e., a steep decay segment, a shallow decay segment, a normal decay segment, a jet-like steep decay segment, and sometimes erratic flares as well. The physical origin of the X-ray emission is highly debatable. We focus here on the physical origin of the X-ray emissions of GRBs 050318 and 060124. We present the XRT light curves and spectra of the two bursts. The light curve decay slopes of the two bursts are normal, and their relations to the spectral indices are consistent with the prediction of the standard forward shock model. The multi-wavelength light curves at 0.5 keV, 1.0 keV, 2.0 keV and 4.0 keV can be reproduced by this model with an isotropic kinetic energy Ek = 2.2 × 10^52 erg, εe = 0.04, εB = 0.01 for GRB 050318 and Ek = 4.2 × 10^53 erg, εe = 0.05, εB = 0.01 for GRB 060124. These facts suggest that the normal decay phases of the X-rays for the two bursts are of the forward shock origin.展开更多
With the successful launch of Swift satellite, more and more data of early X-ray afterglows from short gamma-ray bursts have been collected. Some interesting features such as unusual afterglow light curves and unexpec...With the successful launch of Swift satellite, more and more data of early X-ray afterglows from short gamma-ray bursts have been collected. Some interesting features such as unusual afterglow light curves and unexpected X-ray flares are revealed. Especially, in some cases, there is a flat segment in the X-ray afterglow light curve. Here we present a simplified model in which we believe that the flattening part is due to energy injection from the central engine. We assume that this energy injection arises from the magnetic dipole radiation of a millisecond pulsar formed after the merger of two neutron stars. We check this model with the short GRB 060313. Our numerical results suggest that energy injection from a millisecond magnetar could make part of the X-ray afterglow light curve flat.展开更多
本文回顾了生长因子受体结合蛋白2(growth factor receptor-bound protein 2,GRB2)的发现历程、结构特征及翻译后修饰,系统分析了其在经典与非经典信号通路中的多维调控作用。GRB2作为关键接头蛋白,通过SH2结构域与受体酪氨酸激酶结合,...本文回顾了生长因子受体结合蛋白2(growth factor receptor-bound protein 2,GRB2)的发现历程、结构特征及翻译后修饰,系统分析了其在经典与非经典信号通路中的多维调控作用。GRB2作为关键接头蛋白,通过SH2结构域与受体酪氨酸激酶结合,并利用SH3结构域招募下游效应分子。这种偶联作用驱动RAS/MAPK、PI3K/AKT等经典通路,在细胞增殖、分化、迁移、存活及死亡等过程中发挥着重要作用。同时,GRB2在细胞核内参与DNA损伤应答,通过稳定RAD51、促进同源重组修复并维持复制叉稳定性,发挥“基因组守护者”的非经典作用。GRB2功能具有高度情境依赖性,在不同肿瘤中可表现为促癌或抑癌作用。此外,GRB2在糖尿病、神经退行性疾病及炎症反应中的病理关联日益凸显。靶向GRB2的蛋白质-蛋白质相互作用或表达调控,特别是结合其核功能与合成致死策略,有望为癌症及代谢性疾病提供新型治疗方向。展开更多
Multiband afterglow observations of gamma-ray bursts(GRBs)are important for studying the central engine.GRB 201223A is a GRB with prompt optical detection by GWAC.Here we report on the early optical afterglow of GRB 2...Multiband afterglow observations of gamma-ray bursts(GRBs)are important for studying the central engine.GRB 201223A is a GRB with prompt optical detection by GWAC.Here we report on the early optical afterglow of GRB 201223A detected by NEXT(only 2.8 minutes after the Swift/BAT trigger),which smoothly connects the prompt optical emission and the afterglow phase.Utilizing Amati diagrams and considering the detection of afterglow emission in the Swift u-band,we suggest a redshift range of 0.26–1.85.Based on our optical data and combined with early optical observation from GWAC and early X-ray data from Swift/XRT,a multiband fitting is performed using PyFRS,and we obtain the best afterglow parameters(assuming a redshift of z=1.0):=5.01+10/_(1.70)^(1.91)×^(54)erg,G=-426.58+_(138.18)/^(148.86),θj=-25.98+_(-10.54)^/(9.67)deg,=-n0=0.30+_(-0.26)^(+3.78)cm^(−3),=-p2.32+_(-0.01)/^(+0.01),εe=-3.31+_(-0.86)/^(+1.59)×10^(-5),εB=-3.47+_(-2.62)/^(+4.12)×10^(-1).The late-time X-ray shows a re-brightening,indicating late-time central engine activities.After comparing the leading two central engine models,i.e.,magnetar model and hyperaccreting black hole model,we find that the fallback accretion onto a newborn black hole provides a better explanation for the X-ray re-brightening with fallback accretion rate Mp≈2.76×10^(-9)M⊙s^(-1)and the total fallback accreted mass Mfb≈1.41×10^(−6)M⊙.展开更多
A team of researchers from the Beijing Normal University,the Institute of High Energy Physics(IHEP)under the Chinese Academy of Sciences(CAS),and the National Astronomical Observatories,CAS(NAOC),reported in Nature As...A team of researchers from the Beijing Normal University,the Institute of High Energy Physics(IHEP)under the Chinese Academy of Sciences(CAS),and the National Astronomical Observatories,CAS(NAOC),reported in Nature Astronomy on January 23,2025 their discovery of an X-ray flash about 12.5 billion lightyears away.The signals burst out only 1.2 billion years after the Big Bang,when our 13.8-billion-year-old universe was still in its infancy,and a science satellite swiftly recorded them.展开更多
Early multiwavelength observations offer crucial insights into the nature of the relativistic jets responsible for gamma-ray bursts and their interaction with the surrounding medium.We present data of GRB 240825A from...Early multiwavelength observations offer crucial insights into the nature of the relativistic jets responsible for gamma-ray bursts and their interaction with the surrounding medium.We present data of GRB 240825A from 17 space-and ground-based telescopes/instruments,covering wavelengths from NIR/optical to X-ray and GeV,and spanning from the prompt emission to the afterglow phase triggered by Swift and Fermi.The early afterglow observations were carried out by SVOM/C-GFT,and spectroscopic observations of the afterglow by GTC,VLT,and TNG determined the redshift of the burst(z=0.659)later.A comprehensive analysis of the prompt emission spectrum observed by Swift-BAT and Fermi-GBM/LAT reveals a rare and significant high-energy cutoff at 76 MeV.Assuming this cutoff is due toγγabsorption allows us to place an upper limit on the initial Lorentz factor,Γ_(0)<245.The optical/NIR and GeV afterglow light curves can be described by the standard external shock model,with early-time emission dominated by a reverse shock(RS)and a subsequent transition to forward shock(FS)emission.Our afterglow modeling yields a consistent estimate of the initial Lorentz factor(Γ_(0)∼234).Furthermore,the RS-to-FS magnetic field ratio(R 302B)indicates that the RS region is significantly more magnetized than the FS region.An isotropic-equivalent kinetic energy of E_(k,iso)=5.25×10^(54) erg is derived,and the correspondingγ-ray radiation efficiency is estimated to beη_(γ)=3.1%.On the other hand,the standard afterglow model cannot reproduce the X-ray light curve of GRB 240825A,calling for improved models to characterize all multiwavelength data.展开更多
The nearest GRB 170817A provided an opportunity to probe the angular structure of the jet of this short gamma-ray burst(SGRB),by using its off-axis observed afterglow emission.It is investigated whether the afterglow-...The nearest GRB 170817A provided an opportunity to probe the angular structure of the jet of this short gamma-ray burst(SGRB),by using its off-axis observed afterglow emission.It is investigated whether the afterglow-constrained jet structures can be consistent with the luminosity of the prompt emission of GRB 170817A.Furthermore,by assuming that all SGRBs,including GRB 170817A,have the same explosive mechanism and jet structure,we apply the different jet structures to the calculation of the flux and redshift distributions of the SGRB population,confronting them with the observational distributions of the Swift and Fermi sources.In comparison,it is found that the power-law and double-Gaussian models could be somewhat more favored than the single-Gaussian structure,as the last one could not be very consistent with the flux distribution of the Fermi data.Nevertheless,in view of the large uncertainty of parameters,we are still unable to make a suffciently conclusive judgement at present.展开更多
目的:观察人结直肠癌组织磷酸化哺乳动物雷帕霉素靶蛋白(phosphorylated mammalian target of rapamycin,p-mTOR)、表皮生长因子受体(EGFR)、生长因子受体结合蛋白2(Grb2)和血管内皮生长因子(VEGF)等的表达,并探讨其可能的临床意义。方...目的:观察人结直肠癌组织磷酸化哺乳动物雷帕霉素靶蛋白(phosphorylated mammalian target of rapamycin,p-mTOR)、表皮生长因子受体(EGFR)、生长因子受体结合蛋白2(Grb2)和血管内皮生长因子(VEGF)等的表达,并探讨其可能的临床意义。方法:构建含有185例结直肠癌标本的组织芯片,免疫组化法检测结直肠癌组织及癌旁组织中EGFR、Grb2、p-mTOR和VEGF的表达,并分析不同结直肠癌临床病理学特征下(如年龄、性别、浸润深度、淋巴转移、临床分期和分化程度)各自的表达情况,探讨可能的临床意义。结果:EGFR、Grb2、p-mTOR和VEGF在结直肠癌旁组织中呈少量表达或不表达,在结直肠癌组织中的表达率分别为21.1%、44.9%、42.2%和54.1%,明显高于癌旁组织(P<0.05)。结直肠癌患者不同性别、年龄、肿瘤分化程度下EGFR、Grb2、p-mTOR和VEGF表达率无统计学差异;不同浸润深度和临床分期下EGFR的表达率有统计学差异(P<0.05);不同浸润深度、淋巴转移和临床分期下p-mTOR、VEGF表达率均有统计学差异(P<0.05)。结直肠癌组织EGFR/Grb2/p-mTOR/VEGF蛋白两两间均有一定的相关性(r=0.245～0.567,P<0.05)。结论:EGFR、Grb2、p-mTOR和VEGF表达与结直肠癌的发生、发展相关,值得进一步研究以作为结直肠癌肿瘤靶向治疗新的作用靶点。展开更多
基金the National Natural Science Foundation of China.
文摘The observations with Swift X-ray telescope （XRT） challenge the conventional gamma-ray burst model in many aspects. The XRT light curves are generally composed of four consecutive segments, i.e., a steep decay segment, a shallow decay segment, a normal decay segment, a jet-like steep decay segment, and sometimes erratic flares as well. The physical origin of the X-ray emission is highly debatable. We focus here on the physical origin of the X-ray emissions of GRBs 050318 and 060124. We present the XRT light curves and spectra of the two bursts. The light curve decay slopes of the two bursts are normal, and their relations to the spectral indices are consistent with the prediction of the standard forward shock model. The multi-wavelength light curves at 0.5 keV, 1.0 keV, 2.0 keV and 4.0 keV can be reproduced by this model with an isotropic kinetic energy Ek = 2.2 × 10^52 erg, εe = 0.04, εB = 0.01 for GRB 050318 and Ek = 4.2 × 10^53 erg, εe = 0.05, εB = 0.01 for GRB 060124. These facts suggest that the normal decay phases of the X-rays for the two bursts are of the forward shock origin.
基金Supported by the National Natural Science Foundation of China.
文摘With the successful launch of Swift satellite, more and more data of early X-ray afterglows from short gamma-ray bursts have been collected. Some interesting features such as unusual afterglow light curves and unexpected X-ray flares are revealed. Especially, in some cases, there is a flat segment in the X-ray afterglow light curve. Here we present a simplified model in which we believe that the flattening part is due to energy injection from the central engine. We assume that this energy injection arises from the magnetic dipole radiation of a millisecond pulsar formed after the merger of two neutron stars. We check this model with the short GRB 060313. Our numerical results suggest that energy injection from a millisecond magnetar could make part of the X-ray afterglow light curve flat.
文摘本文回顾了生长因子受体结合蛋白2(growth factor receptor-bound protein 2,GRB2)的发现历程、结构特征及翻译后修饰,系统分析了其在经典与非经典信号通路中的多维调控作用。GRB2作为关键接头蛋白,通过SH2结构域与受体酪氨酸激酶结合,并利用SH3结构域招募下游效应分子。这种偶联作用驱动RAS/MAPK、PI3K/AKT等经典通路,在细胞增殖、分化、迁移、存活及死亡等过程中发挥着重要作用。同时,GRB2在细胞核内参与DNA损伤应答,通过稳定RAD51、促进同源重组修复并维持复制叉稳定性,发挥“基因组守护者”的非经典作用。GRB2功能具有高度情境依赖性,在不同肿瘤中可表现为促癌或抑癌作用。此外,GRB2在糖尿病、神经退行性疾病及炎症反应中的病理关联日益凸显。靶向GRB2的蛋白质-蛋白质相互作用或表达调控,特别是结合其核功能与合成致死策略,有望为癌症及代谢性疾病提供新型治疗方向。
基金supported by the MINECO/FEDER through grant AyA2017-84089.7the science research grants from the China Manned Space Project with NO.CMSCSST-2021-A13CMS-CSST-2021-B11.W.H.Lei acknowledges support by the National Key R&D Program of China(No.2020YFC2201400)。
文摘Multiband afterglow observations of gamma-ray bursts(GRBs)are important for studying the central engine.GRB 201223A is a GRB with prompt optical detection by GWAC.Here we report on the early optical afterglow of GRB 201223A detected by NEXT(only 2.8 minutes after the Swift/BAT trigger),which smoothly connects the prompt optical emission and the afterglow phase.Utilizing Amati diagrams and considering the detection of afterglow emission in the Swift u-band,we suggest a redshift range of 0.26–1.85.Based on our optical data and combined with early optical observation from GWAC and early X-ray data from Swift/XRT,a multiband fitting is performed using PyFRS,and we obtain the best afterglow parameters(assuming a redshift of z=1.0):=5.01+10/_(1.70)^(1.91)×^(54)erg,G=-426.58+_(138.18)/^(148.86),θj=-25.98+_(-10.54)^/(9.67)deg,=-n0=0.30+_(-0.26)^(+3.78)cm^(−3),=-p2.32+_(-0.01)/^(+0.01),εe=-3.31+_(-0.86)/^(+1.59)×10^(-5),εB=-3.47+_(-2.62)/^(+4.12)×10^(-1).The late-time X-ray shows a re-brightening,indicating late-time central engine activities.After comparing the leading two central engine models,i.e.,magnetar model and hyperaccreting black hole model,we find that the fallback accretion onto a newborn black hole provides a better explanation for the X-ray re-brightening with fallback accretion rate Mp≈2.76×10^(-9)M⊙s^(-1)and the total fallback accreted mass Mfb≈1.41×10^(−6)M⊙.
文摘A team of researchers from the Beijing Normal University,the Institute of High Energy Physics(IHEP)under the Chinese Academy of Sciences(CAS),and the National Astronomical Observatories,CAS(NAOC),reported in Nature Astronomy on January 23,2025 their discovery of an X-ray flash about 12.5 billion lightyears away.The signals burst out only 1.2 billion years after the Big Bang,when our 13.8-billion-year-old universe was still in its infancy,and a science satellite swiftly recorded them.
基金supported by the National Key R&D Program of China(grant No.2024YFA1611600)the SVOM project(a mission under the Strategic Priority Program on Space Science of the Chinese Academy of Sciences)+23 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(grant No.XDB0550401)the National Natural Science Foundation of China(NSFC,grant No.12494573)partly supported by Natural Science Foundation of Xinjiang Uygur Autonomous Region(grant No.2024D01D32)Tianshan Talent Training Program(grant No.2023TSYCLJ0053)Tianshan Innovation Team Program(grant No.2024D14015)supported by the Jiangsu Funding Program for Excellent Postdoctoral Talent(grant No.2024ZB110)the Postdoctoral Fellowship Program(grant No.GZC20241916)the General Fund(grant No.2024M763531)of the China Postdoctoral Science Foundationsupported by a Royal Society Dorothy Hodgkin Fellowship(grant Nos.DHF-R1-221175 and DHF-ERE-221005)support by a postdoctoral fellowship from the CNESsupported by the National Key R&D Program of China(grant No.2024YFA1611702)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant No.XDB0550101)the support of the French Agence Nationale de la Recherche(ANR),under grant ANR-23-CE31-0011(project PEGaSUS)financial support from the GRAWITA Large Program Grant(PI P.D’Avanzo)financial support from the Italian Space Agency,contract ASI/INAF No.I/004/11/6support from the INAF project Premiale Supporto Arizona&Italiasupported by the National Natural Science Foundation of China(NSFC,grant No.12133003)supported by the National Natural Science Foundation of China(NSFC,grant No.12373042)the Bagui Scholars Program(No.GXR-6BG2424001)funded by the European Union(ERC,HEAVYMETAL,101071865,Views and opinions expressed are,however,those of the authors only and do not necessarily reflect those of the European Union or the European Research Council Neither the European Union nor the granting authority can be held responsible for them)the Cosmic Dawn Center(DAWN)is funded by the Danish National Research Foundation under grant No.DNRF140supported by the National Natural Science Foundation of China(NSFC,grant Nos.12225305 and 12321003)supported by the National Natural Science Foundation of China(NSFC,grant No.12473049)supported by the General Fund(grant No.2024M763530)of the China Postdoctoral Science Foundation。
文摘Early multiwavelength observations offer crucial insights into the nature of the relativistic jets responsible for gamma-ray bursts and their interaction with the surrounding medium.We present data of GRB 240825A from 17 space-and ground-based telescopes/instruments,covering wavelengths from NIR/optical to X-ray and GeV,and spanning from the prompt emission to the afterglow phase triggered by Swift and Fermi.The early afterglow observations were carried out by SVOM/C-GFT,and spectroscopic observations of the afterglow by GTC,VLT,and TNG determined the redshift of the burst(z=0.659)later.A comprehensive analysis of the prompt emission spectrum observed by Swift-BAT and Fermi-GBM/LAT reveals a rare and significant high-energy cutoff at 76 MeV.Assuming this cutoff is due toγγabsorption allows us to place an upper limit on the initial Lorentz factor,Γ_(0)<245.The optical/NIR and GeV afterglow light curves can be described by the standard external shock model,with early-time emission dominated by a reverse shock(RS)and a subsequent transition to forward shock(FS)emission.Our afterglow modeling yields a consistent estimate of the initial Lorentz factor(Γ_(0)∼234).Furthermore,the RS-to-FS magnetic field ratio(R 302B)indicates that the RS region is significantly more magnetized than the FS region.An isotropic-equivalent kinetic energy of E_(k,iso)=5.25×10^(54) erg is derived,and the correspondingγ-ray radiation efficiency is estimated to beη_(γ)=3.1%.On the other hand,the standard afterglow model cannot reproduce the X-ray light curve of GRB 240825A,calling for improved models to characterize all multiwavelength data.
基金supported by the National Key R&D Program of China(2021YFA0718500)the China Manned Spaced Project(CMS-CSST-2021-A12)+1 种基金the National Natural Science Foundation of China(grant Nos.12393811,U1838203,and11803007)Hubei Provincial Outstanding Young and Middle-aged Science and Technology Innovation Team Project of China(T2021026)。
文摘The nearest GRB 170817A provided an opportunity to probe the angular structure of the jet of this short gamma-ray burst(SGRB),by using its off-axis observed afterglow emission.It is investigated whether the afterglow-constrained jet structures can be consistent with the luminosity of the prompt emission of GRB 170817A.Furthermore,by assuming that all SGRBs,including GRB 170817A,have the same explosive mechanism and jet structure,we apply the different jet structures to the calculation of the flux and redshift distributions of the SGRB population,confronting them with the observational distributions of the Swift and Fermi sources.In comparison,it is found that the power-law and double-Gaussian models could be somewhat more favored than the single-Gaussian structure,as the last one could not be very consistent with the flux distribution of the Fermi data.Nevertheless,in view of the large uncertainty of parameters,we are still unable to make a suffciently conclusive judgement at present.
文摘目的:观察人结直肠癌组织磷酸化哺乳动物雷帕霉素靶蛋白(phosphorylated mammalian target of rapamycin,p-mTOR)、表皮生长因子受体(EGFR)、生长因子受体结合蛋白2(Grb2)和血管内皮生长因子(VEGF)等的表达,并探讨其可能的临床意义。方法:构建含有185例结直肠癌标本的组织芯片,免疫组化法检测结直肠癌组织及癌旁组织中EGFR、Grb2、p-mTOR和VEGF的表达,并分析不同结直肠癌临床病理学特征下(如年龄、性别、浸润深度、淋巴转移、临床分期和分化程度)各自的表达情况,探讨可能的临床意义。结果:EGFR、Grb2、p-mTOR和VEGF在结直肠癌旁组织中呈少量表达或不表达,在结直肠癌组织中的表达率分别为21.1%、44.9%、42.2%和54.1%,明显高于癌旁组织(P<0.05)。结直肠癌患者不同性别、年龄、肿瘤分化程度下EGFR、Grb2、p-mTOR和VEGF表达率无统计学差异;不同浸润深度和临床分期下EGFR的表达率有统计学差异(P<0.05);不同浸润深度、淋巴转移和临床分期下p-mTOR、VEGF表达率均有统计学差异(P<0.05)。结直肠癌组织EGFR/Grb2/p-mTOR/VEGF蛋白两两间均有一定的相关性(r=0.245～0.567,P<0.05)。结论:EGFR、Grb2、p-mTOR和VEGF表达与结直肠癌的发生、发展相关,值得进一步研究以作为结直肠癌肿瘤靶向治疗新的作用靶点。
