Nicholas Seymour's research while affiliated with Curtin University and other places

Publications (8)

Article
Full-text available
We present a detailed analysis of 11 local luminous infrared galaxies from ultraviolet through far-infrared to radio (∼70 MHz to ∼15 GHz) bands. We derive the astrophysical properties through spectral energy distribution (SED) modeling using the Code Investigating GALaxy Emission (CIGALE) and UltraNest codes. The radio SEDs include our new observat...
Preprint
Full-text available
We present the detailed analysis of 11 local luminous infrared galaxies (LIRGs) from ultraviolet through far-infrared to radio ($\sim$70 MHz to $\sim$15 GHz) bands. We derive the astrophysical properties through spectral energy distribution (SED) modeling using the Code Investigating GALaxy Emission (CIGALE) and UltraNest codes. The radio SEDs incl...
Article
Quantifying the energetics and lifetimes of remnant radio-loud active galactic nuclei (AGNs) is much more challenging than for active sources due to the added complexity of accurately determining the time since the central black hole switched off. Independent spectral modelling of remnant lobes enables the derivation of the remnant ratio, Rrem, (i....
Article
At relatively high frequencies, highly sensitive grating sidelobes occur in the primary beam patterns of low frequency aperture arrays (LFAA) such as the Murchison Widefield Array (MWA). This occurs when the observing wavelength becomes comparable to the dipole separation for LFAA tiles, which for the MWA occurs at ${\sim}300$ MHz. The presence of...
Article
Full-text available
The remnant phase of a radio galaxy begins when the jets launched from an active galactic nucleus are switched off. To study the fraction of radio galaxies in a remnant phase, we take advantage of a $8.31$ deg $^2$ subregion of the GAMA 23 field which comprises of surveys covering the frequency range 0.1–9 GHz. We present a sample of 104 radio gala...
Conference Paper
Full-text available
In this chapter, we highlight a number of science investigations that are enabled by the inclusion of Band 5 (4.6-13.8 GHz) for SKA1-MID science operations, while focusing on the astrophysics of star formation over cosmic time. For studying the detailed astrophysics of star formation at highredshift, surveys at frequencies ≳10 GHz have the distinct...
Article
Full-text available
We re-examine a series of archived centimetre radio-continuum observations (lambda=16, 6 and 3 cm) focusing on NGC7793 using the Australia Telescope Compact Array. These new images are both very sensitive (rms=0.011 mJy/beam) and feature reasonably high angular resolution (down to < 3"). Using these images, a total of 76 discrete radio sources are...

Citations

... Follo wing standard synchrotron ageing processes, these sources fade more rapidly towards higher frequencies, becoming detectable only at increasingly long wavelengths before fading altogether (e.g. Murgia et al. 2011 ;Harwood et al. 2013 ;Harwood, Hardcastle & Croston 2015 ;Brienza et al. 2016 ;Godfrey, Morganti & Brienza 2017 ;Turner 2018 ;Turner et al. 2018 ;Quici et al. 2022 ). ...
... Finally, we fitted the N+S flux densities with a power-law function and obtained a spectral index of α = −1.09 ± 0.12, which is much steeper than that of the inner lobes NE and SW, but consistent with the spectral indices of radio relics (Shulevski et al. 2015;Quici et al. 2021 ...
... Owing to the steep spectrum of the synchrotron emission, it dominates at frequencies ࣠ 2 GHz (Basu et al. 2012 ). Since the free-free emission with flat spectrum directly originates as a consequence of star formation, high frequency ( 20 GHz) radio observations are well suited to constrain the cosmic star formation history (Murphy et al. 2011(Murphy et al. , 2015. Ho we ver, performing deep, large sky-area surveys at these frequencies is time e xpensiv e due to the relatively small field of view, and the emission is contaminated by anomalous microwave emission (Leitch et al. 1997 ;Murphy et al. 2010 ). ...
... Pannuti et al. (2011Pannuti et al. ( , 2002 presented 7 radio SNRs, 2 of which coincide with optical SNRs, while the rest of them are new identification. More recently, Galvin et al. (2014) presented a catalogue of 14 radio SNRs that includes 5 of the 7 aforementioned radio SNRs. Two of them coincide with optical SNRs from the work of Blair & Long (1997). ...