Abstract Details

Name: RUBINUR KHATUN
Affiliation: NCRA-TIFR
Conference ID: ASI2021_446
Title : A Radio and Ultraviolet Study of Dual Nuclei in Galaxies
Authors and Co-Authors : Mousumi Das (IIA), Preeti Kharb (NCRA-TIFR)
Abstract Type : Oral
Abstract Category : Thesis
Abstract : Supermassive black hole (SMBH) binaries form due to galaxy mergers . When the SMBHs are accreting, they form dual or binary AGN and can give rise to double-peaked emission lines in the optical spectra of the merger remnant. The double-peaked emission lines could also be due to jet-ISM interaction or rotating disks. One of the best ways to confirm dual/binary AGN in double-peaked AGN (DPAGN) is by using high resolution radio observations. We have observed a sample of 20 DPAGN at two or more frequencies using the Karl G. Jansky Very Large Array (VLA). We have detected dual radio structures at separation of <~10 kpc in three of our sample galaxies. Using the spectral index maps and optical spectra of the sources, we have confirmed that one of them is a dual AGN (DAGN), while the other two can be dual AGN or AGN+ star-forming nuclei pairs. Of the remaining sources, two have clear core-jet structure. The remaining 13 sources are single cores while one source is not detected at any frequency. We find that for our dual AGN detection, the DPAGN emission lines do not originate from the dual/binary AGN. Hence, we conclude that DPAGN identified in low resolution SDSS spectra are not good indicators of DAGN. On the other hand, closely interacting galaxies or merger remnants are good candidates for detecting dual/binary AGN. We started ultra- violet imaging observations of a sample of ~10 dual nuclei galaxies to detect the UV emission from their nuclei as well as star formation from the surrounding regions. We have used the high resolution ultra-violet imaging telescope (UVIT) which is mounted on the Astrosat satellite for these observations. For one of the sources MRK 212, we have done followup multi-wavelength (VLA, GMRT, HCT, UVIT) studies to confirm the nature of the nuclei.