Search Publications
Filaments in the Lupus molecular clouds
Hill, T.; White, G. J.; Arzoumanian, D. +19 more
We have studied the filaments extracted from the column density maps of the nearby Lupus 1, 3, and 4 molecular clouds, derived from photometric maps observed with the Herschel satellite. Filaments in the Lupus clouds have quite low column densities, with a median value of ∼1.5 × 1021 cm-2 and most have masses per unit length …
Galactic interstellar filaments as probed by LOFAR and Planck.
Boulanger, F.; Alves, M. I. R.; Ghosh, T. +13 more
Recent Low-Frequency Array (LOFAR) observations at 115-175 MHz of a field at medium Galactic latitudes (centred at the bright quasar 3C196) have shown striking filamentary structures in polarization that extend over more than 4° across the sky. In addition, the Planck satellite has released full sky maps of the dust emission in polarization at 353…
The Compton hump and variable blue wing in the extreme low-flux NuSTAR observations of 1H0707-495
Harrison, F. A.; Stern, D.; Zhang, W. W. +10 more
The narrow-line Seyfert I galaxy, 1H0707-495, has been well observed in the 0.3-10 keV band, revealing a dramatic drop in flux in the iron Kα band, a strong soft excess, and short time-scale reverberation lags associated with these spectral features. In this paper, we present the first results of a deep 250-ks NuSTAR (Nuclear Spectroscopic Telesco…
Integrated light chemical tagging analyses of seven M31 outer halo globular clusters from the Pan-Andromeda Archaeological Survey
Dotter, Aaron; Venn, Kim A.; Sakari, Charli M. +4 more
Detailed chemical abundances are presented for seven M31 outer halo globular clusters (with projected distances from M31 greater than 30 kpc), as derived from high-resolution integrated light spectra taken with the Hobby-Eberly Telescope. Five of these clusters were recently discovered in the Pan-Andromeda Archaeological Survey (PAndAS) - this pap…
New constraints on the star formation history of the star cluster NGC 1856
Goudfrooij, Paul; Puzia, Thomas H.; Correnti, Matteo +1 more
We use the Wide Field Camera 3 onboard the Hubble Space Telescope to obtain deep, high-resolution photometry of the young (age ∼ 300 Myr) star cluster NGC 1856 in the Large Magellanic Cloud. We compare the observed colour-magnitude diagram (CMD), after having applied a correction for differential reddening, with Monte Carlo simulations of simple s…
Simultaneous spectral and reverberation modelling of relativistic reflection in Mrk 335
Chainakun, P.; Young, A. J.
We present an X-ray spectral and timing model to investigate the broad and variable iron line seen in the high flux state of Mrk 335. The model consists of a variable X-ray source positioned along the rotation axis of the black hole that illuminates the accretion disc producing a back-scattered, ionized reflection spectrum. We compute time lags in…
On the interpretation of sub-giant branch morphologies of intermediate-age star clusters with extended main sequence turnoffs
Girardi, Léo; Marigo, Paola; Goudfrooij, Paul +4 more
High-quality photometry of many star clusters in the Magellanic Clouds with ages of 1-2 Gyr revealed main sequence turnoffs (MSTOs) that are significantly wider than can be accounted for by a simple stellar population (SSP). Such extended MSTOs (eMSTOs) are often interpreted in terms of an age spread of several 108 yr, challenging the t…
Kuiper belt structure around nearby super-Earth host stars
Matthews, Brenda C.; Wyatt, Mark C.; Udry, Stéphane +9 more
We present new observations of the Kuiper belt analogues around HD 38858 and HD 20794, hosts of super-Earth mass planets within 1 au. As two of the four nearby G-type stars (with HD 69830 and 61 Vir) that form the basis of a possible correlation between low-mass planets and debris disc brightness, these systems are of particular interest. The disc…
Was the soft X-ray flare in NGC 3599 due to an AGN disc instability or a delayed tidal disruption event?
Read, A. M.; Komossa, S.; Motta, S. E. +1 more
We present unpublished data from a tidal disruption candidate in NGC 3599 which show that the galaxy was already X-ray bright 18 months before the measurement which led to its classification. This removes the possibility that the flare was caused by a classical, fast-rising, short-peaked, tidal disruption event. Recent relativistic simulations ind…
SXP 5.05 = IGR J00569-7226: using X-rays to explore the structure of a Be star's circumstellar disc
Haberl, F.; Udalski, A.; Bartlett, E. S. +5 more
On MJD 56590-1 (2013 Oct 25-26), observations of the Magellanic Clouds by the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) observatory discovered a previously unreported bright, flaring X-ray source. This source was initially given the identification IGR J00569-7226. Subsequent multiwavelength observations identified the system as ne…