5785( 0) - 07/18/95 17:59 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5785 Version: ********** Check-in Date: ********** 1.Proposal Title: Uniform Analysis of the LyAlpha Forest from z=0 to z=5 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Quasars AR 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Jill Bechtold Steward Observatory CoI: Adam Dobrzycki Center for Astrophysics N ------------------------------------------------------------------------------------ 6. Abstract We propose to combine the available FOS data on the LyAlpha forest at low redshift with our extensive collection of spectra of the LyAlpha forest in about 100 high redshift quasars obtained with ground-based telescopes. There appears to be a change in both the number and rate of evolution of the LyAlpha clouds when samples with z>2.5 are compared to samples with z<1. This change may indicate a change in the population which is being probed, from clouds on the outskirts of galaxies at low z, to truly primordial intergalactic clouds at high redshifts. The statistical significance of this result depends on which ground-based sample the HST results are compared to. There is reason to suspect that all statistical results on the LyAlpha forest suffer from subtle systematic errors from line-blending, the specific analysis technique used, and the non-uniformity in signal-to-noise and spectral resolution of existing data. We propose to treat the LyAlpha forest in a uniform way by (a) using the software that the QSO Absorption Line Key Project developed to analyze our high redshift spectra, (b) using our analysis programs on the Key Project data, and (c) applying our Monte Carlo analysis techniques to all available data to derive evolutionary parameters that are based on objectively derived statistics instead of line lists. In addition we will use archived data on quasars that are not part of the Key project sample to approximately double the number of low redshift LyAlpha lines catalogued. ------------------------------------------------------------------------------------ Observations Description ------------------------ Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 5785( 0) - 07/18/95 17:59 - [ 2] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5785( 0) - 07/18/95 17:59 - [ 3] Summary Form for Proposal 5785 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category AR ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Quasars ------------------------------------------------------------------------------------------------------------------------------------