水脉泽寄主星系的Spitzer中红外特性研究

The Spitzer middle infrared properties of H2O mega-maser host galaxies

截至目前,在已搜寻过的5000多个星系中,只在180多个星系中探测到水脉泽辐射,这种脉泽的绝大多数与活动星系核(AGN)辐射相关.文章利用先进的红外卫星Spitzer对水脉泽星系样本多个波段的观测资料(3.6μm、4.5μm、5.8μm、8.0μm和24.0μm),计算得到该样本的红外辐射光度、谱指数等物理参量.通过统计对比分析水脉泽寄主星系和非水脉泽寄主星系在各个波段的辐射光度和谱指数、中红外能谱分布,结果显示:①水脉泽星系有较大的中红外光度,尤其在长波24μm波段更为明显;②水脉泽和非水脉泽星系的谱指数与能谱分布没有明显区别;③水脉泽光度与其寄主星系的中红外光度统计显示没有明显的相关性.研究结果为将来水脉泽的搜寻工作提供可能的选源指导.

To date,only 180 galaxies are detected with H2O maser emission in more than 5000 targeted galaxies.Active galactic nucleus(AGN)are believed the energy source that stimulate the H2O maser emission.So,the infrared emission from the AGN may be connected with the maser production.In this paper,the middle infrared(MIR)luminosity and spectral indices of the sample are calculated by using the Spitzer photometric data(3.6μm、4.5μm、5.8μm、8.0μm and 24.0μm).Through statistic and comparative analysis on the MIR luminosity at each band,spectral indices and the spectral energy distribution for H2O masers and non-H2O maser sample(without detected H2O maser emission),the results show:①H2O masers tend to have higher MIR luminosity than non-H2O masers,especially at 24.0μm band.②There are no significant difference in spectral indices and spectral energy distribution between H2O masers and non-H2O masers.③The masers emission is not correlated with the MIR emission of its host galaxy.These results should provide possible constraints on the sample selection for the future water maser surveys.