Chinese Journal of Astronomy and Astrophysics最新文献_第5页

Time Lags between the 22 and 37GHz Bursts of 48 Radio-loud AGNs 48个agn的22 ghz和37GHz爆发之间的时间滞后

Chinese Journal of Astronomy and Astrophysics Pub Date : 2008-04-01 DOI: 10.1088/1009-9271/8/2/06

W. Deng, J. Bai, Li Zhang, Xian Yang

{"title":"Time Lags between the 22 and 37GHz Bursts of 48 Radio-loud AGNs","authors":"W. Deng, J. Bai, Li Zhang, Xian Yang","doi":"10.1088/1009-9271/8/2/06","DOIUrl":"https://doi.org/10.1088/1009-9271/8/2/06","url":null,"abstract":"Based on the light curves at 22 and 37 GHz from the Metsahovi monitoring program, we investigate the time lags between the two radio bands for 48 radio-loud AGNs. DCF and ZDCF analyses are applied to the data. Our results show that there is a strong correlation between the two radio frequencies for all the sources, with the variations in the light curves at 37 GHz leading the ones at 22 GHz in general. There is no obvious differences between different sub-class AGNs as regards the time lag. In two sources, it was found that the bursts at the lower frequency lead the ones at the higher frequency. One possible explanation is that electron acceleration dominates the light curve until the radiation reaches the maximum. Some sources, such as 3C 273, 3C 279, 3C 345 and 3C 454.3, have good enough data, so we can calculate their lags burst-by-burst. Our calculations show that different outbursts have different lags. Some bursts have positive lags, most of bursts have no clear lags, and a few have negative lags. This result means that different bursts are triggered by different mechanisms, and the interpretation for the result involves both an intrinsic and a geometric mechanism. The positive lags are well consistent with the shock model, and we use these lags to calculate the typical magnetic field strength of the radiating region.","PeriodicalId":124495,"journal":{"name":"Chinese Journal of Astronomy and Astrophysics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129007252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Speed Distributions of CMEs in Cycle 23 at Low and High Latitudes 低纬度和高纬度第23周期日冕物质抛射的速度分布

Chinese Journal of Astronomy and Astrophysics Pub Date : 2008-04-01 DOI: 10.1088/1009-9271/8/2/02

P. Gao, Ke-Jun Li

引用次数: 4

Bending of Jets in the QSO NRAO 530 QSO NRAO 530中射流的弯曲

Chinese Journal of Astronomy and Astrophysics Pub Date : 2008-04-01 DOI: 10.1088/1009-9271/8/2/05

X. Hong, ChuanLe Sun, Jun-Hui Zhao, D. Jiang, Zhi-qiang Shen, T. An, Weihua Wang, Jun Yang

{"title":"Bending of Jets in the QSO NRAO 530","authors":"X. Hong, ChuanLe Sun, Jun-Hui Zhao, D. Jiang, Zhi-qiang Shen, T. An, Weihua Wang, Jun Yang","doi":"10.1088/1009-9271/8/2/05","DOIUrl":"https://doi.org/10.1088/1009-9271/8/2/05","url":null,"abstract":"We present radio images of NRAO 530 on scales ranging from pc to kpc. The observations include the EVN at 5 GHz, the VLBA at 1.6, 8.6 and 15 GHz, the MERLIN at 1.6 and 5 GHz, and the VLA at 5, 8.4, 15, 22, and 43 GHz. The VLBI images show a core-jet structure with an oscillating trajectory on a scale of about 30 mas north of the strongest compact component (core). Superluminal motions are detected in five of the jet components with apparent velocities in the range of 13.6 to 25.2c. A new component is detected at 15 GHz with the VLBA observations, which appears to be associated with the outburst in 2002. Significant polarized emission is detected around the core with the VLBA observations at 15 GHz. Rapid variations of the polarization intensity and angle are found between the epochs in 2002 and 2004. On the kpc-scale, a distant component (labelled as WL) located 11 aresec west (PA=-86 degrees) of the core is detected beyond the core-jet structure which extended to several hundreds of mas in the north-west direction (-50 degrees). A significant emission between the core-jet structure and the WL is revealed. A clump of diffuse emission (labelled EL, 12 arcsec long) at PA 70 degrees to the core, is also detected in the VLA observations, suggesting the presence of double lobes in the source. The core component shows a flat spectrum, while the distant components WL and EL have steep spectra. The steep spectra of the distant components and the detection of the arched emission suggest that the distant components are lobes or hot-spots powered by the core of NRAO 530. The morphologies from pc- to kpc-scales and the bending of jets are investigated. The observed radio morphology from pc to kcp appears to favor the model in which precession or wobbling of the nuclear disk drives the helical motion of the radio plasma and produces the S-shaped structure on kpc scale.","PeriodicalId":124495,"journal":{"name":"Chinese Journal of Astronomy and Astrophysics","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128542465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Variability Study of the SX Phoenicis Star BL Camelopardalis SX Phoenicis Star BL Camelopardalis的变异研究

Chinese Journal of Astronomy and Astrophysics Pub Date : 2008-04-01 DOI: 10.1088/1009-9271/8/2/11

J. Fu, Chao Zhang, K. Marak, C. Boonyarak, P. Khokhuntod, Shi-yang Jiang

引用次数: 10

Detection of CO Outflow in Rotating Cores 旋转磁芯CO流出量的检测

Chinese Journal of Astronomy and Astrophysics Pub Date : 2008-04-01 DOI: 10.1088/1009-9271/8/2/10

X. Guan, Yue-fang Wu

引用次数: 2

Radio Luminosity, Black Hole Mass and Eddington Ratio for Quasars from the Sloan Digital Sky Survey 来自斯隆数字巡天的类星体的射电光度、黑洞质量和爱丁顿比

Chinese Journal of Astronomy and Astrophysics Pub Date : 2008-03-24 DOI: 10.1088/1009-9271/8/5/03

W. Bian, Yan-Mei Chen, Chen Hu, Kai Huang, Yan Xu

{"title":"Radio Luminosity, Black Hole Mass and Eddington Ratio for Quasars from the Sloan Digital Sky Survey","authors":"W. Bian, Yan-Mei Chen, Chen Hu, Kai Huang, Yan Xu","doi":"10.1088/1009-9271/8/5/03","DOIUrl":"https://doi.org/10.1088/1009-9271/8/5/03","url":null,"abstract":"We investigate the M-BH-sigma* relation for radio-loud quasars with redshift z < 0.83 in Data Release 3 of the Sloan Digital Sky Survey (SDSS). The sample consists of 3772 quasars with better models of the H beta and [O III] lines and available radio luminosity, including 306 radio-loud quasars, 3466 radio-quiet quasars with measured radio luminosity or upper-limit of radio luminosity (181 radio-quiet quasars with measured radio luminosity). The virial supermassive black hole mass (M-BH) is calculated from the broad H beta line, and the host stellar velocity dispersion (sigma*) is traced by the core [O III] gaseous velocity dispersion. The radio luminosity and radio loudness are derived from the FIRST catalog. Our results are as follows: (1) For radio-quiet quasars, we confirm that there is no obvious deviation from the M-BH-sigma* relation defined for inactive galaxies when the uncertainties in M-BH and the luminosity bias are concerned. (2) We find that the radio-loud quasars deviate more from the M-BH-sigma* relation than do the radio-quiet quasars. This deviation is only partly due to a possible cosmological evolution of the M-BH-sigma* relation and the luminosity bias. (3) The radio luminosity is proportional to M-BH(1.28-0.16+.023) (L-Bol/L-Edd)(1.29-0.24+0.31) for radio-quiet quasars and to M-BH(3.10-0.70+0.60) (L-Bol/L-Edd)(4.18-1.10+1.40) for radio-loud quasars. The weaker dependence of the radio luminosity on the mass and the Eddington ratio for radio-loud quasars shows that other physical effects would account for their radio luminosities, such as the spin of the black hole.","PeriodicalId":124495,"journal":{"name":"Chinese Journal of Astronomy and Astrophysics","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127677283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Hyperaccretion after the Blandford-Znajek Process: A New Model for GRBs with X-Ray Flares Observed in Early Afterglows Blandford-Znajek过程后的超吸积:在早期余辉中观测到的带有x射线耀斑的伽马射线暴的新模型

Chinese Journal of Astronomy and Astrophysics Pub Date : 2008-02-04 DOI: 10.1088/1009-9271/8/4/04

W. Lei, Ding-xiong Wang, Y. Zou, Lei Zhang

引用次数: 19

Possible Contribution of Mature γ-ray Pulsars to Cosmic-ray Positrons 成熟γ射线脉冲星对宇宙射线正电子的可能贡献

Chinese Journal of Astronomy and Astrophysics Pub Date : 2008-02-01 DOI: 10.1088/1009-9271/8/1/09

Q. Gao, Zejun Jiang, Li Zhang

引用次数: 4

A New Critical Value Concerning the Genealogy of Long Period Families at L4 in the Restricted Three-body Problem ∗ 受限三体问题中L4处长周期族系谱的一个新临界值*

Chinese Journal of Astronomy and Astrophysics Pub Date : 2008-02-01 DOI: 10.1088/1009-9271/8/1/11

X. Hou, Lin Liu

引用次数: 5

Periodic Orbits in Rotating Second Degree and Order Gravity Fields 旋转二阶重力场和阶重力场中的周期轨道

Chinese Journal of Astronomy and Astrophysics Pub Date : 2008-02-01 DOI: 10.1088/1009-9271/8/1/12

Weiduo Hu, D. Scheeres

引用次数: 43