9181( 2) - 01/31/01 15:18 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9181 Version: 2 Check-in Date: 31-Jan-2001 15:18:11 1.Proposal Title: Exploratory Observations of a New Bright Quasar ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 10 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Karen Leighly University of Oklahoma Norman Campus CoI: Prof. Jules Halpern Columbia University N CoI: Prof. Edward Jenkins Princeton University N CoI: Prof. David Helfand Columbia University N CoI: Prof. Robert Becker LLNL N ------------------------------------------------------------------------------------ 5. Abstract The VLA FIRST radio survey recently discovered a new, extremely bright quasar that is the second brightest optical object in the sky at z > 0.1. Optically classified as a Narrow-line Seyfert 1 galaxy (NLS1), PHL 1811 is not typical of this class of objects because it is a very weak X-ray source. We propose short exploratory UV spectroscopic observations of this new bright quasar that will reveal its true nature and permit us to identify potential applications of future deeper observations. PHL 1811 may be the brightest luminous NLS1, in which case the study of the profiles and ratios of the emission lines will be valuable. Alternatively, PHL 1811 may be the brightest BALQSO, and the structure and composition of the BAL flow may be studied. PHL 1811 may be a useful probe for local LyAlpha absorption and follow-up high resolution spectroscopy will be indicated; furthermore, the proposed HST STIS observation will support the FUSE observation scheduled for this fall. We also request short Chandra observations to identify the origin of the faint X-ray emission. ------------------------------------------------------------------------------------ 9181( 2) - 01/31/01 15:18 - [ 2] Observations Description ------------------------ We propose G140L and G230L UV spectroscopic observations of PHL 1811. At redshift 0.192, the important MgII Lambda 2800 line falls very near the atmospheric cutoff, and we can't guarantee a good measurement from the ground; therefore, a very short observation is proposed using G430L. We will use a 0.2" slit, and therefore no peak-up will be required The continua of the luminous NLS1s that we are studying now are similar to that of the average quasar and show no evidence for reddening intrinsic to the quasar (Leighly 2000; Leighly & Halpern 2000). We expect the same to be true for PHL 1811 which is optically blue. Therefore, for feasibility calculations, we first obtained the continuum shape from the average quasar spectrum provided by STScI and redshifted it into the observer's frame. Next, the Galactic reddening (E(B-V)=0.046) was folded in using the CCM law (Cardelli et al. 1989). Finally the continuum was scaled according to our flux estimate. We estimated the flux from our optical spectrum; this estimate is consistent with the estimated magnitudes from photometry. We estimated the signal-to-noise ratios using the exposure time calculator. We find that we should be able to attain a signal to noise of greater 40, and for some wavelength ranges, up to 80, in just 2 orbits. It is possible that the object is a low ionization BALQSO, although it does not seem likely as we see no evidence for absorption lines to the blue of MgII in our optical spectrum. Nevertheless, if it were a low-ionization BALQSO, the spectrum may be reddened below 2500Angstrom (e.g. Turnshek et al. 1994 Fig. 4). In this case, the S/N in the continuum under strong lines will still be above ~ 35. We use a CR-SPLIT=2 for the CCD observations in order to aid in the removal of hot pixels. At such high potential signal-to-noise ratios, we potentially could have problems with fixed pattern noise or other systematic uncertainties. Therefore, we opt to use a pattern, STIS-ALONG-SLIT, for the MAMA FUV and NUV spectra. We chose 4 positions per grating, and step 0.369 arcseconds (15 pixels) per position. Real Time Justification ----------------------- We propose to schedule our short G430L CCD observation of PHL 1811 in the same orbit as one of the MAMA observations because the proposed CCD observation is short (9 minutes including overheads). We propose two 10 ks observations using the Chandra back-illuminated CCD detector at the ACIS-S aimpoint in timed- exposure mode. We base the feasibility calculation on the BeppoSAX MECS spectrum that we obtained. The statistics of the BeppoSAX spectrum are poor enough that the absorption column and the power law index cannot both be constrained by the spectral fitting. Therefore, for feasibility considerations, we used two generic models that are both able to describe the BeppoSAX spectrum: 1.) no intrinsic absorption and free power-law index; 2.) photon index >=2.6 and intrinsic absorption included. XSPEC was used to estimate the count rates and to generate simulated spectra. The appropriate response matrix and ancillary response matrix for the aimpoint of the ACIS-S were used. We note that the predicted count rates are low enough that pile-up will not be a problem. The simulations demonstrate that because of the softer response of the Chandra back-illuminated CCDs compared with the BeppoSAX MECS we will be able to improve dramatically our estimation of the absorption intrinsic to the object. Then we will be able to determine the intrinsic X-ray continuum and see whether the quasar is still X-ray weak after the absorption has been accounted for. Furthermore, since we will obtain a detection with a signal-to-noise greater than 10 during each 10 ks observation, we will be able to search sensitively for variability. PHL 1811 is a high luminosity AGN. All AGN are variable, but the time scale of variability is observed to be longer for high luminosity objects. Therefore, the Chandra observations should be carried out _contemporaneously_ with the HST observations, and need not be precisely simultaneous, although naturally simultanous observations would produce the least ambiguity. We have requested that the two Chandra observations should be carried out between one and three weeks of each other. The interval should be long enough that intrinsic variability in such a luminous object could be expected, but shorter than the time that it would take for a signal to propagate through the electron scattering region. We note that a GTO FUSE observation of this object is planned, and it will most likely be done during 2001. We did not specify anything about this observation in our Phase I proposal, and therefore, although coordinated/contemporanous observations are naturally desirable and valuable, we can only request that they be done. We will contact STScI when the date of the FUSE observation is finalized to see if a contemporaneous observation may be possible. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9181( 2) - 01/31/01 15:18 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PHL1811 GALAXY, QSO RA=21H 55M 1.53S +/- 0.3", DEC=- J2000 Z=0.192 V = 13.9+/-0.4 09D 22' 24.4" +/- 0.3"PLATE- B-V = 0.0+/-0.4 ID=044F E(B-V) = 0.046 Coordinate Source: GUIDE_STAR_CATALOG 9181( 2) - 01/31/01 15:18 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.369 Coordinate_Frame POS-TARG Pattern_Orient 90 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 9181( 2) - 01/31/01 15:18 - [ 5] Visit: 01 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 PHL1811 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1.4 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 PHL1811 STIS/C ACCUM 52X0.2E G430L 4300 CR-SPLIT=2 ,sizeAXIS2=248 1 4 M CD 1 ------------------------------------------------------------------------------------------------------------------------------------ 3 PHL1811 STIS/N ACCUM 52X0.2 G230L 2376 1 7 M PATTERN 1 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 4 PHL1811 STIS/F ACCUM 52X0.2 G140L 1425 1 11 M PATTERN 1 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 9181( 2) - 01/31/01 15:18 - [ 6] Summary Form for Proposal 9181 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.2E1 52X0.2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/NUV-MAMA STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT sizeAXIS2=248 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G430L G230L G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names PHL1811 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 4300 2376 1425 ------------------------------------------------------------------------------------------------------------------------------------