Search Publications
On the type Ia supernovae 2007on and 2011iv: evidence for Chandrasekhar-mass explosions at the faint end of the luminosity-width relationship
Foley, Ryan J.; Ashall, C.; Hoeflich, P. +7 more
Radiative transfer models of two transitional type Ia supernovae (SNe Ia) have been produced using the abundance stratification technique. These two objects - designated SN 2007on and SN 2011iv - both exploded in the same galaxy, NGC 1404, which allows for a direct comparison. SN 2007on synthesized 0.25 M_{⊙} of 56Ni and was less lumino…
Spatial clustering and halo occupation distribution modelling of local AGN via cross-correlation measurements with 2MASS galaxies
Coil, Alison L.; Krumpe, Mirko; Miyaji, Takamitsu +1 more
We present the clustering properties and halo occupation distribution (HOD) modelling of very low redshift, hard X-ray-detected active galactic nuclei (AGN) using cross-correlation function measurements with Two-Micron All Sky Survey galaxies. Spanning a redshift range of 0.007 < z < 0.037, with a median z = 0.024, we present a precise AGN c…
Tracking the iron K α line and the ultra fast outflow in NGC 2992 at different accretion states
Bianchi, S.; Matt, G.; Braito, V. +3 more
The Seyfert 2 galaxy NGC 2992 has been monitored eight times by XMM-Newton in 2010 and then observed again in 2013, while in 2015 it was simultaneously targeted by Swift and NuSTAR. XMM-Newton always caught the source in a faint state (2-10 keV fluxes ranging from 0.3 to 1.6 × 10-11 erg cm-2 s-1), but NuSTAR showed…
The GALAH survey: stellar streams and how stellar velocity distributions vary with Galactic longitude, hemisphere, and metallicity
Lewis, Geraint F.; Ting, Yuan-Sen; Buder, Sven +30 more
Using GALAH (GALactic Archaeology with HERMES) survey data of nearby stars, we look at how structure in the planar (u, v) velocity distribution depends on metallicity and on viewing direction within the Galaxy. In nearby stars with distance d ≲ 1 kpc, the Hercules stream is most strongly seen in higher metallicity stars [Fe/H] > 0.2. The Hercul…
Dark matter dynamics in Abell 3827: new data consistent with standard cold dark matter
Richard, Johan; Massey, Richard; Smit, Renske +23 more
We present integral field spectroscopy of galaxy cluster Abell 3827, using Atacama Large Millimetre Array (ALMA) and Very Large Telescope/Multi-Unit Spectroscopic Explorer. It reveals an unusual configuration of strong gravitational lensing in the cluster core, with at least seven lensed images of a single background spiral galaxy. Lens modelling …
Vertical propagation of acoustic waves in the solar internetworkas observed by IRIS
Srivastava, A. K.; Murawski, K.; Dwivedi, B. N. +2 more
We investigate the Interface Region Imaging Spectrograph (IRIS) observations of the quiet-Sun (QS) to understand the propagation of acoustic waves in transition region (TR) from photosphere. We selected a few IRIS spectral lines, which include the photospheric (Mn I 2801.25 Å), chromospheric (Mg II k 2796.35 Å), and TR (C II 1334.53 Å), to investi…
The discovery of a five-image lensed quasar at z = 3.34 using PanSTARRS1 and Gaia
McMahon, Richard G.; Fassnacht, Christopher D.; Auger, Matthew W. +8 more
We report the discovery, spectroscopic confirmation and mass modelling of the gravitationally lensed quasar system PS J0630-1201. The lens was discovered by matching a photometric quasar catalogue compiled from Pan-STARRS1 and Wide-field Infrared Survey Explorer photometry to the Gaia data release 1 catalogue, exploiting the high spatial resolutio…
COS-Weak: probing the CGM using analogues of weak Mg II absorbers at z < 0.3
Narayanan, A.; Muzahid, S.; Charlton, J. +5 more
We present a sample of 34 weak metal line absorbers at z < 0.3 selected by the simultaneous >3σ detections of the Si IIλ1260 and C IIλ1334 absorption lines, with Wr(Si II)<0.2 Å and Wr(C II)<0.3 Å, in archival HST/COS spectra. Our sample increases the number of known low-z `weak absorbers' by a factor of >5. Th…
Probing the properties of relic neutrinos using the cosmic microwave background, the Hubble Space Telescope and galaxy clusters
Nunes, Rafael C.; Bonilla, Alexander
We investigate the observational constraints on the cosmic neutrino background (CNB) given by the extended ΛCDM scenario (ΛCDM + N_eff + \sum m_{ν } + c^2_eff + c^2_vis + ξ _{ν }) using the latest observational data from the cosmic microwave background (CMB) as observed by Planck (i.e. temperature power spectrum, low-polarization and lensing recon…
Evidence of a past disc-disc encounter: HV and DO Tau
Clarke, Cathie J.; Booth, Richard A.; Winter, Andrew J.
Theory and observations suggest that star formation occurs hierarchically due to the fragmentation of giant molecular clouds. In this case we would expect substructure and enhanced stellar multiplicity in the primordial cluster. This substructure is expected to decay quickly in most environments, however historic stellar encounters might leave imp…