伽马噪窄线赛弗特1型星系TXS 1206+549的中红外波段光变性质研究  

Mid-infrared Variability Properties of Gamma-ray-loud Narrow Line Seyfert 1 Galaxy TXS 1206+549

作　　者：黄伟天 宁宫明 毛李胜[1] Huang Weitian;Ning Gongming;Mao Lisheng(School of Physics and Electronic Information,Yunnan Normal University,Kunming 650500,China)

机构地区：[1]云南师范大学物理与电子信息学院,云南昆明650500

出　　处：《天文研究与技术》2023年第5期383-395,共13页Astronomical Research & Technology

基　　金：国家自然科学基金(12063007);云南省“兴滇英才支持计划”资助.

摘　　要：TXS 1206+549(红移z=1.344)是目前发现的最遥远的伽马噪窄线赛弗特1型星系。利用广域红外巡天探测器(Wide-field Infrared Survey Explorer,WISE)的长期测光数据,从两个方面系统研究了TXS 1206+549中红外波段的光变性质。首先,联合3种统计方法,研究了TXS 1206+549的日内光变(Intraday Variability,IDV),发现TXS 1206+549在2022年4月29日达到迄今为止所有WISE观测窗口的最亮水平,表现出非常特殊的光变过程:在约1.24天内,3.4μm和4.6μm波段分别持续变暗约1.1 mag和1.0 mag。据调研,这是第1次报道关于TXS 1206+549高置信度的中红外波段日内光变。TXS 1206+549在3.4μm和4.6μm波段的占空系数(Duty Cycle,DC)分别为27.8%和13.7%,明显低于Rakshit等人的结果,这是由于我们采用了相对保守的日内光变标准(大于3σ)。基于所有WISE观测窗口的测光数据(共21个窗口),研究了均方根-流量(rms-flux)关系,发现两者之间存在显著的线性关系。另外,发现TXS 1206+549在长时标上未表现出显著的颜色变化(即消色差),但在天量级时标上普遍表现出变亮变蓝(Bluer-When-Brighter,BWB)的趋势。结果暗示不同时标上TXS 1206+549的中红外波段光变机制不同:长期光变可能与多普勒效应相关,日内光变则可能与喷流中的激波有关。TXS 1206+549(redshift z=1.344)is the most distant gamma-ray-loud narrow line Seyfert 1 galaxy discovered so far.Using long-term photometric data from the Wide-field Infrared Survey Explorer(WISE),we systematically investigate the mid-infrared variability properties of TXS 1206+549 from two aspects.First,the mid-infrared Intraday Variability(IDV)of TXS 1206+549 was investigated by combining three statistical methods.It is found that TXS 1206+549 reached the brightest level of all WISE observational epochs on April 29,2022,exhibiting a very specific IDV:In the 3.4μm and 4.6μm bands,TXS 1206+549 continuously darkened by about 1.1 and 1.0 magnitudes,respectively,within about 1.24 days.The duty cycle(DC)of TXS 1206+549 in the 3.4μm and 4.6μm bands are 27.8%and 13.7%,respectively,which are significantly lower than the results reported by Rakshit et al.(2021).This ascribes to our more conservative IDV criterion(>3σ).The root-mean-square-flux(rms-flux)relationship was investigated based on the photometric data from all WISE observational epochs(21 in total),and a significant linear correlation was found.TXS 1206+549 did not exhibit significant color changes(i.e.,achromatic)during the long-term timescale,but generally exhibited a trend of bluer-when-brighter(BWB)during day-long timescales.These results imply different mechanisms for the mid-infrared variability of TXS 1206+549 at different timescales:the long-term variability may be related to Doppler effect,while the IDVs may be related to shocks in the jet.

关 键 词：赛弗特星系 红外光变 颜色变化 激波 

分 类 号：P157[天文地球—天文学]