Search Publications
X-ray evidence for the accretion disc-outflow connection in 3C 111
Reynolds, C. S.; Tombesi, F.; Reeves, J. N. +2 more
We present the spectral analysis of three Suzaku X-ray Imaging Spectrometer observations of 3C 111 requested to monitor the predicted variability of its ultrafast outflow on ∼7 d time-scales. We detect an ionized iron emission line in the first observation and a blueshifted absorption line in the second, when the flux is ∼30 per cent higher. The l…
A magnetar strength surface magnetic field for the slowly spinning down SGR 0418+5729
Göǧüş, Ersin; Güver, Tolga; Özel, Feryal
The observed upper bound on the spin-down rate of the otherwise typical soft gamma-ray repeater SGR 0418+5729 has challenged the interpretation of this source as a neutron star with ultrastrong magnetic fields. Current limits imply a dipole magnetic field strength of less than 7.5 × 1012 G, which is significantly smaller than that of a …
A faint optical flash in dust-obscured GRB 080603A: implications for GRB prompt emission mechanisms
Melandri, A.; Bloom, J. S.; Frail, D. A. +23 more
We report the detection of a faint optical flash by the 2-m Faulkes Telescope North simultaneously with the second of two prompt γ-ray pulses in INTEGRAL gamma-ray burst (GRB) 080603A, beginning at trest= 37 s after the onset of the GRB. This optical flash appears to be distinct from the subsequent emerging afterglow emission, for which…
Long-term spectral and timing properties of the soft gamma-ray repeater SGR 1833-0832 and detection of extended X-ray emission around the radio pulsar PSR B1830-08
Sakamoto, T.; Wieringa, M. H.; Tiengo, A. +19 more
SGR 1833-0832 was discovered on 2010 March 19, thanks to the Swift detection of a short hard X-ray burst and follow-up X-ray observations. Since then, it was repeatedly observed with Swift, Rossi X-ray Timing Explorer and XMM-Newton. Using these data, which span about 225 d, we studied the long-term spectral and timing characteristics of SGR 1833-…
Spectra of globular clusters in the Sombrero galaxy: evidence for spectroscopic metallicity bimodality
Spitler, Lee R.; Forbes, Duncan A.; Brodie, Jean P. +4 more
We present a large sample of over 200 integrated-light spectra of confirmed globular clusters (GCs) associated with the Sombrero (M104) galaxy taken with the Deep Imaging Multi-Object Spectrograph (DEIMOS) instrument on the Keck telescope. A significant fraction of the spectra have signal-to-noise ratio levels high enough to allow measurements of …
The effect of the environment on the gas kinematics and the structure of distant galaxies
Aragón-Salamanca, Alfonso; Milvang-Jensen, Bo; Zaritsky, Dennis +10 more
With the aim of distinguishing between possible physical mechanisms acting on galaxies when they fall into clusters, we study the properties of the gas and the stars in a sample of 422 emission-line galaxies from the European Southern Observatory Distant Cluster Survey in different environments up to z∼ 1. We identify galaxies with kinematical dis…
Spitzer spectra of evolved stars in ω Centauri and their low-metallicity dust production
van Loon, J. Th.; Gehrz, R. D.; Evans, A. +7 more
Dust production is explored around 14 metal-poor ([Fe/H]=-1.91 to -0.98) giant stars in the Galactic globular cluster ω Centauri using new Spitzer Infrared Spectrograph spectra. This sample includes the cluster's post-asymptotic giant branch (AGB) and carbon stars and is thus the first representative spectral study of dust production in a metal-po…
Searching for the trigger of the active galactic nucleus quasi-periodic oscillation: 8 years of RE J1034+396
Done, Chris; Middleton, Matthew; Uttley, Phil
RE J1034+396 is one of the most extreme narrow-line type 1 Seyfert galaxies detected thus far, showing the only quasi-periodic oscillation (QPO) reliably detected in an active galactic nucleus (AGN). Comparison with similar spectral and timing properties observed in the black hole X-ray binary (BHB) GRS 1915+105 suggests that RE J1034+396 is a sup…
The relationship between star formation rates, local density and stellar mass up to z ∼ 3 in the GOODS NICMOS Survey
Jogee, S.; Conselice, C. J.; Buitrago, F. +6 more
We investigate the relation between star formation rates and local galaxy environment for a stellar-mass-selected galaxy sample in the redshift range 1.5 ≤z≤ 3. We use near-infrared imaging from an extremely deep Hubble Space Telescope survey, the GOODS NICMOS Survey (GNS), to measure local galaxy densities based on the nearest neighbour approach,…
Probing galaxy dark matter haloes in COSMOS with weak lensing flexion
Schrabback, Tim; Kuijken, Konrad; Velander, Malin
Current theories of structure formation predict specific density profiles of galaxy dark matter haloes, and with weak gravitational lensing we can probe these profiles on several scales. On small scales, higher order shape distortions known as flexion add significant detail to the weak lensing measurements. We present here the first detection of a…