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Ultraluminous X-ray sources: new distance indicators?

Różańska, A. and Bresler, K. and Beldycki, B. and Madej, J. and Adhikari, T. P. (2018) Ultraluminous X-ray sources: new distance indicators? Astronomy and Astrophysics, 612 . Art. No. L12. ISSN 0004-6361. doi:10.1051/0004-6361/201832864.

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Aims. In this paper we fit the NuSTAR and XMM-Newton data of three sources: NGC 7793 P13, NGC5907 ULX1, and Circinus ULX5. Methods. Our single model contains emission from a non-spherical system: a neutron star plus an accretion disk directed towards the observer. Results. We obtained a very good fit with the reduced χ2 per degree of freedom equal to 1.08 for P13, 1.01 for ULX1, and 1.14 for ULX5. The normalization of our model constrains the distance to the source. The resulting distances are D = 3.41_(−0.10)^(+0.11), 6.55_(−0.81)^(+0.69), and 2.60_(−0.03)^(+0.05) Mpc for P13, ULX1, and ULX5 respectively. The distances to P13 and ULX5 are in perfect agreement with previous distance measurements to their host galaxies. Conclusions. Our results confirm that P13, ULX1, and ULX5 may contain central hot neutron stars. When the outgoing emission is computed by integration over the emitting surface and successfully fitted to the data, then the resulting model normalization is the direct distance indicator.

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Różańska, A.0000-0002-5275-4096
Alternate Title:Ultra Luminous X-ray sources - new distance indicators?
Additional Information:© 2018 ESO. Article published by EDP Sciences. Received 20 February 2018; Accepted 16 April 2018; Published online 10 May 2018. This research was supported by Polish National Science Center grants No. 2015/17/B/ST9/03422, 2015/18/M/ST9/00541, and 2016/21/N/ST9/03311. This research has made use of data obtained with NuSTAR, a project led by Caltech, funded by NASA, and managed by NASA/JPL, and has utilized the NUSTARDAS software package, jointly developed by ASDC (Italy) and Caltech (USA). This work has also made use of data obtained with XMM-Newton directly funded by ESA Member States.
Subject Keywords:accretion, accretion disks – stars: neutron – X-rays: general
Record Number:CaltechAUTHORS:20171006-100014623
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Official Citation:Ultraluminous X-ray sources: new distance indicators? A. Różańska, K. Bresler, B. Bełdycki, J. Madej and T. P. Adhikari A&A, 612 (2018) L12 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:82155
Deposited By: Joy Painter
Deposited On:06 Oct 2017 17:15
Last Modified:15 Nov 2021 19:48

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