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publications
Keck/KCWI Spectroscopy of Globular Clusters in Local Volume Dwarf Galaxies
Published in Publications of the Astronomical Society of Australia, 2024
A number of nearby dwarf galaxies have globular cluster (GC) candidates that require spectroscopic confirmation. Here we present Keck telescope spectra for 15 known GCs and GC candidates that may be associated with a host dwarf galaxy, and an additional 3 GCs in the halo of M31 that are candidates for accretion from a now disrupted dwarf galaxy. We confirm 6 star clusters (of intermediate-to-old age) to be associated with NGC~247. The vast bulk of its GC system remains to be studied spectroscopically. We also confirm the GC candidates in F8D1 and DDO190, finding both to be young star clusters. The 3 M31 halo GCs all have radial velocities consistent with M31, are old and very metal-poor. Their ages and metallicities are consistent with accretion from a low mass satellite galaxy. Finally, three objects are found to be background galaxies – two are projected near NGC~247 and one (candidate GCC7) is near the IKN dwarf. The IKN dwarf thus has only 5 confirmed GCs but still a remarkable specific frequency of 124.
Recommended citation: Forbes, D. A., Lyon, Daniel, Gannon, J., Romanowsky, A. J., & Brodie, J. P. 2024, Keck/KCWI Spec- troscopy of Globular Clusters in Local Volume Dwarf Galaxies, arXiv. http://ascl.net/2405.11749
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Decomposing Infrared Luminosity Functions into Star-Forming and AGN Components Using CIGALE
Published in Publications of the Astronomical Society of Australia, 2024
This study presents a comprehensive analysis of the infrared (IR) luminosity functions (LF) of star-forming (SF) galaxies and active galactic nuclei (AGN) using data from the ZFOURGE survey. We employ CIGALE to decompose the spectral energy distribution (SED) of galaxies into SF and AGN components to investigate the co-evolution of these processes at higher redshifts and fainter luminosities. Our CIGALE-derived SF and AGN LFs are generally consistent with previous studies, with an enhancement at the faint end of the AGN LFs. We attribute this to CIGALE’s capability to recover low-luminosity AGN more accurately, which may be underrepresented in other works. As anticipated, the CIGALE SF LFs are best fit with a Schechter function, whereas the AGN LFs align more closely with a Saunders function. We find evidence for a significant evolutionary epoch for AGN activity at z ≈ 1, comparable to the peak of cosmic star formation at z ≈ 2, which we also recover well. Based on our results, the gas supply in the early universe favoured the formation of brighter star-forming galaxies until z = 2, below which the gas for SF becomes increasingly exhausted. Conversely, AGN activity peaked earlier and declined more slowly until z ≈ 1, suggesting a possible feedback scenario in which 2.5 − 3 Gyrs offset the evolution of SF and AGN activity.
Recommended citation: Lyon, D. J., Cowley, M. J., Pye, O., & Hopkins, A. M. 2024, Decomposing Infrared Luminosity Functions into Star-Forming and AGN Components Using CIGALE, arXiv, doi: 10.48550/arXiv.2410.08541
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talks
Talk 1 on Relevant Topic in Your Field
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teaching
Teaching experience 1
Undergraduate course, University 1, Department, 2014
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Teaching experience 2
Workshop, University 1, Department, 2015
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