Parsec-scale properties of Markarian 501

被引:187
作者
Giroletti, M
Giovannini, G
Feretti, L
Cotton, WD
Edwards, PG
Lara, L
Marscher, AP
Mattox, JR
Piner, BG
Venturi, T
机构
[1] CNR, Ist Radioastron, I-40129 Bologna, Italy
[2] Univ Bologna, Dipartimento Astron, I-40127 Bologna, Italy
[3] Natl Radio Astron Observ, Charlottesville, VA 22903 USA
[4] Inst Space & Astronaut Sci, Kanagawa 2298510, Japan
[5] Univ Granada, Dept Fis Teor & Cosmos, E-18071 Granada, Spain
[6] CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain
[7] Boston Univ, Inst Astrophys Res, Boston, MA 02215 USA
[8] Francis Marion Univ, Dept Phys & Astron, Florence, SC 29501 USA
[9] Whittier Coll, Dept Phys & Astron, Whittier, CA 90608 USA
关键词
BL Lacertae objects : individual (Markarian 501); galaxies : active; galaxies : jets; galaxies : nuclei;
D O I
10.1086/379663
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present the results of a high angular resolution study of the BL Lac object Markarian 501 in the radio band. We consider data taken at 14 different epochs, ranging between 1.6 and 22 GHz in frequency, and including new Space VLBI observations obtained on 2001 March 5 and 6 at 1.6 and 5 GHz. We study the kinematics of the parsec-scale jet and estimate its bulk velocity and orientation with respect to the line of sight. Limb-brightened structure in the jet is clearly visible in our data, and we discuss its possible origin in terms of velocity gradients in the jet. Quasi-simultaneous, multiwavelength observations allow us to map the spectral index distribution and to compare it to the jet morphology. Finally, we estimate the physical parameters of the parsec-scale jet.
引用
收藏
页码:127 / 140
页数:14
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