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1.
收集了119颗有γ射线噪的Blazar天体样品(97个平谱射电类星体和22个BL Lac天体),用离散相关函数(DCF)方法分析了1GeV γ射线辐射流量(最大值、最小值和平均值)与8.4GHz射电辐射流量之间的相关性.获得的主要结果为:在119个Blazar天体和97个平谱射电类星体中,γ射线辐射流量的最大值以及平均值和射电辐射流量之间有相关性;而γ射线辐射流量的最小值和射电辐射流量之间没有相关性.本文结果表明,γ射线和射电辐射都来自喷流,γ射线很可能产生于同步自康普顿(SSC)过程.
关键词:
Blazar
γ射线
射电辐射
流量密度 相似文献
2.
给出了一个带有射电5.0GHz,8.4GHz 和γ射线辐射流量密度的22个γ噪BL Lac天体的样本,研究了它们在1GeV处的γ射线辐射流量密度最大值、平均值及最小值与射电5.0GHz,8.4GHz辐射流量之间的可能关系.结果表明:1)射电5.0GHz,8.4GHz辐射与γ射线辐射在低态时没有相关,但在高态和平均态时都存在较强的相关,最大相关系数r=0.85,置信度均好于10-4;2)γ射线谱指数和射电谱指数之间也有一个弱相关关系存在.因此,认为γ射线的辐射主要是同步自康普顿辐射.
关键词:
BL Lac天体
γ射线
射电辐射
谱指数 相似文献
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从文献中收集了205个Blazar天体,包括142个BL Lac天体和63个平谱射电类星体(FSRQs).对这些天体的类别与它们的红移、射电5 GHz辐射流量、光学V波段流量、1 keV处X射线流量、X射线光子谱指数进行了相关性和Logistic回归分析.结果表明,对Blazar天体分类产生主要影响的因素是红移、射电5 GHz辐射流量和X射线光子谱指数,综合应用这三个物理量判别Blazar天体的分类的准确率可达到91.2%,得到的分类方程具有良好的预测效果,可以作为Blazar天体分类的一个重要的判据.而光学V波段流量和1 keV处X射线流量不能区分开BL Lac天体和FSRQs,它们与Blazar天体分类没有相关性.本文结果支持将BL Lac天体和FSRQs归为Blazar天体,不同类别的Blazar天体之间能通过一种演化序列相联系.
关键词:
Logistic
分类
Blazar天体 相似文献
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γ射线暴(以下简称γ暴)是来自宇宙空间的一种短时标的高能γ射线爆发现象。它的发现颇有戏剧性:60年代中期,为了监督关于禁止在大气层中进行核试验的条约的执行情况,美国发射了一些卫星,以监测核爆炸中的γ射线事件。1967年开始,Vela卫星真的不时记录到一些γ射线爆发现象,使美国政府十分紧张。军方花了几年的时间终于搞清楚它们均来自于宇宙空间,证实只是一场虚惊。由于军事保密的原因,该现象直到1973年才由美国洛斯阿拉莫斯实验室的Klebesadel、Strong和Olson在ApJ(美国《天体物理杂志》)的一篇快报中以“对源自宇宙空间的γ射线爆发的观测”为题发表出来。 相似文献
7.
报道了以高聚物为载体,以有机染料及添加剂为变色指示剂体系,制备一种辐射变色膜。这种辐射变色膜为无色透明固体薄膜,经60Co γ射线辐照后,其颜色变为蓝色。辐照后样品的紫外-可见吸收光谱表明,在可见光区其最强吸收峰出现在624 nm附近。在10~90 kGy的剂量范围内,不含添加剂的辐射变色膜的光密度变化与吸收剂量呈线性关系,而含有添加剂的辐射变色膜对γ射线辐照的响应在50 kGy时就达到饱和。同时还探索了该体系辐照效应的化学反应机理。 相似文献
8.
假设退激过程中除包含巨偶极共振模式外还存在6He,6Li,6Be,7Li和7Be等粒子集团激发态的退激过程.本文对这一物理假定作了进一步分析.利用据此建立的包括这些过程在内的γ射线强度函数,计算了在核素93Nb,181Ta和天然元素Ag上入射中子能量在0.01—5MeV能区以及在核素197Au上入射中子能量在0.01—10MeV能区的中子辐射俘获反应截面和γ能谱,得到了与实验数据较好符合的结果.特别是可以较好地解释γ能谱中5.5MeV之后的反常突起.这表明,上述物理假定适用于中重核中子辐射俘获反应. 相似文献
9.
意大利和荷兰联合发射的卫星BeppoSAX在1997年2月28日探测到γ暴GRB970228的X射线余辉,随后的地面和哈勃空间望远镜的观测证实在该位置上有一光学瞬变源。哈勃空间望远镜在此光学变源方位观测到一暗的河外天体。 相似文献
10.
1896年,法国物理学家贝克勒尔发现铀具有放射性,能不断放射出一种肉眼看不见而穿透本领很强的射线。后来,科学家经过研究发现放射线是由3种很强的射线组成的:一种是α射线(氦核),另一种是β射线(电子),还有一种是γ射线(光子)。此后,放射线在包括军事领域在内的多方面得到应用。最近,继第三代核武器中子弹研制成功后,一些军事强国又把目光投向了另一种核武器———γ射线弹,使全世界爱好和平的人们心头蒙上了一层新的核阴影。一、γ射线弹一般来说,核爆炸的杀伤力量由4个因素组成:冲击波、光辐射、放射性沾染和贯穿辐射,其中贯穿辐射主要由强γ射线和中子流组成。 相似文献
11.
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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An effect of a proposed Beyond the Standard Model particle physics process on the energy spectra of distant astrophysical objects is presented. It is suggested that TeV gamma rays from distant BL Lacs may kinetically mix with hypothetical hidden sector paraphotons. The latter can traverse vast distances of space because of only very weak interactions with intervening objects or material. These paraphotons would then reconvert back into photons that have identical characteristics as their originators, and are detected on earth. Laser based photon regeneration experiments test this model of hidden sector physics in the range of parameters that would impact the TeV gamma ray energy spectra arriving from distant BL Lacs. 相似文献
13.
In this paper, we use a method to determine some basic parameters for
the $\gamma$-ray loud blazars. The parameters include the central
black mass ($M$), the boosting factor ($\delta$), the propagation
angle (${\it {\it\Phi}}$), the distance along the axis to the site of
the $\gamma$-ray production ($d$). A sample including 32 $\gamma$-ray
loud blazars with available variability time scales has been used to
discuss the above properties. In this method, the $\gamma$-ray
energy, the emission size and the property of the accretion disc
determine the absorption effect. If we take the intrinsic
$\gamma$-ray luminosity to be $\lambda$ times the Eddington
luminosity, i.e. $L_{\gamma}^{\rm in}=\lambda{L_{\rm Edd}}$, then we
have the following results: the mass of the black hole is in the
range of $(0.59-67.99)\times10^{7}M_{\odot} \ (\lambda=1.0)$ or
$(0.90-104.13)\times10^{7}M_{\odot} \ (\lambda=0.1)$; the boosting
factor ($\delta$) in the range of In this paper, we use a method to determine some basic parameters for
the $\gamma$-ray loud blazars. The parameters include the central
black mass ($M$), the boosting factor ($\delta$), the propagation
angle (${\it {\it\Phi}}$), the distance along the axis to the site of
the $\gamma$-ray production ($d$). A sample including 32 $\gamma$-ray
loud blazars with available variability time scales has been used to
discuss the above properties. In this method, the $\gamma$-ray
energy, the emission size and the property of the accretion disc
determine the absorption effect. If we take the intrinsic
$\gamma$-ray luminosity to be $\lambda$ times the Eddington
luminosity, i.e. $L_{\gamma}^{\rm in}=\lambda{L_{\rm Edd}}$, then we
have the following results: the mass of the black hole is in the
range of $(0.59-67.99)\times10^{7}M_{\odot} \ (\lambda=1.0)$ or
$(0.90-104.13)\times10^{7}M_{\odot} \ (\lambda=0.1)$; the boosting
factor ($\delta$) in the range of In this paper, we use a method to determine some basic parameters for
the $\gamma$-ray loud blazars. The parameters include the central
black mass ($M$), the boosting factor ($\delta$), the propagation
angle (${\it {\it\Phi}}$), the distance along the axis to the site of
the $\gamma$-ray production ($d$). A sample including 32 $\gamma$-ray
loud blazars with available variability time scales has been used to
discuss the above properties. In this method, the $\gamma$-ray
energy, the emission size and the property of the accretion disc
determine the absorption effect. If we take the intrinsic
$\gamma$-ray luminosity to be $\lambda$ times the Eddington
luminosity, i.e. $L_{\gamma}^{\rm in}=\lambda{L_{\rm Edd}}$, then we
have the following results: the mass of the black hole is in the
range of $(0.59-67.99)\times10^{7}M_{\odot} \ (\lambda=1.0)$ or
$(0.90-104.13)\times10^{7}M_{\odot} \ (\lambda=0.1)$; the boosting
factor ($\delta$) in the range of In this paper, we use a method to determine some basic parameters for
the $\gamma$-ray loud blazars. The parameters include the central
black mass ($M$), the boosting factor ($\delta$), the propagation
angle (${\it {\it\Phi}}$), the distance along the axis to the site of
the $\gamma$-ray production ($d$). A sample including 32 $\gamma$-ray
loud blazars with available variability time scales has been used to
discuss the above properties. In this method, the $\gamma$-ray
energy, the emission size and the property of the accretion disc
determine the absorption effect. If we take the intrinsic
$\gamma$-ray luminosity to be $\lambda$ times the Eddington
luminosity, i.e. $L_{\gamma}^{\rm in}=\lambda{L_{\rm Edd}}$, then we
have the following results: the mass of the black hole is in the
range of $(0.59-67.99)\times10^{7}M_{\odot} \ (\lambda=1.0)$ or
$(0.90-104.13)\times10^{7}M_{\odot} \ (\lambda=0.1)$; the boosting
factor ($\delta$) in the range of In this paper, we use a method to determine some basic parameters for
the $\gamma$-ray loud blazars. The parameters include the central
black mass ($M$), the boosting factor ($\delta$), the propagation
angle (${\it {\it\Phi}}$), the distance along the axis to the site of
the $\gamma$-ray production ($d$). A sample including 32 $\gamma$-ray
loud blazars with available variability time scales has been used to
discuss the above properties. In this method, the $\gamma$-ray
energy, the emission size and the property of the accretion disc
determine the absorption effect. If we take the intrinsic
$\gamma$-ray luminosity to be $\lambda$ times the Eddington
luminosity, i.e. $L_{\gamma}^{\rm in}=\lambda{L_{\rm Edd}}$, then we
have the following results: the mass of the black hole is in the
range of $(0.59-67.99)\times10^{7}M_{\odot} \ (\lambda=1.0)$ or
$(0.90-104.13)\times10^{7}M_{\odot} \ (\lambda=0.1)$; the boosting
factor ($\delta$) in the range of $0.16-2.09(\lambda=1.0)$ or
$0.24-2.86\ (\lambda=0.1)$; the angle (${\it\Phi}$) in the range of
$9.53^{\circ}-73.85^{\circ}\ (\lambda=1.0)$ or
$7.36^{\circ}-68.89^{\circ}\ (\lambda=0.1)$; and the distance
($d/R_{\rm g}$) in the range of $22.39-609.36\ (\lambda=1.0)$ or
$17.54-541.88\ (\lambda=0.1)$. 相似文献
14.
In this paper, a large sample of extragalactic radio sources is analysed to show their statistical properties. The core and total radio powers are used to determine the core-dominance parameter for galaxies, BL Lacertae objects and quasars; mutual correlations between core radio power, total radio power, redshift and core dominance parameter are examined for different subclasses. A statistically significant correlation between the total and core radio power is confirmed. There are no obvious correlations between core-dominance parameter and the total power for our whole sample and quasars, but there is a statistically significant anti-correlation for our galaxy sample. Some discussions and comparison of the correlations with those obtained by other authors are also given. 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
17.
The spectral hardening with increasing intensity in optical range for four BL Lac objects have been found by analyzing our observed data. Making use of the synchrotron loss of transient injection of relativistic electrons, we succeeded in explaining the phenomenon of the spectral hardening in the outburst phase. The value of magnetic intensity and the limit condition of the transient injection of relativistic electrons seem to be reasonable. 相似文献
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润滑剂分子结构及其润滑作用机理的红外发射光谱研究 总被引:2,自引:0,他引:2
在自制的“原位“摩擦装置上,利用红外发射光谱技术对润滑剂在摩擦过程中的化学行为进行跟踪测量,以期对润滑剂分子结构变化与润滑作用机理进行某些关联。实验证明,红外发射光谱技术可作为原位观测摩擦过程中化学变化的有效手段。 相似文献