Outputs (10)

X-ray spectral residuals in NGC 5408 X-1: diffuse emission from star formation, or the signature of a super-Eddington wind? (2015)
Journal Article
Sutton, A., Roberts, T., & Middleton, M. (2015). X-ray spectral residuals in NGC 5408 X-1: diffuse emission from star formation, or the signature of a super-Eddington wind?. Astrophysical Journal, 814(1), Article 73. https://doi.org/10.1088/0004-637x/814/1/73

If ultraluminous X-ray sources (ULXs) are powered by accretion onto stellar remnant black holes, then many must be accreting at super-Eddington rates. It is predicted that such high accretion rates should give rise to massive, radiatively driven wind... Read More about X-ray spectral residuals in NGC 5408 X-1: diffuse emission from star formation, or the signature of a super-Eddington wind?.

Discovery of a red supergiant counterpart to RX J004722.4-252051, a ULX in NGC 253 (2015)
Journal Article
Heida, M., Torres, M., Jonker, P., Servillat, M., Repetto, S., Roberts, T., …Harrison, F. (2015). Discovery of a red supergiant counterpart to RX J004722.4-252051, a ULX in NGC 253. Monthly Notices of the Royal Astronomical Society, 453(4), 3510-3518. https://doi.org/10.1093/mnras/stv1853

We present two epochs of near-infrared spectroscopy of the candidate red supergiant counterpart to RX J004722.4–252051, a ULX in NGC 253. We measure radial velocities of the object and its approximate spectral type by cross-correlating our spectra wi... Read More about Discovery of a red supergiant counterpart to RX J004722.4-252051, a ULX in NGC 253.

X-ray time lags and non-linear variability in the ultraluminous X-ray sources NGC 5408 X-1 and NGC 6946 X-1 (2015)
Journal Article
Hernández-García, L., Vaughan, S., Roberts, T., & Middleton, M. (2015). X-ray time lags and non-linear variability in the ultraluminous X-ray sources NGC 5408 X-1 and NGC 6946 X-1. Monthly Notices of the Royal Astronomical Society, 453(3), 2877-2884. https://doi.org/10.1093/mnras/stv1830

We present our analysis of the X-ray variability of two ultraluminous X-ray sources (ULXs) based on multiple XMM–Newton observations. We show that the linear rms–flux relation is present in eight observations of NGC 5408 X-1 and also in three observa... Read More about X-ray time lags and non-linear variability in the ultraluminous X-ray sources NGC 5408 X-1 and NGC 6946 X-1.

Ultra-luminous X-Ray Sources in HARO II and the Role of X-Ray Binaries in Feedback in Lyα Emitting Galaxies (2015)
Journal Article
Prestwich, A., Jackson, F., Kaaret, P., Brorby, M., Roberts, T., Saar, S., & Yukita, M. (2015). Ultra-luminous X-Ray Sources in HARO II and the Role of X-Ray Binaries in Feedback in Lyα Emitting Galaxies. Astrophysical Journal, 812(2), Article 166. https://doi.org/10.1088/0004-637x/812/2/166

Lyman Break Analogs (LBAs) are local proxies of high-redshift Lyman Break Galaxies. Spatially resolved studies of nearby starbursts have shown that Lyman continuum and line emission are absorbed by dust and that the Lyα is resonantly scattered by neu... Read More about Ultra-luminous X-Ray Sources in HARO II and the Role of X-Ray Binaries in Feedback in Lyα Emitting Galaxies.

Diagnosing the accretion flow in ultraluminous X-ray sources using soft X-ray atomic features (2015)
Journal Article
Middleton, M. J., Walton, D. J., Fabian, A., Roberts, T. P., Heil, L., Pinto, C., …Sutton, A. (2015). Diagnosing the accretion flow in ultraluminous X-ray sources using soft X-ray atomic features. Monthly Notices of the Royal Astronomical Society, 454(3), 3134-3142. https://doi.org/10.1093/mnras/stv2214

The lack of unambiguous detections of atomic features in the X-ray spectra of ultraluminous X-ray sources (ULXs) has proven a hindrance in diagnosing the nature of the accretion flow. The possible association of spectral residuals at soft energies wi... Read More about Diagnosing the accretion flow in ultraluminous X-ray sources using soft X-ray atomic features.

The hyperluminous X-ray source candidate in IC 4320: another HLX bites the dust (2015)
Journal Article
Sutton, A., Roberts, T., Gladstone, J., & Walton, D. (2015). The hyperluminous X-ray source candidate in IC 4320: another HLX bites the dust. Monthly Notices of the Royal Astronomical Society, 450(1), 787-793. https://doi.org/10.1093/mnras/stv505

The known members of the class of hyperluminous X-ray sources (HLXs) are few in number, yet they are of great interest as they are regarded as the likeliest intermediate-mass black hole (IMBH) candidates amongst the wider population of ultraluminous... Read More about The hyperluminous X-ray source candidate in IC 4320: another HLX bites the dust.

The powerful jet of an off-nuclear intermediate-mass black hole in the spiral galaxy NGC 2276 (2015)
Journal Article
Mezcua, M., Roberts, T., Lobanov, A., & Sutton, A. (2015). The powerful jet of an off-nuclear intermediate-mass black hole in the spiral galaxy NGC 2276. Monthly Notices of the Royal Astronomical Society, 448(2), 1893-1899. https://doi.org/10.1093/mnras/stv143

Jet ejection by accreting black holes is a mass invariant mechanism unifying stellar and supermassive black holes (SMBHs) that should also apply for intermediate-mass black holes (IMBHs), which are thought to be the seeds from which SMBHs form. We pr... Read More about The powerful jet of an off-nuclear intermediate-mass black hole in the spiral galaxy NGC 2276.

NuSTAR and XMM-Newton observations of the extreme ultraluminous X-ray source NGC 5907 ULX1 : a vanishing act (2015)
Journal Article
Walton, D., Harrison, F., Bachetti, M., Barret, D., Boggs, S., Christensen, F., …Zhang, W. (2015). NuSTAR and XMM-Newton observations of the extreme ultraluminous X-ray source NGC 5907 ULX1 : a vanishing act. Astrophysical Journal, 799(2), Article 122. https://doi.org/10.1088/0004-637x/799/2/122

We present results obtained from two broadband X-ray observations of the extreme ultraluminous X-ray source (ULX) NGC 5907 ULX1, known to have a peak X-ray luminosity of ~5 × 1040 erg s–1. These XMM-Newton and NuSTAR observations, separated by only ~... Read More about NuSTAR and XMM-Newton observations of the extreme ultraluminous X-ray source NGC 5907 ULX1 : a vanishing act.

A spectral-timing model for ULXs in the supercritical regime (2015)
Journal Article
Middleton, M., Heil, L., Pintore, F., Walton, D., & Roberts, T. (2015). A spectral-timing model for ULXs in the supercritical regime. Monthly Notices of the Royal Astronomical Society, 447(4), 3243-3263. https://doi.org/10.1093/mnras/stu2644

Ultraluminous X-ray sources (ULXs) with luminosities lying between ∼3 × 1039 and 2 × 1040 erg s−1 represent a contentious sample of objects as their brightness, together with a lack of unambiguous mass estimates for the vast majority of the central o... Read More about A spectral-timing model for ULXs in the supercritical regime.

A deficit of ultraluminous X-ray sources in luminous infrared galaxies (2015)
Journal Article
Luangtip, W., Roberts, T., Mineo, S., Lehmer, B., Alexander, D., Jackson, F., …Fischer, J. (2015). A deficit of ultraluminous X-ray sources in luminous infrared galaxies. Monthly Notices of the Royal Astronomical Society, 446(1), 470-492. https://doi.org/10.1093/mnras/stu2086

We present results from a Chandra study of ultraluminous X-ray sources (ULXs) in a sample of 17 nearby (DL < 60 Mpc) luminous infrared galaxies (LIRGs), selected to have star formation rates (SFRs) in excess of 7 M⊙ yr−1 and low foreground Galactic c... Read More about A deficit of ultraluminous X-ray sources in luminous infrared galaxies.