Search Publications
High angular resolution stellar imaging with occultations from the Cassini spacecraft - II. Kronocyclic tomography
Nicholson, Philip D.; Hedman, Matthew M.; Lloyd, James P. +2 more
We present an advance in the use of Cassini observations of stellar occultations by the rings of Saturn for stellar studies. Stewart et al. demonstrated the potential use of such observations for measuring stellar angular diameters. Here, we use these same observations, and tomographic imaging reconstruction techniques, to produce two-dimensional …
The dependence of the AV prior for SN Ia on host mass and disc inclination
Holwerda, B. W.; Keel, W. C.; Kenworthy, M. A. +1 more
Type Ia supernovae (SNe Ia) are used as `standard candles' for cosmological distance scales. To fit their light-curve shape-absolute luminosity relation, one needs to assume an intrinsic colour and a likelihood of host galaxy extinction or a convolution of these, a colour distribution prior. The host galaxy extinction prior is typically assumed to…
Unified line profiles for hydrogen perturbed by collisions with protons: satellites and asymmetries
Kepler, S. O.; Pelisoli, Ingrid; Santos, M. G.
We present new calculations of unified line profiles for hydrogen perturbed by collisions with protons. We report on new calculations of the potential energies and dipole moments which allow the evaluation of profiles for the lines of the Lyman series up to Lyman δ and the Balmer series up to Balmer 10. Unified calculations only existed for the li…
Witnessing the transformation of a quasar host galaxy at z = 1.6
Humphrey, A.; Villar-Martín, M.; Binette, L. +9 more
A significant minority of high-redshift radio galaxy (HzRG) candidates show extremely red broad-band colours and remain undetected in emission lines after optical `discovery' spectroscopy. In this paper, we present deep GTC optical imaging and spectroscopy of one such radio galaxy, 5C 7.245, with the aim of better understanding the nature of these…
Deep Chandra observations of the NGC 4472 globular cluster black hole XMMU 122939.7+075333: short-term variability from the first globular cluster black hole binary
Maccarone, T. J.; Sivakoff, G. R.; Kraft, R. P. +1 more
In this paper, we discuss the luminosity modulations and spectral analysis results of the recent deep observations of XMMU 122939.7+075333, the first black hole discovered in a globular cluster. The source has been detected many times, typically with LX > 1039 erg s-1, but in a 2010 observation had faded to L
The extreme ultraviolet spectrum of the kinetically dominated quasar 3C 270.1
Punsly, Brian; Marziani, Paola
Only a handful of quasars have been identified as kinetically dominated, their long-term time-averaged jet power, overline{Q}, exceeds the bolometric thermal emission, Lbol, associated with the accretion flow. This Letter presents the first extreme ultraviolet (EUV) spectrum of a kinetically dominated quasar, 3C 270.1. The EUV continuum…
Investigating early-type galaxy evolution with a multiwavelength approach - I. X-ray properties of 12 galaxies observed with Swift and XMM-Newton
Wolter, A.; Marino, A.; Trinchieri, G. +2 more
We report here the results from the X-ray observations of 12 early-type galaxies (ETGs) observed with Swift and XMM-Newton, originally selected from a sample of galaxies with Spitzer and/or GALEX data. With the combined analysis of new X-ray and optical-UV observations and of previously available data from archives, we aim at investigating the rel…
X-rays from the episodic dust maker WR 137
Zhekov, Svetozar A.
We present an analysis of the XMM-Newton observation of the episodic dust maker WR 137. Global spectral fits show that its X-ray spectrum is well matched by a two-temperature optically-thin plasma emission (kT1 ∼ 0.4 keV and kT2 ∼ 2.2 keV). If we adopt the colliding stellar wind (CSW) picture for this wide WR+O binary, the th…
Magnetic fields near spacecraft-explored comets: 3D MHD numerical simulation
Baranov, V. B.; Alexashov, D. B.; Lebedev, M. G.
The magnetohydrodynamic (MHD) model of the interaction between the solar wind and a cometary ionosphere is presented. The model accounts for photoionization of the neutral component of the cometary outflow and the resonance charge exchange between charged and neutral particles, together with the interplanetary magnetic field. The numerical impleme…
Cold galaxies
Clements, David L.; Rowan-Robinson, Michael
We use 350 µm angular diameter estimates from Planck to test the idea that some galaxies contain exceptionally cold (10-13 K) dust, since colder dust implies a lower surface brightness radiation field illuminating the dust, and hence a greater physical extent for a given luminosity. The galaxies identified from their spectral energy distribu…