Search Publications
A representative survey of the dynamics and energetics of FR II radio galaxies
Hardcastle, M. J.; Croston, J. H.; Ineson, J. +1 more
We report the first large, systematic study of the dynamics and energetics of a representative sample of Fanaroff-Riley type II (FR II) radio galaxies with well-characterized group/cluster environments. We used X-ray inverse-Compton and radio synchrotron measurements to determine the internal radio-lobe conditions, and these were compared with ext…
DYNAMO-HST survey: clumps in nearby massive turbulent discs and the effects of clump clustering on kiloparsec scale measurements of clumps
Glazebrook, Karl; Obreschkow, Danail; Abraham, Roberto G. +6 more
We present ∼100 pc resolution Hubble Space Telescope Hα images of 10 galaxies from the DYnamics of Newly-Assembled Massive Objects (DYNAMO) survey of low-z turbulent disc galaxies, and use these to undertake the first detailed systematic study of the effects of resolution and clump clustering on observations of clumps in turbulent discs. In the DY…
Galaxy Zoo: quantitative visual morphological classifications for 48 000 galaxies from CANDELS
Finkelstein, Steven L.; Barro, Guillermo; Bell, Eric F. +46 more
We present quantified visual morphologies of approximately 48 000 galaxies observed in three Hubble Space Telescope legacy fields by the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and classified by participants in the Galaxy Zoo project. 90 per cent of galaxies have z ≤ 3 and are observed in rest-frame optical wavelen…
Mapping substructure in the HST Frontier Fields cluster lenses and in cosmological simulations
Richard, Johan; Vogelsberger, Mark; Pillepich, Annalisa +14 more
We map the lensing-inferred substructure in the first three clusters observed by the Hubble Space Telescope Frontier Fields (HSTFF) Initiative: Abell 2744 (z = 0.308), MACSJ 0416, (z = 0.396) and MACSJ 1149 (z = 0.543). Statistically resolving dark matter subhaloes down to ∼10^{9.5} M_{⊙}, we compare the derived subhalo mass functions (SHMFs) to t…
A merger in the dusty, z = 7.5 galaxy A1689-zD1?
Richard, Johan; Gallazzi, Anna; Knudsen, Kirsten K. +5 more
The gravitationally lensed galaxy A1689-zD1 is one of the most distant spectroscopically confirmed sources (z = 7.5). It is the earliest known galaxy where the interstellar medium (ISM) has been detected; dust emission was detected with the Atacama Large Millimetre Array (ALMA). A1689-zD1 is also unusual among high-redshift dust emitters as it is …
NGC 6819: testing the asteroseismic mass scale, mass loss and evidence for products of non-standard evolution
Chaplin, W. J.; Handberg, R.; Bossini, D. +5 more
We present an extensive peakbagging effort on Kepler data of ∼50 red giant stars in the open star cluster NGC 6819. By employing sophisticated pre-processing of the time series and Markov chain Monte Carlo techniques we extracted individual frequencies, heights and line widths for hundreds of oscillation modes. We show that the 'average' asterosei…
Optical, UV, and X-ray evidence for a 7-yr stellar cycle in Proxima Centauri
Drake, J. J.; Saar, S. H.; Kashyap, V. L. +2 more
Stars of stellar type later than about M3.5 are believed to be fully convective and therefore unable to support magnetic dynamos like the one that produces the 11-yr solar cycle. Because of their intrinsic faintness, very few late M stars have undergone long-term monitoring to test this prediction, which is critical to our understanding of magneti…
A population of eruptive variable protostars in VVV
Minniti, D.; Lucas, P. W.; Thompson, M. A. +10 more
We present the discovery of 816 high-amplitude infrared variable stars (ΔKs > 1 mag) in 119 deg2 of the Galactic mid-plane covered by the VISTA Variables in the Via Lactea (VVV) survey. Almost all are new discoveries and about 50 per cent are young stellar objects (YSOs). This provides further evidence that YSOs are the co…
Effective temperatures of cataclysmic-variable white dwarfs as a probe of their evolution
Reichart, D. E.; Knigge, C.; Gänsicke, B. T. +29 more
We present HST spectroscopy for 45 cataclysmic variables (CVs), observed with HST/COS and HST/STIS. For 36 CVs, the white dwarf is recognisable through its broad Ly α absorption profile and we measure the white dwarf effective temperatures (Teff) by fitting the HST data assuming log g = 8.35, which corresponds to the average mass for CV…
The dust-to-ices ratio in comets and Kuiper belt objects
Fulle, M.; Colangeli, L.; Della Corte, V. +7 more
Comet 67P/Churyumov-Gerasimenko (67P hereinafter) is characterized by a dust transfer from the southern hemi-nucleus to the night-side northern dust deposits, which constrains the dust-to-ices mass ratio inside the nucleus to values a factor of 2 larger than that provided by the lost mass of gas and non-volatiles. This applies to all comets becaus…