Search Publications
The extraordinary amount of substructure in the Hubble Frontier Fields cluster Abell 2744
Kneib, J. -P.; Egami, E.; Eckert, D. +21 more
We present a joint optical/X-ray analysis of the massive galaxy cluster Abell 2744 (z = 0.308). Our strong- and weak-lensing analysis within the central region of the cluster, I.e. at R < 1 Mpc from the brightest cluster galaxy, reveals eight substructures, including the main core. All of these dark matter haloes are detected with a significanc…
Measuring the dynamical state of Planck SZ-selected clusters: X-ray peak - BCG offset
Bersanelli, M.; Maino, D.; Rossetti, M. +6 more
We want to characterize the dynamical state of galaxy clusters detected with the Sunyaev-Zeldovich (SZ) effect by Planck and compare them with the dynamical state of clusters selected in X-rays survey. We analysed a representative subsample of the Planck SZ catalogue, containing the 132 clusters with the highest signal to noise ratio and character…
A Hubble Space Telescope survey of the host galaxies of Superluminous Supernovae
Lyman, J. D.; Angus, C. R.; Fruchter, A. S. +4 more
We present Hubble Space Telescope (HST) Wide Field Camera 3 UV and near-IR (nIR) imaging of 21 Superluminous Supernovae (SLSNe) host galaxies, providing a sensitive probe of star formation and stellar mass within the hosts. Comparing the photometric and morphological properties of these host galaxies with those of core-collapse supernovae (CCSNe) …
A spectroscopic survey of X-ray-selected AGNs in the northern XMM-XXL field
Georgakakis, A.; Salvato, M.; Buchner, J. +10 more
This paper presents a survey of X-ray-selected active galactic nuclei (AGNs) with optical spectroscopic follow-up in a ∼ 18 deg2 area of the equatorial XMM-XXL north field. A sample of 8445 point-like X-ray sources detected by XMM-Newton above a limiting flux of F_{0.5-10 keV} > 10^{-15} erg cm^{-2} s^{-1} was matched to optical (Slo…
Non-parametric analysis of the rest-frame UV sizes and morphological disturbance amongst L* galaxies at 4 < z < 8
Ferguson, H. C.; McLure, R. J.; Dunlop, J. S. +12 more
We present the results of a study investigating the sizes and morphologies of redshift 4 < z < 8 galaxies in the CANDELS (Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey) GOODS-S (Great Observatories Origins Deep Survey southern field), HUDF (Hubble Ultra-Deep Field) and HUDF parallel fields. Based on non-parametric measuremen…
The evolution of the equivalent width of the Hα emission line and specific star formation rate in star-forming galaxies at 1 < z < 5
Cullen, F.; McLure, R. J.; Dunlop, J. S. +3 more
We present the results of a study which uses spectral energy distribution (SED) fitting to investigate the evolution of the equivalent width (EW) of the Hα emission line in star-forming galaxies over the redshift interval 1 < z < 5. After first demonstrating the ability of our SED-fitting technique to recover EW(Hα) using a sample of galaxie…
Direct Simulation Monte Carlo modelling of the major species in the coma of comet 67P/Churyumov-Gerasimenko
Altwegg, K.; Huang, Z.; Erard, S. +26 more
We analyse the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) - the Double Focusing Mass Spectrometer data between 2014 August and 2016 February to examine the effect of seasonal variations on the four major species within the coma of 67P/Churyumov-Gerasimenko (H2O, CO2, CO, and O2), resulting f…
Comet 67P/Churyumov-Gerasimenko preserved the pebbles that formed planetesimals
Rodriguez, J.; Colangeli, L.; Della Corte, V. +16 more
Solar system formation models predict that the building blocks of planetesimals were mm- to cm-sized pebbles, aggregates of ices and non-volatile materials, consistent with the compact particles ejected by comet 67P/Churyumov-Gerasimenko (67P hereafter) and detected by GIADA (Grain Impact Analyzer and Dust Accumulator) on-board the Rosetta spacecr…
Jellyfish: the origin and distribution of extreme ram-pressure stripping events in massive galaxy clusters
Ebeling, Harald; McPartland, Conor; Roediger, Elke +1 more
We investigate the observational signatures and physical origin of ram-pressure stripping (RPS) in 63 massive galaxy clusters at z = 0.3-0.7, based on images obtained with the Hubble Space Telescope. Using a training set of a dozen `jellyfish' galaxies identified earlier in the same imaging data, we define morphological criteria to select 211 addi…
Optically thick outflows in ultraluminous supersoft sources
Soria, R.; Urquhart, R.
Ultraluminous supersoft sources (ULSs) are defined by a thermal spectrum with colour temperatures ∼0.1 keV, bolometric luminosities ∼ a few 1039 erg s-1, and almost no emission above 1 keV. It has never been clear how they fit into the general scheme of accreting compact objects. To address this problem, we studied a sample o…