arXiv subjects

Saianeesh Haridas

Publications and source records attributed to Saianeesh Haridas.

2 recordsLinked to original sources

arXiv2026

Sensitive 3mm Imaging of Discrete Sources in the Fields of X-ray-Selected Galaxy Clusters

In this paper, we present the results of a blind survey for compact sources in 138 galaxy clusters from the eFEDS X-ray survey. Of these clusters, 96 are new observations. These targets have X-ray mass estimates and redshifts that formally place them above the thermal Sunyaev-Zel'dovich effect (tSZ) survey limits from the Atacama Cosmology Telescope (ACT, DR5), yet were not detected. Compact sources with apparent locations close to (<104") the center of a galaxy cluster can in-fill the tSZ flux decrement, resulting in tSZ surveys missing clusters. To quantify the number of missing clusters from ACT, we carried out a survey at 90GHz using MUSTANG2 on the Green Bank Telescope and achieved a 5-sigma detection limit of 1mJy in the center of each cluster. We detected 11 discrete sources, which when scaled, is slightly lower than our previous tSZ selected sample, M2-ACT (8.0% vs 9.9%). All had radio counterparts. However, unlike the M2-ACT sample, the sources in X-ray selected clusters were concentrated closer to the cluster centers. When their effect on the measured tSZ signal is taken into account the sources we found would result in 4.5% of clusters being missed by tSZ surveys - a result similar to the estimate in recent ACT results. Most of the 96 clusters in eFEDS but not in ACT are a result of noise and overestimation of mass from X-ray measurements.

astro-ph.CO↗

arXiv2024

Sensitive 3mm Imaging of Discrete Sources in the Fields of tSZ-Selected Galaxy Clusters

In this paper we present the results of a blind survey for compact sources in 243 Galaxy clusters that were identified using the thermal Sunyaev-Zeldovich effect (tSZ). The survey was carried out at 90 GHz using MUSTANG2 on the Green Bank telescope and achieved a $5σ$ detection limit of 1 mJy in the center of each cluster. We detected 24 discrete sources. The majority (18) of these correspond to known radio sources, and of these, 5 show signs of significant variability, either with time or in spectral index. The remaining sources have no clear counterparts at other wavelengths. Searches for galaxy clusters via the tSZ effect strongly rely on observations at 90 GHz, and the sources found have the potential to bias mass estimates of clusters. We compare our results to the simulation Websky that can be used to estimate the source contamination in galaxy cluster catalogs. While the simulation showed a good match to our observations at the clusters' centers, it does not match our source distribution further out. Sources over 104" from a cluster's center bias the tSZ signal high, for some of our sources, by over 50%. When averaged over the whole cluster population the effect is smaller but still at a level of 1 to 2%. We also discovered that unlike previous measurements and simulations we see an enhancement of source counts in the outer regions of the clusters and fewer sources than expected in the centers of this tSZ selected sample.

astro-ph.CO↗