We have analyzed the NVSS and SUMSS data at 1.4 GHz and 843 MHz for a well defined complete sample of hard X-ray AGN observed by INTEGRAL. A large number (70/79) of sources are detected in the radio band, showing a wide range of radio morphologies, from unresolved or slightly resolved cores to extended emission over several hundreds of kpc scales. The radio fluxes have been correlated with the 2-10 keV and 20-100 keV emission, revealing significant correlations with slopes consistent with those expected for radiatively efficient accreting systems. The high energy emission coming from the inner accretion regions correlates with the radio emission averaged over hundreds of kpc scales (i.e., thousands of years).
J0011+3443: a GPS compact symmetric object, gravitational lens, or dual AGN?
Interdisziplinäres Zentrum für Wissenschaftliches Rechnen (IWR), Universität Heidelberg（海德堡大学跨学科科学计算中心）；Department of Physics and Astronomy, Georgia State University（佐治亚州立大学物理与天文系）；Institut für Theoretische Physik, Universität Heidelberg（海德堡大学理论物理研究所）；CP3-Origins, University of Southern Denmark（南丹麦大学CP3起源研究中心）；Department of Astronomy, University of Maryland, College Park（马里兰大学帕克分校天文学系）
We present a systematic study of X-ray cavities using archival Chandra observations of nearby galaxy clusters selected by their Sunyaev-Zel'dovich (SZ) signature in the Planck survey, which provides a nearly unbiased mass-selected sample to explore the entire AGN feedback duty cycle. Based on X-ray image analysis, we report that 30 of the 164 clusters show X-ray cavities, which corresponds to a detection fraction of 18%. After correcting for spatial resolution to match the high-$z$ SPT-SZ sample, the detection fraction decreases to 9%, consistent with the high-z sample, hinting that the AGN fe…
The origin of the radio emission in radio-quiet quasars (RQQs) remains unclear. Radio emission may be produced by a scaled-down version of the relativistic jets observed in radio-loud (RL) AGN, an AGN-driven wind, the accretion disc corona, AGN photon-ionisation of ambient gas (free-free emission), or star formation (SF). Here, we report a pilot study, part of a radio survey (`PG-RQS') aiming at exploring the spectral distributions of the 71 Palomar-Green (PG) RQQs: high angular resolution observations ($\sim$50 mas) at 45~GHz (7 mm) with the Karl G. Jansky Very Large Array of 15 sources. Sub-…
The X-ray weakness of Little Red Dots and JWST-selected AGN: comparison with local AGN in different accretion regimes
INAF - Osservatorio astronomico di Roma（意大利国家天体物理研究所罗马天文台）；University of Geneva（日内瓦大学）；Universidad Diego Portales（迭戈·波特莱斯大学）；Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所）；Scuola Normale Superiore（比萨高等师范学院）；Peking University（北京大学）；Max-Planck-Institut für extraterrestrische Physik（德国马克斯·普朗克地外物理研究所）；University of Chinese Academy of Sciences（中国科学院大学）；National Astronomical Observatory of China（中国国家天文台）
A wide-frequency radio study of Active Galactic Nuclei (AGN) is crucial to evaluate the intervening radiative mechanisms responsible for the observed emission and relate them with the underlying accretion physics. We present wide frequency (5-45 GHz), high-sensitivity (few microJy/beam), (sub)-kpc JVLA observations of a sample of 30 nearby (0.003 < z < 0.3) AGN detected by INTEGRAL/IBIS at hard-X-ray. We find a high detection fraction of radio emission at all frequencies, i.e. > 95 per cent at 5, 10 and 15 GHz and > 80 per cent at 22 and 45 GHz. Two sources out of 30 remain undetected at our h…
We present the results of simultaneous multi-frequency imaging observations at 22, 43, 86, and 129\,GHz of OJ\,287. We used the Korean VLBI Network as part of the Interferometric MOnitoring of GAmma-ray Bright active galactic nuclei (iMOGABA). The iMOGABA observations were performed during 31 epochs from 2013 January 16 to 2016 December 28. We also used 15\,GHz OVRO and 225\,GHz SMA flux density data. We analyzed four flux enhancements in the light curves. The estimated time scales of three flux enhancements were similar with time scales of $\sim$50 days at two frequencies. A fourth flux enhan…
We conducted a Very Long Baseline Array (VLBA) observation of the low mass active galactic nucleus (AGN) in galaxy NGC 4293 ($z=0.003$). The object is associated with a low-ionization nuclear emission-line region (LINER). Its black hole mass is estimated as $\sim10^5$ or $\sim10^7 M_\odot$. The VLBA 1.5 GHz image shows an inverse symmetric structure with two discrete radio blobs separated by an angular distance of $\sim120$ mas, corresponding to $\sim7$ parsec. Furthermore, its integrated radio spectrum has a turnover at the frequency of $\sim0.44$ GHz. Based on the compactness and spectrum, t…
Chandra X-ray and Hubble Space Telescope Imaging of Optically Selected Kiloparsec-Scale Binary Active Galactic Nuclei II: Host Galaxy Morphology and AGN Activity
Even in deep X-ray surveys, Compton-thick active galactic nuclei (CT AGNs, ${\rm N_H} \geqslant 1.5~\times~10^{24}~{\rm cm}^{-2}$) are difficult to be identified due to X-ray flux suppression and their complex spectral shape. However, the study of CT AGNs is vital for understanding the rapid growth of black holes and the origin of cosmic X-ray background. In the local universe, the fraction of CT AGNs accounts for 30% of the whole AGN population. We may expect a higher fraction of CT AGNs in deep X-ray surveys, however, only 10% of AGNs have been identified as CT AGNs in the 7 Ms \textit{Chand…
