Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 1240c Report Date: 09-May-96:16:22 Version: ********** Check-in Date: ********** 1.Proposal Title: THE FATE OF THE GAS AT THE CENTER OF AN ELLIPTICAL GALAXY: STAR FORMATION OR ACCRETION ON A MASSIVE OBJECT ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID GALAXIES & CLUSTERS GTO/FOC Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Alec Boksenberg ROYAL GREENWICH OBSERVATORY UNITED KIN (0223) 374000 PROFESSOR ------------------------------------------------------------------------------------ 7. Abstract What happens to the gas which is accreted by a galaxy? Does it form stars or is it accreted by a massive object and fuels an active nucleus? To answer these questions we propose to observe the nearby normal elliptical NGC 4278 in which the neutral and ionized gas have been extensively studied. We propose to search for and count massive hot stars recently formed from the accumulated gas within 3 arc sec of the center by taking a direct image with the filter F275W which combines high efficiency of FOC and high contrast of hot stars against galaxy background. We propose to take two long slit spectra in the first order which will give the velocity field, the velocity dispersion, the line intensity ratios [OII] lambda3727/[OIII]lambda5007/H- beta in the gas as a function of distance from center and a detection of or a significant upper limit to the broad component of H-beta indicative of an (intrinsically weak) Seyfert nucleus. The long slit spectra will be taken perpendicular to and along the axis of rotation of the ionized gas within 8 arcsec from center (P.A.=40D +/- 10D; P.A.=130D +/- 10D) which we have determined from the ground. ------------------------------------------------------------------------------------ 8. Scientific Key Words: ELLIPTICAL GALAXY, ACCRETION, SUPERGIANT, SPECTROSCOPY, IMAGING, EMISSION LINE GALAXY ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 3.70 par: 0 10. Num targs pri: 1 par: 0 ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 1240c PI: Alec Boksenberg Proposal Title: THE FATE OF THE GAS AT THE CENTER OF AN ELLIPTICAL GALAXY: STAR FORMATION OR ACCRETION ON A MASSIVE OBJECT ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ H. Butcher GRONINGEN, UNIVERSITY OF NETHERLANDS X Alec Boksenberg ROYAL GREENWICH OBSERVATORY UNITED KING X Marie-Helene Demoulin-Ulrich EUROPEAN SOUTHERN OBSERVATORY GERMANY, WE X ------------------------------------------------------------------------------------ 3. Description of proposed observations. a)Detection of hot stars formed from accumulated gas within 3 arc sec from center: 1 exposure set through filter F275W for best contrast of hot stars against galaxy background, and high efficiency of FOC. 1 exposure set through filter F502M to separate hot stars from globular clusters and foreground stars. b)Long slit spectra (order 1) covering [OII] Lambda3727 and [OIII]Lambda5007 to investigate the velocity field, line width, line ratios. 2 exposures sets: perpendicular to and along rotation axis of gas as obtained from ground based observations (P.A.=40d+/-10d; P.A.=130d+/-10d). c)Mapping of the ioized gas in the most intense emission line: [OII]Lambda 3727 1 exposure though medium band filter F372M. (cont'd from EL # 2) orient 100d +/- 10d is equally good. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. On direct plates which we have taken in B with the CFH Telescope we cannot detect stars fainter than m(B)=24 within ~4 arc sec from the nucleus. The aim of the present ST proposal is to search and count stars with m(B)=26 to 28 in the same area. The distribution of the gas and the velocity field have already been obtained with the best angular resolution from the ground. It is important to obtain observations closer to the center and with higher angular resolution in order to distinguish between rotation, chaotic and inflow motion of the gas. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. The institutions to which we are affiliated are well outfitted in hardware (Vax computers)as well as software for data reduction and analysis. The data will be reduced and analysed in at least two institutions. The interpretation will be done as a group. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Our institutions will fully support us and have the sofware and hardware appropriate for reduction and analysis of ST data. ------------------------------------------------------------------------------------ 13. Imaging and spectroscopy of the central region of the elliptical galaxy NGC 4278 with the following aims: - search for and count massive hot stars recently formed from accumulated gas at center. Deep images will be taken at 2700 A and 5200 A with FOC/96. - determination of the velocity field of the gas from 2 long slit spectra with FOC/48 and grating in 1st order. ------------------------------------------------------------------------------------ 11. Address Information Page 3 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 ------------------------------------------------------------------------------------ Name: MARIE-HELENE DEMOULIN-ULRICH Category: CON Institution: EUROPEAN SOUTHERN OBSERVATORY Address: KARL-SCHWARZSCHILDSTRASSE, 2 D-8046 City: GARCHING BEI MUNCHEN State: Zip Code: Country: GERMANY, WEST Telephone: (89) 32006-232 Telex (or e-mail): 52828222 ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 1240c [ 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 NGC4278 NEARBY ELLIPTICAL RA=12H 17M 36.2S +/- 0.1S, 1950 V=600 EXT 1 V=11.5 GALAXY DEC=+29D 33' 28.04" +/- 0.2" 2 F-CONT(2750)=4 +/- 2E-19 3 F-CONT(2750)=5 +/- 1E-19 4 F-LINE(5007)=1.5 +/- 0.5E-14 5 F-LINE(3727)=4.9 +/- 1.6E-14 Comments: GASP POSITION ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 1240c [ 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 NGC4278 FOC/96 IMAGE 256X256 F502M 4950 1 1000S 4 1 CYCLE 2 / 1-6 COND IF TAC OK / 1 -3 GUID TOL 0.020" / 1-6 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4278 FOC/48 SPEC 256X102 G450M 3600- PIXEL=25X25 1 4000S 4 1 ORIENT 280D +/- 4-SLIT 5300 5 10D Comments: ORIENT 100D +/- 10D EQUALLY GOOD; P.A OF SLIT=40D +/- 10D; FOR INVESTIGATION OF THE GAS (EXP NOS 2-3,6) S/N DEPENDS ON HOW THE GAS IS DISTRIBUTED. GAS IS VERY LIKELY CLUMPED. ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4278 FOC/48 SPEC 256X102 G450M 3600- PIXEL=25X25 1 4000S 4 1 ORIENT 10D +/- 10D 4-SLIT 5300 5 Comments: P.A. OF SLIT = 130D +/- 10D; ORIENT 190D +/- 10D IS EQUALLY GOOD. ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC4278 FOC/96 IMAGE 256X256 F275W 2720 1 1000S 2 1 DARK TIME / 4-5 3 ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC4278 FOC/96 IMAGE 256X256 F502M 4950 1 1000S 4 1 ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC4278 FOC/96 IMAGE 256X256 F372M 3710 1 1000S 5 1 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 1240c [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOC/96 FOC/48 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE SPEC ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters PIXEL=25X25 ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GTO/FOC ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 3.70 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES & CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 2 / 1-6; COND IF TAC OK / 1-3; GUID TOL 0.020" / 1-6; ORIENT 280D +/- 10D; ORIENT 10D +/- 10D; DARK TIME / 4-5; ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F502M G450M F275W F372M ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC4278 ------------------------------------------------------------------------------------------------------------------------------------