235 citations · 399 across the 9 of their papers we have counts for
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A Luminous X-ray Flare From The Nucleus of The Dormant Bulgeless Spiral Galaxy NGC 247
Hua Feng, Luis C. Ho, Philip Kaaret +4
NGC 247 is a nearby late-type bulgeless spiral galaxy that contains an inactive nucleus. We report a serendipitous discovery of an X-ray flare from the galaxy center with a luminos…
A mass of less than 15 solar masses for the black hole in an ultraluminous X-ray source
C. Motch, M. W. Pakull, R. Soria +2
Most ultraluminous X-ray sources (ULXs) display a typical set of properties not seen in Galactic stellar-mass black holes (BHs): higher luminosity Lx > 3 10^39 erg/s, unusually sof…
Towards a dynamical mass of the ultraluminous X-ray source NGC 5408 X-1
D. Cseh, F. Grise, P. Kaaret +5
We obtained multi-epoch Very Large Telescope (VLT) optical spectroscopic data in 2011 and 2012 on the ultraluminous X-ray source (ULX) NGC 5408 X-1. We confirm that the HeII\lambda…
A long-term X-ray monitoring of the ultraluminous X-ray source NGC 5408 X-1 with Swift reveals the presence of dips but no orbital period
Fabien Grisé, Philip Kaaret, Stéphane Corbel +2
NGC 5408 X-1 is a well-studied ultraluminous X-ray source (ULX) that has been seen to emit in X-rays persistently above the Eddington limit of a stellar-mass black hole for years.…
Chandra and HST Observations of the Supersoft ULX in NGC 247: Candidate for Standard Disk Emission
Lian Tao, Hua Feng, Philip Kaaret +2
We report on multiwavelength observations of the supersoft ultraluminous X-ray source (ULX) in NGC 247 made with the Chandra X-ray Observatory and Hubble Space Telescope (HST). We…
The supergiant optical counterpart of ULX P13 in NGC7793
C. Motch, M. W. Pakull, F. Grisé +1
We have identified the optical counterpart of the ULX source P13 in the nearby spiral galaxy NGC 7793. The object is a V ~ 20.5 mag star, ten times brighter than any other establis…