Search Publications
Stellar diameters and temperatures - VI. High angular resolution measurements of the transiting exoplanet host stars HD 189733 and HD 209458 and implications for models of cool dwarfs
López-Morales, Mercedes; Kane, Stephen R.; Brewer, John +24 more
We present direct radii measurements of the well-known transiting exoplanet host stars HD 189733 and HD 209458 using the CHARA Array interferometer. We find the limb-darkened angular diameters to be θLD = 0.3848 ± 0.0055 and 0.2254 ± 0.0072 mas for HD 189733 and HD 209458, respectively. HD 189733 and HD 209458 are currently the only two…
The XMM Cluster Survey: testing chameleon gravity using the profiles of clusters
Hilton, Matt; Zhao, Gong-Bo; Stott, John P. +17 more
The chameleon gravity model postulates the existence of a scalar field that couples with matter to mediate a fifth force. If it exists, this fifth force would influence the hot X-ray emitting gas filling the potential wells of galaxy clusters. However, it would not influence the clusters weak lensing signal. Therefore, by comparing X-ray and weak …
X-ray coherent pulsations during a sub-luminous accretion disc state of the transitional millisecond pulsar XSS J12270-4859.
de Martino, D.; Torres, D. F.; Pellizzoni, A. +4 more
We present the first detection of X-ray coherent pulsations from the transitional millisecond pulsar XSS J12270-4859, while it was in a sub-luminous accretion disc state characterized by a 0.5-10 keV luminosity of 5 × 1033 erg s-1 (assuming a distance of 1.4 kpc). Pulsations were observed by XMM-Newton at an rms amplitude of …
Diversity in extinction laws of Type Ia supernovae measured between 0.2 and 2 µm
Dahle, H.; Lundqvist, P.; Östlin, G. +36 more
We present ultraviolet (UV) observations of six nearby Type Ia supernovae (SNe Ia) obtained with the Hubble Space Telescope, three of which were also observed in the near-IR (NIR) with Wide-Field Camera 3. UV observations with the Swift satellite, as well as ground-based optical and NIR data provide complementary information. The combined data set…
Possible binary progenitors for the Type Ib supernova iPTF13bvn
Fraser, Morgan; Eldridge, J. J.; Smartt, Stephen J. +1 more
Cao et al. reported a possible progenitor detection for the Type Ib supernovae iPTF13bvn for the first time. We find that the progenitor is in fact brighter than the magnitudes previously reported by approximately 0.7-0.2 mag with a larger error in the bluer filters. We compare our new magnitudes to our large set of binary evolution models and fin…
Asteroseismic inference on rotation, gyrochronology and planetary system dynamics of 16 Cygni
García, R. A.; Chaplin, W. J.; Lund, M. N. +13 more
The solar analogues 16 Cyg A and B are excellent asteroseismic targets in the Kepler field of view and together with a red dwarf and a Jovian planet form an interesting system. For these more evolved Sun-like stars we cannot detect surface rotation with the current Kepler data but instead use the technique of asteroseimology to determine rotationa…
Revisiting the relationship between 6 µm and 2-10 keV continuum luminosities of AGN
Hernán-Caballero, A.; Rovilos, E.; Barcons, X. +7 more
We have determined the relation between the AGN luminosities at rest-frame 6 µm associated with the dusty torus emission and at 2-10 keV energies using a complete, X-ray-flux-limited sample of 232 AGN drawn from the Bright Ultra-hard XMM-Newton Survey. The objects have intrinsic X-ray luminosities between 1042 and 1046 …
Decreased specific star formation rates in AGN host galaxies
Koss, Michael; Mushotzky, Richard F.; Rosario, David J. +2 more
We investigate the location of an ultra-hard X-ray selected sample of active galactic nuclei (AGN) from the Swift Burst Alert Telescope (BAT) catalogue with respect to the main sequence (MS) of star-forming galaxies using Herschel-based measurements of the star formation rate (SFR) and M*'s from Sloan Digital Sky Survey photometry where…
Large-scale alignments from WMAP and Planck
Schwarz, Dominik J.; Starkman, Glenn D.; Copi, Craig J. +1 more
We revisit the alignments of the largest structures observed in the cosmic microwave background (CMB) using the seven and nine-year Wilkinson Microwave Anisotropy Probe (WMAP) and first-year Planck data releases. The observed alignments - the quadrupole with the octopole and their joint alignment with the direction of our motion with respect to th…
The stellar initial mass function of early-type galaxies from low to high stellar velocity dispersion: homogeneous analysis of ATLAS3D and Sloan Lens ACS galaxies
Treu, Tommaso; Cappellari, Michele; Ciotti, Luca +2 more
We present an investigation about the shape of the initial mass function (IMF) of early-type galaxies (ETGs), based on a joint lensing and dynamical analysis, and on stellar population synthesis models, for a sample of 55 lens ETGs identified by the Sloan Lens Advanced Camera for Surveys (SLACS). We construct axisymmetric dynamical models based on…