CLASH: Cluster Lensing And Supernova survey with Hubble An HST Multi-Cycle Treasury Program designed to place new constraints on the fundamental components of the cosmos: dark matter, dark energy, and baryons. Use galaxy clusters as cosmic lenses to reveal dark matter and magnify distant galaxies. WFC3 (UVIS + IR) and ACS will be used to image 25 relaxed clusters in 14 passbands from microns. Total exposure time per cluster: 20 orbits. Clusters chosen based on their smooth and symmetric x-ray surface brightness profiles; simpler lenses to model and minimizes lensing bias. All clusters have T > 5 keV with masses ranging from ~5 to ~30 x M. Redshift range covered: keV with masses ranging from ~5 to ~30 x M. Redshift range covered: 0.18 < z < Multiple epochs enable a z > 1 SN search in the surrounding field (where lensing magnification is low). Marc Postman (P.I.) Matthias Bartelmann Narciso Benitez Larry Bradley Tom Broadhurst Dan Coe Megan Donahue Rosa Gonzales-Delgado Holland Ford Leopoldo Infante Daniel Kelson Ofer Lahav Dani Maoz Elinor Medezinski Leonidas Moustakas Eniko Regoes Adam Riess Piero Rosati Stella Seitz Keiichi Umetsu Arjen van der Wel Wei Zheng Adi Zitrin.

CLASH: An HST Multi-Cycle Treasury Program Simulation of dark matter around a forming cluster (Springel et al. 2005) WHERE R IS THE RESULTING SPATIAL RESOLUTION OF THE DARK MATTER MAP R   Einstein N Arcs Deep HST image of massive cluster

CLASH: An HST Multi-Cycle Treasury Program Both strong AND weak lensing measurements are needed to make accurate constraints on the DM profile. CLASH data will allow us to definitively derive the representative equilibrium mass profile shape and robustly measure the cluster DM mass concentrations and their dispersion as a function of cluster mass and their evolution with redshift.

CLASH: An HST Multi-Cycle Treasury Program Abell 209Abell 383 coreAbell 611Abell 963Abell 2261CLJ MACS MACS MACS MACS MACS MACS RXJ Cutouts of Chandra images of 18 of the 25 CLASH clusters from ACCESS database RXJ RXJ MS-2137 core RXJ RXJ

CLASH: An HST Multi-Cycle Treasury Program RXJ (z = 0.45) SUPRIME CAM ImageACS/WFC Image 28.5'3.4'

CLASH: An HST Multi-Cycle Treasury Program Why 14 filters? Mag distn of multiply lensed arcs in A1689 and CL0024 With 14 filters, 80% photo-z completeness is reached at AB ~26 mag and useful redshift information is available for ~5 times as many lensed objects than would be possible solely from spectroscopically acquired redshifts. Will yield photometric redshifts with rms error of ~2% x (1 + z) for sources down to ~26 AB mag.

CLASH: An HST Multi-Cycle Treasury Program The blue and red solid curves show the expected number of z=8 and z=10 galaxies, respectively, to be discovered behind our 25 clusters as a function of magnitude in the detection band (F110W at z=8 and F140W at z=10). A significant advantage of searching for high-z objects behind strongly lensing clusters is that the lens model can also be used to discriminate between highly-reddened objects and truly distant, high-z objects as the projected position of the lensed image is a strong function of the source redshift. The parallel fields of the cluster survey provide the means to find ~10 SNe Ia at z >1 and would double the number of known SNe Ia at z > 1.2 (and potentially more, the precise number depending on the assumed time delay). CLASH is done

CLASH: An HST Multi-Cycle Treasury Program Footprint of our 2 ORIENT survey. ACS FOV in green, WFC3/IR FOV in red, WFC3/UVIS in magenta. The area of the complete 14-band coverage in the cluster center is 4.07 square arcminutes (88% of the WFC3/IR FOV). ~20 o Cluster Pointings ACS Parallels WFC3 Parallels 6 arcmin. = 2.2 z=0.5 F225W F275WF336WF390WF475W F606W F775WF814W F850LP F105WF110WF125WF140WF160W G800L … as needed Orbits per filter per Cluster WFC3-UVISWFC3-IRACS-WFC Limiting SNR=5 AB magnitudes (for flat spectrum point source) for each passband shown above

CLASH: Top STScI Data/CAL Issues Need accurate calibration frames (i.e., flats) for each of our 14 bands that span the 3 detector systems: WFC3/UVIS, ACS/WFC, WFC3/IRNeed accurate calibration frames (i.e., flats) for each of our 14 bands that span the 3 detector systems: WFC3/UVIS, ACS/WFC, WFC3/IR Need accurate geometric distortion maps in all 14 bands, to allow distortion correction to ~0.1 pixel over the full field of view of each camera. Determining the skew terms will, thus, be essential.Need accurate geometric distortion maps in all 14 bands, to allow distortion correction to ~0.1 pixel over the full field of view of each camera. Determining the skew terms will, thus, be essential. Need an efficient way to correct for ACS CTE. I understand that Jay Anderson has a promising algorithm that is currently being evaluated.Need an efficient way to correct for ACS CTE. I understand that Jay Anderson has a promising algorithm that is currently being evaluated. Rapid access to data via dedicated disk with fast FTP (for SN search).Rapid access to data via dedicated disk with fast FTP (for SN search).