Search Publications
First high-resolution detection of a warm absorber in the Broad Line Radio Galaxy 3C 382
Guainazzi, M.; Grandi, P.; Tombesi, F. +4 more
Recent high-resolution measurements suggest that the soft X-ray spectrum of obscured radio galaxies exhibits signatures of photoionized gas (e.g. 3C 445 and 3C 33) similar to those observed in radio-quiet obscured active galactic nuclei. While signatures of warm absorbing gas covering a wide range of temperature and ionization states have been det…
A census of nuclear stellar discs in early-type galaxies
Morelli, L.; Sarzi, M.; Dotti, M. +2 more
Nuclear stellar discs (NSDs), of a few tens to hundreds of parsec across, are a common and yet poorly studied feature of early-type galaxies. Still, such small discs represent a powerful tool to constrain the assembling history of galaxies, since they can be used to trace to the epoch when galaxies experienced their last major merger event. By stu…
The BLAST 250 µm-selected galaxy population in GOODS-South
Smail, I.; Ivison, R. J.; Ade, P. A. R. +33 more
We identify and investigate the nature of the 20 brightest 250µm sources detected by the Balloon-borne Large Aperture Submillimetre Telescope (BLAST) within the central 150arcmin2 of the Great Observatories Origins Deep Survey (GOODS)-South field. Aided by the available deep VLA 1.4GHz radio imaging, reaching S1.4 ~= 40…
X-ray emission from the extended emission-line region of the powerful radio galaxy 3C171
Hardcastle, M. J.; Massaro, F.; Harris, D. E.
We present Chandra X-ray observations of the powerful radio galaxy 3C171, which reveal an extended region of X-ray emission spatially associated with the well-known 10-kpc scale optical emission-line region around the radio jets. We argue that the X-ray emission comes from collisionally ionized material, originally cold gas that has been shock hea…
Type I X-ray bursts, burst oscillations and kHz quasi-periodic oscillations in the neutron star system IGRJ17191-2821
Altamirano, D.; Degenaar, N.; Wijnands, R. +6 more
We present a detailed study of the X-ray energy and power spectral properties of the neutron star transient IGRJ17191-2821. We discovered four instances of pairs of simultaneous kilohertz quasi-periodic oscillations (kHz QPOs). The frequency difference between these kHz QPOs is between 315 and 362Hz. We also report on the detection of five thermon…
New measurement of orbital and spin period evolution of the accretion disc corona source 4U 1822-37
Paul, Biswajit; Jain, Chetana; Dutta, Anjan
4U 1822-37 is a low mass X-ray binary (LMXB) system with an accretion disc corona. It is one of the very few LMXBs that shows narrow X-ray eclipses and small amplitude pulsations of the neutron star. The X-ray eclipse is an excellent reference for measurement of orbital evolution of the binary, and we have obtained 16 new mid-eclipse time measurem…
The evolutionary status of the blue hook stars in ω Centauri
D'Antona, Francesca; Ventura, Paolo; Caloi, Vittoria
Core helium burning is the dominant source of energy of extreme horizontal branch stars, as the hydrogen envelope is too small to contribute to the nuclear energy output. The evolution of each mass in the HR diagram occurs along vertical tracks that, when the core helium is consumed, evolve to higher Teff and then to the white dwarf sta…
Evidence of supercritical disc funnel radiation in X-ray spectra of SS 433
Fabrika, S.; Medvedev, A.
We analysed the XMM-Newton spectra of SS433 using a standard model of adiabatically and radiatively cooling X-ray jets. The multitemperature thermal jet model reproduces the strongest observed emission line fluxes well. Fitting the He- and H-like iron line fluxes, we find that the visible blue jet base temperature is ~17 keV, the jet kinetic lumin…
Evidence for a truncated accretion disc in the low-luminosity Seyfert galaxy, NGC 7213?
Turner, T. J.; Porquet, D.; Reeves, J. N. +4 more
We present the broad-band 0.6-150keV Suzaku and Swift BAT spectra of the low-luminosity Seyfert galaxy, NGC 7213. The time-averaged continuum emission is well fitted by a single power law of photon index Γ = 1.75, and from consideration of the Fermi flux limit we constrain the high-energy cut-off to be 350keV < Ecut < 25MeV. Line …
Estimating the masses of extra-solar planets
Dhillon, V. S.; Littlefair, S. P.; Collier Cameron, A. +2 more
All extra-solar planet masses that have been derived spectroscopically are lower limits since the inclination of the orbit to our line-of-sight is unknown except for transiting systems. In theory, however, it is possible to determine the inclination angle, i, between the rotation axis of a star and an observer's line-of-sight from measurements of …