LOFAR MSSS: The scaling relation between AGN cavity power and radio luminosity at low radio frequencies

Abstract

We present a new analysis of the widely used relation between cavity power and radio luminosity in clusters of galaxies with evidence for strong AGN feedback. We study the correlation at low radio frequencies using two new surveys -the First Alternative Data Release of the TIFR GMRT Sky Survey (TGSS ADR1) at 148 MHz and LOFAR's first all-sky survey, the Multifrequency Snapshot Sky Survey (MSSS) at 140 MHz. We find a scaling relation P cav ∝ L β 148 , with a logarithmic slope of β = 0.51 ± 0.14, which is in good agreement with previous results based on data at 327 MHz. The large scatter present in this correlation confirms the conclusion reached at higher frequencies that the total radio luminosity at a single frequency is a poor predictor of the total jet power. Previous studies have shown that the magnitude of this scatter can be reduced when bolometric radio luminosity corrected for spectral aging is used. We show that including additional measurements at 148 MHz alone is insufficient to improve this correction and further reduce the scatter in the correlation. For a subset of four well-resolved sources, we examine the detected extended structures at low frequencies and compare with the morphology known from higher frequency images and Chandra X-ray maps. In Perseus we discuss details in the structures of the radio mini-halo, while in the 2A 0335+096 cluster we observe new diffuse emission associated with multiple X-ray cavities and likely originating from past activity. For A2199 and MS 0735.6+7421, we confirm that the observed low-frequency radio lobes are confined to the extents known from higher frequencies. This new low-frequency analysis highlights the fact that existing cavity power to radio luminosity relations are based on a relatively narrow range of AGN outburst ages. We discuss how the correlation could be extended using low frequency data from the LOFAR Two-metre Sky Survey (LoTSS) in combination with future, complementary deeper X-ray observations.

Cosmological Simulation of Galaxy Groups and Clusters. II. Studying Different Modes of Feedback through X-Ray Observations

“…By comparing the feedback energy obtained for various modes from our work with that from actual observations, we can comment on the feedback modes that are at play in the real universe. Previous studies have been done to measure the feedback energy estimated from the X-ray cavities produced by the AGN (Bîrzan et al 2004(Bîrzan et al , 2008Rafferty et al 2006;Kokotanekov et al 2017). Our results show an agreement with the energy scale at low redshift obtained from these observations.…”

Powerful Radio Sources in the Southern Sky. I. Optical Identifications

“…Both ionized gas and cold molecular gas components wrap around the radio jet and the X-ray cavities (Tremblay et al 2016), and the cospatial and comoving warm ionized and cold molecular components are consistent with a scenario of chaotic cold accretion, precipitation, and stimulated feedback (Tremblay et al 2018). A ghost cavity at 330 MHz was also detected (Kokotanekov et al 2017). G4Jy 1854: is a lobe-dominated radio QSO having a steep radio spectrum and emission line in its optical spectrum that, if interpreted as Mg II, suggests a redshift estimate of z = 1.39 (Thompson et al 1990).…”

Constraining the AGN duty cycle in the cool-core cluster MS 0735.6+7421 with LOFAR data

“…We note that LOFAR snapshot observations of MS0735 has already been shown by Kokotanekov et al (2017). This observation was performed during the first LOFAR all-sky survey, the Multifrequency Snapshot Sky Survey (MSSS; see Heald et al 2015).…”