Search Publications
Radio galaxy zoo EMU: towards a semantic radio galaxy morphology taxonomy
Adams, Elizabeth A. K.; Norris, Ray P.; Hopkins, Andrew M. +20 more
We present a novel natural language processing (NLP) approach to deriving plain English descriptors for science cases otherwise restricted by obfuscating technical terminology. We address the limitations of common radio galaxy morphology classifications by applying this approach. We experimentally derive a set of semantic tags for the Radio Galaxy…
Intensification of magnetic field in merging magnetic flux tubes driven by supergranular vortical flows
Chian, Abraham C. -L.; Silva, Suzana S. A.; Rempel, Erico L. +2 more
The spatiotemporal dynamics of vorticity and magnetic field in the region of a photospheric vortex at a supergranular junction of the quiet Sun is studied, using Hinode's continuum intensity images and longitudinal magnetograms. We show that in a 30-min interval during the vortex lifetime, the magnetic field is intensified at the centres of two me…
Detached eclipsing binaries in compact hierarchical triples: triple-lined systems BD+442258 and KIC 06525196
Kambe, E.; Maehara, H.; Hełminiak, K. G. +5 more
Compact hierarchical triples (CHTs) are systems with the tertiary star orbiting the inner binary in an orbit shorter than 1000 d. CHT with an eclipsing binary as its inner binary can help us extract a multitude of information about all three stars in the system. In this study, we use independent observational techniques to estimate the orbital, st…
Two new white dwarfs with variable magnetic Balmer emission lines
Hermes, J. J.; Clemens, J. C.; Reding, Joshua S. +2 more
We report the discovery of two apparently isolated stellar remnants that exhibit rotationally modulated magnetic Balmer emission, adding to the emerging DAHe class of white dwarf stars. While the previously discovered members of this class show Zeeman-split triplet emission features corresponding to single magnetic field strengths, these two new o…
The long and the short of it: the benefits and leverage of ultraviolet-radio galaxy fitting
Robotham, Aaron S. G.; Bellstedt, Sabine; Davies, Luke J. M. +1 more
Traditionally, the far-ultraviolet (FUV) to far-infrared (FIR) and radio spectral energy distributions (SEDs) of galaxies have been considered separately despite the common physical process shaping them. In this work, we explore the utility of simultaneously fitting FUV-radio SEDs using an extended version of the PROSPECT SED fitting code consider…
The SOUX AGN sample: SDSS-XMM-Newton optical, ultraviolet, and X-ray selected active galactic nuclei spanning a wide range of parameter space - sample definition
Done, Chris; Lusso, Elisabeta; Landt, Hermine +3 more
We assemble a sample of 696 type 1 active galactic nuclei (AGN) up to a redshift of z = 2.5, all of which have an SDSS spectrum containing at least one broad emission line (H α, H β, or Mg II) and an XMM-Newton X-ray spectrum containing at least 250 counts in addition to simultaneous optical/ultraviolet photometry from the XMM Optical Monitor. Our…
Exploring the influence of different velocity fields on Wolf-Rayet star spectra
Sander, A. A. C.; Shenar, T.; Todt, H. +3 more
Given their strong stellar winds, Wolf-Rayet (WR) stars exhibit emission line spectra that are predominantly formed in expanding atmospheric layers. The description of the wind velocity field $\upsilon (r)$ is therefore a crucial ingredient in the spectral analysis of WR stars, possibly influencing the determination of stellar parameters. In view …
A crystallizing white dwarf in a sirius-like quadruple system
Vanderburg, Andrew; Blouin, Simon; Bédard, Antoine +1 more
The observational signature of core crystallization of white dwarfs has recently been discovered. However, the magnitude of the crystallization-powered cooling delay required to match observed white dwarfs is larger than predicted by conventional models, requiring additional mechanisms of energy release in white dwarf interiors. The most ideal ben…
A catalogue of unusually long thermonuclear bursts on neutron stars
Degenaar, N.; in't Zand, J. J. M.; Kuulkers, E. +10 more
Rare, energetic (long) thermonuclear (Type I) X-ray bursts are classified either as intermediate-duration or 'supern' bursts, based on their duration. Intermediate-duration bursts lasting a few to tens of minutes are thought to arise from the thermonuclear runaway of a relatively thick (≈1010 g cm-2) helium layer, while super…
Colour jumps across the spiral arms of Hubble Ultra Deep Field galaxies
González-Lópezlira, Rosa A.; Martínez-García, Eric E.; Puerari, Ivânio
We have measured, at various wavelengths, the spiral arm pitch angles of a sample of distant spiral galaxies from the Hubble Space Telescope eXtreme Deep Field (XDF). According to density wave (DW) theory, we should detect colour jumps from red-to-blue across the spiral arms. Colour jumps are a consequence of large-scale shocks, which also generat…