TY - JOUR
T1 - Slow decline and rise of the broad [O III] emission line in globular cluster black hole candidate RZ2109
AU - Dage, Kristen C.
AU - Zepf, Stephen E.
AU - Bahramian, Arash
AU - Strader, Jay
AU - Maccarone, Thomas J.
AU - Peacock, Mark B.
AU - Kundu, Arunav
AU - Steele, Matthew M.
AU - Britt, Christopher T.
N1 - Publisher Copyright:
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
PY - 2019/11/11
Y1 - 2019/11/11
N2 - RZ2109 is the first of several extragalactic globular clusters shown to host an ultraluminous X-ray source. RZ2109 is particularly notable because optical spectroscopy shows it has broad, luminous [O III] λλ4959,5007 emission, while also having no detectable hydrogen emission. The X-ray and optical characteristics of the source in RZ2109 make it a good candidate for being a stellar mass black hole accreting from a white dwarf donor (i.e. an ultracompact black hole X-ray binary). In this paper we present optical spectroscopic monitoring of the [O III]5007 emission line from 2007 to 2018. We find that the flux of the emission line is significantly lower in recent observations from 2016 to 2018 than it was in earlier observations in 2007–2011. We also explore the behaviour of the emission line shape over time. Both the core and the wings of the emission line decline over time, with some evidence that the core declines more rapidly than the wings.
AB - RZ2109 is the first of several extragalactic globular clusters shown to host an ultraluminous X-ray source. RZ2109 is particularly notable because optical spectroscopy shows it has broad, luminous [O III] λλ4959,5007 emission, while also having no detectable hydrogen emission. The X-ray and optical characteristics of the source in RZ2109 make it a good candidate for being a stellar mass black hole accreting from a white dwarf donor (i.e. an ultracompact black hole X-ray binary). In this paper we present optical spectroscopic monitoring of the [O III]5007 emission line from 2007 to 2018. We find that the flux of the emission line is significantly lower in recent observations from 2016 to 2018 than it was in earlier observations in 2007–2011. We also explore the behaviour of the emission line shape over time. Both the core and the wings of the emission line decline over time, with some evidence that the core declines more rapidly than the wings.
KW - Globular clusters: individual: RZ2109
KW - White dwarfs
UR - http://www.scopus.com/inward/record.url?scp=85075249519&partnerID=8YFLogxK
U2 - 10.1093/mnras/stz2514
DO - 10.1093/mnras/stz2514
M3 - Article
AN - SCOPUS:85075249519
SN - 0035-8711
VL - 489
SP - 4783
EP - 4790
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 4
ER -