All Outputs (8)

Thermal stability of winds driven by radiation pressure in super-Eddington accretion discs (2019)
Journal Article
Pinto, C., Mehdipour, M., Walton, D., Middleton, M., Roberts, T., Fabian, A., Guainazzi, M., Soria, R., Kosec, P., & Ness, J. .-U. (2020). Thermal stability of winds driven by radiation pressure in super-Eddington accretion discs. Monthly Notices of the Royal Astronomical Society, 491(4), 5702-5716. https://doi.org/10.1093/mnras/stz3392

Ultraluminous X-ray sources (ULXs) are mainly powered by accretion in neutron stars or stellar-mass black holes. Accreting at rates exceeding the Eddington limit by factors of a few up to hundreds, radiation pressure is expected to inflate the accret... Read More about Thermal stability of winds driven by radiation pressure in super-Eddington accretion discs.

Discovery of a soft X-ray lag in the Ultraluminous X-ray Source NGC 1313 X-1 (2019)
Journal Article
Kara, E., Pinto, C., Walton, D., Alston, W., Bachetti, M., Barret, D., Brightman, M., Canizares, C., Earnshaw, H., Fabian, A., Furst, F., Kosec, P., Middleton, M., Roberts, T., Soria, R., Tao, L., & Webb, N. (2020). Discovery of a soft X-ray lag in the Ultraluminous X-ray Source NGC 1313 X-1. Monthly Notices of the Royal Astronomical Society, 491(4), 5172-5178. https://doi.org/10.1093/mnras/stz3318

Ultraluminous X-ray Sources (ULXs) provide a unique opportunities to probe the geometry and energetics of super-Eddington accretion. The radiative processes involved in super-Eddington accretion are not well understood, and so studying correlated var... Read More about Discovery of a soft X-ray lag in the Ultraluminous X-ray Source NGC 1313 X-1.

The Hunt for Pulsating Ultraluminous X-ray Sources (2019)
Journal Article
Song, X., Walton, D., Lansbury, G., Evans, P., Fabian, A., Earnshaw, H., & Roberts, T. (2020). The Hunt for Pulsating Ultraluminous X-ray Sources. Monthly Notices of the Royal Astronomical Society, 491(1), 1260-1277. https://doi.org/10.1093/mnras/stz3036

Motivated by the recent discoveries that six Ultraluminous X-ray Sources (ULXs) are powered by highly super-Eddington X-ray pulsars, we searched for additional pulsating ULX (PULX) candidates by identifying sources that exhibit long-term flux variabi... Read More about The Hunt for Pulsating Ultraluminous X-ray Sources.

Discovery and analysis of a ULX nebula in NGC 3521★ (2019)
Journal Article
López, K., Jonker, P., Heida, M., Torres, M., Roberts, T., Walton, D., Moon, D.-S., & Harrison, F. (2019). Discovery and analysis of a ULX nebula in NGC 3521★. Monthly Notices of the Royal Astronomical Society, 489(1), 1249-1264. https://doi.org/10.1093/mnras/stz2127

We present Very Large Telescope/X-shooter and Chandra X-ray observatory/ACIS observations of the ULX [SST2011] J110545.62+000016.2 in the galaxy NGC 3521. The source identified as a candidate near-infrared counterpart to the ULX in our previous study... Read More about Discovery and analysis of a ULX nebula in NGC 3521★.

Observational limits on the X-ray emission from the bubble nebula surrounding Ho IX X-1 (2019)
Journal Article
Sathyaprakash, R., Roberts, T., & Siwek, M. (2019). Observational limits on the X-ray emission from the bubble nebula surrounding Ho IX X-1. Monthly Notices of the Royal Astronomical Society, 488(4), 4614-4622. https://doi.org/10.1093/mnras/stz2022

Optical and radio observations of shock-ionised bubble nebulae surrounding ultraluminous X-ray sources (ULXs) suggest that they are powered by jets or super-critical outflows presumably launched from the ULX accretion disc. Recent simulations of thes... Read More about Observational limits on the X-ray emission from the bubble nebula surrounding Ho IX X-1.

The Lense-Thirring timing-accretion plane for ULXs (2019)
Journal Article
Middleton, M., Fragile, P., Ingram, A., & Roberts, T. (2019). The Lense-Thirring timing-accretion plane for ULXs. Monthly Notices of the Royal Astronomical Society, 489(1), 282-296. https://doi.org/10.1093/mnras/stz2005

Identifying the compact object in ultraluminous X-ray sources (ULXs) has to-date required detection of pulsations or a cyclotron resonance scattering feature (CRSF), indicating a magnetised neutron star. However, pulsations are observed to be transie... Read More about The Lense-Thirring timing-accretion plane for ULXs.

The discovery of weak coherent pulsations in the ultraluminous X-ray source NGC 1313 X-2 (2019)
Journal Article
Sathyaprakash, R., Roberts, T., Walton, D., Fuerst, F., Bachetti, M., Pinto, C., Alston, W., Earnshaw, H., Fabian, A., Middleton, M., & Soria, R. (2019). The discovery of weak coherent pulsations in the ultraluminous X-ray source NGC 1313 X-2. Monthly Notices of the Royal Astronomical Society, 488(1), L35-L40. https://doi.org/10.1093/mnrasl/slz086

We report the detection of weak pulsations from the archetypal ultraluminous X-ray source (ULX) NGC 1313 X-2. Acceleration searches reveal sinusoidal pulsations in segments of two out of six new deep observations of this object, with a period of ∼1.5... Read More about The discovery of weak coherent pulsations in the ultraluminous X-ray source NGC 1313 X-2.

Discovery of a radio transient in M81 (2019)
Journal Article
Anderson, G., Miller-Jones, J., Middleton, M., Soria, R., Swartz, D., Urquhart, R., Hurley-Walker, N., Hancock, P., Fender, R., Gandhi, P., Markoff, S., & Roberts, T. (2019). Discovery of a radio transient in M81. Monthly Notices of the Royal Astronomical Society, 489(1), 1181-1196. https://doi.org/10.1093/mnras/stz1303

We report the discovery of a radio transient in the spiral galaxy M81. The transient was detected in early 2015 as part of a two year survey of M81 made up of 12 epochs using the Karl G. Jansky Very Large Array. While undetected on 2014 September 12,... Read More about Discovery of a radio transient in M81.