Search Publications
Star cluster formation and evolution in nearby starburst galaxies - II. Initial conditions
Bastian, N.; de Grijs, R.; Anders, P. +3 more
We use the ages, masses and metallicities of the rich young star cluster systems in the nearby starburst galaxies NGC 3310 and 6745 to derive their cluster formation histories and subsequent evolution. We further expand our analysis of the systematic uncertainties involved in the use of broad-band observations to derive these parameters (Paper I) …
Evidence of a high-velocity ionized outflow in a second narrow-line quasar PG 0844+349
O'Brien, P. T.; King, A. R.; Page, K. L. +1 more
Following the discovery of X-ray absorption in a high-velocity outflow from the bright quasar PG 1211 + 143 we have searched for similar features in XMM-Newton archival data of a second (high accretion rate) quasar PG 0844+349. Evidence is found for several faint absorption lines in both the EPIC and RGS spectra, whose most likely identification w…
An XMM-Newton hard X-ray survey of ultraluminous infrared galaxies
Cappi, M.; Franceschini, A.; Bassani, L. +8 more
XMM-Newton observations of 10 ultraluminous infrared galaxies (ULIRGs) from a 200-ks mini-survey programme are reported. The aim is to investigate in hard X-rays a complete ULIRG sample selected from the bright IRAS 60-µm catalogue. All sources are detected in X-rays, five of which for the first time. These observations confirm that ULIRGs a…
X-ray continuum variability of MCG-6-30-15
Nandra, K.; Vaughan, S.; Fabian, A. C.
This paper presents a comprehensive examination of the X-ray continuum variability of the bright Seyfert 1 galaxy MCG-6-30-15. The source clearly shows the strong, linear correlation between rms variability amplitude and flux first seen in Galactic X-ray binaries. The high-frequency power spectral density (PSD) of MCG-6-30-15 is examined in detail…
A pulsational approach to near-infrared and visual magnitudes of RR Lyr stars
Degl'Innocenti, S.; Marconi, M.; Bono, G. +3 more
In this paper, we present an improved theoretical scenario concerning near-infrared and visual magnitudes of RR Lyr variables, as based on up-to-date pulsating models. New relations connecting V and K absolute magnitudes with periods, mass, luminosity and metal content are discussed separately for fundamental and first-overtone pulsators. We also …
Kinematically quiet haloes around z~ 2.5 radio galaxies. Keck spectroscopy
Pentericci, L.; Humphrey, A.; Villar-Martín, M. +3 more
We present the results of the kinematic study of the extended gas in a sample of 10 high-redshift radio galaxies (z~ 2.5) based on high signal-to-noise ratio Keck II and Very Large Telescope (VLT) long-slit spectroscopy. In addition to the typical high surface brightness kinematically perturbed regions (FWHM and velocity shifts >1000 km s-…
The remarkable rapid X-ray, ultraviolet, optical and infrared variability in the black hole XTE J1118+480
Chaty, S.; Cui, W.; Horne, Keith +6 more
The transient black-hole binary XTE J1118+480 exhibited dramatic rapid variability at all wavelengths which were suitably observed during its 2000 April-July outburst. We examine time-resolved X-ray, ultraviolet, optical and infrared data spanning the plateau phase of the outburst. We find that both X-ray and infrared bands show large amplitude va…
A deep survey of heavy element lines in planetary nebulae - I. Observations and forbidden-line densities, temperatures and abundances
Tsamis, Y. G.; Barlow, M. J.; Liu, X. -W. +2 more
We present deep optical spectrophotometry of 12 Galactic planetary nebulae (PNe) and three Magellanic Cloud PNe. Nine of the Galactic PNe were observed by scanning the slit of the spectrograph across the nebula, yielding relative line intensities for the entire nebula that are suitable for comparison with integrated nebular fluxes measured in othe…
Infrared stellar populations in the central parts of the Milky Way galaxy
Blommaert, J. A. D. L.; Glass, I. S.; Omont, A. +7 more
Near- and mid-IR survey data from DENIS and ISOGAL are used to investigate the structure and formation history of the inner 10° (1.4 kpc) of the Milky Way galaxy. Synthetic bolometric corrections and extinction coefficients in the near- and mid-infrared (mid-IR) are derived for stars of different spectral types, to allow the transformation of theo…
The Hubble diagram of type Ia supernovae as a function of host galaxy morphology
Panagia, N.; Wang, L.; Sullivan, M. +41 more
We present new results on the Hubble diagram of distant type Ia supernovae (SNeIa) segregated according to the type of host galaxy. This makes it possible to check earlier evidence for a cosmological constant by explicitly comparing SNe residing in galaxies likely to contain negligible dust with the larger sample. The cosmological parameters deriv…