标题： J1615+5452：ELAIS-N1区域中的一个残余射电星系 显示英文标题

标题： J1615+5452: a remnant radio galaxy in the ELAIS-N1 field

摘要： 我们报告在ELAIS-N1区域发现了遗迹射电AGN J1615+5452。 使用GMRT在150、325和610 MHz的连续谱观测数据，结合1.4 GHz NVSS巡天的存档数据，得到了该源的射电谱。 在红移$z \sim$ 0.33下，J1615+5452的线性尺寸为$\sim$ 100 kpc，光谱指数在$\alpha^{1400}_{610} < -1.5$和$\alpha^{325}_{150} = -0.61 \pm 0.12$之间。 虽然该源在低频处有弥漫的射电辐射，但在$\sim 5$角秒分辨率的1.4 GHz VLA数据中未发现核心、喷流或热点的证据。 这种形态学特征与弯曲的射电谱表明，AGN的能量供应机制出现短缺，这是濒死射电AGN的典型特征。 这与光谱中观测到的陡峭曲率$\Delta\alpha \approx -1$一致，估计的同步辐射年龄为$t_{\rm s}=76.0^{+7.4}_{-8.7}$百万年和$t_{\rm off}/t_{\rm s}$比率为$\sim 0.3$。 显示英文摘要

摘要： We report the discovery of a remnant radio AGN J1615+5452 in the field of ELAIS-N1. GMRT continuum observations at 150, 325 and 610 MHz combined with archival data from the 1.4 GHz NVSS survey were used to derive the radio spectrum of the source. At a redshift $z \sim$ 0.33, J1615+5452 has a linear size of $\sim$ 100 kpc and spectral indices ranging between $\alpha^{1400}_{610} < -1.5$ and $\alpha^{325}_{150} = -0.61 \pm 0.12$. While the source has a diffuse radio emission at low frequencies, we do not find evidence of core, jets or hotspots in the 1.4\,GHz VLA data of $\sim 5$ arcsec angular resolution. Such morphological properties coupled with a curved radio spectrum suggest that the AGN fueling mechanisms undergo a shortage of energy supply which is typical of a dying radio AGN. This is consistent with the observed steep curvature in the spectrum $\Delta\alpha \approx -1$, the estimated synchrotron age of $t_{\rm s}=76.0^{+7.4}_{-8.7}$ Myr and a $t_{\rm off}/t_{\rm s}$ ratio of $\sim 0.3$.