Abstract Details
| Name: Sumana Nandi Affiliation: Manipal Centre for Natural Sciences, Centre of Excellence, Manipal Academy of Higher Education, Manipal, Karnataka - 576104, India Conference ID: ASI2025_644 Title : A new population of DDRG: several episodes of jet activity in multiple directions Authors and Co-Authors : Sumana Nandi Abstract Type : Poster Abstract Category : Galaxies and Cosmology Abstract : For most double-double radio galaxies (DDRGs), two distinct pairs of radio lobes and their common central active galactic nuclei (AGNs) are aligned along the same axis. The change in the direction of the new restarted jets have been observed in the case of misaligned DDRGs. These DDRGs are small in number, but are important to study as they can be hosted by a merger system of supermassive binary black holes. Using high frequency and low frequency radio surveys, we identified a new sample of jet reorientation candidates characterized by 20 to 90 degree misalignment between the successive jet outflows. We carried out low and high frequency radio observations of these sources with GMRT, VLA and VLBI. The optical spectroscopy data were collected through the HCT and DOT and SDSS. The GMRT images detect extremely faint, outer lobes. VLA and VLBI images help to detect inner double structure and resolve central core. The estimated spectral indices, spectral age confirms their episodic nature. The emission line splitting in the optical spectra, the bulge disk decomposition of the host galaxy indicates the possibility of merger of the host. The radio structure, applied kinematic jet precession model, variation of the flux density, and spectral shape can potentially be consistent both with the signature of a young radio source or a binary black hole at the center of these sources. Our study revealed that the misaligned DDRG population may represent the pre-merging stage where two nearby black holes interact at small separation due to dynamical friction. While the DDRGs with linear outflow are in the post merging stage. |