Search Publications
SHARP - V. Modelling gravitationally lensed radio arcs imaged with global VLBI observations
Vegetti, S.; McKean, J. P.; Auger, M. W. +4 more
We present milliarcsecond (mas) angular resolution observations of the gravitationally lensed radio source MG J0751+2716 (at z= 3.2) obtained with global very long baseline interferometry (VLBI) at 1.65 GHz. The background object is highly resolved in the tangential and radial directions, showing evidence of both compact and extended structure acr…
Kinetic Theory and Fast Wind Observations of the Electron Strahl
Wilson, Lynn B., III; Horaites, Konstantinos; Viñas, Adolfo F. +2 more
We develop a model for the strahl population in the solar wind - a narrow, low-density and high-energy electron beam centred on the magnetic field direction. Our model is based on the solution of the electron drift-kinetic equation at heliospheric distances where the plasma density, temperature and the magnetic field strength decline as power laws…
A sextet of clusters in the Vela OB2 region revealed by Gaia
Wright, Nicholas J.; Boffin, Henri M. J.; Jerabkova, Tereza +5 more
Using Gaia DR2 data, combined with OmegaCAM ground-based optical photometry from the Accretion Disc with OmegaCAM survey, and detailed radial velocity measurements from ESO-Gaia, we analyse in detail a 10 × 5 deg region around the Wolf-Rayet Star γ2 Vel, including the previously known clusters Gamma Vel and NGC2547. Using clustering ana…
A potential progenitor for the Type Ic supernova 2017ein
Kilpatrick, Charles D.; Foley, Ryan J.; Pan, Yen-Chen +9 more
We report the first detection of a credible progenitor system for a Type Ic supernova (SN Ic), SN 2017ein. We present spectra and photometry of the SN, finding it to be similar to carbon-rich, low-luminosity SNe Ic. Using a post-explosion Keck adaptive optics image, we precisely determine the position of SN 2017ein in pre-explosion HST images, fin…
The XXL Survey. XVII. X-ray and Sunyaev-Zel'dovich properties of the redshift 2.0 galaxy cluster XLSSC 122
Pierre, M.; Willis, J.; Carlstrom, J. E. +7 more
We present results from a 100 ks XMM-Newton observation of galaxy cluster XLSSC 122, the first massive cluster discovered through its X-ray emission at z ≈ 2. The data provide the first precise constraints on the bulk thermodynamic properties of such a distant cluster, as well as an X-ray spectroscopic confirmation of its redshift. We measure an a…
On the far-infrared metallicity diagnostics: applications to high-redshift galaxies
Marques-Chaves, R.; Magdis, G. E.; Cooray, A. +5 more
In an earlier paper we modelled the far-infrared emission from a star-forming galaxy using the photoionization code CLOUDY and presented metallicity sensitive diagnostics based on far-infrared fine structure line ratios. Here, we focus on the applicability of the [O III] 88 µm/[N II] 122 µm line ratio as a gas-phase metallicity indicat…
The Ultra-fast Outflow of the Quasar PG 1211+143 as Viewed by Time-averaged Chandra Grating Spectroscopy
Kriss, Gerard A.; Lee, Julia C.; Chakravorty, Susmita +8 more
We present a detailed X-ray spectral study of the quasar PG 1211+143 based on Chandra High Energy Transmission Grating Spectrometer (HETGS) observations collected in a multi-wavelength campaign with UV data using the Hubble Space Telescope Cosmic Origins Spectrograph (HST-COS) and radio bands using the Jansky Very Large Array (VLA). We constructed…
The Dispersion of Fast Radio Bursts from a Structured Intergalactic Medium at Redshifts z < 1.5
Shull, J. Michael; Danforth, Charles W.
We analyze the sources of free electrons that produce the large dispersion measures, {DM}≈ 300{--}1600 (in units of cm-3 pc), observed toward fast radio bursts (FRBs). Individual galaxies typically produce {DM}∼ 25{--}60 {{cm}}-3 {pc} from ionized gas in their disk, disk-halo interface, and circumgalactic medium. Toward an FR…
Discovery of 105 Hz coherent pulsations in the ultracompact binary IGR J16597-3704
Altamirano, D.; Sanna, A.; Degenaar, N. +15 more
We report the discovery of X-ray pulsations at 105.2 Hz (9.5 ms) from the transient X-ray binary IGR J16597-3704 using NuSTAR and Swift. The source was discovered by INTEGRAL in the globular cluster NGC 6256 at a distance of 9.1 kpc. The X-ray pulsations show a clear Doppler modulation that implies an orbital period of 46 min and a projected semi-…
WISE J080822.18-644357.3 - a 45 Myr-old accreting M dwarf hosting a primordial disc
Murphy, Simon J.; Mamajek, Eric E.; Bell, Cameron P. M.
WISE J080822.18-644357.3 (WISE J0808-6443) was recently identified as a new M dwarf debris disc system and a candidate member of the 45 Myr-old Carina association. Given that the strength of its infrared excess (LIR/L⋆ ≃ 0.1) appears to be more consistent with a young protoplanetary disc, we present the first optical spectra …