伽马噪窄线赛弗特1型星系的长期红外光变和颜色变化

The Long-term Infrared Brightness and Color Variabilities ofγ-ray-loud Narrow-line Seyfert 1 Galaxies

一些窄线赛弗特(Seyfert)1型星系因具有GeV伽马射线辐射(伽马噪)而受到持续关注,截至目前,共报道22个伽马噪窄线赛弗特1型星系,另有3个高置信度候选体。利用广域红外巡天探测器(Wide-field Infrared Survey Explorer,WISE)数据平台,获取了这些源W 1(3.4μm)和W 2(4.6μm)两个红外波段的2010年1月至2019年12月同时性测光数据。采用参数V和标准额外方差σ_(NXV)^(2)NXV方法,分析了它们的长期光变现象,结果表明,24个源表现出长期亮度(W 1星等)变化,17个源表现出长期颜色(W_(1)-W_(2))变化。通过研究颜色与星等的相关性,发现7个源表现出变亮变红现象(Redder-When-Brighter,RWB),4个源表现出变亮变蓝现象(Bluer-When-Brighter,BWB)。最后简要讨论了颜色变化的可能解释和暗示。

The detection of GeVγ-rays from some narrow-line Seyfert 1 galaxies(γ-ray-loud NLS1s)has received increasing attention.Up to now,22γ-ray-loud NLS1s and other 3 high-confidence candidates has been reported.Using the data platform of Wide-field Infrared Survey Explorer(WISE),we derived the simultaneous photometric data in the W 1(3.4μm)and W 2(4.6μm)bands(from January 2010 to December 2019)for these sources.Then we analyzed their long-term variability via the parameter V and the normalized excess varianceσ_(NXV)^(2) methods.It was found that 24 sources showed long-term brightness(W 1 magnitude)variabilities,and 17 sources showed long-term color(W 1-W 2)variabilities.When studying the correlation between color and magnitude,we found that 7 sources showed a redder-when-brighter(RWB)trend,and 4 sources showed a trend of bluer-when-brighter(BWB).Finally,the possible causes of color changes and implication are briefly discussed.