Dissecting Galaxies: Separating Star Formation, Shock Excitation and AGN Activity in the Central Region of NGC 613

The most rapidly evolving regions of galaxies often display complex optical spectra with emission lines excited by massive stars, shocks and accretion onto supermassive black holes. Standard calibrations (such as for the star formation rate) cannot be applied to such mixed spectra. In this paper we isolate the contributions of star formation, shock excitation and active galactic nucleus (AGN) activity to the emission line luminosities of individual spatially resolved regions across the central 3 $\times$ 3 kpc$^2$ region of the active barred spiral galaxy NGC$\sim$613. The star formation rate and AGN luminosity calculated from the decomposed emission line maps are in close agreement with independent estimates from data at other wavelengths. The star formation component traces the B-band stellar continuum emission, and the AGN component forms an ionization cone which is aligned with the nuclear radio jet. The optical line emission associated with shock excitation is cospatial with strong $H_2$ and [Fe II] emission and with regions of high ionized gas velocity dispersion ($\sigma > 100$ km s$^{-1}$). The shock component also traces the outer boundary of the AGN ionization cone and may therefore be produced by outflowing material interacting with the surrounding interstellar medium. Our decomposition method makes it possible to determine the properties of star formation, shock excitation and AGN activity from optical spectra, without contamination from other ionization mechanisms.Comment: 16 pages, 12 figures. Accepted for publication in MNRA

Characterising the Impact of systematic flat-fielding errors In Huntsman telescope data

Empirical thesis.Bibliography: pages 61-64.1. Introduction -- 2. Methods -- 3. Flat-fielding expectations, strategy and quality control -- 4. Flat-field data characterisation -- 5. Discussion and conclusions -- Appendix -- References.The Huntsman Telescope is a new facility being commissioned at Siding Spring Observatory in Australia. It consists of an array of Canon telephoto lenses. In order to circumvent the systematic errors known to affect mirror based instruments, the Canon lenses act together as a single refracting telescope. They reduce the scattering of light within the optical path,which allows fainter limiting surface brightness levels to be reached. However, at these low surface brightness levels other sources of systematic error must be carefully investigated and scrutinised. In this thesis I will investigate one of the primary sources of systematic error in low surface brightness imaging, flat fielding uncertainties, and how it impacts the Huntsman Telescope.Mode of access: World wide web1 online resource (xii, 64 pages) colour illustration

The environments of accreting supermassive black holes in the nearby Universe: A brief overview of the Southern Seyfert spectroscopic snapshot survey (S7)

Black holes with a mass a million times the mass of our Sun or more—i.e., supermassive black holes—tend to reside in galactic centers. The mass of a supermassive black hole scales with the mass and stellar velocity dispersion of the bulge of the host galaxy. Thus, the central supermassive black hole in a galaxy appears to grow in conjunction with its host, but the physical mechanisms leading to such a coupling are not yet understood. Accreting supermassive black holes also comply with similar scaling relationships, which suggests that the accretion process plays an important role in the evolution of the host galaxy. We are exploring this question using a multiwavelength investigation of a sample of about 130 nearby southern galaxies that have accreting supermassive black holes. This study began as the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7), and we have obtained integral field spectroscopy for the central regions of all 130 of the galaxies. Radio- imaging follow-up work is ongoing, using the Giant Metre-Wave Radio Telescope and the Australia Telescope Compact Array. Several individual galaxies in our sample have been studied in detail as well. All of our data are intended for public release, with the first two releases already done. We present a brief status report of our investigation