Megacam Imaging of the Extended Groth Strip M. Ashby, B. McLeod, J.-S. Huang, P. Barmby, G. Fazio, C. Papovich, S. Willner

Vital Statistics 36 E2V CCDs: 2048x4608 pixels Pixel size: 13.5 microns (0.08 arcsec) Field of view: 25’x25’ Filters: u’ g’ r’ i’ z’ ( nm)

Megacam Performance Gain: 3-4 e-/ADU Read noise: 4-5e- at 200kHz Read time (2x2bin): 25sec including all overheads CCD Temps: -115C to -130C depending on focal plane location

Image Quality PIXEL POSITION FWHM (ARCSEC)

Data Reduction Procedure Basic calibrations done with IRAF/mscred overscan, badpix, bias, flatten i’ and z’ require defringing – either IRAF or custom program wcs solution done with megawcs script

Astrometry RADec RA Err (”) Dec Err (”) Error relative to 2Mass catalog: 0.16”

Astrometry RA Dec RA Err (”) Dec Err (”) Error relative to sdss catalog: 0.09”

Data Reduction Procedure Basic calibrations done with IRAF/mscred overscan, badpix, bias, flatten i’ and z’ require defringing – either IRAF or custom program wcs solution done with megawcs script photometry – not yet fully automated At this point in time: 5% is easy; 1% hard

300mmx300mm Sloan-r filter by Sagem

Photometric Solution Take a sequence of exposures, putting the same star on many different chips Make a master catalog of all the photometry of every star Perform least squares solution minimizing the scatter in the multiple observations of each star

Free Parameters Chip -zero point: c0 + c1 * x + c2 * y -color term: (not yet tested) Exposure –zero point

SDSS Megacam

Goals Construct u-band LF at z=1 for comparison with GALEX low-z data Search for Ly-break dropouts to characterize galaxy population out to z~6

U-band data sec/dither position 5 dithers/pointing 25 pointings Redshifts for LF from DEIMOS

Search for Ly-break dropouts u’ g’ R z=3 (Megacam + Megacam + Subaru) g’ R z’ z=4 (Megacam + Subaru + Megacam) R F814W z’ z=5 (Subaru +HST + Megacam) F814W z’ J z=6 (HST + Megacam +SWIRC) z’ J H (Megacam + SWIRC + SWIRC) getting close to epoch of reionization With IRAC data will be able to draw connections between Ly-break population and IR luminous population