Projects and Collaborations

HIFLUGCS

The HIghest X-ray FLUx Galaxy Cluster Sample (HIFLUGCS) is an X-ray selected sample of 64 galaxy clusters from the ROSAT All-Sky Survey with a flux limit of 2 × 10 -11 erg s-1cm-2 in the (0.1-2.4) keV band and Galactic latitude |b| ≤ 20°. HIFLUGCS is the largest complete sample with full Chandra and XMM-Newton follow-up.

X-ray data are available for these clusters:

From Chandra for all 64 clusters.
From XMM-Newton for all 64 clusters.
From Suzaku for more than 40% of the HIFLUGCS clusters.
From ROSAT PSPC pointing observations for 80%.

Since these systems are the X-ray brightest clusters in the sky, they are also well-studied in other wavebands, e.g., in the radio and optical regime.

In the near future, HIFLUGCS will be tripled in sample size resulting in the new complete high quality sample, eHIFLUGCS. This significantly increased statistics will enable substantial improvements in precision for several studies as well as qualitatively new tests.

Map in Galactic coordinates (in Aitoff projection) showing the positions of the 63 HIFLUGCS clusters without RXJ 1504 (filled circles). 11 clusters above the flux limit but with b < |20°| are also added (open triangles). © Reiprich and Böhringer (2002)

Some HIFLUGCS publications:

Zhang, Y.-Y.; Andernach, H.; Caretta, C. A.; et al., A&A, 2011, 526, A105

Mittal, R.; Hicks, A.; Reiprich, T. H. & Jaritz, V., A&A, 2011, 532, A133

Laganá, T. F.; Zhang, Y.-Y.; Reiprich, T. H. & Schneider, P., ApJ, 2011, 743, 13

Zhang, Y.-Y.; Laganá, T. F.; Pierini, D.; Puchwein, E.; Schneider, P. & Reiprich, T. H., A&A, 2011, 535, A78

Hudson, D. S.; Mittal, R.; Reiprich, T. H.; et al., A&A, 2010, 513, A37

Mittal, R.; Hudson, D. S.; Reiprich, T. H.; et al., A&A, 2009, 501, 835-850

Chen, Y.; Reiprich, T. H.; Böhringer, H.; et al., A&A, 2007, 466, 805-812

Reiprich, T. H., A&A, 2006, 453, L39-L42

Ikebe, Y.; Reiprich, T. H.; Böhringer, H.; Tanaka, Y. & Kitayama, T., A&A, 2002, 383, 773-790

Reiprich, T. H. & Böhringer, H., ApJ, 2002, 567, 716-740

ADS listing of publications containing the word "HIFLUGCS"

eROSITA

The primary science driver for eROSITA is to study dark energy with about 100,000 galaxy clusters. eROSITA will survey the full sky eight times at X-ray wavelengths. It will be launched as the main instrument onboard the Spektr-RG satellite mission in 2019. Technical and scientific descriptions as well as forecasts on eROSITA's cosmological constraining power can be found, e.g., in Predehl et al. (2010), Merloni et al. (2012), Pillepich et al. (2012), Hofmann et al. (2017), Clerc et al. (2018), Pillepich et al. (2018), and Zandanel et al. (2018).

Press release about the successful launch is here.

The architecture of Spektr-RG orbital observatory as of 2010. © Anatoly Zak, Russian Space Web

XMM-XXL

XXL is a survey using the XMM-Newton telescope to cover two regions of 25 deg2 each, with 10 ks observations. This gives a point source sensitivity of 5 x 10-15 erg s-1 cm-2 in the (0.5 - 2) keV band. With more than 6 Ms it is the largest XMM-Newton project approved to date.

600 new galaxy clusters with redshifts up to 2 will be used to constrain the dark energy equation of state.

ASKAP/EMU

The Evolutionary Map of the Universe (EMU, e.g., Norris et al. 2011) is a radio continuum survey performed with the Australian Square Kilometer Array Pathfinder. Because of its very high sensitivity (40 times NVSS) it will discover star forming galaxies up to redshift 1. Moreover, EMU will detect radio halos, radio relics, tailed radio galaxies, etc. in thousands of galaxy clusters.

Euclid

Euclid is a 1.2m optical telescope onboard a spacecraft to be launched around 2022. The primary mission goal is to constrain the nature of dark energy. Euclid will also discover many galaxy clusters up to redshift 2 to trace the growth of structure..

Athena

The European Space Agency (ESA) has selected the Athena X-ray observatory for their next large (billion Euro-class) space mission.

After ESA decided to address the "Hot and Energetic Universe" Science Theme with their next major mission, the Advanced Telescope for High-Energy Astrophysics (Athena) space mission proposal has now been selected by ESA. One of the key science drivers of the Hot and Energetic Universe Science Theme is the study of the largest objects in the Universe, galaxy clusters, from ancient times, about ten billion years ago, when they first formed, down to the present. Most of the normal matter in these systems, intergalactic gas between the galaxies, is so hot, more than ten million degrees, that it is invisible in the optical but radiates at X-ray wavelengths. A team of astrophysicists from many institutes world-wide, including the Argelander-Institute for Astronomy at Bonn University, demonstrated that the X-ray mission Athena has the technical capabilities to solve the outstanding questions about galaxy cluster evolution.

Athena is Europe's next generation X-ray observatory selected as a large mission for the ESA science program. After launch in ~2030 it will be the ultimate X-ray instrument to analyze all the details of the hot and energetic universe. The main science topics are galaxy clusters, the evolution of their physical properties, and the accretion process of black holes.

Further information: