Blazar源的致密结构和光变
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摘要
Blazar天体是活动星系核（Active Galactic Nuclei，AGN）的三大主要类型
之一，它们也是宇宙中产能最大、光变最剧烈的天体。目前标准的活动星系核统
一模型认为：AGN的中央有一个大质量黑洞，环绕该黑洞的是一个吸积盘，
射电强活动星系核还会在吸积盘的旋转轴方向产生一对双向的相对论性喷流。
Blazar的喷流与我们观测视线的夹角很小，喷流的辐射经过Doppler效应增强
后，产生了一个下至射电波段、上至高能γ-ray波段的很宽的频谱。研究blazar
天体能量的起源、传输和变化对宇宙学以及基本物理学都有重要的意义。
二战以后，射电天文学得到了蓬勃发展，导致了类星体、微波背景辐射等一
系列重大发现。在射电天文学中，干涉测量技术始终是发展的主要方向之一。目
前的甚长基线干涉阵（Very Long Baseline Interferometry，VLBI）可以达到亚毫
角秒的观测角分辨率，是唯一能够用来研究blazar致密结构的工具。此外，一
些射电望远镜从60年代开始就对一批blazar源进行单天线流量监测，积累了大
量的资料。运用VLBI和单天线观测资料来研究blazar源的致密结构和光变是
本博士论文的主要内容。
利用申请到的欧洲VLBI网（EVN）和美国VLBI网（VLBA）的观测时间，
我们对blazar源0420-014、1334-127、1504-166、2243-123、2345-167和
J1624+4134的致密结构进行了VLBI观测。作者比较了这些源在不同历元的结
构变化，测量了喷流结构的视超光速运动，研究了新的喷流结构产生与流量爆发
的对应关系。作者首次发现0420-014存在着两种不同类型的射电爆发，它们起
源于喷流中的不同位置。观测还发现了blazar喷流结构可能存在旋转的证据（第
三、四章）。另外，作者提出了一种新的利用多历元VLBI观测来确定喷流视角的
方法。该方法不但可以计算喷流视角的大小，还可以计算视角的变化（第五章）。
探索blazar光变资料中的周期/准周期变化是一个有待深入研究的领域。由
于光变资料的复杂性，目前寻找周期的算法还显得不够完善。在本论文的后半部
分（第六、七章），作者详细讨论了几种有用的周期寻找方法，即CLEAN方法、
最大熵方法和Jurkevich方法。对Jurkevich方法作了改进，每一种方法都编制了
相应的处理软件。综合运用这些方法可以扬长避短，比较准确、可靠地估计周期
信号。此外，作者结合CLEAN思想和Jurkevich算法，提出了周期函数CLEAN
算法，它可以把具体的周期信号从原始的光变资料中提取出来。获得的周期变化
信号对进一步研究它们的特性及物理来源很有帮助。
Blazars, one part of Active Galactic Nuclei (AGN), are the most powerful and
the largest amplitude variable objects in the cosmos. According to the standard
unified model of AGN, there is a central massive black hole, surrounded by an
accretion disk. A powerful reletivistic jet will emanate from the region near the
black hole. The viewing angle of the jet of blazar is very small. Thus, its radiation
will be Doppler enhanced, and generate a wide spectrum from radio band to light
energy -y-ray band. To study how blazars?energy originates, transfers and variates
is very important to cosmology and basic physics.
After world war II, there was a big progress in radio astronomy. It brought
on some great discoveries in astronomy, such as quasar, microwave background
radiation etc. In radio astronomy, interferometry is an important technique which
is still under developing. Today, VLBI (Very Long Baseline Interferometry) can
reach sub-milliarcsecond angular resolution. It is the only tool that can be used
to study the compact strutures of blazars. Furthermore, some radio telescopes
were systematically monitoring the fluxes of blazars since 1960s. We have many
data of the light curves of blazars now. The main purpose of this dissertation
is to study the compact structures and light curves of blazars depend on the
observation of single dish and VLBI.
We applied EVN (European VLBI Network) and VLBA to observe blazar
0420-014, 1334-127, 1504-166, 2243-166, 2345-167 and J1625+4134. We com-
pared their compact structures on different epochs, measured the superluminal
proper motions of their jet components, and studied the relation between the
emanation of new jet component and flux flare. I found that 0420-014 had two
kinds of radio flares which orignated in different positions in jet. Moreover, I
found some evidence that the jet of PKS 0420-014 was probably rotating (Chap-
ter 3 and 4). Also, I proposed a new method to estimate the viewing angles of
the jets of blazars. This method is based on multi-epoch VLBI observation, and
can obtain not only viewing angle but also its variation (Chapter 5).
The periodicity analysis of the light curves of blazars needs improvement.
Due to the complication of blazars?light curves, the present periodicity analysis
methods are not perfect. In the rest part of this dissertation (Chapter 6 and
7), I disscussed in detail some suitable periodicity analysis method, i.e. CLEAN
method, MaJximum entropy method (MEM) and Jurkevich method. I improved
the Jurkevich method. FOr each method, I compiled a corresponding software
which could process real data. Combined CLEAN idea with Jurkevich method,
I proposed a method, called periodical function CLEAN algorithm, to pick-up
periodical signals from original lightcurves. The obtained periodic signals are
very helpful to understand their physical mechanism.
之一，它们也是宇宙中产能最大、光变最剧烈的天体。目前标准的活动星系核统
一模型认为：AGN的中央有一个大质量黑洞，环绕该黑洞的是一个吸积盘，
射电强活动星系核还会在吸积盘的旋转轴方向产生一对双向的相对论性喷流。
Blazar的喷流与我们观测视线的夹角很小，喷流的辐射经过Doppler效应增强
后，产生了一个下至射电波段、上至高能γ-ray波段的很宽的频谱。研究blazar
天体能量的起源、传输和变化对宇宙学以及基本物理学都有重要的意义。
二战以后，射电天文学得到了蓬勃发展，导致了类星体、微波背景辐射等一
系列重大发现。在射电天文学中，干涉测量技术始终是发展的主要方向之一。目
前的甚长基线干涉阵（Very Long Baseline Interferometry，VLBI）可以达到亚毫
角秒的观测角分辨率，是唯一能够用来研究blazar致密结构的工具。此外，一
些射电望远镜从60年代开始就对一批blazar源进行单天线流量监测，积累了大
量的资料。运用VLBI和单天线观测资料来研究blazar源的致密结构和光变是
本博士论文的主要内容。
利用申请到的欧洲VLBI网（EVN）和美国VLBI网（VLBA）的观测时间，
我们对blazar源0420-014、1334-127、1504-166、2243-123、2345-167和
J1624+4134的致密结构进行了VLBI观测。作者比较了这些源在不同历元的结
构变化，测量了喷流结构的视超光速运动，研究了新的喷流结构产生与流量爆发
的对应关系。作者首次发现0420-014存在着两种不同类型的射电爆发，它们起
源于喷流中的不同位置。观测还发现了blazar喷流结构可能存在旋转的证据（第
三、四章）。另外，作者提出了一种新的利用多历元VLBI观测来确定喷流视角的
方法。该方法不但可以计算喷流视角的大小，还可以计算视角的变化（第五章）。
探索blazar光变资料中的周期/准周期变化是一个有待深入研究的领域。由
于光变资料的复杂性，目前寻找周期的算法还显得不够完善。在本论文的后半部
分（第六、七章），作者详细讨论了几种有用的周期寻找方法，即CLEAN方法、
最大熵方法和Jurkevich方法。对Jurkevich方法作了改进，每一种方法都编制了
相应的处理软件。综合运用这些方法可以扬长避短，比较准确、可靠地估计周期
信号。此外，作者结合CLEAN思想和Jurkevich算法，提出了周期函数CLEAN
算法，它可以把具体的周期信号从原始的光变资料中提取出来。获得的周期变化
信号对进一步研究它们的特性及物理来源很有帮助。
Blazars, one part of Active Galactic Nuclei (AGN), are the most powerful and
the largest amplitude variable objects in the cosmos. According to the standard
unified model of AGN, there is a central massive black hole, surrounded by an
accretion disk. A powerful reletivistic jet will emanate from the region near the
black hole. The viewing angle of the jet of blazar is very small. Thus, its radiation
will be Doppler enhanced, and generate a wide spectrum from radio band to light
energy -y-ray band. To study how blazars?energy originates, transfers and variates
is very important to cosmology and basic physics.
After world war II, there was a big progress in radio astronomy. It brought
on some great discoveries in astronomy, such as quasar, microwave background
radiation etc. In radio astronomy, interferometry is an important technique which
is still under developing. Today, VLBI (Very Long Baseline Interferometry) can
reach sub-milliarcsecond angular resolution. It is the only tool that can be used
to study the compact strutures of blazars. Furthermore, some radio telescopes
were systematically monitoring the fluxes of blazars since 1960s. We have many
data of the light curves of blazars now. The main purpose of this dissertation
is to study the compact structures and light curves of blazars depend on the
observation of single dish and VLBI.
We applied EVN (European VLBI Network) and VLBA to observe blazar
0420-014, 1334-127, 1504-166, 2243-166, 2345-167 and J1625+4134. We com-
pared their compact structures on different epochs, measured the superluminal
proper motions of their jet components, and studied the relation between the
emanation of new jet component and flux flare. I found that 0420-014 had two
kinds of radio flares which orignated in different positions in jet. Moreover, I
found some evidence that the jet of PKS 0420-014 was probably rotating (Chap-
ter 3 and 4). Also, I proposed a new method to estimate the viewing angles of
the jets of blazars. This method is based on multi-epoch VLBI observation, and
can obtain not only viewing angle but also its variation (Chapter 5).
The periodicity analysis of the light curves of blazars needs improvement.
Due to the complication of blazars?light curves, the present periodicity analysis
methods are not perfect. In the rest part of this dissertation (Chapter 6 and
7), I disscussed in detail some suitable periodicity analysis method, i.e. CLEAN
method, MaJximum entropy method (MEM) and Jurkevich method. I improved
the Jurkevich method. FOr each method, I compiled a corresponding software
which could process real data. Combined CLEAN idea with Jurkevich method,
I proposed a method, called periodical function CLEAN algorithm, to pick-up
periodical signals from original lightcurves. The obtained periodic signals are
very helpful to understand their physical mechanism.
引文
1． Blandford, R.D. 1990, in Active Galactic Nuclei, eds. T.J.-L. Courvoiser and and M. Mayor, Berlin Springer, p. 161
2． Brotherton, M.S., et al. 2001, ApJ, 546, 775
3． Caccianiga, et al. 1999, ApJ, 513, 51
4． Delia Ceca, R., et al. 1994, ApJ, 430, 533
5． Fanaroff, B.L., and Riley, J.M. 1974, MNRAS, 167, 31
6． Fugmann, W. 1989, A& A, 205, 86
7． Giommi, P., Menna, M.T., and Padovani, P. 1999, MNRAS, 310, 465
8． Greenstein, J., Schmidt, M. 1964, ApJ, 140, 1
9． Hazard, C., Mackey, M.B., and Shimmins, A.J. 1963, Nature, 197, 1037
10． Hermine, L., et al. 2001, MNRAS, in press
11． Hough, J.H., et al. 1991, ApJ, 372, 478
12． Impey, C.D., Lawrence, C.R., and Tapia, S. 1991, ApJ, 375, 46
13． Kellermann, K.I., et al. 1989, AJ, 98, 1195
14． Kock, A., et al. 1996, A& A, 307, 475
15． La Franca, F., et al. 1994, AJ, 108, 1548
16． Laurent-Muehleisen, S.A., et al. 1998, ApJS, 118, 127
17． Mushotzky, R.F. 1982, ApJ, 256, 92
18． Nass, P., et al. 1996, A& A, 309, 419
19． Padovani, P. 1993, MNRAS, 263, 461
20． Perlman, E.S., et al. 1998, AJ, 115, 1253
21． Peterson, B. 1997, An Introduction to Active Galactic Nuclei, Cambridge University Press, 1
22． Quirrenbach, A., et al. 1992, A& A, 258, 279
23． Robson, I. 1996, Active Galactic Nuclei, John Wiley & Sons, 78
24． Sanders, D.B., et al. 1988, ApJ, 325, 74
25． Sanders, D.B., et al. 1989, ApJ, 347, 29
26． Turnshek, D.A. 1988, in QSO Absorption Lines: Probing the Universe, eds. J.C. Blades, D.A. Turnshek, and C.A. Norman, Cambridge University Press, p. 17
27． Valtaoja, E., et al. 1992, A&A, 254, 80
28． Wills, B.J., et al. 1992a, ApJ, 398, 454
29． Wills, B.J., et al. 1992b, ApJ, 400, 96
30． Wilson, A.S., and Colbert, E.J.M. 1995, ApJ, 438, 62
31． Wolter, A., et al. 1997, MNRAS, 284, 225
2． Brotherton, M.S., et al. 2001, ApJ, 546, 775
3． Caccianiga, et al. 1999, ApJ, 513, 51
4． Delia Ceca, R., et al. 1994, ApJ, 430, 533
5． Fanaroff, B.L., and Riley, J.M. 1974, MNRAS, 167, 31
6． Fugmann, W. 1989, A& A, 205, 86
7． Giommi, P., Menna, M.T., and Padovani, P. 1999, MNRAS, 310, 465
8． Greenstein, J., Schmidt, M. 1964, ApJ, 140, 1
9． Hazard, C., Mackey, M.B., and Shimmins, A.J. 1963, Nature, 197, 1037
10． Hermine, L., et al. 2001, MNRAS, in press
11． Hough, J.H., et al. 1991, ApJ, 372, 478
12． Impey, C.D., Lawrence, C.R., and Tapia, S. 1991, ApJ, 375, 46
13． Kellermann, K.I., et al. 1989, AJ, 98, 1195
14． Kock, A., et al. 1996, A& A, 307, 475
15． La Franca, F., et al. 1994, AJ, 108, 1548
16． Laurent-Muehleisen, S.A., et al. 1998, ApJS, 118, 127
17． Mushotzky, R.F. 1982, ApJ, 256, 92
18． Nass, P., et al. 1996, A& A, 309, 419
19． Padovani, P. 1993, MNRAS, 263, 461
20． Perlman, E.S., et al. 1998, AJ, 115, 1253
21． Peterson, B. 1997, An Introduction to Active Galactic Nuclei, Cambridge University Press, 1
22． Quirrenbach, A., et al. 1992, A& A, 258, 279
23． Robson, I. 1996, Active Galactic Nuclei, John Wiley & Sons, 78
24． Sanders, D.B., et al. 1988, ApJ, 325, 74
25． Sanders, D.B., et al. 1989, ApJ, 347, 29
26． Turnshek, D.A. 1988, in QSO Absorption Lines: Probing the Universe, eds. J.C. Blades, D.A. Turnshek, and C.A. Norman, Cambridge University Press, p. 17
27． Valtaoja, E., et al. 1992, A&A, 254, 80
28． Wills, B.J., et al. 1992a, ApJ, 398, 454
29． Wills, B.J., et al. 1992b, ApJ, 400, 96
30． Wilson, A.S., and Colbert, E.J.M. 1995, ApJ, 438, 62
31． Wolter, A., et al. 1997, MNRAS, 284, 225