Low-frequency radio study of MACS clusters at 610 and 235 MHz using the GMRT
Bibliographic record
Abstract
Abstract Studies have shown that mergers of massive galaxy clusters produce shocks and turbulence in the intracluster medium, these events possibly creating radio relics, as well as radio haloes. Here we present Giant Metrewave Radio Telescope (GMRT) dual-band (235- and 610-MHz) radio observations of four such clusters from the MAssive Cluster Survey (MACS) catalogue. We report the discovery of a very faint, diffuse, elongated radio source with a projected size of about 0.5 Mpc in cluster MACSJ0152.5−2852. We also confirm the presence of a radio-relic-like source (about 0.4 Mpc, previously reported at 325 MHz) in cluster MACSJ0025.4−1222. Proposed relics in both these clusters are found apparently inside the virial radius, instead of at their usual peripheral location, while no radio haloes are detected. These high-redshift clusters (z = 0.584 and 0.413) are among the earliest merging systems detected from cluster radio emission. In cluster MACSJ1931.8-2635, we found a radio mini-halo and an interesting highly bent pair of radio jets. Also, we present here a maiden study of low-frequency (GMRT 235- and 610-MHz) spectral and morphological signatures of the previously known radio cluster MACSJ0014.3−3022 (Abell 2744). This cluster hosts a relatively flat spectrum ($\alpha ^{610}_{235}\sim -1.15$), giant (∼1.6 Mpc each) halo–relic structure and a nearby high-speed ($1769\pm ^{148}_{359}$ km s−1) merger shock ($\mathcal {M}=2.02\pm ^{0.17}_{0.41}$) originating from a possible second merger in the cluster.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".