! Proposal 6717, submission 1 ! PI: Christopher O'Dea ! Received Fri Feb 9 16:42:06 EST 1996 ! From: odea@stsci.edu ! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template ! $Id: 6717,v 6.1 1996/11/27 14:59:29 pepsa Exp $ ! Hubble Space Telescope Cycle 6 (1996) Phase II Proposal Template ! $Id: 6717,v 6.1 1996/11/27 14:59:29 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: Lucas ! Phone: 410-338-4716 , E-mail: lucas@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Name of Phase I Proposal: archive-0846.odea.prop ! Date generated: Fri Dec 22 16:39:56 EST 1995 ! Proposal_Information ! Section 4 Title: UV Spectroscopy of the Luminous Cooling Flow Nebula in A2597 Proposal_Category: GO Scientific_Category: GALAXIES & CLUSTERS Cycle: 6 Investigators PI_name: Christopher O'Dea PI_Institution: Space Telescope Science Institute CoI_Name: Stefi Baum CoI_Institution: Space Telescope Science Institute Contact: ! Y or N (designate at most one contact) CoI_Name: Megan Donahue CoI_Institution: Space Telescope Science Institute Contact: ! Y or N (designate at most one contact) CoI_Name: Jack Gallimore CoI_Institution: Max-Planck-Institute fuer Extraterrestrische Physik Contact: ! Y or N (designate at most one contact) CoI_Name: Anton Koekemoer CoI_Institution: Institut d'Astrophysique de Paris Contact: ! Y or N (designate at most one contact) CoI_Name: Brian McNamara CoI_Institution: Harvard/Smithsonian Center for Astrophysics Contact: ! Y or N (designate at most one contact) CoI_Name: Craig Sarazin CoI_Institution: University of Virginia Contact: ! Y or N (designate at most one contact) CoI_Name: Mark Voit CoI_Institution: Space Telescope Science Institute Contact: ! Y or N (designate at most one contact) CoI_Name: Mike Wise CoI_Institution: Massachusetts Institute of Technology Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) We propose UV spectroscopy with the FOS of the emission line nebula in the luminous cooling flow cluster Abell 2597. These observations will provide the first detection of UV lines (other than Ly-alpha\ which was detected by IUE) in the spectrum of a cooling flow nebula. This will allow us to determine line ratios (or limits) on lines which are diagnostic for (1) gas cooling from the hot ICM, (2) gas in shocks, (3) gas irradiated by the EUV and soft X-rays from cooling gas, gas in mixing layers, or shocked gas, (4) gas energized by cosmic ray heating. We will determine the source of ionization for the cooling flow nebula and investigate its relationship to the ICM and the cooling flow using our groundbased optical, ISO, ROSAT, and VLA and VLBA HI observations. Questions ! Free format text (please update) Observing_Description: We propose to obtain FOS UV spectroscopy of the emission line nebula in Abell 2597. We will cover the spectrum from 1140 to 4800 Angstrom using the G160L, G270H, and G400H gratings on the blue side. We will stay on the blue side since the blue side sensitivity is sufficient for our purposes and to avoid the overhead penalty of the side switch. The G160L and G270H give us coverage of the important diagnostic UV lines from Ly -alpha through MgII2800. The G400H exposure is only a few minutes and bridges the gap between the UV and our optical ground based spectra and allows us to match the flux scales and determine accurate ratios of optical to UV lines. In order to increase thoughput in the UV (and at the cost of spectral resolution), we are using the 1.0 arcsec aperture and the G160L grating. The loss of spectral resolution is not a problem, since even at 18.5 Angstrom resolution the majority of the diagnostic lines are unblended. Resolution of the individual line profiles is not necessary for this project. In order to optimise the spectroscopy, we include one orbit to obtain a narrow band image of OII3727 in the F410M filter which will be used as an ``Early-Acq" image to locate a large bright filament or knot in the target area of the emission line nebula. However if the McNamara Etal proposal is granted time for their narrow band image of OII, we will forgo this exposure and return that part of our allocation. Because of its huge equivalent width (270 Angstrom at the nucleus), the O II emission line will dominate the flux in this filter. At O II, the galaxy continuum is 21.4 mag/arcsec^2 and the sky background is 23.1 mag/arcsec^2. The nuclear O II surface brightness is 4.8 * 10^-15 erg s^-1 cm^-2 arcsec^-2. We predict a S/N of 10 in 9 WF pixels in about 45 minutes, or 1 orbit. Continuum subtraction will probably not be necesssary, but could be done using the U-band image of McNamara Etal (if obtained) or the F450W image from Trauger-6228 which is already in the archive. In order to detect a full range of UV diagnostic lines we need to reach a 5Sigma detection threshold of 2.0times10^-16 ergs s\mone\ cm\mtwo\ Angstrom\mone\ which is about one-third of H Beta. We illustrate the sensitivity of the observations for a couple critical lines. At the position of the CIV 1550 line (redshifted to 1677 Angstrom\ in the G160L), the flux of 2.0times10^-16 ergs s^-1 cm^-2 Angstrom\mone\ gives a count rate of 0.014 counts/s/diode which is twice the dark count. Then, the time required to reach a signal-to-noise of 5 is 2700s. The MgII line in the G270H spectrum which is redshifted to 3027 Angstrom would produce a count rate of about 0.04 counts/s/diode and a signal-to-noise of 5 in about 10 minutes. The sensitivity of the G400H grating is similar. Adopting a 52 minute visibility for A2597, we plan to structure our orbits in the following way. First orbit: 3-stage peakup target acquisition on the galaxy nucleus. Second orbit: 6 min GS reacq, 40 min FOS/blue G160L ACCUM, 6 min overhead. Third orbit: 6 min GS reacq, 10 min G160L ACCUM, 10 min G270H ACCUM, 8 min G400H ACCUM, 18 min total overhead for the three exposures. We will repeat the exposures in orbits 2 and 3 at two off nuclear positions: one on the bright blue lobe to the northeast and the second to the north west away from the blue lobe. Thus we request 1 orbit for target acquistion and 6 orbits for spectroscopy. Real_Time_Justification: None. We have obtained deep optical spectra at Palomar Observatory (Figure 2). We will also use the continuum imaging data from the cycle 6 McNamarra Etal proposal if that is approved and will use the archival F450W and F702W WFPC2 data from Trauger GTO-6228. We also plan to obtain 21cm HI observations with the VLBA to study the fine scale structure in the HI. We will combine all these data with our UV spectroscopy and ROSAT and radio continuum data to perform the definitive study of this archetypal cooling flow nebula. The currently existing radio observations (Sarazin Etal 1995) and follow on higher resolution radio observations (MERLIN) we will propose, will also provide a powerful independent constraint on the ionization of the gas. The spatial co-incidence of the radio emission with the blue lobes suggests that the radio jet has some affect on the optical appearance of the source. Our UV/optical HST line diagnostics, to be taken at three spatial locations in the source, coupled with the radio data will allow us to investigate the radio-optical continuum-emission line correlations. If shocks dominate the ionization we expect to see line ratios diagnostic of shocks where the radio jets are bright. On the other hand, in places where the radio emission is less bright, the influence of the radio source may shift to providing cosmic rays which energize the clouds - thus the emission line diagnostics may vary on and off the bright radio structure. We will look for such variations and their correlation with the radio morphology itself. We will compare the energetics of the radio lobes with the energetics required for shocks or cosmic ray ionization models, as implied by the emission-line data that we propose to obtain. We have listed A2597 as a first priority target for ISO. We will observe the fine structure lines of Si II35Mu, O I63Mu, C II158Mu and the continuum at 60, 90, 160, and 200 Mu. These data will be combined with our groundbased optical and HST UV spectroscopy to cover a wide range of diagnostic lines. Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number:1 Target_Name:A2597-NUC Alternate_Names: Description:GALAXY, Elliptical, Radio Galaxy, CLUSTER OF GALAXIES, Rich Cluster, BCM Position:RA=23H 25M 19.73S +/- 0.2S, ! Most common format is DEC=-12D 7' 26.9" +/- 1", ! RA=0H 0M 0.00S +/- 0S, PLATE-ID=00WQ ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox:J2000.0 RV_or_Z:Z=0.0821 RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: ! Include at least V and B-V B-V = 1.08 SURF(V)=19.7 Comments: Fixed_Targets ! Section 5.1 Target_Number:2 Target_Name:A2597-NUC-FOS Alternate_Names: Description:GALAXY, Elliptical, Radio Galaxy, CLUSTER OF GALAXIES, Rich Cluster, BCM Position:RA=23H 25M 19.735S +/- 0.05S, ! Most common format is DEC=-12D 7' 26.41" +/- 0.5", ! RA=0H 0M 0.00S +/- 0S, PLATE-ID=00WQ ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox:J2000.0 RV_or_Z:Z=0.0821 RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: ! Include at least V and B-V B-V = 1.08 SURF(V)=19.7 Comments: Target_Number:3 Target_Name:A2597-LOBE Alternate_Names: Description:GALAXY, Elliptical, Radio Galaxy, CLUSTER OF GALAXIES, Rich Cluster, BCM Position:RA=23H 25M 19.835S +/- 0.05S, ! Most common format is DEC=-12D 7' 23.64" +/- 0.5", ! RA=0H 0M 0.00S +/- 0S, PLATE-ID=00WQ ! DEC=0D 0' 0.0" +/- 0", Equinox:J2000.0 RV_or_Z:Z=0.0821 RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: ! Include at least V and B-V B-V = 1.08 SURF(V)=19.7 Comments:position updated sept 6 1996 Target_Number:4 Target_Name:A2597-KNOT Alternate_Names: Description:GALAXY, Elliptical, Radio Galaxy, CLUSTER OF GALAXIES, Rich Cluster, BCM Position:RA=23H 25M 19.871S +/- 0.05S, ! Most common format is DEC=-12D 7' 26.87" +/- 0.5", ! RA=0H 0M 0.00S +/- 0S, PLATE-ID=00WQ ! DEC=0D 0' 0.0" +/- 0", Equinox:J2000.0 RV_or_Z:Z=0.0821 RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: ! Include at least V and B-V B-V = 1.08 SURF(V)=19.7 Comments:position updated sept 6 1996 Target_Number:5 Target_Name:A2597-STAR Alternate_Names: Description:STAR Position:RA=23H 25M 18.328S +/- 0.05S, ! Most common format is DEC=-12D 7' 48.93" +/- 0.5", ! RA=0H 0M 0.00S +/- 0S, PLATE-ID=00WQ ! DEC=0D 0' 0.0" +/- 0", Equinox:J2000.0 RV_or_Z:Z=0.0 RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux: ! Include at least V and B-V V-I = 2.3 V=15.0 Comments:position updated sept 6 1996 ! 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 ! DROP TO GYRO IF NECESSARY [NO REACQuisition] ! ORIENTation TO ! ORIENTation TO FROM ! ORIENTation TO FROM NOMINAL ! SAME ORIENTation AS ! CVZ ! PARallel ! SCHEDulability ! AFTER [BY [TO ]] ! AFTER ! BEFORE ! BETWEEN AND ! GROUP WITHIN