Galactic scale radio-mode feedback in compact radio galaxies
| dc.contributor.author | Duggal, Chetna | |
| dc.contributor.examiningcommittee | Taylor, Gregory (University of New Mexico) | |
| dc.contributor.examiningcommittee | Fiege, Jason (Physics and Astronomy) | |
| dc.contributor.examiningcommittee | Mammei, Juliette (Physics and Astronomy) | |
| dc.contributor.supervisor | O'Dea, Christopher | |
| dc.contributor.supervisor | Baum, Stefi | |
| dc.date.accessioned | 2024-08-29T21:01:35Z | |
| dc.date.available | 2024-08-29T21:01:35Z | |
| dc.date.issued | 2024-08-27 | |
| dc.date.submitted | 2024-08-27T19:35:52Z | en_US |
| dc.degree.discipline | Physics and Astronomy | |
| dc.degree.level | Doctor of Philosophy (Ph.D.) | |
| dc.description.abstract | In the early stages of radio galaxy evolution, where the nuclear jets reside entirely within the host galaxy, the interaction of an expanding radio source with the surrounding interstellar medium is likely to be the most pronounced. These kpc-scale jets will cause nearby clouds to collapse and trigger starbursts in a direct consequence of radio-mode feedback from Active Galactic Nuclei (AGN). In this thesis, I present the first systematic search for ultraviolet emission signatures from radio source-driven AGN feedback in Compact Steep Spectrum (CSS) radio galaxies. Owing to their characteristic sub-galactic jets (1-20 kpc projected linear sizes), CSS hosts are excellent laboratories for probing galaxy- scale feedback via jet-triggered star formation. The sample consists of 7 powerful CSS galaxies, and 2 galaxies host to radio sources >20 kpc as control, at low to intermediate redshifts (z<0.6). Imaging with the Hubble Space Telescope shows extended UV continuum emission in six out of seven CSS galaxies; with five CSS hosts exhibiting UV knots co-spatial and aligned along the radio-jet axis. Young, massive stellar populations are likely to be the dominant source of the blue excess emission in radio galaxies at these redshifts, hence the radio-aligned UV regions could be attributed to jet-induced starbursts. Lower near-UV star formation rates compared to other indicators suggest low scattered AGN light contribution to the observed UV. Dust attenuation of UV emission appears unlikely from high internal extinction correction estimates in most sources. Comparison with evolutionary synthesis models shows that the observations are consistent with recent (1-8 Myr) activity likely triggered by current or an earlier episode of radio emission, or by a confined radio source that has frustrated growth due to a dense environment. While follow-up spectroscopic and polarized light observations are needed to constrain the activity-related components in the observed UV, the detection of jet-induced star formation is a confirmation of an important prediction of the jet feedback paradigm. | |
| dc.description.note | October 2024 | |
| dc.identifier.uri | http://hdl.handle.net/1993/38462 | |
| dc.language.iso | eng | |
| dc.rights | open access | en_US |
| dc.subject | active galactic nuclei | |
| dc.subject | jets | |
| dc.subject | feedback | |
| dc.subject | star formation | |
| dc.title | Galactic scale radio-mode feedback in compact radio galaxies | |
| dc.type | doctoral thesis | en_US |
| local.subject.manitoba | no |