164 citations · 1.4k across the 37 of their papers we have counts for
37 papers
A Broadband X-ray Analysis and Optical Counterpart Search of IC5052 ULX
Nabil Brice, Dominic J. Walton, Felix Fürst +10
We present broadband X-ray spectral and timing analysis of the Ultra-luminous X-ray source (ULX) in IC5052 using simultaneous XMM-Newton and NuSTAR observations from 2022, suppleme…
Deep optical spectroscopic monitoring of the pulsating ULX NGC 1313 X-2 with longslit Gemini observations
Rajath Sathyaprakash, Timothy. P. Roberts
This study reports the nature of the companion star to the pulsating ULX NGC 1313 X-2, using long-slit spectroscopic data from Gemini-South observations, based on archival data fro…
Significant or Not? The Impact of Randomisation During Data Reduction on Confirming a New Pulsating Ultraluminous X-ray Source Candidate in Centaurus A
Amy H. Knight, Timothy P. Roberts, Callum Potter +2
We report the discovery of a new candidate pulsating ultraluminous X-ray source (PULX) in NGC 5128 (Centaurus A). The candidate, 4XMM J132542.2-425943, is a transient source, ident…
The long-term variability of a population of ULXs monitored by Chandra
Hannah P. Earnshaw, Gauri Patti, Murray Brightman +5
We present preliminary results of a Chandra Large Program to monitor the ultraluminous X-ray source (ULX) populations of three nearby, ULX-rich galaxies over the course of a year,…
Exploring the case for hard-X-ray beaming in NGC 6946 X-1
Tobias Beuchert, Matthew J. Middleton, Roberto Soria +5
In order to understand the nature of super-Eddington accretion we must explore both the emission emerging directly from the inflow and its impact on the surroundings. In this paper…
Skipping a beat: discovery of persistent quasi-periodic oscillations associated with pulsed fraction drop of the spin signal in M51 ULX-7
Matteo Imbrogno, Sara Elisa Motta, Roberta Amato +24
The discovery of pulsations in (at least) six ultraluminous X-ray sources (ULXs) has shown that neutron stars can accrete at (highly) super-Eddington rates, challenging the standar…
The High Energy X-ray Probe (HEX-P): Studying Extreme Accretion with Ultraluminous X-ray Sources
Matteo Bachetti, Matthew J. Middleton, Ciro Pinto +25
Ultraluminous X-ray sources (ULXs) represent an extreme class of accreting compact objects: from the identification of some of the accretors as neutron stars to the detection of po…
A multi-wavelength view of distinct accretion regimes in the pulsating ultraluminous X-ray source NGC 1313 X-2
Rajath Sathyaprakash, Timothy P. Roberts, Fabien Grisè +7
NGC 1313 X-2 is one of the few known pulsating ultraluminous X-ray sources (PULXs), and so is thought to contain a neutron star that accretes at highly super-Eddington rates. Howev…
A New Transient Ultraluminous X-ray Source in NGC 7090
D. J. Walton, M. Heida, M. Bachetti +17
We report on the discovery of a new, transient ultraluminous X-ray source (ULX) in the galaxy NGC 7090. This new ULX, which we refer to as NGC 7090 ULX3, was discovered via monitor…
The Unusual Broadband X-ray Spectral Variability of NGC 1313 X-1 seen with XMMNewton, Chandra and NuSTAR
D. J. Walton, C. Pinto, M. Nowak +19
We present results from the major coordinated X-ray observing program on the ULX NGC 1313 X-1 performed in 2017, combining -, and , focusing on the e…
XMM-Newton Campaign On Ultraluminous X-ray Source NGC 1313 X-1: Wind vs. State Variability
C. Pinto, D. J. Walton, E. Kara +12
Most ultraluminous X-ray sources (ULXs) are thought to be powered by neutron stars and black holes accreting beyond the Eddington limit. If the compact object is a black hole or a…
The Hunt for Pulsating Ultraluminous X-ray Sources
X. Song, D. J. Walton, G. B. Lansbury +4
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)…
The discovery of weak coherent pulsations in the ultraluminous X-ray source NGC 1313 X-2
R. Sathyaprakash, T. P. Roberts, D. J. Walton +8
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…
Discovery of a 2.8 s pulsar in a 2 d orbit High-Mass X-ray Binary powering the Ultraluminous X-ray source ULX-7 in M51
G. A. Rodríguez Castillo, G. L. Israel, A. Belfiore +26
We discovered 2.8 s pulsations in the X-ray emission of the ultraluminous X-ray source (ULX) M51 ULX-7 within the UNSEeN project, which was designed to hunt for new pulsating ULXs…
Thermal stability of winds driven by radiation pressure in super-Eddington accretion disks
Ciro Pinto, Missagh Mehdipour, Dom J. Walton +7
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 fe…
A new, clean catalogue of extragalactic non-nuclear X-ray sources in nearby galaxies
H. P. Earnshaw, T. P. Roberts, M. J. Middleton +2
We have created a new, clean catalogue of extragalactic non-nuclear X-ray sources by correlating the 3XMM-DR4 data release of the XMM-Newton Serendipitous Source Catalogue with the…
A long hard-X-ray look at the dual active galactic nuclei of M51 with NuSTAR
M. Brightman, M. Baloković, M. Koss +14
We present a broadband X-ray spectral analysis of the M51 system, including the dual active galactic nuclei (AGN) and several off-nuclear point sources. Using a deep observation by…
Lense-Thirring precession in ULXs as a possible means to constrain the neutron star equation-of-state
M. J. Middleton, P. C. Fragile, M. Bachetti +11
The presence of neutron stars in at least three ultraluminous X-ray sources is now firmly established and offers an unambiguous view of super-critical accretion. All three systems…
A Systematic Search for Near-Infrared Counterparts of Nearby Ultraluminous X-ray sources (II)
K. M. López, M. Heida, P. G. Jonker +5
We present the results of our continued systematic search for near-infrared (NIR) candidate counterparts to ultraluminous X-ray sources (ULXs) within 10 Mpc. We observed 42 ULXs in…
Spitzer IRAC observations of IR excess in Holmberg IX X-1: A circumbinary disk or a variable jet?
R. P. Dudik, C. T. Berghea, T. P. Roberts +4
We present Spitzer Infrared Array Camera (IRAC) photometric observations of the Ultra-luminous X-ray Source (ULX, X-1) in Holmberg IX. We construct a spectral energy distribution (…
The ultraluminous X-ray source NGC 5643 ULX1: a large stellar mass black hole accreting at super-Eddington rates?
F. Pintore, L. Zampieri, A. D. Sutton +3
A sub-set of the brightest ultraluminous X-ray sources (ULXs), with X-ray luminosities well above erg s, typically have energy spectra which can be well described…
Discovery of a red supergiant counterpart to RX~J004722.4-252051, a ULX in NGC 253
M. Heida, M. A. P. Torres, P. G. Jonker +6
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…
X-ray time lags and nonlinear variability in the ultraluminous X-ray sources NGC 5408 X-1 and NGC 6946 X-1
L. Hernández-García, S. Vaughan, T. P. Roberts +1
We present our analysis of the X-ray variability of two ultraluminous X-ray sources (ULXs) based on multiple XMM--Newton observations. We show the linear rms-flux relation is prese…
Ultra-Luminous X-ray Sources in Haro 11 and the Role of X-ray Binaries in Feedback in Lyman-alpha Emitting Galaxies
A. H. Prestwich, F. Jackson, P. Kaaret +4
Lyman Break Analogs (LBA) are local proxies of high-redshift Lyman Break Galaxies (LBG). Studies of nearby starbursts have shown that Lyman continuum and line emission are absorbed…