Search Publications
A deep X-ray observation of M82 with XMM-Newton
Maiolino, R.; Ranalli, P.; Comastri, A. +1 more
We report on the analysis of a deep (100-ks) observation of the starburst galaxy M82 with the EPIC and RGS instruments onboard the X-ray telescope XMM-Newton. The broad-band (0.5-10 keV) emission is due to at least three spectral components: (i) continuum emission from point sources; (ii) thermal plasma emission from hot gas; and (iii) charge-exch…
Globular clusters in the outer halo of M31: the survey
Tanvir, N. R.; Ferguson, A. M. N.; Lewis, G. F. +4 more
We report the discovery of 40 new globular clusters (GCs) that have been found in surveys of the halo of M31 based on the Isaac Newton Telescope/Wide-Field Camera and Canada-France-Hawaii Telescope/Megacam imagery. A subset of these new GCs are of an extended, diffuse nature and include those already found in Huxor et al. The search strategy is de…
Cool X-ray emitting gas in the core of the Centaurus cluster of galaxies
Fabian, A. C.; Allen, S. W.; Sanders, J. S. +3 more
We use a deep XMM-Newton Reflection Grating Spectrometer observation to examine the X-ray emission from the core of the Centaurus cluster of galaxies. We clearly detect FeXVII emission at four separate wavelengths, indicating the presence of cool X-ray emitting gas in the core of the cluster. Fe ions from FeXVII toXXIV are observed. The ratio of t…
Point spread function tails and the measurements of diffuse stellar halo light around edge-on disc galaxies
de Jong, Roelof S.
Measuring the integrated stellar halo light around galaxies is very challenging. The surface brightness of these haloes is expected to be many magnitudes below dark sky and the central brightness of the galaxy. Here, I show that in some of the recent literature the effect of very extended Point Spread Function (PSF) tails on the measurements of ha…
Properties of the ultraviolet flux of Type Ia supernovae: an analysis with synthetic spectra of SN 2001ep and SN 2001eh
Challis, P.; Kirshner, R. P.; Filippenko, A. V. +7 more
The spectral properties of Type Ia supernovae in the ultraviolet (UV) are investigated using the early-time spectra of SN 2001ep and SN 2001eh obtained using the Hubble Space Telescope. A series of spectral models is computed with a Monte Carlo spectral synthesis code, and the dependence of the UV flux on the elemental abundances and the density g…
Centimetre-wave continuum radiation from the ρ Ophiuchi molecular cloud
Paladini, Roberta; Lim, Tanya; Casassus, Simon +8 more
The ρ Oph molecular cloud is undergoing intermediate-mass star formation. Ultraviolet radiation from its hottest young stars heats and dissociates exposed layers, but does not ionize hydrogen. Only faint radiation from the Rayleigh-Jeans tail of ~10-100 K dust is expected at wavelengths longwards of ~3 mm. Yet cosmic background imager (CBI) observ…
Chandra observation of the edge-on spiral NGC 5775: probing the hot galactic disc/halo connection
Wang, Q. Daniel; Li, Zhiyuan; Li, Jiang-Tao +2 more
We study the edge-on galaxy NGC 5775, utilizing a 58.2 ks Chandra ACIS-S observation together with complementary Hubble Space Telescope (HST) ACS, Spitzer IRAC and other multi-wavelength data sets. This edge-on galaxy, with its disc-wide active star formation, is particularly well suited for studying the disc/halo interaction on subgalactic scales…
Baryonic Tully-Fisher relation for extremely low mass Galaxies
Sharina, M. E.; Begum, Ayesha; Chengalur, Jayaram N. +1 more
We study Tully-Fisher (TF) relations for a sample that combines extremely faint (MB < -14) galaxies along with bright (i.e. ~L*) galaxies. Accurate (~10 per cent) distances, I-band photometry and B - V colours are known for the majority of the galaxies in our sample. The faint galaxies are drawn from the Faint Irregular Ga…
The early expansion of cluster cores
Bastian, N.; Smith, L. J.; Goodwin, S. P. +4 more
The observed properties of young star clusters, such as the core radius and luminosity profile, change rapidly during the early evolution of the clusters. Here we present observations of six young clusters in M51 where we derive their sizes using Hubble Space Telescope (HST) imaging and ages using deep Gemini-North spectroscopy. We find evidence f…
A microlensing study of the accretion disc in the quasar MG 0414+0534
Wyithe, J. S. B.; Bate, N. F.; Floyd, D. J. E. +1 more
Observations of gravitational microlensing in multiply imaged quasars currently provide the only direct probe of quasar emission region structure on submicroarcsecond scales. The analyses of microlensing variability are observationally expensive, requiring long-term monitoring of lensed systems. Here, we demonstrate a technique for constraining th…