| Name: GAYATHRI C J |
| Affiliation: University of Calicut |
| Conference ID: ASI2026_632 |
| Title: Spectral Decomposition of Selected BAL Quasars: Temporal Variations and Inter- Component Correlations. |
| Abstract Type: Poster |
| Abstract Category: Galaxies and Cosmology |
| Author(s) and Co-Author(s) with Affiliation: Gayathri C J(Department of Physics, University of Calicut, Malappuram 673 635, India), M Vivek(Indian Institute of Astrophysics, Koramangala, Bengaluru 560 034, India), C D Ravikumar(Department of Physics, University of Calicut, Malappuram 673 635, India) |
| Abstract: Active galactic nuclei (AGNs), powered by accretion onto supermassive black holes, represent the highly energetic centres of massive galaxies. Their extreme luminosities enable detailed observational studies even at high redshifts, providing critical insights into galaxy evolution across cosmic time. Quasar outflows, identified through blueshifted emission and absorption line features, are widely considered manifestations of AGN feedback, a process capable of regulating the energy and momentum budget of the host galaxy. In this study, we investigate the nature of emission and absorption outflows in broad absorption line (BAL) quasars, with particular emphasis on high-velocity C IV emission and absorption features. We analyse multi-epoch spectra of selected sources drawn from a sample of 126 BAL quasars observed as part of the Sloan Digital Sky Survey Data Release 16 Reverberation Mapping (SDSS DR16 RM) program and the Sloan Digital Sky Survey Data Release 19 Black Hole Mapper (SDSS DR19 BHM) program. Spectral decomposition and continuum fitting are performed using the Bayesian AGN Decomposition Analysis for SDSS Spectra (BADASS), an open-source tool optimized for detailed modelling of SDSS spectra. Emission-line strengths are obtained from the decomposition, while absorption strengths are computed independently. A strong correlation between blue-shifted emission and absorption variability would favour a smooth, well-collimated outflow geometry with relatively uniform density, ionization state, and velocity structure, as both components would respond coherently to changes in the ionizing continuum. Conversely, a weakened or absent correlation would indicate a clumpy outflow structure. Additional effects such as light-travel-time delays, ionization stratification, and density or velocity gradients may further dilute the observed correlations.Overall, this study aims to constrain the physical nature and geometry of quasar outflows and to place meaningful limits on their opening angles, thereby improving our understanding of AGN-driven feedback mechanisms.Results will be presented at the meeting.
|
