6602( 8) - 03/11/97 11:13 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6602 Version: 8 Check-in Date: 11-Mar-1997 11:10:56 1.Proposal Title: B2114+022: a gravitational lens system and/or an example of multiple active nuclei? ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle COSMOLOGY GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Ian Browne NRAL CoI: Peter Wilkinson NRAL Jodrell Bank N CoI: Sunita Nair NRAL Jodrell Bank N CoI: Pedro Augusto NRAL Jodrell Bank N CoI: Chris Fassnacht Caltech N CoI: Donna Womble Caltech N ------------------------------------------------------------------------------------ 6. Abstract We propose to image the radio source B2114+022 with the prime objective of finding out whether or not the unique configuration of radio images is a result of gravitational lensing. The object was observed in the Jodrell Bank -- VLA Astrometric Survey (JVAS) of flat spectrum radio sources and found to consist of four compact (<= 20mas) components. Three of the components form an equilateral triangle and lie within 300 mas of each other, while the fourth is 2 arcsec away. The components all have flat spectra but they are not identical. The geometry is atypical of that produced by gravitational lensing. Hence, though lensing is probably contributing to the complexity of the radio image, it may not be the whole story. Extended optical emission has been detected from the ground and may be a blend of a lensing galaxy and lensed images. HST observations will enable us to check this and other possibilities. . ------------------------------------------------------------------------------------ 6602( 8) - 03/11/97 11:13 - [ 2] Observations Description ------------------------ The observations are aimed at detecting point sources of magnitude 20 or fainter, together with extended galaxy emission of integrated magnitude of 19. In the 555 filter a magnitude 20 point source will produce about 55 electrons per second. The extended galaxy will produce about 2 electrons per second in the central pixel on the basis of the curve of figure 6.1 in the WFPC2 handbook. The figures for the 814 filter are roughly similar. We propose to take two exposures in each filter: one short (so as not to saturate on the point sources) and one long in order to look for faint images and study the morphology of the lensing galaxy. The available observing time per orbit is between 43 and 47 minutes, taking into account occultation and guide star acquisition. Allowing 16 minutes for exposure overheads (one CR-SPLIT and one NO-CR -SPLIT in each filter) this gives between 27 and 31 minutes for science exposures. In the deeper exposure in each filter we will therefore obtain about 12-15 minutes' integration. This will be enough to collect 1400 electrons in the central pixel of the lensing galaxy. The point sources will be easily detected in the short (~1 min) exposures. Real Time Justification ----------------------- We have time allocated on the VLBA which we will use to make 1 mas resolution maps of the 2114+022 system. Hopefully these will reveal substructure in the images that can be used to constrain lensing models. We also intend to pursue the optical spectroscopy in order to check if the emission line is HAlpha and to look for other features which might be associated with a possible lensed object. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: ------------------------------------------------------------------------------------ 6602( 8) - 03/11/97 11:13 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 QSO- GALAXY RA=21H 16M 50.744S +/- 0.01S, J2000 V = 20+/-1 211650+02254 DEC=02D 25' 46.26" +/- 0.1" 6 6602( 8) - 03/11/97 11:13 - [ 4] Visit: 01 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 QSO-211650+ WFPC2 IMAGE PC1 F555W 1 1000 S 022546 ------------------------------------------------------------------------------------------------------------------------------------ 15 QSO-211650+ WFPC2 IMAGE PC1 F814W 1 1000 S 022546 ------------------------------------------------------------------------------------------------------------------------------------ 20 QSO-211650+ WFPC2 IMAGE PC1 F814W 1 1000 S 022546 ------------------------------------------------------------------------------------------------------------------------------------ 25 QSO-211650+ WFPC2 IMAGE PC1 F814W 1 1000 S 022546 ------------------------------------------------------------------------------------------------------------------------------------ 6602( 8) - 03/11/97 11:13 - [ 5] Summary Form for Proposal 6602 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category COSMOLOGY ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names QSO-211650+022546 ------------------------------------------------------------------------------------------------------------------------------------