Zobrazeno 1 - 10
of 255
pro vyhledávání: '"Dominic J. Walton"'
Autor:
Elias Kammoun, Anne M. Lohfink, Megan Masterson, Dan R. Wilkins, Xiurui Zhao, Mislav Balokovic, Peter G. Boorman, Riley Connors, Paolo Coppi, Andrew Fabian, Javier A. García, Kristin K. Madsen, Nicole Rodriguez Cavero, Navin Sridhar, Daniel Stern, John Tomsick, Thomas Wevers, Dominic J. Walton, Stefano Bianchi, Johannes Buchner, Francesca M. Civano, Giorgio Lanzuisi, Labani Mallick, Giorgio Matt, Andrea Merloni, Emanuele Nardini, Joanna M. Piotrowska, Claudio Ricci, Ka-Wah Wong, Abderahmen Zoghbi
Publikováno v:
Frontiers in Astronomy and Space Sciences, Vol 10 (2024)
The hard X-ray emission in active galactic nuclei (AGN) and black hole X-ray binaries is thought to be produced by a hot cloud of electrons referred to as the corona. This emission, commonly described by a power law with a high-energy cutoff, is sugg
Externí odkaz:
https://doaj.org/article/89d4444f0ddb4266a2823787d2cadb21
Autor:
Matteo Bachetti, Matthew J. Middleton, Ciro Pinto, Andrés Gúrpide, Dominic J. Walton, Murray Brightman, Bret Lehmer, Timothy P. Roberts, Georgios Vasilopoulos, Jason Alford, Roberta Amato, Elena Ambrosi, Lixin Dai, Hannah P. Earnshaw, Hamza El Byad, Javier A. García, Gian Luca Israel, Amruta Jaodand, Kristin Madsen, Chandreyee Maitra, Shifra Mandel, Kaya Mori, Fabio Pintore, Ken Ohsuga, Maura Pilia, Daniel Stern, George Younes, Anna Wolter
Publikováno v:
Frontiers in Astronomy and Space Sciences, Vol 10 (2023)
Introduction: 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 powerful winds travelling at 0.1–0.2 c, the increasing e
Externí odkaz:
https://doaj.org/article/8a30718b913d4e20b3ce8ab2b4efeaa2
Return to the Forgotten Ultraluminous X-Ray Source: A Broadband NICER+NuSTAR Study of NGC 4190 ULX-1
Autor:
Hannah P. Earnshaw, Matteo Bachetti, Murray Brightman, Felix Fürst, Fiona A. Harrison, Matthew Middleton, Renee Ludlam, Sean N. Pike, Daniel Stern, Dominic J. Walton
Publikováno v:
The Astrophysical Journal, Vol 968, Iss 2, p 111 (2024)
We observed the nearby and relatively understudied ultraluminous X-ray source (ULX) NGC 4190 ULX-1 jointly with Neutron Star Interior Composition Explorer (NICER) and NuSTAR to investigate its broadband spectrum, timing properties, and spectral varia
Externí odkaz:
https://doaj.org/article/fbd55caeb1fe4f54a317f77c1ddfa4ac
Autor:
M. Lynne Saade, Murray Brightman, Daniel Stern, Thomas Connor, S. G. Djorgovski, Daniel J. D’Orazio, K. E. S. Ford, Matthew J. Graham, Zoltán Haiman, Hyunsung D. Jun, Elias Kammoun, Ralph P. Kraft, Barry McKernan, Alexei Vikhlinin, Dominic J. Walton
Publikováno v:
The Astrophysical Journal, Vol 966, Iss 1, p 104 (2024)
We present an analysis of NuSTAR X-ray observations of three active galactic nuclei (AGN) that were identified as candidate subparsec binary supermassive black hole (SMBH) systems in the Catalina Real-Time Transient Survey based on apparent periodici
Externí odkaz:
https://doaj.org/article/584e442a17d949f8b62508e773cb6497
Autor:
Andrea Belfiore, Ruben Salvaterra, Lara Sidoli, Gian Luca Israel, Luigi Stella, Andrea De Luca, Sandro Mereghetti, Paolo Esposito, Fabio Pintore, Antonino D’Aì, Guillermo Rodrìguez Castillo, Dominic J. Walton, Felix Fürst, Danilo Magistrali, Anna Wolter, Matteo Imbrogno
Publikováno v:
The Astrophysical Journal, Vol 965, Iss 1, p 78 (2024)
We report on the orbit of the binary system powering the most extreme ultraluminous X-ray pulsar known to date: NGC 5907 ULX-1 (hereafter ULX1). ULX1 has been the target of a substantial multi-instrument campaign, mainly in the X-ray band, but no cle
Externí odkaz:
https://doaj.org/article/cad3f76641de4c7aaa95afbeeab218be
Autor:
Megan Masterson, Erin Kara, Dheeraj R. Pasham, Daniel J. D’Orazio, Dominic J. Walton, Andrew C. Fabian, Matteo Lucchini, Ronald A. Remillard, Zaven Arzoumanian, Otabek Burkhonov, Hyeonho Choi, Shuhrat A. Ehgamberdiev, Elizabeth C. Ferrara, Muryel Guolo, Myungshin Im, Yonggi Kim, Davron O. Mirzaqulov, Gregory S. H. Paek, Hyun-Il Sung, Joh-Na Yoon
Publikováno v:
The Astrophysical Journal Letters, Vol 945, Iss 2, p L34 (2023)
The nuclear transient AT2019cuk/Tick Tock/SDSS J1430+2303 has been suggested to harbor a supermassive black hole (SMBH) binary near coalescence. We report results from high-cadence NICER X-ray monitoring with multiple visits per day from 2022 January
Externí odkaz:
https://doaj.org/article/f23a2a84a71241c09800a90625f5cf17
Autor:
Murray Brightman, Jean-Marie Hameury, Jean-Pierre Lasota, Ranieri D. Baldi, Gabriele Bruni, Jenna M. Cann, Hannah Earnshaw, Felix Fürst, Marianne Heida, Amruta Jaodand, Margaret Lazzarini, Matthew J. Middleton, Dominic J. Walton, Kimberly A. Weaver
Publikováno v:
The Astrophysical Journal, Vol 951, Iss 1, p 51 (2023)
Ultraluminous X-ray sources (ULXs) are our best laboratories for studying extreme super-Eddington accretion. Most studies of these objects are of relatively persistent sources; however, there is growing evidence to suggest a large fraction of these s
Externí odkaz:
https://doaj.org/article/3ab29fc1d1b146aa9948199c9c398426
Autor:
Honghui Liu, Jiachen Jiang, Zuobin Zhang, Cosimo Bambi, Andrew C. Fabian, Javier A. García, Adam Ingram, Erin Kara, James F. Steiner, John A. Tomsick, Dominic J. Walton, Andrew J. Young
Publikováno v:
The Astrophysical Journal, Vol 951, Iss 2, p 145 (2023)
We present a high-density relativistic reflection analysis of 21 spectra of six black hole X-ray binaries in the hard state with data from NuSTAR and Swift. We find that 76% of the observations in our sample require a disk density higher than the 10
Externí odkaz:
https://doaj.org/article/050b9d16aaa24dcc933fd75420f70eeb
Autor:
Erin Barillier, Victoria Grinberg, David Horn, Michael A. Nowak, Ronald A. Remillard, James F. Steiner, Dominic J. Walton, Jörn Wilms
Publikováno v:
The Astrophysical Journal, Vol 944, Iss 2, p 165 (2023)
4U 1957+11 is a black hole candidate system that has been in a soft X-ray spectral state since its discovery. We present analyses of recent joint NICER and NuSTAR spectra, which are extremely well described by a highly inclined disk accreting into a
Externí odkaz:
https://doaj.org/article/95833e0cb8b54d679b05823a562d4917
Autor:
Didier Barret, Dominic J. Walton, Michael Parker, Yerong Xu, Andrew C. Fabian, P. Kosec, Giancarlo Cusumano, Stefano Bianchi, Matteo Guainazzi, Ciro Pinto
Publikováno v:
Monthly Notices of the Royal Astronomical Society
Monthly Notices of the Royal Astronomical Society, 2021, 508 (4), pp.6049-6067. ⟨10.1093/mnras/stab2984⟩
Mon.Not.Roy.Astron.Soc.
Mon.Not.Roy.Astron.Soc., 2021, 508 (4), pp.6049-6067. ⟨10.1093/mnras/stab2984⟩
Monthly Notices of the Royal Astronomical Society, 2021, 508 (4), pp.6049-6067. ⟨10.1093/mnras/stab2984⟩
Mon.Not.Roy.Astron.Soc.
Mon.Not.Roy.Astron.Soc., 2021, 508 (4), pp.6049-6067. ⟨10.1093/mnras/stab2984⟩
Ultra-fast outflows (UFOs) have been detected in the high-quality X-ray spectra of a number of active galactic nuclei (AGN) with fairly high accretion rates and are thought to significantly contribute to the AGN feedback. After a decade of dedicated