论文标题
pks1413+135：哦，h，z = 0.247 with meerkat
PKS1413+135: OH and HI at z = 0.247 with MeerKAT
论文作者
论文摘要
大型调查项目“ Meerkat吸收线调查”（MALS）在L波段中观察到BL LAC PKS 1413+135，在1139 MHz和1293-1379 MHz中观察到，针对Z = 0.24671的HI和OH线。如缺乏重力图像所暗示的那样，无线电连续体被认为来自低于0.5的背景对象。 HI吸收线在高信号到噪声下被检测到具有狭窄的中央组件和红翼，证实了先前的结果。在（Maser）发射中清楚地检测到OH 1720 MHz线，相对于HI峰，以速度峰值峰值升至-10升至-15 km/s。 1612 MHz线由于无线电干扰而丢失。 OH 1667 MHz主线在吸收中暂时检测到1665 MHz。 30年来，由于无线电结的静光动作引起的视线迅速变化，在光学深度中观察到很高的可变性。 HI线的深度差异为20％，而OH-1720 MHz深度的变化为因子4。中心速度的位置和宽度也有所不同。吸收的银河系是一种早期型螺旋（也许是S0），带有突出的尘埃道，覆盖了整个磁盘。鉴于测得的质量浓度，并且在厘米波长时的无线电连续大小（对应于z = 0.25的400 pc），核区域的吸收线的宽度预计可高达250 km/s。观察到的线的狭窄（<15 km/s）表明吸收来自外部气环，正如在S0星系中经常观察到的那样。毫米的线甚至更窄（<1 km/s），对应于限制在核心的连续大小。核心源被单个1 PC分子云（柱密度）的单个1 pc分子云覆盖，这与X射线中检测到的气屏兼容。
The BL Lac PKS 1413+135 was observed by the Large Survey Project "MeerKAT Absorption Line Survey" (MALS) in the L-band, at 1139 MHz and 1293-1379 MHz, targeting the HI and OH lines in absorption at z = 0.24671. The radio continuum is thought to come from a background object at redshift lower than 0.5, as suggested by the absence of gravitational images. The HI absorption line is detected at high signal-to-noise, with a narrow central component, and a red wing, confirming previous results. The OH 1720 MHz line is clearly detected in (maser) emission, peaking at a velocity shifted by -10 to -15 km/s with respect to the HI peak. The 1612 MHz line is lost due to radio interferences. The OH 1667 MHz main line is tentatively detected in absorption, but not the 1665 MHz one. Over 30 years, a high variability is observed in optical depths, due to the rapid changes of the line of sight, caused by the superluminal motions of the radio knots. The HI line has varied by 20 per cent in depth, while the OH-1720 MHz depth has varied by a factor 4. The position of the central velocity and the widths also varied. The absorbing galaxy is an early-type spiral (maybe S0) seen edge-on, with a prominent dust lane, covering the whole disk. Given the measured mass concentration, and the radio continuum size at centimeter wavelengths (100 mas corresponding to 400 pc at z = 0.25), the width of absorption lines from the nuclear regions are expected up to 250 km/S. The narrowness of the observed lines (< 15 km/s) suggest that the absorption comes from an outer gas ring, as frequently observed in S0 galaxies. The millimetric lines are even narrower (< 1 km/s), which corresponds to the continuum size restricted to the core. The core source is covered by individual 1 pc molecular clouds, of column density a few 10^22 cm-2, which is compatible with the gas screen detected in X-rays.
