Probing the Origin of Diffuse Radio Emission in the Cool Core of the Phoenix Galaxy Cluster

Raja, Ramij; Rahaman, Majidul; Datta, Abhirup; Burns, Jack O.; Alden, Brian; Intema, H. T.; Weeren, R. J. van; Hallman, Eric J.; Rapetti, David; Paul, Surajit

doi:10.3847/1538-4357/ab620d

Cited by 9 publications

(20 citation statements)

References 64 publications

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“…In addition, the GMRT data suffers from a relatively poor angular resolution and sensitivity compared to the VLA, so we cannot make any definite claims on the spectrum of the mini halo in the outer regions. Our reported value for the radio luminosity at 1.4 GHz is consistent with previous estimates by Van Weeren et al (2014) and Raja et al (2020), who calculated values of P 1.4 GHz = (10.4 ± 3.5) × 10 24 W Hz −1 and P 1.4 GHz = (14.38 ± 1.80) × 10 24 W Hz −1 , respectively.…”

Section: The Origin Of the Mini Halosupporting

confidence: 92%

“…The X-band data of this project was previously presented by McDonald et al (2019). In the L band, the VLA observed in both A and B configuration, which we complement with archival CnB-configuration observations (PI: Datta, 14B-397) recently presented by Raja et al (2020). In the S , C, and X bands, the VLA observed in A, B, and C configuration.…”

Section: Observations and Data Reductionsupporting

confidence: 82%

“…We mapped the spectral index of the mini halo and derive an integrated spectral index between the L and S bands of −0.95 ± 0.10, which is consistent with the spectral index of −0.98 ± 0.16 as derived by Raja et al (2020) between 610 MHz and 1.5 GHz. We were unable to find evidence for a radial gradient in the spectral index map due to the low signal-to-noise ratio.…”

Section: The Origin Of the Mini Halosupporting

confidence: 81%

“…Observations using the Giant Metrewave Radio Telescope (GMRT) by Van Weeren et al (2014) uncovered a mini halo surrounding the BCG, which spans a region of 400-500 kpc. This mini halo was later observed by Raja et al (2020) using the Karl G. Jansky Very Large Array (VLA) in CnB configuration. By subtracting compact emission from their data, they detect the mini halo and derive a flux density of the mini halo at 1.5 GHz of 9.65 ± 0.97 mJy.…”

Section: The Phoenix Clustermentioning

confidence: 83%

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Very Large Array observations of the mini-halo and AGN feedback in the Phoenix cluster

Timmerman

Weeren

McDonald

et al. 2021

A&A

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Context. The relaxed cool-core Phoenix cluster (SPT-CL J2344-4243) features an extremely strong cooling flow, as well as a mini halo. Strong star formation in the brightest cluster galaxy indicates that active galactic nucleus (AGN) feedback has been unable to inhibit this cooling flow. Aims. We aim to study the strong cooling flow in the Phoenix cluster by determining the radio properties of the AGN and its lobes. In addition, we used spatially resolved radio observations to investigate the origin of the mini halo. Methods. We present new multifrequency Very Large Array 1–12 GHz observations of the Phoenix cluster, which resolve the AGN and its lobes in all four frequency bands as well as the mini-halo in the L and S bands. Results. Using our L-band observations, we measure the total flux density of the radio lobes at 1.5 GHz to be 7.6 ± 0.8 mJy, and the flux density of the mini halo to be 8.5 ± 0.9 mJy. Using high-resolution images in the L and X bands, we produced the first spectral index maps of the lobes from the AGN and find the spectral indices of the northern and southern lobes to be −1.35 ± 0.07 and −1.30 ± 0.12, respectively. Similarly, using L- and S-band data, we mapped the spectral index of the mini halo, and obtain an integrated spectral index of α = −0.95 ± 0.10. Conclusions. We find that the mini halo is most likely formed by turbulent re-acceleration powered by sloshing in the cool core due to a recent merger. In addition, we find that the feedback in the Phoenix cluster is consistent with the picture that stronger cooling flows are to be expected for massive clusters such as this one, as these may feature an underweight supermassive black hole due to their merging history. Strong time variability of the AGN on Myr timescales may help explain the disconnection between the radio and the X-ray properties of the system. Finally, a small amount of jet precession of the AGN likely contributes to the relatively low intracluster medium re-heating efficiency of the mechanical feedback.

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Section: The Origin Of the Mini Halosupporting

confidence: 92%

Section: Observations and Data Reductionsupporting

confidence: 82%

Section: The Origin Of the Mini Halosupporting

confidence: 81%

Section: The Phoenix Clustermentioning

confidence: 83%

See 2 more Smart Citations

Very Large Array observations of the mini-halo and AGN feedback in the Phoenix cluster

Timmerman

Weeren

McDonald

et al. 2021

A&A

View full text Add to dashboard Cite

show abstract

“…Observations using the Giant Metrewave Radio Telescope (GMRT) by Van Weeren et al (2014) uncovered a mini-halo surrounding the BCG, which extends a region of 400-500 kpc. This mini-halo was later observed by Raja et al (2020) using the Karl G. Jansky Very Large Array (VLA) in CnB-configuration. By subtracting compact emission from their data, they detect the mini-halo and derive a flux density of the mini-halo at 1.5 GHz of 9.65 ± 0.97 mJy.…”

Section: The Phoenix Clustermentioning

confidence: 82%

Very Large Array observations of the mini-halo and AGN feedback in the Phoenix cluster

Timmerman,

van Weeren,

McDonald

et al. 2020

Preprint

View full text Add to dashboard Cite

Context. The relaxed cool-core Phoenix cluster (SPT-CL J2344-4243) features an extremely strong cooling flow, as well as a minihalo. Strong star-formation in the brightest cluster galaxy indicates that AGN feedback has been unable to inhibit this cooling flow. Aims. We have studied the strong cooling flow in the Phoenix cluster by determining the radio properties of the AGN and its lobes. In addition, we use spatially resolved radio observations to investigate the origin of the mini-halo. Methods. We present new multifrequency Very Large Array 1-12 GHz observations of the Phoenix cluster which resolve the AGN and its lobes in all four frequency bands, and resolve the mini-halo in L-and S-band. Results. Using our L-band observations, we measure the total flux density of the radio lobes at 1.5 GHz to be 7.6 ± 0.8 mJy, and the flux density of the mini-halo to be 8.5 ± 0.9 mJy. Using high-resolution images in L-and X-band, we produce the first spectral index maps of the lobes from the AGN and measure the spectral indices of the northern and southern lobes to be -1.35 ± 0.07 and -1.30 ± 0.12, respectively. Similarly, using L-and S-band data, we map the spectral index of the mini-halo, and obtain an integrated spectral index of α = −0.95 ± 0.10. Conclusions. We find that the mini-halo is most likely formed by turbulent re-acceleration powered by sloshing in the cool core due to a recent merger. In addition, we find that the feedback in the Phoenix cluster is consistent with the picture that stronger cooling flows are to be expected for massive clusters like the Phoenix cluster, as these may feature an underweight supermassive black hole due to their merging history. Strong time variability of the AGN on Myr-timescales may help explain the disconnection between the radio and the X-ray properties of the system. Finally, a small amount of jet precession of the AGN likely contributes to the relatively low ICM re-heating efficiency of the mechanical feedback.

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Exploring diffuse radio emission in galaxy clusters and groups with uGMRT and SKA

et al. 2023

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Probing the Origin of Diffuse Radio Emission in the Cool Core of the Phoenix Galaxy Cluster

Cited by 9 publications

References 64 publications

Very Large Array observations of the mini-halo and AGN feedback in the Phoenix cluster

Very Large Array observations of the mini-halo and AGN feedback in the Phoenix cluster

Very Large Array observations of the mini-halo and AGN feedback in the Phoenix cluster

Exploring diffuse radio emission in galaxy clusters and groups with uGMRT and SKA

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