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53 papers
The giant outburst of EXO 2030+375 II: Broadband spectroscopy and evolution
R. Ballhausen, P. Thalhammer, P. Pradhan +13
In 2021, the high-mass X-ray binary EXO 2030+375 underwent a giant X-ray outburst, the first since 2006, that reached a peak flux of (3-50\,keV). The go…
The High Energy X-ray Probe (HEX-P): A New Window into Neutron Star Accretion
R. M. Ludlam, C. Malacaria, E. Sokolova-Lapa +15
Accreting neutron stars (NSs) represent a unique laboratory for probing the physics of accretion in the presence of strong magnetic fields ( G). Additionally, the ma…
Probing the nature of the low state in the extreme ultraluminous X-ray pulsar NGC 5907 ULX1
F. Fuerst, D. J. Walton, G. L. Israel +13
NGC 5907 ULX1 is the most luminous ultra-luminous X-ray pulsar (ULXP) known to date, reaching luminosities in excess of 1e41 erg/s. The pulsar is known for its fast spin-up during…
Unveiling the disc structure in ultraluminous X-ray source NGC 55 ULX-1
F. Barra, C. Pinto, D. J. Walton +11
Despite two decades of studies, it is still not clear whether ULX spectral transitions are due to stochastic variability in the wind or variations in the accretion rate or in the s…
Quasi-periodic dipping in the ultraluminous X-ray source, NGC 247 ULX-1
W. N. Alston, C. Pinto, D. Barret +15
Most ultraluminous X-ray sources (ULXs) are believed to be stellar mass black holes or neutron stars accreting beyond the Eddington limit. Determining the nature of the compact obj…
Long-term pulse period evolution of the ultra-luminous X-ray pulsar NGC 7793 P13
F. Fuerst, D. J. Walton, M. Heida +14
Ultra-luminous X-ray pulsars (ULXPs) provide a unique opportunity to study super-Eddington accretion. We present the results of a monitoring campaign of ULXP NGC 7793 P13. Over our…
XMM-Newton campaign on the ultraluminous X-ray source NGC 247 ULX-1: outflows
C. Pinto, R. Soria, D. Walton +13
Most ULXs are believed to be powered by super-Eddington accreting neutron stars and, perhaps, black holes. Above the Eddington rate the disc is expected to thicken and to launch po…
The Ultraluminous X-ray sources population of the galaxy NGC 7456
F. Pintore, M. Marelli, R. Salvaterra +28
Ultraluminous X-ray sources (ULXs) are a class of accreting compact objects with X-ray luminosities above 1e39 erg/s. The ULX population counts several hundreds objects but only a…
The X-ray Polarization Probe mission concept
Keith Jahoda, Henric Krawczynski, Fabian Kislat +100
The X-ray Polarization Probe (XPP) is a second generation X-ray polarimeter following up on the Imaging X-ray Polarimetry Explorer (IXPE). The XPP will offer true broadband polarim…
Spectral and Timing Analysis of the accretion-powered pulsar 4U 1626-67 observed with Suzaku and NuSTAR
Wataru B. Iwakiri, Katja Pottschmidt, Sebastian Falkner +13
We present an analysis of the spectral shape and pulse profile of the accretion-powered pulsar 4U 1626-67 observed with Suzaku and NuSTAR during a spin-up state. The pulsar, which…
Variability in high-mass X-ray binaries
F. Fuerst, P. Kretschmar, V. Grinberg +5
Strongly magnetized, accreting neutron stars show periodic and aperiodic variability over a wide range of time scales. By obtaining spectral and timing information on these differe…
Probing the Black Hole Engine with Measurements of the Relativistic X-ray Reflection Component
Javier A. García, Matteo Bachetti, David R. Ballantyne +21
Over the last decades X-ray spectroscopy has proven to be a powerful tool for the estimation of black hole spin and several other key parameters in dozens of AGN and black hole X-r…
On the contribution of ULXs to stellar feedback: an intermediate mass black hole candidate and the population of ULXs in the low-metallicity starburst galaxy ESO 338-4
Lidia M. Oskinova, Arjan Bik, J. Miguel Mas-Hesse +5
X-ray radiation from accreting compact objects is an important part of stellar feedback. The metal-poor galaxy ESO 338-4 has experienced vigorous starburst during the last 40 Myr a…
NuSTAR reveals the hidden nature of SS433
M. J. Middleton, D. J. Walton, W. Alston +25
SS433 is the only Galactic binary system known to persistently accrete at highly super-critical (or hyper-critical) rates, similar to those in tidal disruption events, and likely n…
Multiple cyclotron line-forming regions in GX 301-2
F. Fuerst, S. Falkner, D. Marcu-Cheatham +6
We present two observations of the high-mass X-ray binary GX 301-2 with NuSTAR, taken at different orbital phases and different luminosities. We find that the continuum is well des…
A tale of two periods: determination of the orbital ephemeris of the super-Eddington pulsar NGC 7793 P13
F. Fuerst, D. J. Walton, M. Heida +10
We present a timing analysis of multiple XMM-Newton and NuSTAR observations of the ultra-luminous pulsar NGC 7793 P13 spread over its 65d variability period. We use the measured pu…
The Hard State of the Highly Absorbed High Inclination Black Hole Binary Candidate Swift J1658.2-4242 Observed by NuSTAR and Swift
Yanjun Xu, Fiona A. Harrison, Jamie A. Kennea +9
We present a spectral and timing analysis of the newly reported Galactic X-ray transient Swift J1658.2-4242 observed by NuSTAR and Swift. The broad-band X-ray continuum is typical…
Evidence for Pulsar-like Emission Components in the Broadband ULX Sample
D. J. Walton, F. Fuerst, M. Heida +7
We present broadband X-ray analyses of a sample of bright ultraluminous X-ray sources with the goal of investigating the spectral similarity of this population to the known ULX pul…
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…
Studying the accretion geometry of EXO 2030+375 at luminosities close to the propeller regime
F. Fuerst, P. Kretschmar, J. J. E. Kajava +10
The Be X-ray binary EXO 2030+375 was in an extended low luminosity state during most of 2016. We observed this state with NuSTAR and Swift, supported by INTEGRAL observations as we…
EXO 2030+375 Restarts in Reverse
Peter Kretschmar, Felix Fuerst, Colleen A. Wilson-Hodge +8
The Be X-ray binary pulsar EXO 2030+375, first detected in 1985, has shown a significant detected X-ray outburst at nearly every periastron passage of its 46-day orbit for the past…
Disentangling the Complex Broadband X-ray Spectrum of IRAS 13197-1627 with NuSTAR, XMM-Newton and Suzaku
D. J. Walton, M. Brightman, G. Risaliti +8
We present results from a coordinated -+ observation of the type 1.8 Seyfert galaxy IRAS 13197-1627. This is a highly complex source, with strong contributions…
Broadband X-ray spectral analysis of the Seyfert 1 galaxy GRS 1734-292
A. Tortosa, A. Marinucci, G. Matt +14
We discuss the broadband X-ray spectrum of GRS 1734-292 obtained from non-simultaneous XMM-Newton and NuSTAR observations, performed in 2009 and 2014, respectively. GRS1734-292 is…
Discovery and Modeling of a Flattening of the Positive Cyclotron Line/Luminosity Relation in GX 304-1 with RXTE
Richard E. Rothschild, Matthias Kuehnel, Katja Pottschmidt +8
The RXTE observed four outbursts of the accreting X-ray binary transient source, GX 304-1 in 2010 and 2011. We present results of detailed 3-100 keV spectral analysis of 69 separat…