5974(  4) - 12/12/95 15:54  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      5974
                                                       Version: 4
                                                       Check-in Date: **********

1.Proposal Title:
The Evolution of Radio-Loud Quasars
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2. Scientific Category   3. Proposal For  4. Cycle
Quasars                     GO               5
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5. Investigators
                                                                                     Contact?
    PI: Matthew Lehnert                   Institute of Geophysics and Planetary
                                          Physics
   CoI: Wil van Breugel                   Institute of Geophysics and Planetary         N
                                          Physics, LLNL, 7000 East Ave., L-413,
   CoI: Vijay Kapahi                      National Center for Radio Astrophysics,       N
                                          TIFR, Pune 411 007, India
   CoI: Timothy Heckman                   Dept. of Physics & Astron, Johns Hopkins      N
                                          University, Baltimore, MD 21218
   CoI: Patrick McCarthy                  Carnegie Observatories, 813 Santa Barbara     N
                                          St., Pasadena, CA 91101

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6. Abstract

The co-moving space density of highly luminous quasars has decreased by roughly 3
orders of magnitude from z=2-3 to the current epoch. Understanding the physical
processes responsible for this decrease could profoundly influence how we think the
universe and galaxies have evolved.  We therefore propose to conduct a broad-band
imaging survey of the host galaxies of 20 radio-loud quasars over a large redshift
range (~0.3 to 2.7) using WFPC2.  HST observations are crucial for separating the
``blinding'' nuclear emission (AGN) from that of the extended ``fuzz'' (parent
galaxy). The quasars are selected from a complete sample and span a range of radio
properties. Filters are chosen such that all the quasars will be imaged at rest-
wavelengths near 2000 Angstrom .  These data will allow us to study the properties
and evolution of quasar host galaxies at constant wavelength over look-back times of
25 to 85% of the age of the universe.  When compared with the so far much better
studied radio galaxies in other HST programs, we will be able to address the
important question of whether radio-loud quasars and radio galaxies are members of
the same parent population as is fashionable in the AGN unification schemes, and
investigate how the hosts of luminous AGN have evolved over the epochs where
luminous quasars have become virtually extinct.
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  Observations Description
  ------------------------

     Quasar Sample To investigate the astrophysically important issues raised in the
     scientific justification, we propose to image a small sample of 20 radio-loud
     quasars using a broad- band filter and the Planetary Camera on HST.  These
     quasars all have redshifts of between 0.276 and 2.667 and are chosen from the
     Molonglo Reference Catalog of radio sources. We have split the sample into
     three redshift bins (z<0.7, 0.7<z<1.75, 1.75<z<2.7) and all the bins are of
     roughly equal size in units of log(1+z) evolution with epoch is usually
     parameterized as (1+z)^Beta.  In each of these bins we have chosen 3 or 4
     quasars which represent the a range of radio properties  i.e., compact radio
     sizes (l_r \ltwid2'') and steep radio spectral index (alpha_0.4-1.4 \ GHz<-
     0.7), extended radio emission (radio sizes ~ 2'' - 100'') and steep radio
     spectra, and compact flat spectrum source (alpha_0.4-1.4 \ GHz > -0.5).  0.05in
     Continuum Imaging: Our choice of continuum filter is dictated by three
     criteria.  First, the filter bandpass should exclude bright emission lines.
     Second, the filter should be among the most efficient broad-band filters
     available on the WFPC2 and also correspond roughly to common ground-based
     filters to yield `real' magnitudes. Third, the central wavelength should
     correspond roughly to a uniform rest wavelength in all the quasars over the
     whole redshift range.  The most suitable choices are F336W (~U, for quasars
     with z<0.7), F439W (~B, for quasars with 0.7<z<1.25), F555W (~V, for quasars
     with 1.25<z<2.0) and F675W (~R, for quasars with 2.0<z<2.7).  These four
     filters will allow us to measure the morphology and brightness of the extended
     continuum emission at central rest-frame wavelengths of about 1800-
     2500Angstrom \ for all quasars in our sample.  The band-pass does include
     CIIILambda1909 for many of the quasars, but spectroscopic observations of the
     fuzz around radio-loud quasars show that this line is extremely weak there: <=
     few\ LyAlpha (Heckman et al 1992b).  Thus, there is only significant CIII
     emission in the quasar broad-line region and not in the host galaxy. We will
     observe each quasar for one full orbit. Dynamic range considerations will limit
     the exposure times to ~ 10 minutes. After allowing for guide star acquisition
     and setup time we will be able to observe each quasar for ~ 3 * 10 in one
     orbit. The filter, depending on the redshift of the quasar, is either F336W,
     F439W, F555W, or F675W.  Total integration times of ~ 30 minutes will allow us
     to detect the extended near-nuclear emission and clumpy structure on scales of
     a << 1 kpc (even at the highest redshifts) down to 25.8 magnitudes HST PSF^-1
     in the F336W filter (the `slowest' filter) for the lowest redshift quasars and
     to 27.7 magnitudes HST PSF^-1 in the F675W (the `fastest' filter) for the
     highest redshift quasars.  We emphasize that previous data taken with HST on
     radio galaxies and quasars indicates that these magnitude limits are easily
     deep enough to reveal significant structure near such objects -- see Hutchings
     Etal 1994, ApJ, 429, L1; and Miley Etal 1992.  We therefore request a total of
     20 orbits to image a statistically significant sample of 20 quasars with a
     range of redshift and radio properties to determine their rest- frame UV
     magnitudes and morphologies. In Cycle 4, we note that there is a program to
     take ``snap shots'' of 3CR radio sources, including some quasars (Sparks PI).
     While this is a valuable program to investigate some of the issues raised in
     the justification, we note that this snap shot program has short exposure times
     and that the images of all of the sources, regardless of redshift, are taken
     through the same filter. Our images will go deeper and have the advantage that
     they will image all 20 of the quasars at nearly the same rest wavelength.
     While the two programs are in some sense complimentary, we emphasize that many
     of the astrophysically important issues raised in the justification can only be
     investigated using the observational strategy of this proposal.

  Real Time Justification
  -----------------------

     We have no special requirements.

  Calibration Justification
  -------------------------


  Additional Comments
  -------------------

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                                                5974(  4) - 12/12/95 15:54  - [  3]

  Data Distribution

  Media:           8MM
  Blocking Factor: 10
  Ship To:         Matt Lehnert*Sterrewacht Leiden*2300 RA
                   Leiden*The Netherlands
  Ship Via:        UPS
  Email:           __Diagnostic-Sum-Section__ Software-Version (Contro,
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TARGET LIST    a) Fixed Targets
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Tar|   Target   |         Target        |            Target              |Coord   | Radial |             Flux data
No |    Name    |       Description     |           Position             |Eqnx    |  Vel.  |
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1   MRC0022-297  Galaxy, Quasar          RA=00H 22M 00.25S +/- 0.03S,     B1950.0  Z=0.406  B=17.80
                                         DEC=-29D 45' 31.6" +/- 0.5"

2   MRC0029-271  Galaxy, Quasar          RA=00H 29M 21.28S +/- 0.03S,     B1950.0  Z=0.333  B=19.40
                                         DEC=-27D 08' 58.2" +/- 0.5"

3   MRC1244-255  Galaxy, Quasar          RA=12H 44M 06.72S +/- 0.03S,     B1950.0  Z=0.635  V=17.30
                                         DEC=-25D 31' 25.9" +/- 0.5"

4   MRC0133-266  Galaxy, Quasar          RA=01H 33M 05.36S +/- 0.03S,     B1950.0  Z=1.540  V=18.50
                                         DEC=-26D 38' 56.6" +/- 0.5"

5   MRC0142-278  Galaxy, Quasar          RA=01H 42M 44.99S +/- 0.03S,     B1950.0  Z=1.157  B=18.50
                                         DEC=-27D 48' 35.5" +/- 0.5"

6   MRC2257-270  Galaxy, Quasar          RA=22H 57M 42.82S +/- 0.03S,     B1950.0  Z=1.476  B=20.20
                                         DEC=-27D 00' 29.7" +/- 0.5"

7   MRC0451-282  Galaxy, Quasar          RA=04H 51M 15.13S +/- 0.03S,     B1950.0  Z=2.560  B=18.50
                                         DEC=-28D 12' 29.3" +/- 0.5"

8   MRC1114-220  Galaxy, Quasar          RA=11H 14M 26.02S +/- 0.03S,     B1950.0  Z=2.282  B=20.80
                                         DEC=-22D 00' 29.0" +/- 0.5"

9   MRC1311-270  Galaxy, Quasar          RA=13H 11M 02.94S +/- 0.03S,     B1950.0  Z=2.186  V=19.00
                                         DEC=-27D 00' 56.5" +/- 0.5"

10  MRC2256-217  Galaxy, Quasar          RA=22H 56M 34.37S +/- 0.03S,     B1950.0  Z=1.779  V=19.70
                                         DEC=-21D 43' 43.1" +/- 0.5"

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Visit: 01
     Visit Requirements:  <none>
     On Hold Comments:    <none>
     Additional Comments: <none>


Exposures
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Exposure|   Target  |Instr | Oper. | Aper  |Spectral|Central|   Optional    |Num|  Time |               Special
 Number |    Name   |Config| Mode  |or FOV |Element |Waveln.|  Parameters   |Exp|       |             Requirements
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1        MRC0022-297 WFPC2  IMAGE   PC1     F336W    3344    CR-SPLIT=NO     3   700S
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Visit: 02
     Visit Requirements:  <none>
     On Hold Comments:    <none>
     Additional Comments: <none>


Exposures
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Exposure|   Target  |Instr | Oper. | Aper  |Spectral|Central|   Optional    |Num|  Time |               Special
 Number |    Name   |Config| Mode  |or FOV |Element |Waveln.|  Parameters   |Exp|       |             Requirements
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1        MRC0029-271 WFPC2  IMAGE   PC1     F336W    3344    CR-SPLIT=NO     3   700S
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Visit: 03
     Visit Requirements:  <none>
     On Hold Comments:    <none>
     Additional Comments: <none>


Exposures
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Exposure|   Target  |Instr | Oper. | Aper  |Spectral|Central|   Optional    |Num|  Time |               Special
 Number |    Name   |Config| Mode  |or FOV |Element |Waveln.|  Parameters   |Exp|       |             Requirements
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1        MRC1244-255 WFPC2  IMAGE   PC1     F336W    3344    CR-SPLIT=NO     3   700S
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Visit: 04
     Visit Requirements:  <none>
     On Hold Comments:    <none>
     Additional Comments: <none>


Exposures
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Exposure|   Target  |Instr | Oper. | Aper  |Spectral|Central|   Optional    |Num|  Time |               Special
 Number |    Name   |Config| Mode  |or FOV |Element |Waveln.|  Parameters   |Exp|       |             Requirements
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1        MRC0133-266 WFPC2  IMAGE   PC1     F555W    5407    CR-SPLIT=NO     3   700S
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                                                5974(  4) - 12/12/95 15:54  - [  9]

Visit: 05
     Visit Requirements:  <none>
     On Hold Comments:    <none>
     Additional Comments: <none>


Exposures
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Exposure|   Target  |Instr | Oper. | Aper  |Spectral|Central|   Optional    |Num|  Time |               Special
 Number |    Name   |Config| Mode  |or FOV |Element |Waveln.|  Parameters   |Exp|       |             Requirements
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1        MRC0142-278 WFPC2  IMAGE   PC1     F439W    4300    CR-SPLIT=NO     3   700S
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Visit: 06
     Visit Requirements:  <none>
     On Hold Comments:    <none>
     Additional Comments: <none>


Exposures
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Exposure|   Target  |Instr | Oper. | Aper  |Spectral|Central|   Optional    |Num|  Time |               Special
 Number |    Name   |Config| Mode  |or FOV |Element |Waveln.|  Parameters   |Exp|       |             Requirements
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1        MRC2257-270 WFPC2  IMAGE   PC1     F555W    5407    CR-SPLIT=NO     3   700S
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Visit: 07
     Visit Requirements:  <none>
     On Hold Comments:    <none>
     Additional Comments: <none>


Exposures
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Exposure|   Target  |Instr | Oper. | Aper  |Spectral|Central|   Optional    |Num|  Time |               Special
 Number |    Name   |Config| Mode  |or FOV |Element |Waveln.|  Parameters   |Exp|       |             Requirements
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1        MRC0451-282 WFPC2  IMAGE   PC1     F675W    6714    CR-SPLIT=NO     3   700S
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Visit: 08
     Visit Requirements:  <none>
     On Hold Comments:    <none>
     Additional Comments: <none>


Exposures
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Exposure|   Target  |Instr | Oper. | Aper  |Spectral|Central|   Optional    |Num|  Time |               Special
 Number |    Name   |Config| Mode  |or FOV |Element |Waveln.|  Parameters   |Exp|       |             Requirements
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1        MRC1114-220 WFPC2  IMAGE   PC1     F675W    6714    CR-SPLIT=NO     2   700S
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2        MRC1114-220 WFPC2  IMAGE   PC1     F675W    6714    CR-SPLIT=NO     1   600S
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                                                5974(  4) - 12/12/95 15:54  - [ 13]

Visit: 09
     Visit Requirements:  <none>
     On Hold Comments:    <none>
     Additional Comments: <none>


Exposures
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Exposure|   Target  |Instr | Oper. | Aper  |Spectral|Central|   Optional    |Num|  Time |               Special
 Number |    Name   |Config| Mode  |or FOV |Element |Waveln.|  Parameters   |Exp|       |             Requirements
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1        MRC1311-270 WFPC2  IMAGE   PC1     F675W    6714    CR-SPLIT=NO     3   700S
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Visit: 10
     Visit Requirements:  <none>
     On Hold Comments:    <none>
     Additional Comments: <none>


Exposures
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Exposure|   Target  |Instr | Oper. | Aper  |Spectral|Central|   Optional    |Num|  Time |               Special
 Number |    Name   |Config| Mode  |or FOV |Element |Waveln.|  Parameters   |Exp|       |             Requirements
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1        MRC2256-217 WFPC2  IMAGE   PC1     F555W    5407    CR-SPLIT=NO     2   700S
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2        MRC2256-217 WFPC2  IMAGE   PC1     F555W    5407    CR-SPLIT=NO     1   600S
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            Summary Form for Proposal  5974

  Item                         Used in this proposal
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  Configurations               WFPC2
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  Opmodes                      IMAGE
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  Optional Parameters          CR-SPLIT=NO
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  Proposal Category            GO
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  Scientific Category          Quasars
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  Spectral Elements            F336W F555W F439W F675W
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  Target Names                 MRC0022-297 MRC0029-271 MRC1244-255 MRC0133-266 MRC0142-278 MRC2257-270 MRC0451-282 MRC1114-220
                               MRC1311-270 MRC2256-217
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