| Name: | Siddhant Manna |
| Affiliation: | IIT HYDERABAD |
| Conference ID : | ASI2024_251 |
| Title : | Search for GeV Gamma-Ray Emission from South Pole Telescope selected Galaxy Clusters with 15 years of Fermi-LAT data |
| Authors : | Siddhant Manna, Shantanu Desai |
| Authors Affiliation: | 1 Indian Institute of Technology Hyderabad, Sangareddy, Telangana-502285, India |
| Mode of Presentation: | Poster |
| Abstract Category : | High Energy Phenomena, Fundamental Physics and Astronomy |
| Abstract : | Galaxy clusters could produce gamma-rays from inverse Compton scattering of cosmic ray electrons or hadronic interactions of cosmic ray protons with the intracluster medium. It is still an open question on whether gamma-ray emission (> GeV energies) has been detected from galaxy clusters. We carry out a systematic search for gamma-ray mission based on 300 galaxy clusters selected from the 2500 deg^2 SPT-SZ survey after sorting them in descending order of M500/z^2, using about 15 years of Fermi-LAT data in the energy range between 1-300 GeV. We were able to detect gamma-ray emission with significance of about 6.1σ from one cluster, viz SPT-CL J2012-5649. The estimated photon energy flux from this cluster is approximately equal to 1.3×10^−6 MeV cm^−2 s^−1. The gamma-ray signal is observed between 1 − 10 GeV with the best-fit spectral index equal to −3.61 ±0.33. However, since there are six radio galaxies spatially coincident with SPT-CL J20125649 within the Fermi-LAT PSF, we cannot rule out the possibility this signal could be caused by some of these radio galaxies. Six other SPT-SZ clusters show evidence for gamma-ray emission with significance between 3 − 5σ. None of the remaining clusters show statistically significant evidence for gamma-ray emission. |
