The Most Distant X-ray Massive Galaxy Cluster
XMMU J2235.3-2557  z=1.4


[click on the image for a better view]

The distant, massive galaxy cluster as it existed when the Universe was less than 5 billion years old or 1/3 its present age. This is a color composite image of an XMM-Newton X-ray image (orange channel) and ESO-VLT optical/near-infrared images (red, green, and blue channels). Old cluster galaxies are the small red objects and the diffuse, hot gas is revealed by the X-ray emission.

Details: orange channel: XMM-Newton soft X-ray image (0.5-2.0 keV, 45ks); the red channel: VLT-ISAAC Ks-band image (3600s); the green channel: VLT-FORS2 z-band image (480s); the blue channel: VLT-FORS2 R-band image (1140s). 2.5' x 2.5' field-of-view corresponding to 1. 3 Mpc x 1.3 Mpc at the cluster redshift.
[If the X-ray channel is not blinking, your browser/firewall is the culprit; click on the image for an alternate view]

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Related Papers

Title: Discovery of an X-ray-Luminous Galaxy Cluster at z=1.4
    Astrophysical Journal Letters, 2005, ApJ, 623, L85. [pdf] [ApJL] [ADS]
Authors: C.R. Mullis, P. Rosati, G. Lamer, H. Boehringer, A. Schwope, P. Schuecker and R. Fassbender
    Correction to Figure 3 (top panel)

Title: Galaxy Cluster Archaeology
    ESO Messenger, 2005, 120, 33. [pdf]
Authors: H. Boehringer, C.R. Mullis, P. Rosati, G. Lamer, R. Fassbender, A. Schwope, and P. Schuecker

Image & Data Gallery
XMM-Newton observation of the nearby galaxy NGC7314 (bright object at center) from which the distant cluster (white box) was serendipitously identified. The inset covers the same region (2.8' x 2.8') of the sky as the previous image and shows the diffuse X-ray emission from XMMU J2235.3-2557, coming from a distance of 9 billion light-years. Note that the circular field-of-view of XMM-Newton is one-half degree in diameter which is the same angular size as the full Moon.
Download this JPG image: small (51 kb), medium (158 kb), large (1 Mb)

 
Schematic diagram of the distribution of known galaxy clusters in space. As Earth-bound observers look out from the bottom point toward the top of the cone, they view an increasingly distant and early universe. Distance (redshift) is marked on the right axis and the corresponding cosmic look-back time is indicated on the left axis. The newly discovered cluster at z=1.4 (labeled "XMMU J2235") illuminates a remote regime which is well beyond the horizon of previous studies (labeled "ROSAT horizon").
Download this JPG image: small (22 kb), medium (45 kb), large (316 kb)

 
Left: VLT-FORS2 R-band image (1140s) overlaid with X-ray contours from a 45ks XMM-Newton observation. The 0.5-2.0 keV X-ray image from the EPIC M1+M2 detectors has been smoothed with a 4" Gaussian kernel; eight logarithmically-spaced contours are drawn between 0.2 and 1 count per 2" pixel. The prominent X-ray point source north-west and 2.3' further off-axis than the cluster is a Seyfert 2 galaxy at z=0.4060. Right: VLT-ISAAC Ks image (3600s) overlaid with the same X-ray contours. Spectroscopically confirmed members (1.38 < z < 1.40) are marked in red. Two galaxies at 1.37 < z < 1.38 are marked in orange. In both cases circles indicate absorption line galaxies and triangles indicate emission line galaxies. [from Mullis et al. 2005]

 
Color image of XMMU J2235.3-2557 (z=1.393) overlaid with the same X-ray flux contours as in previous figure. The red channel is a VLT-ISAAC Ks image (3600s); the green channel is a VLT-FORS2 z-band image (480s); the blue channel is a VLT-FORS2 R-band image (1140s). [from Mullis et al. 2005]

 
Top: Color-magnitude diagram of the 7' x 7' field around XMMU J2235.3-2557. Spectroscopically confirmed cluster galaxies (1.38 < z < 1.40) are highlighted in red; two galaxies at 1.37 < z < 1.38 in orange (circle: absorption line gal.; triangle: emission line gal.). The horizontal line indicates the predicted color of a z=1.393 cluster elliptical. Bottom: VLT-FORS2 spectrum of the brightest cluster galaxy (z=1.3943 +/- 0.0003, 4 hour integration). [updated from Mullis et al. 2005]

 
Histogram of galaxy redshifts measured in the VLT-FORS2 MXU observations of the 7' x 7' region around XMMU J2235.3-2557. Spectroscopically confirmed cluster galaxies (1.38 < z < 1.40) are highlighted in red; two galaxies at 1.37 < z < 1.38 in orange. [from Mullis et al. 2005]

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