data reduction

From: Kyle S Dawson (KDawson@lbl.gov)
Date: Mon Nov 19 2007 - 22:12:07 PST

  • Next message: Kyle Dawson: "one more set of images"

    Hello All,

    It's been a while since I've sent an email around, and I'd like to update everyone on what has been done for the analysis of the HST data. We just finished our work on the reduction pipeline for the ACS images, a large project undertaken mainly by Nao Suzuki. We are now finishing our photometry for the SN light curves.

    We will not be spending any more time on the data reduction here. The images are in very good shape and can be used for galaxy morphology and photometry. We also posted the tools that we used to generate these images, along with notes pertaining to the reduction. We are now releasing our final stacked images and preprocessed images to all of you so we can finish the SN analysis.

    The details are in the README files but in short, we removed failed exposures, performed both absolute and relative astrometry, and subtracted sky and scattered light. We used the latest multidrizzle (v3.0.0, June 2007) to generate the stacked image.

    Images are getting big. It would be a good use of computers if you could run 'wget' command and retrieve all of the images over the holiday.

    1) Stacked Image can be found on the following website (note the small change in address from the earlier website:
    v45 : 0.05"/pix sampling with default STScI parameters
    v46 : 0.03"/pix sampling with gaussian kernel
    http://supernova.lbl.gov:8083/HSTclusterSN/(cityname)/stacked/README
    http://supernova.lbl.gov:8083/HSTclusterSN/(cityname)/stacked/v45/
    http://supernova.lbl.gov:8083/HSTclusterSN/(cityname)/stacked/v46/

    2) WCS fixed FLT images (reference files and scripts are also posted)
    http://supernova.lbl.gov:8083/HSTclusterSN/(cityname)/wcsfixed_flts/README
    http://supernova.lbl.gov:8083/HSTclusterSN/(cityname)/wcsfixed_flts/v46/

    I encourage you to download the images and check the quality of the data and the README files describing the reduction. Please contact Nao Suzuki (nsuzuki@lbl.gov) or Kyle Dawson (kdawson@lbl.gov) with any questions or comments.

    I also want to take this opportunity to update everyone with our progress in the SN studies. We are nearly finished with the spectroscopic typing of the Ia that were observed from Subaru, VLT, and Keck. We will probably have ~5 spectroscopically confirmed Ia's at high redshift. We plan to type a subset of SNe from this program by the host properties. We have good spectra of each of the E hosts, 5 in clusters and 3 in the field. We will probably write a spectroscopy paper on the typing of SNe and another paper on the host properties of the early type SNe. Right now I am writing the survey paper which describes the clusters, observation strategy, SN search, SN discoveries, and science objectives. We will write up the dust-free cosmology result when the analysis is complete. I hope to have these four papers submitted before the HST proposal deadline in March.

    On that note, I'd like to ask if anyone has made progress in the cluster analysis. As far as I know, the only papers accepted for publication associated with this program are:
    http://arxiv.org/abs/astro-ph/0703381
    http://arxiv.org/abs/0708.3258
    We will most likely be submitting a proposal for the next HST cycle and I think it is essential that we have a wide variety of results to show from the Cycle 14 program. How far have you all gotten in the analysis of the ACS data and when do you expect to have results?

    -- Kyle & Nao



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