The thermal and non-thermal components within and between galaxy clusters Abell 399 and Abell 401

Radiconi, Federico; Vacca, V.; Battistelli, E. S.; Bonafede, A.; Capalbo, Valentina; Devlin, Mark J.; Mascolo, Luca Di; Feretti, L.; Gallardo, Patricio A.; Gill, Ajay; Giovannini, G.; Govoni, F.; Guan, Yilun; Hilton, Matt; Hincks, Adam D.; Hughes, John P.; Iacobelli, M.; Isopi, Giovanni; Loi, F.; Moodley, Kavilan; Mroczkowski, Tony; Murgia, M.; Orrù, E.; Paladino, R.; Partridge, B.; Sarazin, Craig L.; Scherer, Jack Orlowski; Sifón, Cristobál; Cristian, Vargas,; Vazza, Franco; Wollack, Edward J.

doi:10.1093/mnras/stac3015

Cited by 8 publications

(1 citation statement)

References 76 publications

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“…A joint analysis of WMAP and Planck data has been conducted in Watts et al (2024). The data products have reinforced our comprehension of CMB lensing (Omori et al 2019(Omori et al , 2023Qu et al 2024), cosmic infrared background (Kilerci et al 2023), Sunyaev Zel'dovich effect (Calafut et al 2021;Gatti et al 2022;Radiconi et al 2022;Mallaby-Kay et al 2023;Meinke et al 2023), Galactic dust science (Guan et al 2021;Lowe et al 2022;Córdova Rosado et al 2024), and related fields.…”

Section: Introductionmentioning

confidence: 93%

Sensitivity-improved Polarization Maps at 40 GHz with CLASS and WMAP Data

Shi 时,

Appel,

Bennett

et al. 2024

ApJ

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Improved polarization measurements at frequencies below 70 GHz with degree-level angular resolution are crucial for advancing our understanding of the Galactic synchrotron radiation and the potential polarized anomalous microwave emission and ultimately benefiting the detection of primordial B modes. In this study, we present sensitivity-improved 40 GHz polarization maps obtained by combining the CLASS 40 GHz and Wilkinson Microwave Anisotropy Probe (WMAP) Q-band data through a weighted average in the harmonic domain. The decision to include WMAP Q-band data stems from similarities in the bandpasses. Leveraging the accurate large-scale measurements from the WMAP Q band and the high-sensitivity information from the CLASS 40 GHz band at intermediate scales, the noise level at ℓ ∈ [30, 100] is reduced by a factor of 2–3 in the map space. A pixel domain analysis of the polarized synchrotron spectral index (β s ) using the WMAP K band and the combined maps (mean and 16th/84th percentiles across the β s map: − 3.08 − 0.20 + 0.20 ) reveals a stronger preference for spatial variation (probability to exceed for a uniform β s hypothesis smaller than 0.001) than the results obtained using WMAP K and Ka bands ( − 3.08 − 0.14 + 0.14 ). The cross-power spectra of the combined maps follow the same trend as other low-frequency data, and validation through simulations indicates negligible bias introduced by the combination method (subpercent level in the power spectra). The products of this work are publicly available on LAMBDA (https://lambda.gsfc.nasa.gov/product/class/class_prod_table.html).

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Section: Introductionmentioning

confidence: 93%

Sensitivity-improved Polarization Maps at 40 GHz with CLASS and WMAP Data

Shi 时,

Appel,

Bennett

et al. 2024

ApJ

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Probing diffuse radio emission in bridges between galaxy clusters with uGMRT

Pignataro,

Bonafede,

Bernardi

et al. 2024

A&A

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Recent X-ray and Sunyaev-Zeldovich (SZ) observations have detected thermal emission between early-stage merging galaxy clusters. The main purpose of this work is to investigate the properties of the non-thermal emission in the interacting cluster pairs Abell 0399-Abell 0401 and Abell 21-PSZ2 G114.9. These two unique cluster pairs have been found in an interacting state. In both cases, their connection along a filament is supported by an SZ effect detected by the Planck satellite and, in the special case of Abell 0399-Abell 0401, the presence of a radio bridge has been already confirmed by LOFAR observations at 140 MHz. Here, we analyse new high-sensitivity, wideband (250-500 MHz) uGMRT data of these two systems and describe an injection procedure to place limits on the spectrum of Abell 0399-Abell 0401 and on the radio emission between Abell 21-PSZ2 G114.9. In both cases, the low-surface-brightness diffuse emission is not detected in Band 3 (250-500 MHz). For the A399-A401 pair, we are able to constrain the steep spectral index of the bridge emission to be $ with a 95<!PCT!> confidence level between 140 MHz and 400 MHz. We also detect a small patch of the bridge with a flatter spectral index, which may suggest a variable spectral index distribution across the bridge area. For the A21-PSZ2 G114.9 pair, we are able to place an upper limit on the flux density of the bridge emission with two different methods, finding at the central frequency of 383 MHz a conservative value of u <260$ mJy at a 95<!PCT!> confidence level, and a lower value of $f_ u <125$ mJy at an 80<!PCT!> confidence level, based on visual inspection and a morphological criterion. Our work provides a constraint on the spectrum in the bridge A399-A401 that disfavours shock acceleration as the main mechanism for the radio emission. The methods that we propose for the limits on the radio emission in the A21-PSZ2 G114.9 system represent a first step towards a systematic study of these sources.

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Constraints on the magnetic field in the intercluster bridge A399–A401

Balboni,

Bonafede,

Bernardi

et al. 2023

A&A

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Galaxy cluster mergers are natural consequences of structure formation in the Universe. Such events involve the dissipation of a large amount of energy (∼1063 erg) during the process. Part of this energy can be channelled in particle acceleration and magnetic field amplification, enhancing non-thermal emission of the intra- and intercluster environment. Recently, low-frequency observations led to the detection of a bridge of diffuse synchrotron emission connecting two merging galaxy clusters, Abell 399 and Abell 401. This result provides clear observational evidence of relativistic particles and magnetic fields in between clusters. In this work, we used LOw Frequency ARray (LOFAR) observations at 144 MHz to study the polarised emission in the A399–A401 bridge region for the first time. No polarised emission was detected from the bridge region. Assuming a model where polarisation is generated by multiple shocks, depolarisation can be due to Faraday dispersion in the foreground medium with respect to the shocks. We constrained its Faraday dispersion to be greater than 0.10 rad m−2 at 95% confidence level, which corresponds to an average magnetic field in the bridge region of greater than 0.46 nG (or 0.41 nG if we include regions of the Faraday spectrum that are contaminated by Galactic emission). This result is largely consistent with the predictions from numerical simulations for megaparsec regions where the gas density is about 300 times higher than the mean gas density.

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The thermal and non-thermal components within and between galaxy clusters Abell 399 and Abell 401

Cited by 8 publications

References 76 publications

Sensitivity-improved Polarization Maps at 40 GHz with CLASS and WMAP Data

Sensitivity-improved Polarization Maps at 40 GHz with CLASS and WMAP Data

Probing diffuse radio emission in bridges between galaxy clusters with uGMRT

Constraints on the magnetic field in the intercluster bridge A399–A401

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