TM65m望远镜谱线观测系统的频率校准  

Frequency Calibration of Molecular Line Observing System of the TM65m Radio Telescope

作　　者：李娟[1,2] 吴亚军[1,2] 乔海花 王均智[1,2] 左秀婷[1,2] 

机构地区：[1]中国科学院上海天文台上海200030 [2]中国科学院射电天文重点实验室上海200030 [3]中国科学院大学北京100049

出　　处：《天文学报》2015年第6期648-657,共10页Acta Astronomica Sinica

基　　金：973项目(2012CB821800);国家自然科学基金项目(11103006,11173051)资助

摘　　要：频率校准是进行谱线天文观测前必做的准备工作,对上海天文台TM65m射电望远镜的谱线终端DIBAS(Digital Backend System)进行了频率校准及测试工作,发现它有良好的性能.首先,进行了PCAL信号注入测试,对DIBAS终端的频率分辨率、频率漂移、谱之间间隔的稳定性进行了测试.1 h内,单个尖峰频率漂移的最大变化幅度为0.03通道,尖峰之间间隔的最大起伏为0.05通道.然后,通过对大质量恒星形成区的H_2CO脉泽与吸收线的观测,以及与GBT(Robert C.Byrd Green Bank Telescope)观测结果的比较,发现频率校准的结果是正确的.最后,对W3(OH)进行了1个多小时的羟基脉泽观测和5个多小时的甲醇脉泽观测,发现谱线的谱型保持一致,观测噪声与理论噪声一致,说明频率校准程序是稳定可靠的.In order to carry out molecular line observations with the TM65m ra- dio telescope, we carry out the frequency calibration and test observations of DIBAS （Digital Backend System）, which is the spectrometer of the telescope. First, we test the performance of DIBAS with PCAL signals. We find that the spectral resolution is equal to the channel width, and the inaccuracy of spectral resolution is much lower than the channel width. Second, we observed H2CO lines toward two sources. The centroid velocity of calibrated data is consistent with GBT （Robert C. Byrd Green Bank Telescope） observations. At last, we observed 1665 MHz OH maser lines toward W3（OH） for one hour. The line shapes keep stable, and the RMS （Root Mean Squares） noise levels are consistent with theoretical values. We also observed 6.7 GHz methanol masers toward W3（OH） for several scans with a separation of about one hour. The line shapes of each scans are well consistent with each other.

关 键 词：技术:测光 谱线:证认 射电谱线:星际介质 星际介质:分子 

分 类 号：P161[天文地球—天文学]