Feedback Factory: Multiple faint radio-jets detected in a cluster at z=2
Boris S. Kalita, Emanuele Daddi, Rosemary T. Coogan, Ivan Delvecchio, Raphael Gobat, Francesco Valentino, Veronica Strazzullo, Evangelia Tremou, David Elbaz, Ca… 展开作者
Boris S. Kalita, Emanuele Daddi, Rosemary T. Coogan, Ivan Delvecchio, Raphael Gobat, Francesco Valentino, Veronica Strazzullo, Evangelia Tremou, David Elbaz, Carlos Gómez-Guijarro, Alexis Finoguenov
We report the detection of multiple faint radio sources, that we identify as AGN-jets, within CLJ1449+0856 at z=2 using 3 GHz VLA observations. We study the effects of radio-jet based kinetic feedback at high redshifts, which has been found to be crucial in low redshift clusters to explain the observed thermodynamic properties of their ICM. We investigate this interaction at an epoch featuring high levels of AGN activity and a transitional phase of ICM in regards to the likelihood of residual cold-gas accretion. We measure a total flux of $\rm 30.6 \pm 3.3~μJy$ from the 6 detected jets. Their power contribution is estimated to be $1.2 ~(\pm 0.6)~ \times 10^{44} ~\rm ergs~ s^{-1}$, although this value could be up to $4.7 ~ \times 10^{44} ~\rm ergs~ s^{-1}$. This is a factor $\sim 0.25 - 1.0$ of the previously estimated instantaneous energy injection into the ICM of CLJ1449+0856 from AGN outflows and star formation, that have already been found to be sufficient in globally offsetting the cooling flows in the cluster core. In line with the already detected abundance of star formation, this mode of feedback being distributed over multiple sites, contrary to a single central source observed at low redshifts, points to accretion of gas into the cluster centre. This also suggests a 'steady state' of the cluster featuring non cool-core like behaviour. Finally, we also examine the TIR-radio luminosity ratio for the known sample of galaxies within the cluster core and find that dense environments do not have any serious consequence on the compliance of galaxies to the IR-radio correlation.
SKA-VLBI Probes of High-energy Emission Processes in Relativistic Jets
University of Manchester(曼彻斯特大学);University of Bristol(布里斯托大学);Max Planck Institute for Radio Astronomy(马克斯·普朗克射电天文研究所);Joint Institute for VLBI ERIC(甚长基线干涉测量联合研究所);University of Turku(图尔库大学);Aalto University(阿尔托大学)
A population of galaxy-scale jets discovered using LOFAR
来自高光度射电活动星系核的反馈效应在文献中已被广泛讨论,但来自低光度射电活动星系核的反馈还不太清楚。高灵敏度、高角分辨率、大视场望远镜(如LOFAR)的出现,现在首次允许对这种微弱源进行广域研究。利用LOFAR两米巡天(LoTSS)的第一次数据发布,我们报告了我们发现的195个射电星系的人口与150 MHz的光度之间的$3\times10^{22}$和$1.5\times10^{25}\text{ W Hz}^{-1}$和总的无线电发射不大于80千秒差距。这些物体,我们称之为星系尺度喷流(GSJ),足够小,可以直接影响宿主在星系尺度上的演化。我们的样本的典型主机属性的报告,发现9%的主机由螺旋与其余的主机由椭圆星系。其中两个螺旋型的GSJ是非常不寻常的,具有低射电光度和类似FRII的形态。我们的GSJ的主机属性表明,它们是普通的活动星系核在其生命的一个阶段后不久,无线电发射已扩大超出主机的中心区域。根据我们的估计,我们发现,大约有一半的GSJ有内部无线电波瓣能量的ISM能量的一个数量级内,这样,即使忽略任何可能的冲击,GSJ积极能够影响主机的演变。GSJ目前的样本将随着未来LoTSS的发布而增加,也可以为进一步研究低光度射电源的反馈奠定基础。
Identification of Large-Scale (>100 kpc) Radio Jets in Narrow-Line Seyfert 1 Galaxies
Indian Institute of Astrophysics(印度天体物理研究所);National Remote Sensing Centre (NRSC), Indian Space Research Organisation (ISRO)(国家遥感中心(NRSC),印度空间研究组织(ISRO));Inter-University Centre for Astronomy and Astrophysics (IUCAA)(大学间天文学与天体物理学中心(IUCAA))
Identification and Study of Irregular Radio Sources with SKA Continuum Surveys
National Astronomical Observatories, Chinese Academy of Sciences(中国科学院国家天文台);Guangxi Normal University(广西师范大学);Xiamen University(厦门大学);Jadavpur University(贾达普大学);Zhejiang University(浙江大学)