The low-frequency properties of FR 0 radio galaxies
The low-frequency properties of FR 0 radio galaxies
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FR 0 射电星系的低频特性
DOI：
10.1051/0004-6361/201936254
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发表时间：
2019
影响因子：
6.5
通讯作者：
U. Groningen
中科院分区：
文献类型：
--
作者：
A. Capetti;R. D. Baldi;M. Brienza;R. Morganti;G. V. I. ;Italy;S. O. Physics;Astronomy;U. Southampton;UK.;D. Astronomia;U. Bologna;I. D. R. Astronomia;Italy Astron;The Netherlands Institute for Radio Astronomy;The Netherlands.;U. Groningen
利用TIFR GMRT巡天（TGSS）的替代数据发布，我们研究了FR 0射电星系的低频特性，FR 0射电星系是与1.4 GHz巡天发现的红质量早期星系相关的大量紧密型射电源。我们考虑了来自FR0CAT的TGSS观测，这是一个由104个FR0组成的样本，在z < 0.05时，除了一个外，其余都被TGSS覆盖，其中43个被检测到高于17.5 mJy的5σ极限。在FR 0附近没有探测到扩展的发射，对应于在100 kpc × 100 kpc的面积上的光度极限为> 4 × 1023 whz−1。除了8个FR 0外，所有FR 0在150 MHz和1.4 GHz之间都具有平坦或倒置的光谱形状（α < 0.5）：这种光谱行为证实了TGSS光束内光学薄扩展发射的普遍缺乏，正如其紧凑的1.4 GHz形态所期望的那样。5ghz的数据被用来构建他们的无线电频谱，在更高的频率下，这些频谱通常也是平坦的。通过聚焦1.4 GHz时磁通密度为bbb50 mJy的FR 0s子样品，我们发现其中约75%具有凸谱，但曲率小于更强大的GHz峰谱源（GPS）。典型的FR 0s无线电频谱可以通过向高频逐渐变陡来更好地描述，而不是从光学厚到光学薄的过渡，可能仅在约15%的样品中观察到。
Using the alternative data release of the TIFR GMRT Sky Survey (TGSS), we studied the low-frequency properties of FR 0 radio galaxies, the large population of compact radio sources associated with red massive early-type galaxies revealed by surveys at 1.4 GHz. We considered TGSS observations from FR0CAT, a sample formed by 104 FR 0s at z < 0.05: all but one of them are covered by the TGSS, and 43 of them are detected above a 5σ limit of 17.5 mJy. No extended emission has been detected around the FR 0s, corresponding to a luminosity limit of ≲4 × 1023 W Hz−1 over an area of 100 kpc × 100 kpc. All but eight FR 0s have a flat or inverted spectral shape (α < 0.5) between 150 MHz and 1.4 GHz: this spectral behavior confirms the general paucity of optically thin extended emission within the TGSS beam, as is expected for their compact 1.4 GHz morphology. Data at 5 GHz were used to build their radio spectra, which are also generally flat at higher frequencies. By focusing on a sub-sample of FR 0s with flux density > 50 mJy at 1.4 GHz, we found that ∼75% of them have a convex spectrum, but with a smaller curvature than the more powerful gigahertz peaked-spectrum sources (GPS). The typical FR 0s radio spectrum is better described by a gradual steepening toward high frequencies, rather than to a transition from an optically-thick to an optically-thin regime, possibly observed in only ∼15% of the sample.
FR0 射电星系的高分辨率 VLA 观测：紧凑射电源的特性和性质
影响因子：
4.8
作者：
Baldi R
通讯作者：
Baldi R
影响因子：
6.5
作者：
van Haarlem, M. P.;Wise, M. W.;van Zwieten, J.
通讯作者：
van Zwieten, J.