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Outputs (11)

X-ray spectral evolution in the ultraluminous X-ray source M33 X-8 (2011)
Journal Article
Middleton, M., Sutton, A., & Roberts, T. (2011). X-ray spectral evolution in the ultraluminous X-ray source M33 X-8. Monthly Notices of the Royal Astronomical Society, 417(1), 464-471. https://doi.org/10.1111/j.1365-2966.2011.19285.x

The bright ultraluminous X-ray source (ULX), M33 X-8, has been observed several times by XMM–Newton, providing us with a rare opportunity to ‘flux bin’ the spectral data and search for changes in the average X-ray spectrum with flux level. The aggreg... Read More about X-ray spectral evolution in the ultraluminous X-ray source M33 X-8.

2XMM ultraluminous X-ray source candidates in nearby galaxies (2011)
Journal Article
Walton, D., Roberts, T., Mateos, S., & Heard, V. (2011). 2XMM ultraluminous X-ray source candidates in nearby galaxies. Monthly Notices of the Royal Astronomical Society, 416(3), 1844-1861. https://doi.org/10.1111/j.1365-2966.2011.19154.x

Ultraluminous X-ray sources (ULXs) are some of the most enigmatic X-ray bright sources known to date. It is generally accepted that they cannot host black holes as large as those associated with active galaxies, but they appear to be significantly mo... Read More about 2XMM ultraluminous X-ray source candidates in nearby galaxies.

Comparing spectral models for ultraluminous X-ray sources with NGC 4517 ULX1 (2011)
Journal Article
Walton, D., Gladstone, J., Roberts, T., Fabian, A., Caballero-Garcia, M., Done, C., & Middleton, M. (2011). Comparing spectral models for ultraluminous X-ray sources with NGC 4517 ULX1. Monthly Notices of the Royal Astronomical Society, 414(2), 1011-1022. https://doi.org/10.1111/j.1365-2966.2011.18397.x

We present the previously unanalysed high quality XMM-Newton spectrum of an ultraluminous X-ray source candidate in NGC4517. As with other high quality ULX spectra, a downturn in the spectrum is observed at 6 keV. Both of the recent disc reflection a... Read More about Comparing spectral models for ultraluminous X-ray sources with NGC 4517 ULX1.

Investigating the Nuclear Activity of Barred Spiral Galaxies: The Case of NGC 1672 (2011)
Journal Article
Jenkins, L., Brandt, W., Colbert, E., Koribalski, B., Kuntz, K., Levan, A., …Zezas, A. (2011). Investigating the Nuclear Activity of Barred Spiral Galaxies: The Case of NGC 1672. Astrophysical Journal, 734(1), Article 33. https://doi.org/10.1088/0004-637x/734/1/33

We have performed an X-ray study of the nearby barred spiral galaxy NGC 1672, primarily to ascertain the effect of the bar on its nuclear activity. We use both Chandra and XMM-Newton observations to investigate its X-ray properties, together with sup... Read More about Investigating the Nuclear Activity of Barred Spiral Galaxies: The Case of NGC 1672.

A large catalogue of ultraluminous X-ray source candidates in nearby galaxies (2011)
Journal Article
Walton, D., Gladstone, J., Roberts, T., & Fabian, A. (2011). A large catalogue of ultraluminous X-ray source candidates in nearby galaxies. Astronomical Notes, 332(4), 354-357. https://doi.org/10.1002/asna.201011498

Since their discovery, Ultraluminous X-ray sources (ULXs) have attracted attention due to their combination of extreme luminosities and extra-nuclear locations. However, they are a fairly rare phenomenon, and attempts to investigate the general prope... Read More about A large catalogue of ultraluminous X-ray source candidates in nearby galaxies.

(No) dynamical constraints on the mass of the black hole in two ULXs (2011)
Journal Article
Roberts, T., Gladstone, J., Goulding, A., Swinbank, A., Ward, M., Goad, M., & Levan, A. (2011). (No) dynamical constraints on the mass of the black hole in two ULXs. Astronomical Notes, 332(4), 398-401. https://doi.org/10.1002/asna.201011508

We present the preliminary results of two Gemini campaigns to constrain the mass of the black hole in an ultraluminous X-ray source (ULX) via optical spectroscopy. Pilot studies of the optical counterparts of a number of ULXs revealed two candidates... Read More about (No) dynamical constraints on the mass of the black hole in two ULXs.

Unlocking the nature of ultraluminous X-ray sources using their X-ray spectra (2011)
Journal Article
Gladstone, J., Roberts, T., & Done, C. (2011). Unlocking the nature of ultraluminous X-ray sources using their X-ray spectra. Astronomical Notes, 332(4), 345-348. https://doi.org/10.1002/asna.201011496

We explore the nature of ultraluminous X-ray sources through detailed investigations of their spectral shape using some of the highest quality data available in the XMM-Newton public archives. Phenomenological models allow us to characterise their sp... Read More about Unlocking the nature of ultraluminous X-ray sources using their X-ray spectra.

Key results from an XMM-Newton and Chandra study of a new sample of extreme ULXs from the 2XMM catalogue (2011)
Journal Article
Sutton, A., Roberts, T., & Walton, D. (2011). Key results from an XMM-Newton and Chandra study of a new sample of extreme ULXs from the 2XMM catalogue. Astronomical Notes, 332(4), 362-366. https://doi.org/10.1002/asna.201011500

We present highlights from a study of a sample of 10 extreme-luminosity candidate ultraluminous X-ray sources (LX > 5×1040 erg s −1), all at distances

New observations of ULX supershells, and their implications (2011)
Journal Article
Russell, D., Yang, Y., Gladstone, J., Wiersema, K., & Roberts, T. (2011). New observations of ULX supershells, and their implications. Astronomical Notes, 332(4), 371-374. https://doi.org/10.1002/asna.201011502

New optical narrowband imaging observations of the fields of several ultra-luminous X-ray sources (ULXs) are presented. Known supershell nebulae are associated with a number of these ULXs, which we detect in emission lines filters such as [S II], He... Read More about New observations of ULX supershells, and their implications.