5784( 0) - 07/18/95 17:58 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5784 Version: ********** Check-in Date: ********** 1.Proposal Title: Ionization Equilibrium in BALQSOs ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Quasars AR 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Nahum Arav University of Colorado CoI: Kirk Korista University of Kentucky N CoI: Mitchell Begelman University of Colorado N CoI: Michael Shull University of Colorado N CoI: Martijn de Kool Max-Planck Institute N ------------------------------------------------------------------------------------ 6. Abstract About 10\ resonance lines of ions from abundant species. One of the prominent questions in the study of these objects is: What is the ionization equilibrium that gives rise to the observed BALs? For answering this question, ground-based spectra are of limited value. The main problem is that only about four BALs are typically observed from the ground (even in high redshift QSOs), and each arises from a different element. Therefore, attempts at determining the ionization equilibrium from ground based spectra are foiled by too many free parameters. However, the HST (through UV spectroscopy) has already observed many more BALs in a few objects, and combined with ground-based spectra we now have data on BALs from two to four ions for each of the CNO elements. This situation can dramatically improve our understanding of the ionization equilibrium. We propose to perform a detailed analysis on the BALQSO data in the HST archive, in order to extract the column densities and attempt to determine the optical depth as a function of velocity for all these BALs. We then plan to use three of the available ionization codes to infer the intrinsic shape of the ionizing continuum, the ionization parameter and the abundance of different elements. ------------------------------------------------------------------------------------ Observations Description ------------------------ Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 5784( 0) - 07/18/95 17:58 - [ 2] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5784( 0) - 07/18/95 17:58 - [ 3] Summary Form for Proposal 5784 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category AR ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Quasars ------------------------------------------------------------------------------------------------------------------------------------