Volume 531, July 2011
|Number of page(s)||4|
|Published online||04 July 2011|
Letter to the Editor
Discovery of a massive X-ray luminous galaxy cluster at z = 1.579⋆
European Space Astronomy Centre (ESAC)/ESA, Madrid, Spain
2 Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße, 85748 Garching, Germany
3 European Southern Observatory, Karl-Schwarzschild Strasse 2, 85748 Garching, Germany
4 INAF-Osservatorio Astronomico di Trieste, via Tiepolo 11, 34133 Trieste, Italia
5 Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica de Chile, Casilla 306, Santiago 22, Chile
6 Astrophysikalisches Institut Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
7 CEASaclay, Service d’Astrophysique, L’Orme des Merisiers, Bât. 709, 91191 Gif-sur-Yvette Cedex, France
Received: 4 May 2011
Accepted: 30 May 2011
We report on the discovery of a very distant galaxy cluster serendipitously detected in the archive of the XMM-Newton mission, within the scope of the XMM-Newton Distant Cluster Project (XDCP). XMMUJ0044.0-2033 was detected at a high significance level (5σ) as a compact, but significantly extended source in the X-ray data, with a soft-band flux f(r < 40″) = (1.5 ± 0.3) × 10-14 erg s-1 cm2. Optical/NIR follow-up observations confirmed the presence of an overdensity of red galaxies matching the X-ray emission. The cluster was spectroscopically confirmed to be at z = 1.579 using ground-based VLT/FORS2 spectroscopy. The analysis of the I − H colour − magnitude diagram shows a sequence of red galaxies with a colour range [3.7 < I − H < 4.6] within 1′ from the cluster X-ray emission peak. However, the three spectroscopic members (all with complex morphology) have significantly bluer colours relative to the observed red-sequence. In addition, two of the three cluster members have [OII] emission, indicative of on-going star formation. Using the spectroscopic redshift we estimated the X-ray bolometric luminosity, Lbol,40″ ~ 5.8 × 1044 erg s-1, implying a massive galaxy cluster. This places XMMU J0044.0-2033 at the forefront of massive distant clusters, closing the gap between lower redshift systems and recently discovered proto- and low-mass clusters at z > 1.6.
Key words: galaxies: clusters: individual: XMMUJ0044.0-2033 / galaxies: high-redshift / X-rays: galaxies: clusters
This work is based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and the USA (NASA); and on observations carried out using the New Technology Telescope and the Very Large Telescope at the La Silla Paranal Observatory, under Program IDs 079.A-0634(B), 081.A-0312(A) and 084.A-0844(A).
© ESO, 2011
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.