Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 1223c Report Date: 09-May-96:16:20 Version: ********** Check-in Date: ********** 1.Proposal Title: STUDY OF THE NUCLEUS OF THE SEYFERT 2 GALAXY NGC 5728 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID QSO, AGN,SEYFERTS GTO/FOC Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Alec Boksenberg ROYAL GREENWICH OBSERVATORY UNITED KIN 0223 374000 PROFESSOR ------------------------------------------------------------------------------------ 7. Abstract Seyfert 2 galaxies are most probably photoionized. The nature of the nonthermal continuum responsible for this photoionization is unknown; it has been seen in only one case, NGC 1068. NGC 5728 is a Seyfert 2 galaxy with an extended (~10") nuclear emission region (probably the most extended known). High angular resolution images, in the UV to get rid of the stellar continuum, through narrow band filters chosen to isolate emission lines or the continuum may allow the detection of a possibly extended non-thermal continuum and the similarity or the difference of its morphology with that of the emission nebulosity. This could be a first step in understanding the nature of this continuum. ------------------------------------------------------------------------------------ 8. Scientific Key Words: SEYFERT GALAXY ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 1.00 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 1223c PI: Alec Boksenberg Proposal Title: STUDY OF THE NUCLEUS OF THE SEYFERT 2 GALAXY NGC 5728 ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Philip Veron HAUTE PROVENCE OBSERVATORY FRANCE X Alec Boksenberg ROYAL GREENWICH OBSERVATORY UNITED KING X ------------------------------------------------------------------------------------ 3. Description of proposed observations. We propose to observe NGC 5728 with the FOC in the F/96 mode with the 512 x 512 pixels format, providing a field of vbiew of 11.2 x 11.2 arcsec, adequate for this object. Three sets of exposures are requested, one through each of the following filters: F152M LambdaLambda 1450-1600 c IV Lambda 1550; peak transmission 15% F140M LambdaLAmbda 1350-1450 continuum 15% F170M LambdaLambda 1600-1800 He II Lambda 1640 20% (The heliocentric radial velocity of NGC 5728 is V = 2800 km s^-1). The target is an extended nebulosity with, most probably, a large range of surface brightness, therefore exposure times, required signal-to- noise ratio, etc...., cannot be defined accurately. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. These observations cannot be made from the ground, not only because the best photographs obtainable have a resolution limited by the seeing to ~0.7", but also because it is essential to work in the UV to avoid the very strong starlight contamination due to the bulge of the galaxy which makes it impossible to detect in the visible very faint non-thermal extensions. ------------------------------------------------------------------------------------ 6. Description of special calibration exposures. Filter F152M and F140M both transmit some OI airglow emission; a dark sky (solar zenith angle larger than 100D) is definitely required for the exposure with the F140M filter and probably for the exposures with the F152M filter as well. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The ESO image processing system IHAP, on an HP computer, has been used extensively by us to reduce CCD frames. It seems to contain most, if not all the functions required for this project. In addition we will have access to the STARLINK CAVAD clusterat RGO for data reduction. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). We expect that our institutions will support us. ------------------------------------------------------------------------------------ 13. Seyfert 2 galaxies are most probably photoionized. The nature of the nonthermal continuum responsilbe for this photoionization is unknown; it has been seen in only one case, NGC1068. NGC5728 is a Seyfert 2 galaxy with an extended (~10") nuclear emission region (probably the most extended known). High angular resolution images, in the UV to get rid of the stellar continuum, through narrow band filters chosen to isolate emission lines or the continuum may allow the detection of a possibly extended non-thermal continuum and the similarity or the difference of its morphology with that of the emission nebulosity. This could be a first step in understanding the nature of this continuum. ------------------------------------------------------------------------------------ 11. Address Information Page 3 Name: PHILIP VERON Category: CON Institution: OBSERVATOIRE DE HAUTE PROVENCE Address: F-04870 SAINT-MICHEL L'OBSERVATOIRE City: State: Zip Code: Country: FRANCE Telephone: (92) 766368 Telex (or e-mail): 410690 ------------------------------------------------------------------------------------ Name: ALEC BOKSENBERG Category: PI Institution: ROYAL GREENWICH OBSERVATORY Address: MADINGLEY ROAD CB3 0EZ City: CAMBRIDGE State: Zip Code: Country: UNITED KINGDOM Telephone: (44) 223 374000 Telex (or e-mail): 817235 ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 1223c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC5728 SEYFERT 2 GALAXY RA=14H 39M 36.85S +/- 0.03S, 1950 V=2970 EXT 1 V=12.5 +/- 0.3 DEC=-17D 02' 28.34" +/- 0.5" Comments: GASP COG MEASURE USED ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 1223c [ 5] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC5728 FOC/96 IMAGE 512X512 F152M 1500 1 1000S 1 DARK TIME / 1-3 CYCLE 2 / 1-4 GUID TOL 0.020" / 1-4 COND IF TAC OK / 1 -4 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC5728 FOC/96 IMAGE 512X512 F140M 1390 1 1000S 2 ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC5728 FOC/96 IMAGE 512X512 F170M 1760 1 1000S 2 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 1223c [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOC/96 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/FOC ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 1.00 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category QSO, AGN,SEYFERTS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements DARK TIME / 1-3; CYCLE 2 / 1-4; GUID TOL 0.020" / 1-4; COND IF TAC OK / 1-4; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F152M F140M F170M ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC5728 ------------------------------------------------------------------------------------------------------------------------------------