NIR Counterparts to ULXs (III): Completing the photometric survey and selected spectroscopic results*
López, K.M.; Heida, M.; Jonker, P.G.; Torres, M.A.P.; Roberts, T.P.; Walton, D.J.; Moon, D-S.; Harrison, F.A.
Professor Tim Roberts firstname.lastname@example.org
We present results from the remaining sources in our search for near-infrared (NIR) candidate counterparts to ultraluminous X-ray sources (ULXs) within ≃ 10 Mpc. We observed 23 ULXs in 15 galaxies and detected NIR candidate counterparts to six of them. Two of these have an absolute magnitude consistent with a single red supergiant (RSG). Three counterparts are too bright for a RSG and spatially extended, and thus we classify them as stellar clusters. The other candidate is too faint for a RSG. Additionally, we present the results of our NIR spectroscopic follow-up of five sources: four originally classified as RSG and one as a stellar cluster on the basis of previous photometry. The stellar cluster candidate is actually a nebula. Of the four RSGs candidates, one source has a broad Hα emission line redshifted by ∼z = 1, making it a background AGN. Two other sources show stellar spectra consistent with them being RSGs. The final RSG candidate is too faint to classify, but does not show strong (nebular) emission lines in its spectrum. After our search for NIR counterparts to 113 ULXs, where we detected a candidate counterpart for 38 ULXs, we have spectroscopically confirmed the nature of 12: five sources are nebulae, one source is not classified, one source is an AGN and five are RSGs. These possible five ULX-RSG binary systems would constitute ≃ (4±2)% of the observed ULXs, a fraction almost four times larger than what was predicted by binary evolution simulations.
López, K., Heida, M., Jonker, P., Torres, M., Roberts, T., Walton, D., …Harrison, F. (2020). NIR Counterparts to ULXs (III): Completing the photometric survey and selected spectroscopic results*. Monthly Notices of the Royal Astronomical Society, 497(1), 917-932. https://doi.org/10.1093/mnras/staa1920
|Journal Article Type||Article|
|Acceptance Date||May 31, 2020|
|Online Publication Date||Jul 7, 2020|
|Deposit Date||Jul 9, 2020|
|Publicly Available Date||Aug 23, 2020|
|Journal||Monthly Notices of the Royal Astronomical Society|
|Publisher||Royal Astronomical Society|
|Peer Reviewed||Peer Reviewed|
Published Journal Article
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
You might also like
The hyperluminous X‐ray source population
Unveiling the disc structure in ultraluminous X-ray source NGC 55 ULX-1
The variability behavior of NGC 925 ULX-3
A transient ultraluminous X-ray source in NGC 55