Multiband counterparts of two eclipsing ultraluminous X-ray sources in M51

We present the discovery and interpretation of ionized nebulae around two ultraluminous X-ray sources in M 51; both sources share the rare property of showing X-ray eclipses by their companion stars and are therefore prime targets for follow-up studies. Using archival Hubble Space Telescope images,...

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Main Authors: Urquhart, Ryan, Soria, Roberto, Johnston, H., Pakull, M., Motch, C., Schwope, A., Miller-Jones, James, Anderson, Gemma
Format: Journal Article
Published: Oxford University Press 2018
Online Access:http://purl.org/au-research/grants/arc/FT140101082
http://hdl.handle.net/20.500.11937/66814
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author Urquhart, Ryan
Soria, Roberto
Johnston, H.
Pakull, M.
Motch, C.
Schwope, A.
Miller-Jones, James
Anderson, Gemma
author_facet Urquhart, Ryan
Soria, Roberto
Johnston, H.
Pakull, M.
Motch, C.
Schwope, A.
Miller-Jones, James
Anderson, Gemma
author_sort Urquhart, Ryan
building Curtin Institutional Repository
collection Online Access
description We present the discovery and interpretation of ionized nebulae around two ultraluminous X-ray sources in M 51; both sources share the rare property of showing X-ray eclipses by their companion stars and are therefore prime targets for follow-up studies. Using archival Hubble Space Telescope images, we found an elongated, 100-pc-long emission-line structure associated with one X-ray source (CXOM51 J132940.0+471237; ULX-1 for simplicity), and a more circular, ionized nebula at the location of the second source (CXOM51 J132939.5+471244; ULX-2 for simplicity). We observed both nebulae with the Large Binocular Telescope’s Multi-Object Double Spectrograph. From our analysis of the optical spectra, we argue that the gas in the ULX-1 bubble is shock-ionized, consistent with the effect of a jet with a kinetic power of ≈2 × 1039 erg s−1. Additional X-ray photoionization may also be present, to explain the strength of high-ionization lines such as He II λ4686 and [Ne V] λ3426. On the other hand, the emission lines from the ULX-2 bubble are typical for photoionization by normal O stars suggesting that the nebula is actually an H II region not physically related to the ULX but is simply a chance alignment. From archival Very Large Array data, we also detect spatially extended, steep-spectrum radio emission at the location of the ULX-1 bubble (consistent with its jet origin), but no radio counterpart for ULX-2 (consistent with the lack of shock-ionized gas around that source).
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spelling curtin-20.500.11937-668142022-11-28T04:16:05Z Multiband counterparts of two eclipsing ultraluminous X-ray sources in M51 Urquhart, Ryan Soria, Roberto Johnston, H. Pakull, M. Motch, C. Schwope, A. Miller-Jones, James Anderson, Gemma We present the discovery and interpretation of ionized nebulae around two ultraluminous X-ray sources in M 51; both sources share the rare property of showing X-ray eclipses by their companion stars and are therefore prime targets for follow-up studies. Using archival Hubble Space Telescope images, we found an elongated, 100-pc-long emission-line structure associated with one X-ray source (CXOM51 J132940.0+471237; ULX-1 for simplicity), and a more circular, ionized nebula at the location of the second source (CXOM51 J132939.5+471244; ULX-2 for simplicity). We observed both nebulae with the Large Binocular Telescope’s Multi-Object Double Spectrograph. From our analysis of the optical spectra, we argue that the gas in the ULX-1 bubble is shock-ionized, consistent with the effect of a jet with a kinetic power of ≈2 × 1039 erg s−1. Additional X-ray photoionization may also be present, to explain the strength of high-ionization lines such as He II λ4686 and [Ne V] λ3426. On the other hand, the emission lines from the ULX-2 bubble are typical for photoionization by normal O stars suggesting that the nebula is actually an H II region not physically related to the ULX but is simply a chance alignment. From archival Very Large Array data, we also detect spatially extended, steep-spectrum radio emission at the location of the ULX-1 bubble (consistent with its jet origin), but no radio counterpart for ULX-2 (consistent with the lack of shock-ionized gas around that source). 2018 Journal Article http://hdl.handle.net/20.500.11937/66814 10.1093/mnras/sty014 http://purl.org/au-research/grants/arc/FT140101082 Oxford University Press fulltext
spellingShingle Urquhart, Ryan
Soria, Roberto
Johnston, H.
Pakull, M.
Motch, C.
Schwope, A.
Miller-Jones, James
Anderson, Gemma
Multiband counterparts of two eclipsing ultraluminous X-ray sources in M51
title Multiband counterparts of two eclipsing ultraluminous X-ray sources in M51
title_full Multiband counterparts of two eclipsing ultraluminous X-ray sources in M51
title_fullStr Multiband counterparts of two eclipsing ultraluminous X-ray sources in M51
title_full_unstemmed Multiband counterparts of two eclipsing ultraluminous X-ray sources in M51
title_short Multiband counterparts of two eclipsing ultraluminous X-ray sources in M51
title_sort multiband counterparts of two eclipsing ultraluminous x-ray sources in m51
url http://purl.org/au-research/grants/arc/FT140101082
http://hdl.handle.net/20.500.11937/66814