YNAO OpenIR  > 射电天文研究组
Thesis Advisor屈中权 ; 汪敏
Degree Grantor中国科学院研究生院(云南天文台)
Place of Conferral北京
Degree Discipline天体物理
Keyword射电望远镜 脉冲星 色散效应 平均轮廓
Abstract云南天文台40米射电望远镜始建于2004年,于2006年5月21日建成并投入观测。该天线建设的目的是接收“嫦娥工程”中月球探测卫星的下行数据以及使用VLBI天文测量方法对卫星进行定轨。作为目前国内第二大射电望远镜,如何使之用于射电天文观测研究方面,例如国际VLBI观测,单天线的脉冲星观测等,是我们努力要做的工作。 在这篇博士论文中,我们利用现有的VLBI终端设备建立 了一套脉冲星观测系统和并对流量较高的几颗脉冲星进行了试观测研究,对观测数据进行了软件相干消色散处理,取得了如下结果: 对船帆座脉冲星Vela(PSR J0835-4510)进行了2次长时间的观测,先相干消色散然后按周期折叠获得了其脉冲的平均轮廓,并发现了其周期变化较快的特点,具体表现在其脉冲轮廓半宽的展宽。对于DM(色散量)值较小的脉冲星PSR J0332+5434采用了直接累加的方法获得其脉冲轮廓,这两种情况下信噪比的差别不大(1-2)。 虑到天线及现在使用的VLBI终端的各项参数,40米天线的标称的最小可测灵敏度为16.8mJy,脉冲星的流量在L波段基本都在0.1-1mJy的范围之内,而40米天线现在使用的接收机是S和X波段,脉冲星的射电辐射在各个波段都有,表现为幂律谱,其谱指数在S波段为-1.6至-1.8之间,我们采用的是S波段接收机来接收射电辐射,因此,脉冲星的流量也随之下降。这样我们考虑采用增加带宽和积分时间的方法来提高信噪比,以及提高观测系统的灵敏度。 最后,我们对这个研究领域未来的工作方向进行了展望,并结合我们目前的研究进展,给出了切合实际的长远研究计划。
Other AbstractThe 40m radio telescope of YNAO was built from 2004 and finished on May. 21th, 2006, and began to carry out the observation from then. The aims of the construction are to receive the downlink scientific data of CLEP and use the astronomical measure method to determine the orbit of CE-1. As the second largest radio telescope in China, we have been considering how to use it on radio astronomical observation researches, such as international VLBI observations and single dish pulsar observations, etc. In this Ph.D. thesis, we use the VLBI terminal to do the observations on some high flux pulsars, then we do the software coherent de-dispersion to the data. The results are obtained as follows: For pulsar Vela(PSR J0835-4510), we had done several long time observations. First we fold the time domain data with the sight period and get the mean pulsar profiles, and we find the variety rate of its period is very quick which is specifically showed on the broaden half-width of mean pulsar profile. For the pulsars whose DM are very small, like PSR 0332+5434, we obtain the profiles by folding the data in the single channel. Compared to the coherent de-dispersion method, the difference of the two methods is not significant(1-2). Considering the parameters of the telescope and the using VLBI terminal, the smallest sensitivity of 40m radio telescope is 16.8mJy. The flux of pulsars in L band is basically in the range of 0.1-1mJy, but the receiver of 40m radio telescope works at S and X band. The pulsars emit on the whole radio band, and the spectrum index is between -1.6 and -1.8 in S band. Now we use the S band receiver to receive the radio emission of pulsars, while the flux decreases in this band. Therefore, we are need to raise the bandwidth and integration time to increase the SNR and the sensitivity of the system. Finally, we have made a prospect to the research topics of this field in the future. Considering our present research status, a long-term project is proposed.
Subject Area天文学
Document Type学位论文
Recommended Citation
GB/T 7714
郝龙飞. 云南天文台40米望远镜脉冲星观测系统的建立[D]. 北京. 中国科学院研究生院(云南天文台),2010.
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