9161( 2) - 02/13/01 17:35 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9161 Version: 2 Check-in Date: 13-Feb-2001 17:34:32 1.Proposal Title: The Ultraviolet Properties of Obscured QSOs ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 10 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Paul Smith University of Arizona CoI: Dr. Gary Schmidt University of Arizona N CoI: Dr. Dean Hines University of Arizona N CoI: Dr. Belinda Wilkes Smithsonian Astrophysical Observatory N CoI: Dr. Roc Cutri California Institute of Technology N CoI: Dr. Brant Nelson California Institute of Technology N ------------------------------------------------------------------------------------ 5. Abstract The Two Micron All-Sky Survey (2MASS) is compiling a large sample of new, red, active galaxies. These objects add significantly to the number density of known active galactic nuclei (AGN) and could be important contributors to the cosmic far- infrared and X-ray backgrounds. The optical polarizations and near-IR-to-optical flux ratios of 2MASS AGN are generally higher than for UV-selected objects, indicating the presence of substantial obscuration toward the nuclear energy source. We propose STIS ultraviolet spectroscopy of a subset of 2MASS-discovered QSOs to: 1) determine if UV absorption- line features are present as seen in several other highly polarized AGN populations; 2) test relationships between X-ray (through an approved Chandra Cycle 2 GO program) and UV/optical attenuation, AGN spectral type, optical polarization, and detected UV absorption-line features; and 3) characterize the spectral energy distributions (SEDs) and UV properties of obscured QSOs. Comparison with AGN selected by other means will allow us to place the new sources in context, and in particular, whether they are the missing "obscured AGN" that are predicted by the Unified Scheme. ------------------------------------------------------------------------------------ 9161( 2) - 02/13/01 17:35 - [ 2] Observations Description ------------------------ Target selection from the 2MASS QSO sample is largely dictated by these factors: (1) the target must be scheduled to be observed by the Chandra X-Ray Observatory, (2) the survey should include a variety of AGN spectral types to reflect the variety observed in the 2MASS sample, and (3) the practical requirement that dust extinction and/or redshift are not so high that UV spectra with S/N > 10 cannot be obtained in a single orbit (~40 min exposure). The combined Chandra and HST observations are particularly important as they will define the high-energy portion of the SED. Because the overall UV spectral properties of obscured QSOs are of greatest initial interest, the PRISM with the 52 x 0.5 arcsec slit and NUV-MAMA is the most efficient STIS configuration for these observations. The PRISM has the advantage of covering the entire UV spectral region. Since the redshifts of the QSO are low (z = 0.08-0.21), the higher resolution offered by the low-resolution gratings is offset by the fact that the C IV emission line and any possible C IV absorption features fall close to the red or blue ends of G140L and G230L, respectively, and lie in regions of very low throughput. In addition, the redshifts are high enough that both G140L and G230L would be needed to cover Ly_alpha and C IV for most objects and necessitate at least 2 orbits per object. Resolution will clearly suffer for lambda > 2000 Angstroms with the PRISM because of its nonlinear dispersion, but the low redshifts of the objects insures that C IV falls in regions where R ~ 100. The resolution in this portion of the spectrum yields a 3 sigma detection limit in equivalent width for an unresolved absorption line of ~ 8 Angstroms given a S/N of 10 in the continuum; adequate to detect typical broad absorption-line systems observed in higher-z BALQSOs. We do not expect any useful emission/absorption-line diagnostics from C III and Mg II because of the extremely low resolutions at these lines, but very broad features such as the 2200 Angstrom dust feature will still be discerned and there will be no gap between the UV data and ground-based spectrophotometry. The expected S/N of the UV spectra was estimated using the STIS Exposure Time Calculator (ETC). To accommodate typical observing overheads, we assumed an exposure length of 2400 s per orbit. The ETC QSO template spectrum was used modified by an estimate for extinction. Dust attenuation was assumed to follow the average Galactic extinction law, and the offset in wavelength between the redshifted-QSO spectra and z = 0 extinction curve was ignored given the low redshifts of the objects. For each object, the extinction was estimated by assuming that the average B- K_s color index for PG QSOs with z < 0.6 (~ 3) represents a typical QSO whose SED is not attenuated by dust in the line of sight. The higher B-K_s color indices of the 2MASS objects are assumed to be the result of extinction intrinsic to the QSOs. For this case, E(B-V) can be estimated and range from ~0.3-0.7 mag. Unfortunately, there are no objects with B-K_s > 6.0 that are included in the Chandra Cycle 2 GO program that would not require prohibitively long STIS exposures. However, the QSOs selected explore a wide range of objects with much larger F_IR/F_opt than observed in traditional UV/optical AGN samples. Figure 4 (see Phase I proposal) shows the ETC results for a typical object in the UV sample: 2MASSI J095504.6+170556 (z = 0.139; B = 18.1; B-K_s = 4.7). Objects in the UV sample attain a S/N > 10 per resolution element at C IV. The objects are isolated so there are no complications for target acquisition, and all are faint enough (even with no extinction correction) that NUV-MAMA illumination limits are not an issue. 2MASSI J151653.2+190048 (z = 0.19) is a special case. This Type-1 AGN exhibiting strong Fe II emission features is not only more than a magnitude brighter optically than the other sample members, it is the most highly polarized (Smith et al. 2000b). We propose to observe this extreme object with the G140L and G230L gratings. Based on its B-K_s color index, A_V ~ 1 mag and the ETC indicates that the spectra will have S/N > 10-20 in a 2400 s exposure for each grating. Therefore, we request 2 orbits to observe this interesting object. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9161( 2) - 02/13/01 17:35 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 2MASSI- GALAXY, QSO RA=00H 07M 03.54S +/- 0.5", J2000 Z = V = 16.8+/-0.5 J000703.6+15 DEC=+15D 54' 23.7" +/- 0.5", 0.114 5423 PLATE-ID=01G3 Coordinate Source: GSC_SURVEY_PLATE 2 2MASSI- GALAXY, QSO RA=01H 20M 31.57S +/- 0.5", J2000 Z = V = 17.5+/-0.5 J012031.5+20 DEC=+20D 03' 27.8" +/- 0.5", 0.087 0327 PLATE-ID=021K Coordinate Source: GSC_SURVEY_PLATE 3 2MASSI- GALAXY, QSO RA=09H 18M 48.61S +/- 0.5", J2000 Z = V = 18.0+/-0.5 J091848.6+21 DEC=+21D 17' 17.1" +/- 0.5", 0.149 1717 PLATE-ID=0389 Coordinate Source: GSC_SURVEY_PLATE 4 2MASSI- GALAXY, QSO RA=09H 55M 04.53S +/- 0.5", J2000 Z = V = 17.6+/-0.5 J095504.5+17 DEC=+17D 05' 55.7" +/- 0.5", 0.139 0556 PLATE-ID=021L Coordinate Source: GSC_SURVEY_PLATE 5 2MASSI- GALAXY, QSO RA=10H 51M 44.21S +/- 0.5", J2000 Z = V = 17.3+/-0.5 J105144.2+35 DEC=+35D 39' 31.0" +/- 0.5", 0.158 3930 PLATE-ID=01R8 Coordinate Source: GSC_SURVEY_PLATE 6 2MASSI- GALAXY, QSO RA=13H 00M 05.34S +/- 0.5", J2000 Z = V = 15.6+/-0.5 J130005.3+16 DEC=+16D 32' 14.7" +/- 0.5", 0.080 3214 PLATE-ID=01PP Coordinate Source: GSC_SURVEY_PLATE 7 2MASSI- GALAXY, QSO RA=15H 16M 53.24S +/- 0.5", J2000 Z = V = 15.2+/-0.5 J151653.2+19 DEC=+19D 00' 48.1" +/- 0.5", 0.190 0048 PLATE-ID=00ZE Coordinate Source: GSC_SURVEY_PLATE 8 2MASSI- GALAXY, QSO RA=16H 59M 39.77S +/- 0.5", J2000 Z = V = 17.8+/-0.5 J165939.7+18 DEC=+18D 34' 36.8" +/- 0.5", 0.170 3436 PLATE-ID=02D2 Coordinate Source: GSC_SURVEY_PLATE 9 2MASSI- GALAXY, QSO RA=17H 14M 42.85S +/- 0.5", J2000 Z = V = 17.1+/-0.5 J171442.7+26 DEC=+26D 02' 48.0" +/- 0.5", 0.163 0248 PLATE-ID=02HC Coordinate Source: GSC_SURVEY_PLATE 10 2MASSI- GALAXY, QSO RA=22H 22M 21.18S +/- 0.5", J2000 Z = V = 17.1+/-0.5 J222221.1+19 DEC=+19D 59' 47.2" +/- 0.5", 0.211 5947 PLATE-ID=03QN Coordinate Source: GSC_SURVEY_PLATE 9161( 2) - 02/13/01 17:35 - [ 4] 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 2MASSI-J000 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 3 S 703.6+15542 CD P 3 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSI-J000 STIS/N ACCUM 52X0.5 PRISM 1200 1 2400 S 703.6+15542 UV-MAM 3 A ------------------------------------------------------------------------------------------------------------------------------------ 9161( 2) - 02/13/01 17:35 - [ 5] Visit: 02 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 2MASSI-J012 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 4 S 031.5+20032 CD P 7 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSI-J012 STIS/N ACCUM 52X0.5 PRISM 1200 1 2400 S 031.5+20032 UV-MAM 7 A ------------------------------------------------------------------------------------------------------------------------------------ 9161( 2) - 02/13/01 17:35 - [ 6] Visit: 03 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 2MASSI-J091 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 8 S 848.6+21171 CD P 7 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSI-J091 STIS/N ACCUM 52X0.5 PRISM 1200 1 2400 S 848.6+21171 UV-MAM 7 A ------------------------------------------------------------------------------------------------------------------------------------ 9161( 2) - 02/13/01 17:35 - [ 7] Visit: 04 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 2MASSI-J095 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 4 S 504.5+17055 CD P 6 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSI-J095 STIS/N ACCUM 52X0.5 PRISM 1200 1 2400 S 504.5+17055 UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 9161( 2) - 02/13/01 17:35 - [ 8] Visit: 05 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 2MASSI-J105 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 3 S 144.2+35393 CD P 0 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSI-J105 STIS/N ACCUM 52X0.5 PRISM 1200 1 2400 S 144.2+35393 UV-MAM 0 A ------------------------------------------------------------------------------------------------------------------------------------ 9161( 2) - 02/13/01 17:35 - [ 9] Visit: 06 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 2MASSI-J130 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1 S 005.3+16321 CD P 4 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSI-J130 STIS/N ACCUM 52X0.5 PRISM 1200 1 2400 S 005.3+16321 UV-MAM 4 A ------------------------------------------------------------------------------------------------------------------------------------ 9161( 2) - 02/13/01 17:35 - [ 10] Visit: 07 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 2MASSI-J151 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1 S 653.2+19004 CD P 8 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSI-J151 STIS/N ACCUM 52X0.5 G230L 2376 1 2400 S 653.2+19004 UV-MAM 8 A ------------------------------------------------------------------------------------------------------------------------------------ 3 2MASSI-J151 STIS/F ACCUM 52X0.5 G140L 1425 1 2700 S 653.2+19004 UV-MAM 8 A ------------------------------------------------------------------------------------------------------------------------------------ 9161( 2) - 02/13/01 17:35 - [ 11] Visit: 08 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 2MASSI-J165 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 7 S 939.7+18343 CD P 6 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSI-J165 STIS/N ACCUM 52X0.5 PRISM 1200 1 2400 S 939.7+18343 UV-MAM 6 A ------------------------------------------------------------------------------------------------------------------------------------ 9161( 2) - 02/13/01 17:35 - [ 12] Visit: 09 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 2MASSI-J171 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 3 S 442.7+26024 CD P 8 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSI-J171 STIS/N ACCUM 52X0.5 PRISM 1200 1 2400 S 442.7+26024 UV-MAM 8 A ------------------------------------------------------------------------------------------------------------------------------------ 9161( 2) - 02/13/01 17:35 - [ 13] Visit: 10 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 2MASSI-J222 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 3 S 221.1+19594 CD P 7 ------------------------------------------------------------------------------------------------------------------------------------ 2 2MASSI-J222 STIS/N ACCUM 52X0.5 PRISM 1200 1 2400 S 221.1+19594 UV-MAM 7 A ------------------------------------------------------------------------------------------------------------------------------------ 9161( 2) - 02/13/01 17:35 - [ 14] Summary Form for Proposal 9161 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.5 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/NUV-MAMA STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR PRISM G230L G140L ------------------------------------------------------------------------------------------------------------------------------------ Target Names 2MASSI-J000703.6+155423 2MASSI-J012031.5+200327 2MASSI-J091848.6+211717 2MASSI-J095504.5+170556 2MASSI-J105144.2+353930 2MASSI-J130005.3+163214 2MASSI-J151653.2+190048 2MASSI-J165939.7+183436 2MASSI-J171442.7+260248 2MASSI-J222221.1+195947 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1200 2376 1425 ------------------------------------------------------------------------------------------------------------------------------------