TY - JOUR
T1 - CLASH
T2 - Photometric redshifts with 16 HST bands in galaxy cluster fields
AU - Jouvel, S.
AU - Host, O.
AU - Lahav, O.
AU - Seitz, S.
AU - Molino, A.
AU - Coe, D.
AU - Postman, M.
AU - Moustakas, L.
AU - Benìtez, N.
AU - Rosati, P.
AU - Balestra, I.
AU - Grillo, C.
AU - Bradley, L.
AU - Fritz, A.
AU - Kelson, D.
AU - Koekemoer, A. M.
AU - Lemze, D.
AU - Medezinski, E.
AU - Mercurio, A.
AU - Moustakas, J.
AU - Nonino, M.
AU - Scodeggio, M.
AU - Zheng, W.
AU - Zitrin, A.
AU - Bartelmann, M.
AU - Bouwens, R.
AU - Broadhurst, T.
AU - Donahue, M.
AU - Ford, H.
AU - Graves, G.
AU - Infante, L.
AU - Jimenez-Teja, Y.
AU - Lazkoz, R.
AU - Melchior, P.
AU - Meneghetti, M.
AU - Merten, J.
AU - Ogaz, S.
AU - Umetsu, K.
N1 - Funding Information:
S.J. and O.H. acknowledge STFC-supported Post-doctoral Felowships at UCL, O.L. acknowledges a Royal Society Wolfson Research Merit Award, a Leverhulme Senior Research Fellowship and an Advanced ERC Grant. S.J. is supported by the Spanish Science MinistryAYA2009-13936 Consolider-Ingenio CSD2007-00060, project2009SGR1398 from Generalitat de Catalunya and by the European Commissions Marie Curie Initial Training Network CosmoComp (PITN- GA-2009-238356). The Dark Cosmology Centre is funded by the Danish National Research Foundation. S. Seitz acknowledges support from the Transregional Collaborative Research Centre TRR 33 “The Dark Universe” and from the DFG cluster of excellence “Origin and Structure of the Universe”. This research is partially supported by PRIN INAF 2010: “Architecture and Tomography of Galaxy Clusters”. A.F. acknowledges support from INAF through PRIN 2008 and 2010 grants. Support for A.Z. is provided by NASA through Hubble Fellowship grant #HST-HF-51334.01-A awarded by STScI. Part of this work was also supported by contract research “Internationale Spitzenforschung II/2-6” of the Baden Württemberg Stiftung. A.M. acknowledges support from AYA2006-14056BES-2007-16280.
PY - 2014/2
Y1 - 2014/2
N2 - Context. The Cluster Lensing And Supernovae survey with Hubble (CLASH) is a Hubble Space Telescope (HST) Multi-Cycle Treasury programme that observes 25 massive galaxy clusters, 20 of which were X-ray-selected to preferably choose dynamically relaxed clusters, and 5 additional "high magnification" clusters, which were selected based on their optical lensing properties. CLASH aims to study the dark matter distribution of the clusters and find magnified high-redshift galaxies behind them. CLASH observations were carried out in 16 bands from UV to NIR to derive accurate and reliable estimates of photometric redshifts. Aims. We present the CLASH photometric redshifts using 16 HST bands and study the photometric redshift accuracy including a detailed comparison between photometric and spectroscopic redshifts for the strong lensing arcs using the measurements from the cluster MACSJ1206.2-0847. Methods. We used the publicly available Le Phare and BPZ photometric redshift estimation codes on 17 CLASH galaxy clusters for which the full photo-z data processing had been completed at the time of this analysis, and derive an estimate of the CLASH photo-z accuracy. Results. Using Le Phare code for objects with a S/N ≥ 10, we reach a precision of 3%(1 + z) for the strong lensing arcs, which is reduced to 2.4%(1 + z) after removing outliers. For galaxies in the cluster field, the corresponding values are 4%(1 + z) and 3%(1 + z). Using mock galaxy catalogues, we show that 3%(1+z) precision is what is expected using the baseline sky substraction algorithm when taking into account extinction from dust, emission lines, and the finite range of SEDs included in the photo-z template library. An improved method for estimating galaxy colours that yields more accurate photometric redshifts will be explored in a forthcoming paper. We study photo-z results for different aperture photometry techniques and find that the SExtractor isophotal photometry works best. We check the robustness of the arcs photo-z results by rederiving the input photometry in the case of MACS1206. We describe and release a photometric redshift catalogue of the MACS1206 cluster we study. Conclusions. Our photo-z codes give similar results for the strong lensing arcs, as well as for galaxies of the cluster field. Results are improved when optimizing the photometric aperture shape that shows an optimal aperture size around 1″ radius, giving results that are equivalent to isophotal photometry. Tailored photometry of the arcs improves the photo-z results by showing more consistency between the different arcs of the same strong lensing system.
AB - Context. The Cluster Lensing And Supernovae survey with Hubble (CLASH) is a Hubble Space Telescope (HST) Multi-Cycle Treasury programme that observes 25 massive galaxy clusters, 20 of which were X-ray-selected to preferably choose dynamically relaxed clusters, and 5 additional "high magnification" clusters, which were selected based on their optical lensing properties. CLASH aims to study the dark matter distribution of the clusters and find magnified high-redshift galaxies behind them. CLASH observations were carried out in 16 bands from UV to NIR to derive accurate and reliable estimates of photometric redshifts. Aims. We present the CLASH photometric redshifts using 16 HST bands and study the photometric redshift accuracy including a detailed comparison between photometric and spectroscopic redshifts for the strong lensing arcs using the measurements from the cluster MACSJ1206.2-0847. Methods. We used the publicly available Le Phare and BPZ photometric redshift estimation codes on 17 CLASH galaxy clusters for which the full photo-z data processing had been completed at the time of this analysis, and derive an estimate of the CLASH photo-z accuracy. Results. Using Le Phare code for objects with a S/N ≥ 10, we reach a precision of 3%(1 + z) for the strong lensing arcs, which is reduced to 2.4%(1 + z) after removing outliers. For galaxies in the cluster field, the corresponding values are 4%(1 + z) and 3%(1 + z). Using mock galaxy catalogues, we show that 3%(1+z) precision is what is expected using the baseline sky substraction algorithm when taking into account extinction from dust, emission lines, and the finite range of SEDs included in the photo-z template library. An improved method for estimating galaxy colours that yields more accurate photometric redshifts will be explored in a forthcoming paper. We study photo-z results for different aperture photometry techniques and find that the SExtractor isophotal photometry works best. We check the robustness of the arcs photo-z results by rederiving the input photometry in the case of MACS1206. We describe and release a photometric redshift catalogue of the MACS1206 cluster we study. Conclusions. Our photo-z codes give similar results for the strong lensing arcs, as well as for galaxies of the cluster field. Results are improved when optimizing the photometric aperture shape that shows an optimal aperture size around 1″ radius, giving results that are equivalent to isophotal photometry. Tailored photometry of the arcs improves the photo-z results by showing more consistency between the different arcs of the same strong lensing system.
KW - Galaxies: clusters: general
KW - Galaxies: distances and redshifts
UR - http://www.scopus.com/inward/record.url?scp=84894127885&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84894127885&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201322419
DO - 10.1051/0004-6361/201322419
M3 - Article
AN - SCOPUS:84894127885
SN - 0004-6361
VL - 562
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A86
ER -