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For 163 metal-rich Quasars, the mv-logZ diagram shows a very close correlation. Using multiple regression analysis for these sources (N = 163), we obtained q0,= 1.142 and correlation coefficient γ = 0.69. These results suggested that the Universe is closed and all metal-rich quasars
are of a single category. On the other hand, the evolution is very small at Z⩽2 for metal-rich quasars. 相似文献
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观测到了BLLac天体Mark421在光学波段的短时标爆发.在26min的爆发期间内,Mark421从B=1576mag到B=1432mag迅速变化了134mag.更为有趣的是观测结果与1996年由Gaidos等观测到的TeVγ射线爆发的结果非常相似,特别是在时标变化和光变曲线等方面两者有相同之处.由上述观测数据结果可以得出:爆发产生于相同的发射区域,这个区域为R=59×1011m,并由此推导出Mark421中心黑洞质量为M=3×106M⊙,这对目前的γ辐射理论模型提出了新的挑战,可以认为Mark421的
关键词: 相似文献
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收集了29个有γ噪的Blazar天体(其中有16个BL Lac天体和13个平谱射电类星体)的近红外流量密度和γ射线流量密度,获得以下主要结果:1)23个天体中的γ射线流量密度和近红外流量密度在低态时存在较强的相关性而在高态时有弱的相关性.2)在29个天体中,有6个天体只有一个观测数据点,将其认为是高态时,γ射线流量密度与近红外光流量密度之间有弱相关性,而认为是低态时有强相关性.3)29个源的γ射线流量密度与X射线流量密度在低态时有相关性,但是γ射线流量与光学流量密度,γ射线流量与射电流量密度均没有相关性.4)在16个BL Lac天体中γ射线流量与近红外光流量不论在高态还是低态都有相关性,而13个平谱射电类星体没有相关性.讨论了γ噪Blazar天体的γ射线辐射机制,认为γ射线的辐射机制主要是同步自康普顿散射.而逆康普顿散射来自绕中心核且温度约为2000K的尘埃,这些尘埃的区域大约有r=3pc,聚束的相对论电子也可能是这种尘埃模型辐射机制的一个重要补充.平谱射电类星体和BL Lac天体的γ辐射机制可能有些不同.
关键词:
Blazar天体
星系γ射线观测辐射机制
非热辐射 相似文献
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On the basis of the beaming model, we have derived a relation between the observed polarization (Pob) and Doppler-corrected optical magnitude (mcorr), log Pob=0.4(1-k) mcorr+C. We tested the correlation between Pob} and mcorr. The main results are as follows: (1) for both high and low states, there are strong correlations between Pob and mcorr for 29 RBLs with well-observed polarization and Doppler factor, where mcorr=mob+(3+α)logδ/0.4, and δ is the optical Doppler factor; (2) no correlation exists between Pob and the observed optical magnitude, mob, for the 29 RBLs in high state, but there is a close correlation for the 29 RBLs in low state; (3) however, there is an obvious anti-correlation between Pob and mcorr for 35 XBLs with good simultaneous observation data. Our results show that (i) a new difference in polarization is found between RBLs and XBLs; (ii) this difference in polarization between RBLs and XBLs seems really to be physical differences. 相似文献
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过去有关两载流平行导线间作用力的演示,仪器的效果不够好,演示现象不显著.为了加孩演示效果和活合大班使用,特制作这套演示仪器,效果颇佳.现介绍出来供参考. 整体装置如图1所示,在有可调螺旋的三脚支架上固定一木板A,板上装有二个 相似文献
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The stationary properties of a single-mode laser with positive and negative correlations between additive and multiplicative white-noise terms are investigated. By virtue of a simple rule and decoupling ansatz, the intensity correlation function and correlation time for the laser model are derived. We found that: (1) the fluctuation of light intensity with negative correlations between the noise terms are reduced in comparison with those for positive correlations; (2) the coupling between additive and multiplicative noises enhances the rate of decay of intensity correlation; (3) the effects of negative correlations between the noise terms are more remarkable than those of positive correlations. 相似文献
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We present a strong correlation of the gamma-ray (above 100 MeV) mean spectral indices αγ and X-ray (1 keV) mean spectral indices αX for 34 gamma-ray-loud blazars (16 BL Lac objects and 18 flat spectrum radio quasars). A strong correlation is also found between the gamma-ray flux densities Fγ and X-ray flux densities FX in the low state for 47 blazars (17 BL Lac and 30 flat spectrum radio quasars). Possible correlation on the gamma-ray emission mechanism is discussed. We suggest that the main gamma-ray radiation mechanism is probably the synchrotron process. The gamma-ray emission may be somewhat different from that of BL Lac objects and flat spectrum radio quasars. 相似文献
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