GaBoDS: The Garching-Bonn Deep Survey

Hildebrandt, Hendrik; Erben, T.; Dietrich, J. P.; Cordes, O.; Haberzettl, L.; Hetterscheidt, M.; Schirmer, M.; Schmithuesen, O.; Schneider, Peter; Simon, Patrick; Trachternach, C.

doi:10.1051/0004-6361:20054278

Cited by 87 publications

(104 citation statements)

References 14 publications

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“…Basic data reduction is performed using the THELI pipeline for multi-chip cameras (Erben et al 2005;Schirmer 2013), adapted to MMT/Megacam. We employ the photometric calibration by Hildebrandt et al (2006). Following Dietrich et al (2007), regions of the THELI coadded images not suitable for WL shear measurements are masked.…”

Section: Weak Lensing Analysismentioning

confidence: 99%

The 400d Galaxy Cluster Survey weak lensing programme

Israel

Reiprich²,

Erben³

et al. 2014

A&A

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Context. Scaling properties of galaxy cluster observables with cluster mass provide central insights into the processes shaping clusters. Calibrating proxies for cluster mass that are relatively cheap to observe will moreover be crucial to harvest the cosmological information available from the number and growth of clusters with upcoming surveys like eROSITA and Euclid. The recent Planck results led to suggestions that X-ray masses might be biased low by ∼40%, more than previously considered. Aims. We aim to extend knowledge of the weak lensing -X-ray mass scaling towards lower masses (as low as 1 × 10 14 M ) in a sample representative of the z ∼ 0.4-0.5 population. Thus, we extend the direct calibration of cluster mass estimates to higher redshifts. Methods. We investigate the scaling behaviour of MMT/Megacam weak lensing (WL) masses for 8 clusters at 0.39 ≤ z ≤ 0.80 as part of the 400d WL programme with hydrostatic Chandra X-ray masses as well as those based on the proxies, e.g. Y X = T X M gas . Results. Overall, we find good agreement between WL and X-ray masses, with different mass bias estimators all consistent with zero. When subdividing the sample into a low-mass and a high-mass subsample, we find the high-mass subsample to show no significant mass bias while for the low-mass subsample, there is a bias towards overestimated X-ray masses at the ∼2σ level for some mass proxies. The overall scatter in the mass-mass scaling relations is surprisingly low. Investigating possible causes, we find that neither the greater range in WL than in X-ray masses nor the small scatter can be traced back to the parameter settings in the WL analysis. Conclusions. We do not find evidence for a strong (∼40%) underestimate in the X-ray masses, as suggested to reconcile recent Planck cluster counts and cosmological constraints. For high-mass clusters, our measurements are consistent with other studies in the literature. The mass dependent bias, significant at ∼2σ, may hint at a physically different cluster population (less relaxed clusters with more substructure and mergers); or it may be due to small number statistics. Further studies of low-mass high-z lensing clusters will elucidate their mass scaling behaviour.

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Section: Weak Lensing Analysismentioning

confidence: 99%

The 400d Galaxy Cluster Survey weak lensing programme

Israel

Reiprich²,

Erben³

et al. 2014

A&A

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“…However, since fringing acts mostly on small angular scales, its treatment will affect the shapes of the small and faint background galaxies used for weak lensing. To investigate this we obtained a set of 10 archival images of the Deep3 field (Hildebrandt et al 2006), taken with the Wide Field Imager at the 2.2 m MPG/ESO telescope through their I-band filter. As the Deep3 field does not contain any massive clusters it is very well suited for this test.…”

Section: Pre-processingmentioning

confidence: 99%

Weak lensing density profiles and mass reconstructions of the galaxy clusters Abell 1351 and Abell 1995

Holhjem

Schirmer

Dahle

2009

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Aims. The aim of the present work is to study the overall mass distribution of the galaxy clusters Abell 1351 and Abell 1995 using weak gravitational lensing. These clusters have a very different mass structure and dynamical state and are the two extremes from a larger sample of 38 X-ray luminous clusters of similar size and redshift. Methods. We measure the shear values of faint background galaxies and correct for PSF anisotropies using the KSB+ method. Twodimensional mass maps of the clusters are created using a finite-field mass reconstruction algorithm, and verified with aperture mass statistics. The masses inferred from the reconstructions are compared to those obtained from fitting spherically symmetric SIS-and NFW-models to the tangential shear profiles. We discuss the NFW concentration parameters in detail. Results. From the mass reconstructions we infer M 2D (< r 200 )-masses of 11.7 ± 3.1 × 10 14 h −1 70 M and 10.5 ± 2.7 × 10 14 h −1 70 M for Abell 1351 and Abell 1995, respectively. About 3 northeast of the main mass peak of Abell 1351, we detect a significant secondary peak both in the mass reconstruction and from aperture mass statistics. This feature is also traced by cluster members selected by means of their V − I colour, and is therefore likely a real substructure of Abell 1351. From our fits to the tangential shear we infer masses of the order of M 200 ∼ 8−9 × 10 14 h −1 70 M (Abell 1351) and M 200 ∼ 5−6 × 10 14 h −1 70 M (Abell 1995). The concentration parameters remain poorly constrained by our weak lensing analysis.

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“…(2)) of those individual frames we consider to be taken under photometric conditions. As detailed in Hildebrandt et al (2006), corrected zeropoints are a useful consistency check, as they are the same for exposures obtained in photometric conditions. -Coaddition: conforming with THELI standard, SWarp is used to stack ("coadd") images.…”

Section: Discussionmentioning

confidence: 99%

“…The photometric calibration of our data is largely based on the method developed by Hildebrandt et al (2006) but using AB magnitudes, SDSS-like filters, and the SDSS Data Release Six (Adelman-McCarthy et al 2008, DR6) as our calibration catalogue. As mentioned in Sect.…”

Section: Calibration Pipelinementioning

confidence: 99%

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The400dGalaxy Cluster Survey weak lensing programme

Israel¹,

Erben²,

Reiprich³

et al. 2010

A&A

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Context. Studying cosmological structure formation provides insights into all of the universe's components: baryonic matter, dark matter, and, notably, dark energy. Measuring the mass function of galaxy clusters at high redshifts is particularly useful probe for both learning about the history of structure formation and constraining cosmological parameters. Aims. We attempt to derive reliable masses for a high-redshift, high-luminosity sample of galaxy clusters selected from the 400d X-ray selected cluster survey. Weak gravitational lensing allows us to determine masses that can be compared with those inferred from X-rays, forming an independent test. We focus on a particular object, CL0030+2618 at z = 0.50. Methods. Using deep imaging in three passbands acquired using the Megacam instrument at MMT, we show that Megacam is well-suited to measuring gravitational shear, i.e., the shapes of faint galaxies. A catalogue of background galaxies is constructed by analysing the photometric properties of galaxies in the g r i bands. Results. Using the aperture mass technique, we detect the weak lensing signal of CL0030+2618 at 5.8σ significance. We find significant tangential alignment of galaxies out to ∼10 or a distance of >2 r 200 from the cluster centre. The weak lensing centre of CL0030+2618 agrees with several X-ray measurements and the position of the brightest cluster galaxy. Finally, we infer a weak lensing virial mass of M 200 = 7.2 +3.6+2.3 −2.9−2.5 × 10 14 M for CL0030+2618. Conclusions. Despite complications caused by a tentative foreground galaxy group along the line of sight, the X-ray and weak lensing estimates for CL0030+2618 are in remarkable agreement.

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GaBoDS: The Garching-Bonn Deep Survey

Cited by 87 publications

References 14 publications

The 400d Galaxy Cluster Survey weak lensing programme

The 400d Galaxy Cluster Survey weak lensing programme

Weak lensing density profiles and mass reconstructions of the galaxy clusters Abell 1351 and Abell 1995

The400dGalaxy Cluster Survey weak lensing programme

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