Page   1
    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID 2553c
                                                       Report Date: 09-May-96:17:11
                                                       Version: **********
                                                       Check-in Date: **********

1.Proposal Title:
THE ABSORPTION CROSS-SECTIONS OF NEARBY GALAXIES
------------------------------------------------------------------------------------
2. Scientific Category   3. Proposal For  4. Proposal Type        5. Continuation ID
QUASARS & AGN               GO               1 Long Term yrs         <none>
Sub Category
QUASAR ABSORPTION
------------------------------------------------------------------------------------
6. Principal Investigator   Institution                    Country    Telephone
Dr. J. chris  Blades        SPACE TELESCOPE SCIENCE INST   USA        301-338-4805
ASTRONOMER
------------------------------------------------------------------------------------
7. Abstract
Absorption redshift systems found in the spectra of QSOs with Zabs<Zem are generally
thought to arise in intervening galaxies. They can provide unique information on the
physical conditions and distribution of galaxies at earlier epochs which otherwise
are difficult to study.  Yet, we have little knowledge of the nature and extent of
absorbing gas in external systems via direct observations of QSOs shining through
intervening galaxies.  In this proposal we seek HST time to carry out a statistical
determination of the sizes of halos of nearby galaxies to an equivalent width limit
of 35 mA in C IV and 70 mA in MgII absorption, for direct comparisons with estimates
established from high-redshift QSO systems.  For this purpose, we have assembled
samples of background QSOs close to low-redshift galaxies for both CIV and MgII. In
many cases, these GSO-galaxy pairs were found by ourselves either through searching
UK Schmidt objective prism plates or literature surveys.
------------------------------------------------------------------------------------
8. Scientific Key Words:   NEARBY GALAXIES, ABSORPTION CROSS-SECTIONS, INTERSTELLAR
MEDIUM, ABSORPTION LINES, HALOS, DISKS, QSOS
------------------------------------------------------------------------------------
9. Est obs time (hours) pri: 20.00    par: 0       10. Num targs pri: 6      par: 0
------------------------------------------------------------------------------------
11. Instruments requested:  HRS
------------------------------------------------------------------------------------
------------------------------------------------------------------------------------
                                                                  Page   2
I. GENERAL FORM    Proposal 2553c
PI: Dr. J. chris  Blades
Proposal Title:
THE ABSORPTION CROSS-SECTIONS OF NEARBY GALAXIES
------------------------------------------------------------------------------------

1. Proposers:
Proposers                        Institution                       Country       ESA
------------------------------------------------------------------------------------
Ci Michael V. Penston            ROYAL GREENWICH OBSERVATORY       UK             X
Ci Max Pettini                   ANGLO-AUSTRALIAN OBSERVATORY      AUSTRALIA      X
Pi J. Chris Blades               SPACE TELESCOPE SCIENCE           USA
                                 INSTITUTE
------------------------------------------------------------------------------------
  2. Scientific Justification.
  The narrow metal absorption lines that are commonly found in the spectra of QSOs
 are generally thought to arise in intervening matter associated with galaxies in
 the line of sight.  If this interpretation is correct then QSO spectra provide a
 unique tool to probe the physical conditions and distribution of galaxies at
 earlier epochs, where they cannot otherwise be observed. Yet, we have little
 direct knowledge of the intervening material.  For  example, it is not clear if
 the metal-line systems are formed predominantly in the halos of galaxies broadly
 similar to present-day spirals. Otherinterpretations suggest they may arise (i)
 in galaxies still undergoing gravitational collapse, (ii) in dwarf galaxies,
 (iii) in cooling flows in rich clusters of galaxies, or (iv) in material tidally
 stripped in interacting galaxies (c.f. the Magellanic Stream). The unique
 capabilities of HST allow us to devise a simple observational test of whether the
 metal-line systems arise in galaxies similar to our own. With HST we  shall
 observe directly the absorption properties of nearby galaxies of different
 morphological types and in different environments.  We will be able to recognize
 clearly the nature of the gas producing the metal-lines in QSO spectra and
 subsequently identify the evolutionary effects in the interstellar media of
 galaxies over a significant fraction of the age of the Universe.   Our
 observations will yield the basic data set to make full use of QSOs as probes of
 the early universe; it is precisely the lack of information on metal-line systems
 in present-day galaxies which has limited the interpretation of QSO absorption
 line spectra until now. 2. Goals Of Proposed Program We wish to obtain high-
 resolution spectra of the brightest background QSOs in our sample of QSO-galaxy
 pairs (or groupings) with the aim of measuring the strengths and profiles of
 interstellar C IV and Mg II absorption lines formed in the foreground galaxies.
 We propose to use the R = 20,000 mode of the GHRS.  The good resolution and
 sensitivity of this spectrograph will allow us to distinguish between local
 absorption in our Galaxy and that of the intervening system. (The galactic
 absorption is of considerable interest, in its own right, of course.)  To achieve
 the detection limits necessary we shall bin up the data from 15 to 45 km/sec
 which we consider optimum for the goals of this program. While the measurement of
 line equivalent widths is our main aim, at this resolution we shall be sensitive
 to the velocity structure of the absorption and will be able to deduce ion column
 densities by modelling the line profiles.  Our calculated exposure   times are
 aimed at setting 3 sigma equivalent width limits of 35 mA in C IV and 70 mA in Mg
 II.  These limits are superior to those achieved for surveys of metal-line
 systems in high redshift QSOs and both allow for and provide a stimulus to
 improvement in these data in future years. 3.   TAC Comments: Impressive ground-
 based work was carried out in preparation. Worried about need for HRS to just
 detect lines-these lines may be saturated, so that detailed study of the line
 profiles may not be possible.  The statistical issue may be answered by FOS.
 Recommendations: Eliminate 2 GTO Targets: 0955+326, 1302-102.
                                                                  Page   3
------------------------------------------------------------------------------------
  5. Description of special scheduling requirements.
  I HAVE REQUESTED EVERY ACQ BE DARK TIME.  THIS WAS BECAUSE OF MY CONCERN THAT
 GEOCORONAL LYMAN ALPHA MAY CONTAMINATE THE TARGET ACQUISITION.  I SHALL REQUEST
 THE GHRS TEAM TO LOOK AT THIS PROBLEM SOME MORE.  IF IT BECOMES IMPOSSIBLE TO
 SCHEDULE THIS PROGRAM PLEASE LET ME KNOW.
------------------------------------------------------------------------------------
11. Address Information
Name:  J. CHRIS  BLADES                                    Category: PI
Institution: SPACE TELESCOPE SCIENCE INSTITUTE
Address:  3700 SAN MARTIN DRIVE
City: BALTIMORE                                 State: MD
Zip Code: 21218                                 Country: USA
Telephone: 301-338-4805
Telex (or e-mail): 6849101
------------------------------------------------------------------------------------
TARGET LIST    a) Fixed Targets                                                                    ID = 2553c            [  4]
------------------------------------------------------------------------------------------------------------------------------------
 1 |     2      |           3           |              4             |  5     |   6    |  7  |              8
------------------------------------------------------------------------------------------------------------------------------------
Tar|   Target   |         Target        |            Target          |Coord   | Radial |Acqui|FLX|     Flux data
No |    Name    |       Description     |           Position         |Eqnx    |  Vel.  |Prblm|REF|
   |            |                       |                            |        |        |     |   |
------------------------------------------------------------------------------------------------------------------------------------
1   1211+143     QSO                     RA= 12H 14M 17.68S +/- 0.3", 2000     Z=0.085        1   B=14.63
                                         DEC= +14D 03' 12.3" +/- 0.3"
     Comments: PLATE-ID=01TJ
------------------------------------------------------------------------------------------------------------------------------------
2   0219+428     QSO                     RA= 02H 22M 39.62S +/- 0.3", 2000     Z=0.444        1   V=15.5
                                         DEC= +43D 2' 7.98" +/- 0.3"
     Comments: PLATE-ID = O1WN
------------------------------------------------------------------------------------------------------------------------------------
3   1004+130     QSO                     RA= 10H 7M 26.10S +/- 0.3",  2000     Z=0.241        1   V=15.15
                                         DEC= +12D 48' 56.0" +/- 0.3"
     Comments: PLATE-ID = 028W
------------------------------------------------------------------------------------------------------------------------------------
4   1219+755     QSO                     RA= 12H 21M 44.04S +/- 0.3", 2000     Z=0.07         1   V=14.5
                                         DEC= +75D 18' 38.2" +/- 0.3"
     Comments: PLATE-ID = 01G5
------------------------------------------------------------------------------------------------------------------------------------
5   1341+258     QSO                     RA= 13H 43M 56.7S +/- 0.3",  2000     Z=0.087        1   B=15.93
                                         DEC= +25D 38' 46.9" +/- 0.3"
     Comments: CHECK CHART,GASP PLATE 01GF
------------------------------------------------------------------------------------------------------------------------------------
EXPOSURE LOGSHEET                                                                                  ID = 2553c            [  5]
------------------------------------------------------------------------------------------------------------------------------------
 1      |   2   |      3    |  4   |   5   |   6   |    7   |   8   |       9       |10 |   11  |   12    |13 |14|        15
------------------------------------------------------------------------------------------------------------------------------------
  Line  |  Seq  |   Target  |Instr | Oper. | Aper  |Spectral|Central|   Optional    |Num|  Time |   S/N   |Flx|Pr|     Special
 Number | Name  |    Name   |Config| Mode  |or FOV |Element |Waveln.|  Parameters   |Exp|       |Rel. Time|Ref|  |   Requirements
------------------------------------------------------------------------------------------------------------------------------------
1                1211+143    HRS    ACQ     2.0     MIRROR-N2        SEARCH-SIZE=3   1   9S                1   1  CYCLE 1
                                                                     FAINT=1300                                   ONBOARD ACQ FOR 2
     Comments: SEE GF #5 ABOUT DARK TIME/
               SCHEDULING PROBLEMS.
------------------------------------------------------------------------------------------------------------------------------------
2                1211+143    HRS    ACCUM   2.0     G270M    2796-   COMB=FOUR       1   900S    10        1   1  CYCLE 1
                                                             2825    FP-SPLIT=TWO                900S
                                                                     STEP-PATT=DEF
------------------------------------------------------------------------------------------------------------------------------------
3                0219+428    HRS    ACQ     2.0     MIRROR-N2        SEARCH-SIZE=3   1   9S                1   1  CYCLE 1
                                                                     FAINT=350                                    ONBOARD ACQ FOR 4-
                                                                                                                  5
                                                                                                                  DARK TIME
------------------------------------------------------------------------------------------------------------------------------------
4                0219+428    HRS    ACCUM   2.0     G270M    2796-   COMB=FOUR       5   1152S   10        1   1  CYCLE 1
                                                             2809    FP-SPLIT=TWO                5760S
                                                                     STEP-PATT=DEF
------------------------------------------------------------------------------------------------------------------------------------
5                0219+428    HRS    ACCUM   2.0     G270M    2852-   COMB=FOUR       5   1152S   10        1   1  CYCLE 1
                                                             2870    FP-SPLIT=TWO                5760S
                                                                     STEP-PATT=DEF
------------------------------------------------------------------------------------------------------------------------------------
6                1004+130    HRS    ACQ     2.0     MIRROR-N2        SEARCH-SIZE=3   1   9S                1   1  CYCLE 1
                                                                     FAINT=700                                    ONBOARD ACQ FOR 7-
                                                                                                                  8
------------------------------------------------------------------------------------------------------------------------------------
7                1004+130    HRS    ACCUM   2.0     G160M    1548-   COMB=FOUR       13  914S    10        1   1  CYCLE 1
                                                             1553    FP-SPLIT=TWO                11882S
                                                                     STEP-PATT=DEF
------------------------------------------------------------------------------------------------------------------------------------
8                1004+130    HRS    ACCUM   2.0     G270M    2796-   COMB=FOUR       3   960S    10        1   1  CYCLE 1
                                                             2806    FP-SPLIT=TWO                2880S
                                                                     STEP-PATT=DEF
------------------------------------------------------------------------------------------------------------------------------------
9                1219+755    HRS    ACQ     2.0     MIRROR-N2        SEARCH-SIZE=3   1   9S                1   1  CYCLE 1
                                                                     FAINT=1830                                   ONBOARD ACQ FOR 10
                                                                                                                  -11
------------------------------------------------------------------------------------------------------------------------------------
10               1219+755    HRS    ACCUM   2.0     G270M    2796-   COMB=FOUR       3   960S    10        1   1  CYCLE 1
                                                             2817    FP-SPLIT=TWO                2880S
                                                                     STEP-PATT=DEF
------------------------------------------------------------------------------------------------------------------------------------
11               1219+755    HRS    ACCUM   2.0     G160M    1548-   COMB=FOUR       13  920S    10        1   1  CYCLE 1
                                                             1558    FP-SPLIT=TWO                11960S
                                                                     STEP-PATT=DEF
------------------------------------------------------------------------------------------------------------------------------------
12               1341+258    HRS    ACQ     2.0     MIRROR-N2        SEARCH-SIZE=3   1   9S                1   1  CYCLE 1
                                                                     FAINT=400                                    ONBOARD ACQ FOR 13
                                                                                                                  -14
                                                                                                                  DARK TIME
------------------------------------------------------------------------------------------------------------------------------------
EXPOSURE LOGSHEET                                                                                  ID = 2553c            [  6]
------------------------------------------------------------------------------------------------------------------------------------
 1      |   2   |      3    |  4   |   5   |   6   |    7   |   8   |       9       |10 |   11  |   12    |13 |14|        15
------------------------------------------------------------------------------------------------------------------------------------
  Line  |  Seq  |   Target  |Instr | Oper. | Aper  |Spectral|Central|   Optional    |Num|  Time |   S/N   |Flx|Pr|     Special
 Number | Name  |    Name   |Config| Mode  |or FOV |Element |Waveln.|  Parameters   |Exp|       |Rel. Time|Ref|  |   Requirements
------------------------------------------------------------------------------------------------------------------------------------
13               1341+258    HRS    ACCUM   2.0     G270M    2850-   COMB=FOUR       4   1080S   10        1   1  CYCLE 1
                                                             2858    FP-SPLIT=TWO                4320S
                                                                     STEP-PATT=DEF
------------------------------------------------------------------------------------------------------------------------------------
14               1341+258    HRS    ACCUM   2.0     G160M    1578-   COMB=FOUR       12  900S    7         1   1  CYCLE 1
                                                             1581    FP-SPLIT=TWO                10800S
                                                                     STEP-PATT=DEF
------------------------------------------------------------------------------------------------------------------------------------
            Summary Form for Proposal 2553c                                                                              [  7]

  Item                          Used in this proposal
------------------------------------------------------------------------------------------------------------------------------------
  Configurations                HRS
------------------------------------------------------------------------------------------------------------------------------------
  Opmodes                       ACQ ACCUM
------------------------------------------------------------------------------------------------------------------------------------
  Optional Parameters           SEARCH-SIZE=3 FAINT=1300 COMB=FOUR FP-SPLIT=TWO STEP-PATT=DEF FAINT=350 FAINT=700 FAINT=1830
                                FAINT=400
------------------------------------------------------------------------------------------------------------------------------------
  Proposal for                  GO
------------------------------------------------------------------------------------------------------------------------------------
  S/C Hours                     20.00
------------------------------------------------------------------------------------------------------------------------------------
  Scientific Category           QUASARS & AGN
------------------------------------------------------------------------------------------------------------------------------------
  Scientific Sub-category       QUASAR ABSORPTION
------------------------------------------------------------------------------------------------------------------------------------
  Special Requirements          CYCLE 1; ONBOARD ACQ FOR 2; CYCLE 1 ONBOARD ACQ FOR 4-5; DARK TIME ONBOARD ACQ FOR 7-8 ONBOARD ACQ
                                FOR 10-11 ONBOARD ACQ FOR 13-14;
------------------------------------------------------------------------------------------------------------------------------------
  Spectral Elements             MIRROR-N2 G270M G160M
------------------------------------------------------------------------------------------------------------------------------------
  Target Names                  1211+143 0219+428 1004+130 1219+755 1341+258
------------------------------------------------------------------------------------------------------------------------------------