论文标题
在低亮度射线星系NGC 5322中发现罕见的大型FR-I喷气机的Lofar发现
LOFAR discovery of rare large FR-I jets in low-luminosity radio galaxy NGC 5322
论文作者
论文摘要
在这里使用144 MHz Lofar图像在此报告了附近椭圆形NGC 5322中附近椭圆形的NGC 5322中微弱的Fr〜i无线电喷气机的发现。喷气机的角度范围为$ \ sim40 $ arcmin或预计的物理范围$ \ sim350 $ kpc。微弱的喷气机保持良好的准直，并在白术介质中消失，没有任何可见的热点或无线电裂片。在较高频率下最多检测到$ \ sim20 $ kpc范围的喷气机相对明亮，在星系的光学范围内，但在外部突然变得微弱，仅在Lofar图像中进行检测。 Galaxy在144 MHz的总无线电发光度估计为$ 3.7（\ pm0.4）\ times10^{22} $ W Hz $^{ - 1} $。光学范围之外的微弱喷气机的144 MHz无线电发光度估计为$ 7.1（\ pm2.0）\ times10^{21} $ W Hz $^{ - 1} $。与一般射电星系相比，喷气机的无线电发光程度异常较大。它使NGC 5322成为罕见的射电星系群体的成员，此前在其他无线电调查中未发现。恒星核心耗竭和喷气机周围的低密度环境的综合作用是从先前在其他波带上的研究中推断出来的，导致周围材料夹带到喷气机上的夹带较弱，尽管无线电亮度低，但仍可能导致其大尺寸。
The discovery of faint FR~I radio jets in the nearby elliptical galaxy NGC 5322 is reported here using 144 MHz LOFAR image. The jets have an angular extent of $\sim40$ arcmin or a projected physical extent of $\sim350$ kpc. The faint jets remain well collimated and disappear in the intergalactic medium, without any visible hotspot or radio lobes. The jets detected up to $\sim20$ kpc extent at higher frequencies are relatively bright within the optical extent of the galaxy but become faint abruptly outside, where detection is made only in the LOFAR image. The total radio luminosity of the galaxy at 144 MHz is estimated to be $3.7(\pm0.4)\times10^{22}$ W Hz$^{-1}$. The 144 MHz radio luminosity of the faint jets outside the optical extent is estimated to be $7.1(\pm2.0)\times10^{21}$ W Hz$^{-1}$. The extent of the jets for its radio luminosity is abnormally large when compared to the general population of radio galaxies. It makes NGC 5322 a member of a rare population of radio galaxies, previously not detected in other radio surveys. A combined effect of stellar core depletion and low-density environment around the jets, inferred from previous studies in other wave-bands, resulting into weak entrainment of surrounding material to the jets could be responsible for its large size despite a low radio luminosity.
