! 5934_hopr.prop ! For repeat of lost G190H observations ! ! Proposal 5934, submission 1 ! PI: Dr. Christopher P. O'Dea ! Received Wed Feb 15 18:39:37 EST 1995 ! From: odea@stsci.edu ! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template ! $Id: 5934,v 5.1 1996/09/09 20:15:37 pepsa Exp $ ! ! Refer to the HST Phase II Proposal Instructions to fill this out ! ! Anything after a "!" is ignored, and may be deleted ! ! All keywords with multiple entries are comma delimited except the ! Visit_Requirements and Special_Requirements keywords which can be ! delimited with carriage returns or semi-colons, but not commas ! ! For help call your Program Coordinator: Ray Lucas ! Phone: 410 338-4716 , E-mail: lucas@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Date generated: Sat Dec 17 10:50:42 EST 1994 ! Proposal_Information ! Section 4 Title: A SEARCH FOR UV ABSORPTION LINES IN THE INTRACLUSTER MEDIUM OF ABELL 1030 Proposal_Category: GO Scientific_Category: Galaxies & Clusters Cycle: 5 Investigators PI_name: Dr. Christopher P. O'Dea PI_Institution: Space Telescope Science Institute CoI_Name: Dr. Stefi A. Baum CoI_Institution: Space Telescope Science Institute Contact: ! Y or N (designate at most one contact) CoI_Name: Dr. Craig Sarazin CoI_Institution: University of Virginia Contact: ! Y or N (designate at most one contact) CoI_Name: Dr. Frazer Owen CoI_Institution: National Radio Astronomy Observatory Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) The existence of a cold component of the ICM is suggested by the recent observations of low-energy x-ray absorption (e.g., White Etal 1991). However, the physical state of this cold gas is completely unknown. Abell 1030 (z=0.177) contains the brightest uv source currently known in an Abell cluster -- the quasar B2 1028+313. We propose to seize this unique opportunity to use the bright uv continuum of the quasar to probe the ICM. We will conduct a very sensitive search (with only modest amounts of observing time) for absorption lines from a cold component of the ICM. If the material cannot be detected, very restrictive limits will be placed on the amounts of any such material in the form of molecular gas, atomic gas, or ionized gas up to temperatures of ~ 5 * 10^5 K, i.e., N_H lae 10^14 cm^-2 in atomic hydrogen or N_H_2 lae 10^15 cm^-2 in molecular hydrogen. If strong UV absorption lines are detected, (1) the physical state of this material will be assessed from the species responsible for the absorption (molecules, atoms, or ions); (2) we will determine its kinematics from the velocity structure of the absorption lines; and (3) we will use the set of absorptions to determine better estimates of the column densities, velocity widths, and abundances of the clouds. The detection of a colder component of the ICM would have profound implications for our understanding of (1) cooling flows, (2) Lyman-Alpha forest systems, (3) galaxy formation, and (4) the magnetic field in the ICM. Questions ! Free format text (please update) Observing_Description: Observable absorption lines exist covering the full range of temperatures and ionizations from cold molecular or neutral gas up to very highly ionized gas (O VI). The higher ionization lines would be detected if the X-ray absorption is due to ``warm'' gas at ~10^5 K, as has been suggested in A2256 (Miyaji Etal 1993). At the reshift of the source, the hydrogen Lyman-Alpha line and the H_2 and HD Lyman and Werner bands are within the spectral range covered by the G130H grating. In our integrations, columns smaller than N_H lae 10^14 cm^-2 in atomic hydrogen or N_H_2 lae 10^15 cm^-2 in molecular hydrogen will be detectable. In this proposal, we are taking the point of view that our object is to place the broadest possible observational limits on the cold component of the ICM, without resort to theory. centerline TABLE 1 We are proposing observations with the FOS using the G130H (blue detector), G190H (red detector), and G270H (red detector) gratings through the 1.0 arcsec aperture. The spectral resolution (1300) implies a velocity resolution of 230 km sec. The measured IUE flux F_2000 ~eq 10^-14 ergs s^-1 cm^-2 AA^-1 (Lanzetta Etal 1993) gives the following count rates in the three gratings, (these are wavelength dependent and represent conservative choices). N_Lambda(G130H) = 0.06 countssdiode N_Lambda(G190H) = 0.75 countssdiode N_Lambda(G270H) = 4 countssdiode Since the source is bright enough for a binary acquisition, the overall overheads are low and the proposal is relatively efficient. With 3 orbits at G130H and one orbit each at G190H and G270H, the signal to noise ratio per pixel will be 20 in G130H, 43 in G190H, and 100 in G270H. This implies that the errors in determining the equivalent widths will be less than 0.05 Angstrom in all three gratings. Appendix: Details of the Equivalent Width Calculations The measured excess X-ray absorptions in clusters of galaxies are typically 1--3 * 10^21 cm^-2. For the purposes of estimating the strengths of absorption lines, we will assume N_H = 1.5 * 10^21 cm^-2. As noted above, the bulk of the absorption is actually due to oxygen. Real_Time_Justification: There are no special requirements. We are conducting VLA and ground based optical imaging and spectroscopic observations. We also plan to conduct searches for HI and CO in the ICM. Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name:B21028+313 Alternate_Names:Abell-1030 Description:Cluster of Galaxies, BCM, Rich Cluster, Galaxy, Quasar Position:RA=10H 30M 59.09S +/- 0.01S, DEC=31D 02' 55.6" +/- 0.1", PLATE-ID=01AK ! Most common specification format is ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox:J2000 RV_or_Z:z=0.177 RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux:V=16.75 U=16.40 F-CONT(3000)=1.0E-14 ! Include at least V and B-V Comments: COORDS ARE FROM GASP. ! This is a template for a single visit containing a single exposure ! Repeat exposure and visit blocks as needed Visits ! Section 6 Visit_Number:1 Visit_Requirements: ! Section 7.1 ! Uncomment or copy visit level special requirements needed ! Most of these requirements (including ORIENT) will limit scheduling ! PCS MODE [Fine | Gyro] ! GUIDing TOLerance ! ORIENTation TO ! ORIENTation TO FROM ! ORIENTation TO FROM NOMINAL ! SAME ORIENTation AS ! CVZ ! PARallel ! AFTER [BY [TO ]] ! AFTER ! BEFORE ! BETWEEN AND ! GROUP WITHIN