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Space-Time Geometry of Quark and Strange Quark Matter 夸克和奇异夸克物质的时空几何
Chinese Journal of Astronomy and Astrophysics Pub Date : 2007-12-01 DOI: 10.1088/1009-9271/7/6/02
I. Yilmaz, C. Aktaş
{"title":"Space-Time Geometry of Quark and Strange Quark Matter","authors":"I. Yilmaz, C. Aktaş","doi":"10.1088/1009-9271/7/6/02","DOIUrl":"https://doi.org/10.1088/1009-9271/7/6/02","url":null,"abstract":"We study quark and strange quark matter in the context of general relativity. For this purpose, we solve Einstein's field equations for quark and strange quark matter in spherical symmetric space-times. We analyze strange quark matter for the different equations of state (EOS) in the spherical symmetric space-times, thus we are able to obtain the space-time geometries of quark and strange quark matter. Also, we discuss the features of the obtained solutions. The obtained solutions are consistent with the results of Brookhaven Laboratory, i.e. the quark-gluon plasma has a vanishing shear (i.e. quark-gluon plasma is perfect).","PeriodicalId":124495,"journal":{"name":"Chinese Journal of Astronomy and Astrophysics","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128391377","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: 10
Very Early Optical Afterglows for Geometric Models of X-ray Flashes and X-ray Rich GRBs x射线闪光和富x射线伽马射线暴几何模型的早期光学余辉
Chinese Journal of Astronomy and Astrophysics Pub Date : 2007-12-01 DOI: 10.1088/1009-9271/7/6/05
T. Yan, T. Yan, D. Wei, D. Wei, Yizhong Fan, Yizhong Fan
{"title":"Very Early Optical Afterglows for Geometric Models of X-ray Flashes and X-ray Rich GRBs","authors":"T. Yan, T. Yan, D. Wei, D. Wei, Yizhong Fan, Yizhong Fan","doi":"10.1088/1009-9271/7/6/05","DOIUrl":"https://doi.org/10.1088/1009-9271/7/6/05","url":null,"abstract":"If X-ray flashes (XRFs) and X-ray rich Gamma-ray Bursts (XRRGs) have the same origin as the Gamma-ray bursts (GRBs) but are viewed off-center from structured jets, their early afterglows may differ from those of GRBs, and when the ultra-relativistic outflow interacts with the surrounding medium, there are two shocks formed, a forward shock (FS), and a reverse shock (RS). We calculate numerically the early afterglow powered by uniform jets, Gaussian jets and power-law jets in the forward-reverse shock scenario. A set of differential equations govern the dynamical evolution. The synchrotron self-Compton effect has been taken into account in the calculation. In the uniform jets, the very early afterglows of XRRGs and XRFs are significantly lower than the GRBs and the observed peak times of RS emission are later in the interstellar medium environment. The RS components in XRRGs and XRFs are difficult to detect, but in the stellar wind environment, the reduction of the very early flux and the delay of the RS peak time are not so remarkable. In nonuniform jets (Gaussian and power-law jets), where there are emission materials on the line of sight, the very early light curve resembles equivalent isotropic ejecta in general although the RS flux decay index shows notable deviations if the RS is relativistic (in stellar wind).","PeriodicalId":124495,"journal":{"name":"Chinese Journal of Astronomy and Astrophysics","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115452340","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: 8
CO Clouds around SNR G21.8-0.6 and G32.8-0.1 信噪比G21.8-0.6和G32.8-0.1附近的CO云
Chinese Journal of Astronomy and Astrophysics Pub Date : 2007-10-20 DOI: 10.1088/1009-9271/7/5/11
Jianjun Zhou, Xi-Zheng Zhang, Hongbo Zhang, J. Esimbek, Ju-Yong Zhang, B. Ju
{"title":"CO Clouds around SNR G21.8-0.6 and G32.8-0.1","authors":"Jianjun Zhou, Xi-Zheng Zhang, Hongbo Zhang, J. Esimbek, Ju-Yong Zhang, B. Ju","doi":"10.1088/1009-9271/7/5/11","DOIUrl":"https://doi.org/10.1088/1009-9271/7/5/11","url":null,"abstract":"We made the first CO(1–0) mapping to SNR G21.8–0.6 and SNR G32.8–0.1, both associated with OH 1720 MHz maser. Based on the morphological correspondence and velocity and position agreement between the radio remnant and the CO clouds, we tentatively identify the clouds that are respectively interacting with the two SNRs.","PeriodicalId":124495,"journal":{"name":"Chinese Journal of Astronomy and Astrophysics","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125158775","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
Luminosity function of the cluster of galaxies abell 566 星系团abell 566的光度函数
Chinese Journal of Astronomy and Astrophysics Pub Date : 2007-10-01 DOI: 10.1088/1009-9271/7/5/02
Q. Xiao, Z. Shao, Xu Zhou
{"title":"Luminosity function of the cluster of galaxies abell 566","authors":"Q. Xiao, Z. Shao, Xu Zhou","doi":"10.1088/1009-9271/7/5/02","DOIUrl":"https://doi.org/10.1088/1009-9271/7/5/02","url":null,"abstract":"We investigate the Luminosity Function (LF) of the cluster of galaxies Abell 566. The photometric data of 15 intermediate-bands are obtained from the Beijing-Arizona-Taiwan-Connecticut (BATC) photometric sky survey. For each of the 15 wavebands, the LF of cluster galaxies is well modelled by the Schechter function, with characteristic luminosities from –18.0 to –21.9 magnitude, from the a- to the p-band. Morphological dependence of the LF is investigated by separating the cluster members into `red' and `blue' subsamples. It is clear that late type galaxies have a steeper shape of LF than the early type galaxies. We also divided the sample galaxies by their local environment. It was found that galaxies in the sparser region have steeper shape of LF than galaxies in the denser region. Combining the results of morphological and environmental dependence of LFs, we show that Abell 566 is a well relaxed cluster with positive evidence of galaxy interaction and merger, and excess number of bright early type galaxies located in its denser region.","PeriodicalId":124495,"journal":{"name":"Chinese Journal of Astronomy and Astrophysics","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122173937","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: 1
A statistical study of XBLs, RBLs and FSRQs at 1.5 GHz 1.5 GHz下XBLs、RBLs和fsrq的统计研究
Chinese Journal of Astronomy and Astrophysics Pub Date : 2007-10-01 DOI: 10.1088/1009-9271/7/5/03
Ji-Liang Zhou, J. Fan, Juan Li, Yi Liu
{"title":"A statistical study of XBLs, RBLs and FSRQs at 1.5 GHz","authors":"Ji-Liang Zhou, J. Fan, Juan Li, Yi Liu","doi":"10.1088/1009-9271/7/5/03","DOIUrl":"https://doi.org/10.1088/1009-9271/7/5/03","url":null,"abstract":"BL Lac objects are similar to theflat spectrumradioquasarsin manyaspects except regarding the emission lines. In order to study their relationship, we selected 56 BL Lacertae objects (33 X-ray-selected, 23 radio-selected) and 45 flat spectrum radio quasars, analyzed their radio luminosities and core-dominanceparameters. We found that the radio luminosities of the radio selected BL Lac objects located in between the X-ray selected BL Lac objects and the flat spectrum radio quasars. However, this intermediate position does not hold for the core-dominance parameter: the RBLs have the largest core-dominanceparameters. This sug- gests that the core-dominance parameter can not be taken as a sequencing criterion. We also investigatedthe correlationbetween the luminosity and the core-dominanceparameterfor the three subclasses. We concluded that, here, the sequence XBL-RBL—FSRQ still exists.","PeriodicalId":124495,"journal":{"name":"Chinese Journal of Astronomy and Astrophysics","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133830411","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
A Study on the Technique of Observing Interplanetary Scintillation with Simultaneous Dual-Frequency Measurements 双频同步观测行星际闪烁技术的研究
Chinese Journal of Astronomy and Astrophysics Pub Date : 2007-10-01 DOI: 10.1088/1009-9271/7/5/12
Xi-zhen Zhang
{"title":"A Study on the Technique of Observing Interplanetary Scintillation with Simultaneous Dual-Frequency Measurements","authors":"Xi-zhen Zhang","doi":"10.1088/1009-9271/7/5/12","DOIUrl":"https://doi.org/10.1088/1009-9271/7/5/12","url":null,"abstract":"Ground-based observation of Interplanetary Scintillation (IPS) is an important approach of monitoring solar wind speed. We describe both the principle and method of observing the solar wind speed by using the normalized cross-spectrum of simultaneous dual-frequency IPS measurement. The effects of the solar wind properties and the angular size of the scintillation source on the measurement of solar wind speed are investigated by numerical analysis. We carry out a comparison of this method with the traditional single station-single frequency method. We outline a new IPS observation system using this method now under construction at the National Astronomical Observatories, CAS (NAOC).","PeriodicalId":124495,"journal":{"name":"Chinese Journal of Astronomy and Astrophysics","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134375006","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: 9
Small-Scale Brightenings in the UV Continuum of an M9.1 Solar Flare M9.1太阳耀斑紫外连续体中的小尺度增亮
Chinese Journal of Astronomy and Astrophysics Pub Date : 2007-10-01 DOI: 10.1088/1009-9271/7/5/13
Lin Wang, C. Fang, M. Ding
{"title":"Small-Scale Brightenings in the UV Continuum of an M9.1 Solar Flare","authors":"Lin Wang, C. Fang, M. Ding","doi":"10.1088/1009-9271/7/5/13","DOIUrl":"https://doi.org/10.1088/1009-9271/7/5/13","url":null,"abstract":"We analyze an M9.1 two-ribbon solar flare which occurred on 2004 July 22 using the TRACE white-light and 1700 A images, the RHESSI, and the SOHO/MDI data. We find many small-scale fast-varying brightenings that appeared in the white-light and 1700 A images along the flare ribbons. Some of them underwent rapid motions in weak magnetic field regions. We identify these short-lived brightenings as UV continuum enhancement. Our preliminary result shows that the brightenings are closely related to the HXR emission. They have a lifetime of 30–60 s and a typical size of about 1''–2''. The intensity enhancement is about 150–200 times the mean value of the quiet-Sun. According to previous works, we infer that the 1700 A enhancement may be dominated by the increased emission of 1680 A continuum coming from the temperature minimum region. The impulsive feature in the 1700 A light curves of the small-scale brightenings may be due to the irradiation of the impulsive CIV line intensity caused by the bombardment of non-thermal electron beams.","PeriodicalId":124495,"journal":{"name":"Chinese Journal of Astronomy and Astrophysics","volume":"363 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134400346","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: 8
Shallow decay of X-ray afterglows in short GRBs: Energy injection from a millisecond magnetar? 短伽马射线暴中x射线余辉的浅衰减:来自毫秒磁星的能量注入?
Chinese Journal of Astronomy and Astrophysics Pub Date : 2007-10-01 DOI: 10.1088/1009-9271/7/5/07
Yu Yu, Yong-Feng Huang
{"title":"Shallow decay of X-ray afterglows in short GRBs: Energy injection from a millisecond magnetar?","authors":"Yu Yu, Yong-Feng Huang","doi":"10.1088/1009-9271/7/5/07","DOIUrl":"https://doi.org/10.1088/1009-9271/7/5/07","url":null,"abstract":"With the successful launch of Swift satellite, more and more data of early X-ray afterglows from short gamma-ray bursts have been collected. Some interesting features such as unusual afterglow light curves and unexpected X-ray flares are revealed. Especially, in some cases, there is a flat segment in the X-ray afterglow light curve. Here we present a simplified model in which we believe that the flattening part is due to energy injection from the central engine. We assume that this energy injection arises from the magnetic dipole radiation of a millisecond pulsar formed after the merger of two neutron stars. We check this model with the short GRB 060313. Our numerical results suggest that energy injection from a millisecond magnetar could make part of the X-ray afterglow light curve flat.","PeriodicalId":124495,"journal":{"name":"Chinese Journal of Astronomy and Astrophysics","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128836150","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: 17
An Infrared Photometric Study of Galaxies with Extragalactic H2O Maser Sources 河外水脉泽源星系的红外光度研究
Chinese Journal of Astronomy and Astrophysics Pub Date : 2007-10-01 DOI: 10.1088/1009-9271/7/5/06
P. S. Chen, Y. Gao, H. Shan
{"title":"An Infrared Photometric Study of Galaxies with Extragalactic H2O Maser Sources","authors":"P. S. Chen, Y. Gao, H. Shan","doi":"10.1088/1009-9271/7/5/06","DOIUrl":"https://doi.org/10.1088/1009-9271/7/5/06","url":null,"abstract":"All galaxies with extragalactic H2O maser sources observed so far are collected. With the 2MASS and the IRAS photometric data an infrared study is performed on those galaxies. By a comparison between the H2O maser detected sources and non-detected sources in the infrared it is indicated that infrared properties in the IRAS 12–25 μm and 60–100 μm are important for producing H2O masers in galaxies. It is also found that the H2O maser galaxies with different nuclear activity types have rather different infrared properties mainly in the IRAS 12–60 μm region.","PeriodicalId":124495,"journal":{"name":"Chinese Journal of Astronomy and Astrophysics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131271742","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: 0
X-ray spectroscopy of dips of Cir X-1 Cir X-1的x射线光谱
Chinese Journal of Astronomy and Astrophysics Pub Date : 2007-10-01 DOI: 10.1088/1009-9271/7/5/10
Y. Lei, F. Lu, J. Qu, Liming Song, Chengmin Zhang
{"title":"X-ray spectroscopy of dips of Cir X-1","authors":"Y. Lei, F. Lu, J. Qu, Liming Song, Chengmin Zhang","doi":"10.1088/1009-9271/7/5/10","DOIUrl":"https://doi.org/10.1088/1009-9271/7/5/10","url":null,"abstract":"We present X-ray spectral analyses of the low-mass X-ray binary Cir X-1 during X-ray dips, using the Rossi X-ray Timing Explorer (RXTE) data. Each dip was divided into several segments, and the spectrum of each segment was fitted with a three-component blackbody model, in which the first two components are affected by partial covering and the third one is unaffected. A Gaussian emission line is also included in the spectral model to represent the Fe K alpha line at similar to 6.4keV. The fitted temperatures of the two partially covered components are about 2 keV and I keV, while the uncovered component has a temperature of similar to 0.5-0.6keV. The equivalent blackbody emission radius of the hottest component is the smallest and that of the coolest component is the largest. During the dips the fluxes of the two hot components are linearly correlated, while that of the third component does not show any significant variation. The Fe line flux remains constant, within the errors, during the short dips. However, during the long dips the line flux varies significantly and is positively correlated with the fluxes of the two hot components. These results suggest: (1) that the temperature of the X-ray emitting region decreases with radius, (2) that the Fe Ka line emitting region is close to the hot continuum emitting region, and (3) that the size of the Fe line emitting region is larger than that of the obscuring matter causing the short dips but smaller than the region of that causing the long dips.","PeriodicalId":124495,"journal":{"name":"Chinese Journal of Astronomy and Astrophysics","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132586118","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: 1
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