1. July 21, 2004 Natalia Kuznetsova NICMOS Analysis of ACS04-076 ● Data Inventory ● Calibration ● Bad pixel mask ● Extracting photometry ● Next steps 1

2. July 21, 2004 Natalia Kuznetsova Data Inventory Date Images 4/16 F8010 5/11 F9010 5/23 Fa010, fa020, fa030 Date Images 4/16 F8020, f8030 5/5 F6010, f6020 5/17 F7010, f7020, f7030 J-band H-band 2

3. July 21, 2004 Natalia Kuznetsova Calibration ●Process the data with: 1. Vitaliy's version of calnica It does everything that the standard calnica does (dark subtraction, flatfielding, etc.) and in addition features an improved cosmic rejection algorithm 2. Pedsky for sky and pedestal subtraction 3. Drizzling (or mosaicing with calnicb) is only used for cross-checks Pipeline-processed data Custrom-processed data 3

4. July 21, 2004 Natalia Kuznetsova Bad pixel mask ● Using Vitaliy's ROOT-based software that finds outliers (the pixels that are consistently – over many images – too high or too low). ● For this purpose, I've used ~20 files from the HST data archives, covering the month of April. 4

5. July 21, 2004 Natalia Kuznetsova Photometry ● Because the supernova is dim, located on the outskirts of a galaxy, and because the quality of NICMOS images is low, aperture photometry will not produce good results ● So, try PSF photometry with Vitaliy's ROOT- based software. – Use TinyTim v6.3 for PSF modeling – Simple linear (in x and y) model for the background for now – Account for sky errors – Perform a fit for the SN flux, position, and the background parameters “Tiny Tim” PSF in F110W 5

6. July 21, 2004 Natalia Kuznetsova J-band results ● For now, only have J-band points – There appear to be problems with some fits – no reason to go on with H-band until they are sorted out – Here, N/A means the fit didn't converge 6

7. July 21, 2004 Natalia Kuznetsova Fit residuals Good fit (4/16 #1) Bad fit (5/11 #1) 7

8. July 21, 2004 Natalia Kuznetsova VERY PRELIMINARY lightcurve! If you trust these very preliminary results in a single band ( which you shouldn't ), this SN appears to be more consistent with z ~ 1.4. 8

9. July 21, 2004 Natalia Kuznetsova Next steps ● Understand why the fit fails on a few points. – Perhaps the problem is inaccurate initial estimate of the SN position on late epoch images – perhaps using SHIFTFIND will help ● A quick check using shifts from the header shows that the initial estimates are reasonable, however ● Refine the background model ● Run the fitter on combined (drizzled) images, check for consistency 9