摘要
使用澳大利亚致密阵 (ATCA)对一个红外光度高达 1 0 1 1 .8- 1 0 1 2 .8L⊙ 的IRAS星系样本进行了 8.6 ,4.8,2 .4和 1 .4GHz的射电观测 .发现其中有 4个源在高频为陡谱 ,在较低频率上流量降低 ,呈峰状 ,峰值在几GHz .讨论了造成频谱倒转的两种可能机制 :同步自吸收和free free吸收 .通过对 0 0 1 99- 742 6 ,0 2 5 87- 6 3 3 6 ,0 70 2 0 - 5 4 2 3和 2 1 5 4 7- 5 82 3的频谱分析 ,我们认为free free吸收可能导致了低频倒转谱的形成 .通过对观测数据的模拟 。
An IRAS galaxy sample with infrared luminosity high up to 10 11.8 to 10 12.8 L ⊙ was observed using the Australia Compact Array (ATCA) at 8.6, 4.8, 2.4 and 1.4 GHz. The 4 galaxies in the sample are found to be steep spectra at high frequencies and decreasing flux densities at relatively low frequencies. Their spectra show a peak like pattern with the peak flux at several GHz. Two possible mechanisms for the turning down over in the low frequency side, synchrotron self absorption and free free absorption, are discussed. From the analysis of the spectra of 00199-7426, 02587-6336, 07020-5423 and 21547-5823, we conclude that free free absorption may cause the low frequency turnover. By the model fitting to the observations, we obtain some related parameters of these sources.
出处
《天文学报》
CSCD
北大核心
2001年第4期408-413,共6页
Acta Astronomica Sinica
