Deep low-frequency radio observations of Abell 2256

Rajpurohit, K.; Osinga, E.; Brienza, M.; Botteon, A.; Brunetti, G.; Forman, W.; Riseley, C. J.; Vazza, Franco; Bonafede, A.; Weeren, R. J. van; Brüggen, M.; Rajpurohit, Sangeeta; Drabent, A.; Dallacasa, D.; Rossetti, M.; Rajpurohit, A. S.; Hoeft, M.; Bonnassieux, E.; Cassano, R.; Miley, G. K.

doi:10.1051/0004-6361/202244925

Cited by 18 publications

(19 citation statements)

References 107 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They report a significant variation of correlation slope over frequency, indicating the presence of a high-frequency cutoff. However, there are cases where the slope remains constant as a function of frequency: A2744 (Rajpurohit et al 2021b), A2256 (Rajpurohit et al 2023). Similarly, in A521, we discovered that the correlation slope is nearly constant across the frequency range of our study.…”

Section: Spatial Correlation Between the X-ray And Radio Surface Brig...supporting

confidence: 67%

“…A sublinear slope of b 400MHz = 0.61 ± 0.06, b 650MHz = 0.55 ± 0.08, is obtained at 400 and 650 MHz respectively. The point-to-point correlation studies for the ultra-steep spectrum radio halo (A2256, Rajpurohit et al 2023;andMACSJ1149+222.3, Bruno et al 2021) show a similar range of values.…”

Section: Spatial Correlation Between the X-ray And Radio Surface Brig...mentioning

confidence: 80%

“…Bonafede et al (2022) discovered an increase in the correlation slope for the Coma cluster. While Rajpurohit et al (2023) has also reported variation in the correlation slope across subregions. In our case, we discovered different slopes in the two subregions at increasing radii.…”

Section: Radial Variation Of the Correlation Strengthmentioning

confidence: 97%

“…To date, point-to-point analysis between the radio surface brightness and the X-ray surface brightness has been done for many radio halos, mostly at 1.4 GHz. For giant radio halos, the correlation slope predominantly shows sublinear to linear values (e.g., Govoni et al 2001;Giacintucci et al 2005;Rajpurohit et al 2018;Cova et al 2019;Hoang et al 2019;Xie et al 2020;Rajpurohit et al 2021b;Bruno et al 2021;Hoang et al 2021;Bonafede et al 2022;Rajpurohit et al 2023). This relationship between the X-ray (I X ) and radio surface brightness (I R ) is generally described in the form of a power law:…”

Section: Spatial Correlation Between the X-ray And Radio Surface Brig...mentioning

confidence: 99%

“…Only for very few clusters, high-resolution resolved spectral maps, and robust estimations of the spectral index, are available. Some halos show a uniform spectral index all over the spatial scales, whereas some show small-scale fluctuations in the resolved spectral maps (Pearce et al 2017;Botteon et al 2020b;Rajpurohit et al 2023). Resolved spectral maps for the steep spectrum radio halos are not explored significantly, which can throw light on the self-similarity behavior (if any) of the global spectral index at local kiloparsec scales.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

A Deep uGMRT View of the Ultra-steep Spectrum Radio Halo in A521

Santra,

Kale,

Giacintucci

et al. 2024

ApJ

Self Cite

View full text Add to dashboard Cite

We present the first detailed analysis of the ultra-steep spectrum radio halo in the merging galaxy cluster A521, based on upgraded Giant Metrewave Radio telescope observations. The combination of radio observations (300–850 MHz) and archival X-ray data provides a new window into the complex physics occurring in this system. When compared to all previous analyses, our sensitive radio images detected the centrally located radio halo emission to a greater extent of ∼1.3 Mpc. A faint extension of the southeastern radio relic has been discovered. We detected another relic, recently discovered by MeerKAT, and coincident with a possible shock front in the X-rays, at the northwest position of the center. We find that the integrated spectrum of the radio halo is well-fitted with a spectral index of −1.86 ± 0.12. A spatially resolved spectral index map revealed the spectral index fluctuations, as well as an outward radial steepening of the average spectral index. The radio and X-ray surface brightness is well correlated for the entire and different subparts of the halo, with sublinear correlation slopes (0.50–0.65). We also found a mild anticorrelation between the spectral index and X-ray surface brightness. Newly detected extensions of the SE relic and the counter relic are consistent with the merger in the plane of the sky.

show abstract

Section: Spatial Correlation Between the X-ray And Radio Surface Brig...supporting

confidence: 67%

Section: Spatial Correlation Between the X-ray And Radio Surface Brig...mentioning

confidence: 80%

Section: Radial Variation Of the Correlation Strengthmentioning

confidence: 97%

Section: Spatial Correlation Between the X-ray And Radio Surface Brig...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Deep uGMRT View of the Ultra-steep Spectrum Radio Halo in A521

Santra,

Kale,

Giacintucci

et al. 2024

ApJ

Self Cite

View full text Add to dashboard Cite

show abstract

The diffuse radio emission in the high-redshift cluster PSZ2 G091.83+26.11: Total intensity and polarisation analysis with Very Large Array 1–4 GHz observations

Gennaro¹,

Brüggen²,

Weeren³

et al. 2023

A&A

View full text Add to dashboard Cite

Context. Diffuse radio emission in galaxy clusters, namely radio halos and radio relics, is usually associated with merger events. Despite the tremendous advances in observations in the last decades, the particle (re-)acceleration and magnetic field amplification mechanisms and the connection with the stage and geometry of the cluster merger are still uncertain. Aims. In this paper, we present the peculiar case of PSZ2 G091.83+26.11 at z = 0.822. This cluster hosts a megaparsec-scale radio halo and an elongated radio source whose morphology resembles that of a radio relic. However, the location of this diffuse radio source with respect to the intracluster medium (ICM) distribution and to the cluster centre is not consistent with a simple merger scenario. Methods. We use Karl Jansky Very Large Array data at 1–4 GHz to investigate the spectral and polarisation properties of the diffuse radio emission. We combine these data with previously published data from the Low Frequency Array (LOFAR) in the 120–168 MHz band and from the upgraded Giant Metrewave Radio Telescope (uGMRT) at 250–500 and 550–900 MHz. Finally, we complement the radio data with Chandra X-ray observations in order to compare the thermal and non-thermal emission of the cluster. Results. The elongated radio emission east of the cluster is visible up to 3.0 GHz and has an integrated spectral index of α144 MHz3.0 GHz = −1.24 ± 0.03, with a steepening from −0.89 ± 0.03 to −1.39 ± 0.03. These values correspond to Mach numbers ℳradio, int = 3.0 ± 0.19 and ℳradio, inj = 2.48 ± 0.15. Chandra data revealed a surface brightness discontinuity at the location of the radio source with a compression factor of C = 2.22 −0.30+0.39 (i.e. MXray = 1.93−0.32+0.42). We also found that the source is polarised at GHz frequencies. Using QU-fitting, we estimate an intrinsic polarisation fraction of p0 ∼ 0.2, a Rotation Measure of ∼50 rad m−2 (including the Galactic contribution), and an external depolarisation of σRM ∼ 60 rad m−2. The polarisation B-vectors are aligned with the major axis of the source, suggesting magnetic field compression. Hence, we classify this source as a radio relic. Finally, we found a trend consistent with a linear or super-linear correlation between the non-thermal and thermal emission. Conclusions. We propose an off-axis merger and/or multiple merger events to explain the position and orientation of the relic with the respect to the ICM emission. Given the properties of the radio relic, we speculate that PSZ2 G091.83+26.11 is in a fairly young merger state.

show abstract

A combined LOFAR and XMM-Newton analysis of the disturbed cluster PSZ2G113.91-37.01

Campitiello,

Bonafede,

Botteon

et al. 2024

A&A

View full text Add to dashboard Cite

In this work, we investigated the interplay between the X-ray and radio emission of the cluster PSZ2G113.91-37.01 ($z = 0.371$) using the high-quality XMM-Newton observations of the Cluster HEritage project with XMM-Newton - Mass Assembly and Thermodynamics at the Endpoint of structure formation (CHEX-MATE), and the images of the LOFAR Two-meter Sky Survey-Data release 2 (LoTSS-DR2). The cluster is undergoing a merger along the north-south axis, and shows a central radio halo and two radio relics, one in the southern and one in the northern regions. The analysis of the intracluster medium (ICM) distribution revealed the presence of a northern surface brightness (SB) jump associated to the merger event. By extracting spectra across this discontinuity, we classified the edge as a cold front. Furthermore, we made use of upgraded Giant Metrewave Radio Telescope observations that allowed us to perform a spectral analysis of the G113 radio emission. We found evidence of re-acceleration of particles in the northern relic, and we measured an associated Mach number of $ M as inferred from radio observations. We then performed a point-to-point analysis of the X-ray and radio emission both in the halo and in the northern relic regions. We found a strong correlation for the halo and an anti-correlation for the relic. The former behaviour is in agreement with previous studies. The relic anti-correlation is likely related to the reverse radial distribution of the X-ray (increasing towards the cluster centre) and radio (decreasing towards the cluster centre) emissions. Finally, we performed a point-to-point analysis of the radio emission and the residuals obtained by subtracting a double beta model to the X-ray emission. We found a strong correlation between the two quantities. This behaviour suggests the presence of a connection between the process responsible for the radio emission and the one that leaves fluctuations in the X-ray observations.

show abstract

Deep low-frequency radio observations of Abell 2256

Cited by 18 publications

References 107 publications

A Deep uGMRT View of the Ultra-steep Spectrum Radio Halo in A521

A Deep uGMRT View of the Ultra-steep Spectrum Radio Halo in A521

The diffuse radio emission in the high-redshift cluster PSZ2 G091.83+26.11: Total intensity and polarisation analysis with Very Large Array 1–4 GHz observations

A combined LOFAR and XMM-Newton analysis of the disturbed cluster PSZ2G113.91-37.01

Contact Info

Product

Resources

About