Related papers: Further Observations of the Intermediate Mass Blac…
The brightest Ultra-Luminous X-ray source HLX-1 in the galaxy ESO 243-49 provides strong evidence for the existence of intermediate mass black holes. As the luminosity and thus the mass estimate depend on the association of HLX-1 with ESO…
The small subset of hyper-luminous X-ray sources with luminosities in excess of ~1E41 erg/s are hard to explain without the presence of an intermediate mass black hole, as significantly super-Eddington accretion and/or very small beaming…
In this Letter we report a spectroscopic confirmation of the association of HLX-1, the brightest ultra-luminous X-ray source, with the galaxy ESO 243-49. At the host galaxy distance of 95 Mpc, the maximum observed 0.2 - 10 keV luminosity is…
The Ultra Luminous X-ray (ULX) source HLX-1 in the galaxy ESO 243-49 has an observed maximum unabsorbed X-ray luminosity of 1.3e42 erg/s (0.2-10.0 keV). From the conservative assumption that this value exceeds the Eddington limit by at most…
Ultra-luminous X-ray sources are extragalactic objects located outside the nucleus of the host galaxy with bolometric luminosities >10^39 erg s^-1. These extreme luminosities - if the emission is isotropic and below the theoretical (i.e.…
The hyper luminous X-ray source HLX-1 in the galaxy ESO 243-49, currently the best intermediate mass black hole candidate, displays spectral transitions similar to those observed in Galactic black hole binaries, but with a luminosity…
The point-like X-ray source HLX-1 is the brightest known ultraluminous X-ray source and likely the strongest intermediate-mass black hole candidate. HLX-1 is hosted in the S0 galaxy ESO 243-49, but offset with respect to the nucleus, and…
With an inferred bolometric luminosity exceeding 10^42 erg/s, HLX-1 in ESO 243-49 is the most luminous of ultraluminous X-ray sources and provides one of the strongest cases for the existence of intermediate mass black holes. We obtain good…
Aims. ESO 243-49 HLX-1, otherwise known as HLX-1, is an intermediate mass black hole (IMBH) candidate located 8" (3.7 Kpc) from the centre of the edge-on S0 galaxy ESO 243-49. How the black hole came to be associated with this galaxy, and…
The brightest Ultra-Luminous X-ray source (ULX), ESO 243-49 HLX-1, with a 0.2 - 10 keV X-ray luminosity of up to 10^42 erg s^-1, provides the strongest evidence to date for the existence of intermediate mass black holes. Although small…
The existence of black holes of masses ~ 10^2-10^5 Msun has important implications for the formation and evolution of star clusters and supermassive black holes. One of the strongest candidates to date is the hyperluminous X-ray source…
The point-like X-ray source HLX-1, close to the S0 galaxy ESO 243-49, is the brightest known ultraluminous X-ray source and one the strongest intermediate-mass black hole candidates. We argue that the counterpart of HLX-1 may be the nucleus…
The point-like X-ray source HLX-1, close to the S0 galaxy ESO 243-49, is one the strongest intermediate-mass black hole candidates, but the nature of its counterpart is still puzzling. By means of N-body/smoothed particle hydrodynamics…
The ultra-luminous X-ray (ULX) source ESO 243-49 HLX-1 currently provides the strongest evidence for the existence of intermediate mass black holes. We conduct an ongoing monitoring campaign with the Swift X-ray Telescope and found that…
The lenticular galaxy ESO 243-49 hosts the ultraluminous X-ray source HLX-1, the best candidate intermediate mass black hole (IMBH) currently known. The environments of IMBHs remain unknown, however the proposed candidates include the…
The point-like X-ray source HLX-1, close to the S0 galaxy ESO 243-49, is one of the strongest intermediate-mass black hole candidates. We discuss the hypothesis that ESO 243-49 is undergoing a minor merger with a gas-rich disc galaxy. We…
We present dedicated quasi-simultaneous X-ray (Swift) and optical (Very Large Telescope (VLT), V- and R-band) observations of the intermediate mass black hole candidate ESO 243-49 HLX-1 before and during the 2012 outburst. We show that the…
The known members of the class of hyperluminous X-ray sources (HLXs) are few in number, yet they are of great interest as they are regarded as the likeliest intermediate-mass black hole (IMBH) candidates amongst the wider population of…
We present follow-up radio observations of ESO 243-49 HLX-1 from 2012 using the Australia Telescope Compact Array (ATCA) and the Karl G. Jansky Very Large Array (VLA). We report the detection of radio emission at the location of HLX-1…
We report the results of Swift/XRT observations (2008-2015) of a hyper-luminous X-ray source, ESO 243-49 HLX-1. We found a strong observational evidence that ESO 243-49 HLX-1 underwent spectral transitions from the low/hard state to the…