6528( 4) - 03/06/96 08:57 - [ 1]
PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only
ID: 6528
Version: 4
Check-in Date: 06-Mar-1996
08:55:45
1.Proposal Title:
PG 1416-129: The Only X-ray Bright BAL QSO, or the Missing Link?
------------------------------------------------------------------------------------
2. Scientific Category 3. Proposal For 4. Cycle
QSO ABSORPTION LINES GO 6
------------------------------------------------------------------------------------
5. Investigators
Contact?
PI: Dr. Paul J. Green Smithsonian Astrophysical Observatory
CoI: Dr. Thomas Aldcroft Smithsonian Astrophysical Observatory N
CoI: Dr. Smita Mathur Smithsonian Astrophysical Observatory N
------------------------------------------------------------------------------------
6. Abstract
In the last year, convincing empirical evidence has been presented that QSOs with
broad absorption lines (BALs) in their UV spectra are remarkably quiet in the soft X
-ray bandpass. One X-ray bright exception may exist, the QSO PG1416--129. Previous
IUE UV spectra have revealed hints of BALs, but may instead be weaker, associated
absorption. We propose HST (FOS) spectra of signal-to-noise (S/N) ~20 in the
continuum to resolve this question. If rather than BALs, the lines are intrinsic,
associated absorption, these data will also yield fresh insight into a poorly
understood phenomenon in the interiors of QSOs. Recent studies have demonstrated,
using both UV and X-ray data, that associated UV absorption lines and soft X-ray
absorption are due to the same material. The constraints provided by combining UV
and X-ray datasets is powerful for determining the physical conditions and
ionization state of the absorber, determined to be low density, highly ionized,
outflowing material situated outside the broad line region, similar to the BAL
absorbers. The intriguing but low S/N IUE spectra suggest that PG1416--129 could
prove to be a bridge between the BALQSOs and AGN with associated absorption.
Fortunately, it is also bright, and extremely well-observed in the X-ray band (via
ROSAT, GINGA, and ASCA). The FOS spectra we propose will thus test new unifying
models for the absorbing material deep in the nucleus of QSOs.
------------------------------------------------------------------------------------
6528( 4) - 03/06/96 08:57 - [ 2]
Observations Description
------------------------
We propose to use the FOS, with the 0.5" aperture, the G130H and G190H
gratings, and the blue detector, to obtain spectra of PG 1416-129 covering 1200
- 2200 Angstrom. This instrumental setup can efficiently cover the absorption
lines we need for our modeling. The spectral resolution (R ~ 2000) is adequate
either to measure narrow associated lines and to resolve the velocity structure
of broad lines. We have used the STSDAS synphot package to calculate the
predicted count rates for this source. We used 3 IUE observations (1980 through
1988), where the UV continuum flux runs from ~1.2 to 0.6 * 10^-14 ergs s^-1
cm^2 AA^-1 over the observed range LambdaLambda1400 - 2200. Note that the S/N
will be substantially better near the strong emission lines of our object. The
revised observation times for Phase 2 are based on an observational sequence
consisting of one orbit for both acquisition and science exposure with the
G190H. Because the object is non- extended, non-variable (Deltam_V < 1, Elvis
et al. 1994, ApJS, 95, 1), with a well known energy distribution, we use the
ACQ/BIN sequence followed by a single stage peakup. We are aware of the
scattered light problem when observing at the shortest wavelengths (Ross 1994,
Bartko et al. 1992). Precise post-facto corrections for this effect for PG 1416
- 129 will be possible because of the well-known energy distribution and the
intrinsically blue nature of this object. The SED of this object is covered
from 1000Angstrom out to 7Mum, as compiled for a study of QSO SEDs (Elvis et
al. 1994). From these data, the variability in the B band is <1mag.
Real Time Justification
-----------------------
Calibration Justification
-------------------------
Additional Comments
-------------------
------------------------------------------------------------------------------------
Data Distribution
Media: 8MM
Blocking Factor: 10
Ship To: PI_Address
Ship Via: UPS
Email: ,
------------------------------------------------------------------------------------
6528( 4) - 03/06/96 08:57 - [ 3]
TARGET LIST a) Fixed Targets
------------------------------------------------------------------------------------------------------------------------------------
Tar| Target | Target | Target |Coord | Radial | Flux data
No | Name | Description | Position |Eqnx | Vel. |
------------------------------------------------------------------------------------------------------------------------------------
1 PG1416-129 GALAXY,QSO RA=14H 19M 03.81S +/- 0.04S,DEC= B2000 Z = V = 16.10+/-0.5
-13D 10' 44.7" +/- 0.5", PLATE- 0.129 B-V = 0.32+/-0.1
ID=03YH E(B-V) = 0.14+/-0.05
F-CONT(1680)=9+/-2e-15
F-CONT(1380)=9+/-2e-15
F-LINE(1550)=1.4+/-0.3e-14
W-LINE(1550)=40+/-5
F-LINE(1903)=0.7+/-0.3e-14
W-LINE(1903)=50+/-10
6528( 4) - 03/06/96 08:57 - [ 4]
Visit: 01
Visit Requirements: SCHED 50%
On Hold Comments: <none>
Additional Comments: We would like to schedule this HST observation close to the time of our XTE
observation of the same object (XTE Proposal number:10334, PI: Mathur)
Exposures
------------------------------------------------------------------------------------------------------------------------------------
Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special
Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements
------------------------------------------------------------------------------------------------------------------------------------
10 PG1416-129 FOS/BL ACQ/BIN 4.3 MIRROR 1 12.1S ONBOARD ACQ FOR 20
ARY
------------------------------------------------------------------------------------------------------------------------------------
20 PG1416-129 FOS/BL ACQ/PEA 0.3 G190H SCAN-STEP- 1 8.8S ONBOARD ACQ FOR 30
K Y=0.17,SCAN-
STEP-
X=0.17,SEARCH-
SIZE-Y=3,SEARCH
Comments: -SIZE-X=3
------------------------------------------------------------------------------------------------------------------------------------
30 PG1416-129 FOS/BL ACCUM 0.5 G190H 1 17M
------------------------------------------------------------------------------------------------------------------------------------
6528( 4) - 03/06/96 08:57 - [ 5]
Summary Form for Proposal 6528
Item Used in this proposal
------------------------------------------------------------------------------------------------------------------------------------
Configurations FOS/BL
------------------------------------------------------------------------------------------------------------------------------------
Opmodes ACQ/BINARY ACQ/PEAK ACCUM
------------------------------------------------------------------------------------------------------------------------------------
Optional Parameters SCAN-STEP-Y=0.17 SCAN-STEP-X=0.17 SEARCH-SIZE-Y=3 SEARCH-SIZE-X=3
------------------------------------------------------------------------------------------------------------------------------------
Proposal Category GO
------------------------------------------------------------------------------------------------------------------------------------
Scientific Category QSO ABSORPTION LINES
------------------------------------------------------------------------------------------------------------------------------------
Special Requirements SCHED 50% ONBOARD ACQ FOR 20 ONBOARD ACQ FOR 30
------------------------------------------------------------------------------------------------------------------------------------
Spectral Elements MIRROR G190H
------------------------------------------------------------------------------------------------------------------------------------
Target Names PG1416-129
------------------------------------------------------------------------------------------------------------------------------------