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Mainak Singha

Updated: Jul 9, 2025

University of Manitoba

Mainak’s research investigates how weakly accreting ‘Active Galactic Nuclei’ (AGN) can drive galaxy evolution processes. Most successful galaxy evolution models require the AGN to launch galactic-scale outflows to drive the galaxy evolution processes. In order to trace the signs of outflows, he uses spectroscopic data (spectra) from SDSS (Sloan Digital Sky Survey). The emission lines from these spectra pin-point the evidence of ionization caused by the photons from the AGN accretion disks or the shocks from the AGN. Any asymmetry in the emission line profiles indicates the gas moving towards / moving away from us which are the signatures of outflows.

Standard BPT diagram from SDSS DR7. The radio galaxy J142041+025930 lies in the LINER (Low Ionization Nuclear Emission Line Region) region of the part suggesting it to be a Low Excitation radio galaxy (LERG).
Standard BPT diagram from SDSS DR7. The radio galaxy J142041+025930 lies in the LINER (Low Ionization Nuclear Emission Line Region) region of the part suggesting it to be a Low Excitation radio galaxy (LERG).
Spectral modeling of J142041+025930. A blue wing is clearly visible in highly ionized gas [OIII] despite suggesting an outflow. This is in contrary with the assumption that LERGs weakly ionize gas. The shaded region indicates the velocity offset between the narrow line region and the kinematically disturbed region due to the outflow (around – 320 km/s).
Spectral modeling of J142041+025930. A blue wing is clearly visible in highly ionized gas [OIII] despite suggesting an outflow. This is in contrary with the assumption that LERGs weakly ionize gas. The shaded region indicates the velocity offset between the narrow line region and the kinematically disturbed region due to the outflow (around – 320 km/s).

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