Search Publications
Bottom-heavy initial mass function in a nearby compact l{star} galaxy.
La Barbera, F.; Vazdekis, A.; Ferreras, I. +4 more
We present orbit-based dynamical models and stellar population analysis of Sloan Digital Sky Survey J151741.75-004217.6, a low-redshift (z = 0.116) early-type galaxy (ETG) which, for its moderate luminosity, has an exceptionally high velocity dispersion. We aim to determine the central black hole (BH) mass (M•), the i-band stellar mass-…
Simulations of the merging galaxy cluster Abell 3376
Lima Neto, Gastão B.; Machado, Rubens E. G.
Observed galaxy clusters often exhibit X-ray morphologies suggestive of recent interaction with an infalling subcluster. A3376 is a nearby (z = 0.046) massive galaxy cluster whose bullet-shaped X-ray emission indicates that it may have undergone a recent collision. It displays a pair of Mpc-scale radio relics and its brightest cluster galaxy is lo…
An examination of the spectral variability in NGC 1365 with Suzaku
Elvis, M.; Nardini, E.; Brenneman, L. W. +1 more
We present jointly analysed data from three deep Suzaku observations of NGC 1365. These high-signal-to-noise spectra enable us to examine the nature of this variable, obscured active galactic nucleus (AGN) in unprecedented detail on time-scales ranging from hours to years. We find that in addition to the power-law continuum and absorption from ion…
The SCUBA-2 Cosmology Legacy Survey: demographics of the 450-µm population
Smail, I.; Ivison, R. J.; van Kampen, E. +47 more
We investigate the multiwavelength properties of a sample of 450-µm-selected sources from the SCUBA-2 Cosmology Legacy Survey. A total of 69 sources were identified above 4σ in deep SCUBA-2 450-µm observations overlapping the UDS and COSMOS fields and covering 210 arcmin2 to a typical depth of σ450 = 1.5 mJy. Reli…
Luminosity profiles and sizes of massive star clusters in NGC 7252
Bastian, N.; Larsen, S. S.; Kissler-Patig, M. +2 more
We present Hubble Space Telescope (HST) Wide-Field Camera 3 (WFC3) images of the merger remnant NGC 7252. In particular, we focus on the surface brightness profiles and effective radii Reff of 36 young massive clusters (YMCs) within the galaxy. All the clusters have masses exceeding 105 M⊙ and are, despite the 64 M…
Circumstellar habitable zones of binary-star systems in the solar neighbourhood
Eggl, S.; Haghighipour, N.; Pilat-Lohinger, E. +2 more
Binary and multiple systems constitute more than half of the total stellar population in the solar neighbourhood. Their frequent occurrence as well as the fact that more than 70 planets have already been discovered in such configurations - most notably the telluric companion of α Cen B - make them interesting targets in the search for habitable wo…
Time lags in the ultraluminous X-ray source NGC 5408 X-1: implications for the black hole mass
Belloni, T.; Cappi, M.; Ponti, G. +4 more
We present the analysis of the X-ray variability and spectral timing properties of the ultraluminous X-ray source (ULX) NGC 5408 X-1, one of the most variable ULXs known so far. The variability properties are used as a diagnostic of the accretion state of the source and to derive estimates of the black hole (BH) mass. The observed high level of fa…
Optical interferometry of early-type stars with PAVO@CHARA - I. Fundamental stellar properties
White, T. R.; Tuthill, P. G.; Huber, D. +8 more
We present interferometric observations of seven main-sequence and three giant stars with spectral types from B2 to F6 using the Precision Astronomical Visible Observations beam combiner at the Center for High Angular Resolution Astronomy array. We have directly determined the angular diameters for these objects with an average precision of 2.3 pe…
Broad iron line in the fast spinning neutron-star system 4U 1636-53
Hiemstra, Beike; Belloni, Tomaso; Méndez, Mariano +3 more
We analysed the X-ray spectra of six observations, simultaneously taken with XMM-Newton and Rossi X-ray Timing Explorer (RXTE), of the neutron-star low-mass X-ray binary 4U 1636-53. The observations cover several states of the source, and therefore a large range of inferred mass accretion rate. These six observations show a broad emission line in …
New Compton-thick AGN in the circumnuclear H2O maser hosts UGC 3789 and NGC 6264
Kadler, M.; Panessa, F.; Henkel, C. +2 more
Large column densities, derived from X-ray studies, are typically measured towards active galactic nuclei (AGN) hosting water masers, especially when the H2O emission is associated with the nuclear accretion disc. In addition, possible correlations between the intrinsic X-ray luminosity and the characteristics of the H2O mase…