Outputs (142)

The most extreme ultraluminous X-ray sources: evidence for intermediate-mass black holes? (2012)
Journal Article
Sutton, A. D., Roberts, T. P., Walton, D. J., Gladstone, J. C., & Scott, A. E. (2012). The most extreme ultraluminous X-ray sources: evidence for intermediate-mass black holes?. Monthly Notices of the Royal Astronomical Society, 423(2), 1154-1177. https://doi.org/10.1111/j.1365-2966.2012.20944.x

We present the results from an X-ray and optical study of a new sample of eight extreme luminosity ultraluminous X-ray source (ULX) candidates, which were selected as the brightest ULXs (with LX > 5 × 1040 erg s−1) located within 100 Mpc identified i... Read More about The most extreme ultraluminous X-ray sources: evidence for intermediate-mass black holes?.

On the nature of high X-ray luminosities in Sloan Digital Sky Survey galaxies (2012)
Journal Article
Jackson, F., Roberts, T., Alexander, D., Gelbord, J., Goulding, A., Ward, M., …Watson, M. (2012). On the nature of high X-ray luminosities in Sloan Digital Sky Survey galaxies. Monthly Notices of the Royal Astronomical Society, 422(1), 2-13. https://doi.org/10.1111/j.1365-2966.2011.20164.x

Surveys have revealed a class of object displaying both high X-ray luminosities (LX > 1042 erg s−1) and a lack of a discernible active galactic nucleus (AGN) in the optical band. If these sources are powered by star formation activity alone, they wou... Read More about On the nature of high X-ray luminosities in Sloan Digital Sky Survey galaxies.

The missing link: a low mass X-ray binary in M31 seen as an ultraluminous X-ray source (2012)
Journal Article
Middleton, M., Sutton, A., Roberts, T., Jackson, F., & Done, C. (2012). The missing link: a low mass X-ray binary in M31 seen as an ultraluminous X-ray source. Monthly Notices of the Royal Astronomical Society, 420(4), 2969-2977. https://doi.org/10.1111/j.1365-2966.2011.20145.x

A new, transient ultraluminous X-ray source (ULX) was recently discovered by Chandra in M31 with a luminosity at ∼5 × 1039 erg s−1. Here we analyse a series of five subsequent XMM–Newton observations. These show a steady decline in X-ray luminosity o... Read More about The missing link: a low mass X-ray binary in M31 seen as an ultraluminous X-ray source.

Chandra observations of the collisional ring galaxy NGC 922 (2012)
Journal Article
Prestwich, A., Galache, J., Linden, T., Kalogera, V., Zezas, A., Roberts, T., …Trinchieri, G. (2012). Chandra observations of the collisional ring galaxy NGC 922. Astrophysical Journal, 747(2), Article 150. https://doi.org/10.1088/0004-637x/747/2/150

In this paper, we report on Chandra observations of the starburst galaxy NGC 922. NGC 922 is a drop-through ring galaxy with an expanding ring of star formation, similar in many respects to the Cartwheel galaxy. The Cartwheel galaxy is famous for hos... Read More about Chandra observations of the collisional ring galaxy NGC 922.

Hot and cold galactic gas in the NGC 2563 galaxy group (2012)
Journal Article
Rasmussen, J., Bai, X., Mulchaey, J. S., van Gorkom, J., Jeltema, T. E., Zabludoff, A. I., …Roberts, T. P. (2012). Hot and cold galactic gas in the NGC 2563 galaxy group. Astrophysical Journal, 747(1), Article 31. https://doi.org/10.1088/0004-637x/747/1/31

The role of environmentally induced gas stripping in driving galaxy evolution in groups remains poorly understood. Here we present extensive Chandra and Very Large Array mosaic observations of the hot and cold interstellar medium within the members o... Read More about Hot and cold galactic gas in the NGC 2563 galaxy group.

Identifying a new intermediate polar using XMM-Newton and INTEGRAL (2012)
Journal Article
Middleton, M., Cackett, E., Shaw, C., Ramsay, G., Roberts, T., & Wheatley, P. (2012). Identifying a new intermediate polar using XMM-Newton and INTEGRAL. Monthly Notices of the Royal Astronomical Society, 419(1), 336-341. https://doi.org/10.1111/j.1365-2966.2011.19696.x

The bright X-ray source 2XMMi J180438.7−145647 is fortunate to have long baseline observations in INTEGRAL that complement observations taken by other missions. Optical spectroscopy of this object has suggested a distance of ∼7 kpc and an identificat... Read More about Identifying a new intermediate polar using XMM-Newton and INTEGRAL.

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.