Search Publications
Investigating the X-ray time lags in PG 1244+026 using an extended corona model
Chainakun, P.; Young, A. J.
We present an extended corona model based on ray-tracing simulations to investigate X-ray time lags in active galactic nuclei (AGNs). This model consists of two axial point sources illuminating an accretion disc that produce the reverberation lags. These lags are due to the time delays between the directly observed and reflection photons and are a…
The Magellanic Inter-Cloud Project (MAGIC) III: first spectroscopic evidence of a dwarf stripping a dwarf
Conn, Blair C.; Carrera, Ricardo; Noël, Noelia E. D. +2 more
The Magellanic Bridge (MB) is a gaseous stream that links the Large (LMC) and Small (SMC) Magellanic Clouds. Current simulations suggest that the MB forms from a recent interaction between the Clouds. In this scenario, the MB should also have an associated stellar bridge formed by stars tidally stripped from the SMC by the LMC. There are several o…
The nearby Type Ibn supernova 2015G: signatures of asymmetry and progenitor constraints
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Wood-Vasey, W. Michael +24 more
We present the results of an extensive observational campaign on the nearby Type Ibn SN 2015G, including data from radio through ultraviolet wavelengths. SN 2015G was asymmetric, showing late-time nebular lines redshifted by ∼1000 km s-1. It shared many features with the prototypical SN Ibn 2006jc, including extremely strong He I emissi…
Peculiar architectures for the WASP-53 and WASP-81 planet-hosting systems★
Smalley, Barry; Hellier, Coel; Triaud, Amaury H. M. J. +16 more
We report the detection of two new systems containing transiting planets. Both were identified by WASP as worthy transiting planet candidates. Radial velocity observations quickly verified that the photometric signals were indeed produced by two transiting hot Jupiters. Our observations also show the presence of additional Doppler signals. In addi…
A dichotomy between the hard state spectral properties of black hole and neutron star X-ray binaries
Sunyaev, R.; Gilfanov, M.; Burke, M. J.
We analyse the spectra of black hole (BH) and neutron star (NS) X-ray binaries (XBs) in the hard state using archival RXTE observations. We find that there is a clear dichotomy in the strength of Comptonization between NS and BH sources, as measured by both the Compton y-parameter and the amplification factor A, with distinct groups of BH and NS X…
Radio jets in NGC 4151: where eMERLIN meets HST
Muxlow, T. W. B.; Argo, M. K.; Knapen, J. H. +11 more
We present high-sensitivity eMERLIN radio images of the Seyfert galaxy NGC 4151 at 1.51 GHz. We compare the new eMERLIN images to those from archival MERLIN observations in 1993 to determine the change in jet morphology in the 22 yr between observations. We report an increase by almost a factor of 2 in the peak flux density of the central core com…
H2 in low-ionization structures of planetary nebulae
Gonçalves, Denise R.; Akras, Stavros; Ramos-Larios, Gerardo
We report the detection of near-IR H2 emission from the low-ionization structures (knots) in two planetary nebulae. The deepest ever high-angular-resolution H2 (1-0) S(1) at 2.122 µm, H2 (2-1) S(1) at 2.248 µm and Brγ images of K 4-47 and NGC 7662, obtained using the Near InfraRed Imager and Spectromete…
Seasonal changes of the volatile density in the coma and on the surface of comet 67P/Churyumov-Gerasimenko
Altwegg, Kathrin; Rubin, Martin; Läuter, Matthias +1 more
Starting from several monthly data sets of Rosetta's COmetary Pressure Sensor, we reconstruct the gas density in the coma around comet 67P/Churyumov-Gerasimenko. The underlying inverse gas model is constructed by fitting ten thousands of measurements to thousands of potential gas sources distributed across the entire nucleus surface. The ensuing s…
On the redshift distribution and physical properties of ACT-selected DSFGs
Frayer, D. T.; Bond, J. R.; Partridge, B. +25 more
We present multi-wavelength detections of nine candidate gravitationally lensed dusty star-forming galaxies (DSFGs) selected at 218 GHz (1.4 mm) from the Atacama Cosmology Telescope (ACT) equatorial survey. Among the brightest ACT sources, these represent the subset of the total ACT sample lying in Herschel SPIRE fields, and all nine of the 218 GH…
Epoch of reionization 21 cm forecasting from MCMC-constrained semi-numerical models
Davé, Romeel; Finlator, Kristian; Hassan, Sultan +1 more
The recent low value of Planck Collaboration XLVII integrated optical depth to Thomson scattering suggests that the reionization occurred fairly suddenly, disfavouring extended reionization scenarios. This will have a significant impact on the 21 cm power spectrum. Using a semi-numerical framework, we improve our model from instantaneous to includ…