Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 2295c Report Date: 09-May-96:17:02 Version: ********** Check-in Date: ********** 1.Proposal Title: BLACK HOLES IN ELLIPTICAL GALAXIES ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID GALAXIES & CLUSTERS GO Sub Category NUCLEI/CORES ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Dr. Giuseppina Fabbiano CFA USA 617-495-7203 ------------------------------------------------------------------------------------ 7. Abstract We propose to observe at high resolution the central regions of eight early-type galaxies, for which X-ray and radio continuum data are available. Four of these have radio core power comparable with that of M87, and four are radio quiet. We seek to measure the UV emission of a nonthermal nuclear source, and/or to find evidence of a central stellar spike, which could indicate the presence of a central mass concentration. These measurements will enable us to investigate the origin of nuclear activity in ellipticals with particular reference on the mass of the central black hole as a crucial element. ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 4.50 par: 0 10. Num targs pri: 8 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOC ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 2295c PI: Dr. Giuseppina Fabbiano Proposal Title: BLACK HOLES IN ELLIPTICAL GALAXIES ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Ginevra Trinchieri CFA USA P.I. Giuseppina Fabbiano CFA USA ------------------------------------------------------------------------------------ 3. Description of proposed observations. We have selected eight bright elliptical galaxies of similar optical and x-ray luminosities (Mv ~ -21;-23 and Lx ~1-6 x 10exp(41) ergs/s), but with quite different radio power and morphology. Three of these galaxies host extended, double lobed radio sources, with a powerful radio nucleus; one has a compact central source; the others have a low level radio emission, with low luminosities and small spatial extent. Similar objects are included in the GTO observing programs, usually in studies of the nuclei and central regions of normal galaxies, but with no specific emphasis in comparing similar objects with vastly different radio properties. Three galaxies are in common with the GTO program, and we propose complementary observations to those. The program galaxies are bright and nearby (mb ~ 10-13, D ~ 20-150 Mpc), and the FOC F/96 resolution corresponds to linear resolutions of 2-20 pc. We shall observe each galaxy in three wide band filters, in the ultraviolet, blue and red bands: F175W, F342W and F480LP. The exposure times are calculated to provide a S/N of 10 in each filter. We want to obtain colors in the optical band, that will extend to the very inner regions the shape of the stellar continuum observed at larger radii. They will also provide the normal stellar profile at small radii, so that we can discern a stellar cusp from a non-thermal point source, which should be more prominent in the ultraviolet. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. The aim of our program is to observe the signature of a central mass concentration, which should give rise, if present, to a stellar spike, as observed in M87 (Young et al. 1978, Ap. J. 221, 721). The high resolution of HST, corresponding to a linear resolution of < 2 pc for the closer galaxies, and of ~ 20 pc for the farthest, will allow the detection of a small light concentration over the stellar background. The availability of high resolution imaging in the ultraviolet adds crucial information in obtaining reliable parameters for a central compact nucleus. Typical elliptical galaxies show a rapid decline in their ultraviolet spectra, with a drop in the continuum of a factor of 15 between emission around 3600 A and 2000 A. A non-thermal source will then be enhanced against the weaker background by an equivalent amount. For one of the radio loud galaxies, IC 4296, ground based observations suggest this possibility. These observations are not able to resolve the emission from this source against the strong galactic starlight. The small pixel size of the FOC F/96, corresponding to 6 pc, is crucial for this purpose, because it will reduce the average starlight contamination in the central pixels and enhance the contrast for the detection of a central point source. The average surface brightness of 18 mb arcsecexp(-2) observed in the central few arcsec will be reduced to an average mb 26 per pixel (if the surface brightness has a flat distribution). Page 3 ------------------------------------------------------------------------------------ 5. Description of special scheduling requirements. The observations of these eight galaxies, complemented by the GTO program, will be able to provide good optical and ultraviolet data for the central regions of galaxies with similar x-ray and optical properties and vastly different radio characteristics, to study the range of parameters for central compact sources and their relation to the radio activity of elliptical and S0 galaxies. If we assume M87 as a model galaxy on which to base our expectations, which has comparable radio nuclear luminosities to the radio loud galaxies, a central spike (in M87, mv 16.5, from Young et 1978, Ap. J. 221, 721) should have mv = 20 at the distance of the radio loud objects. For a central surface brightness of 16-18 V magnitudes arcsecexp(-2), the source should be evident against an average surface brightness from stellar light of 24-26 per FOC pixel. With our exposure times, we should moreover be able to detect point sources of about 24 mag in each band (S/N 3), which will ensure the detection of much fainter nuclei than the M87 example. The set of three filter observations, including one minute per observation for a filter change, gives observation lenghts for each galaxy close to the optimum time of 45 minutes. ------------------------------------------------------------------------------------ 7. Data reduction and analysis plans. Initial data reduction and analysis will be performed at STScI so that we may become familiar with the details of the FOC and its operation and with S/W tools. SAO will have the complete HST IRAF package running on its SUN network, so that the bulk of the data analysis will be done at SAO. ------------------------------------------------------------------------------------ 10. Resources to be supplied by investigator's institution(s). Resources to be supplied by the Smithsonian Institution in support of the project include a fully supported SUN network consisting of individual workstations and system S/W. The system presently runs IRAF and is planned to support the STScI data analysis system. An image processing laboratory is also available. ------------------------------------------------------------------------------------ 11. Address Information Name: GIUSEPPINA FABBIANO Category: PI Institution: SMITHSONIAN INSTITUTION Address: 60 GARDEN STREET City: CAMBRIDGE State: MA Zip Code: 02138 Country: Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 2295c [ 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 NGC1316 GALAXY; EARLY TYPE; RA = 03H 20M 47.209S +/- 1950 1 B = 23 CORE 0.015S, DEC = -37D 23' 08.22" +/- 0.23" ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC3998 GALAXY; EARLY TYPE; RA = 11H 55M 20.9S +/- 1", 1950 1 B = 23 CORE DEC = +55D 43' 54.6" +/- 1" ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4382 GALAXY; EARLY TYPE; RA = 12H 22M 53.2S +/- 4", 1950 1 B = 23 CORE DEC = +18D 28' 03" +/- 4" ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC4636 GALAXY; EARLY TYPE; RA = 12H 40M 16.68S +/- 1950 1 B = 23 CORE 0.5", DEC = +02D 57' 41.4" +/- 0.5" ------------------------------------------------------------------------------------------------------------------------------------ 5 IC4296 GALAXY; EARLY TYPE; RA = 13H 33M 47.18S +/- 1950 1 B = 23 CORE 0.1", DEC = -33D 42' 39.4" +/- 0.1" ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC5846 GALAXY; EARLY TYPE; RA = 15H 03M 56.9S +/- 2", 1950 1 B = 23 CORE DEC = +01D 47' 52.5" +/- 2" ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 2295c [ 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 NGC1316 FOC/96 IMAGE 512X512 F480LP, 1 460S 3 1 1 CYCLE 1 / 1-18 F1ND,F2ND ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC1316 FOC/96 IMAGE 512X512 F342W, 1 240S 3 1 1 F1ND ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC1316 FOC/96 IMAGE 512X512 F175W 1 2040S 3 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC3998 FOC/96 IMAGE 512X512 F480LP, 1 460S 3 1 2 F1ND,F2ND ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC3998 FOC/96 IMAGE 512X512 F342W, 1 240S 3 1 2 F1ND ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC3998 FOC/96 IMAGE 512X512 F175W 1 2040S 3 1 2 ------------------------------------------------------------------------------------------------------------------------------------ 7 NGC4382 FOC/48 IMAGE 512X512 F430W 1 460S 3 1 3 ------------------------------------------------------------------------------------------------------------------------------------ 8 NGC4382 FOC/48 IMAGE 512X512 F342W 1 240S 3 1 3 ------------------------------------------------------------------------------------------------------------------------------------ 9 NGC4382 FOC/48 IMAGE 512X512 F175W 1 2040S 3 1 3 ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC4636 FOC/96 IMAGE 512X512 F480LP 1 460S 3 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 11 NGC4636 FOC/96 IMAGE 512X512 F342W 1 240S 3 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 12 NGC4636 FOC/96 IMAGE 512X512 F175W 1 2040S 3 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 13 IC4296 FOC/96 IMAGE 512X512 F480LP 1 460S 3 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 14 IC4296 FOC/96 IMAGE 512X512 F342W 1 240S 3 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 15 IC4296 FOC/96 IMAGE 512X512 F175W 1 2040S 3 1 1 ------------------------------------------------------------------------------------------------------------------------------------ 16 NGC5846 FOC/48 IMAGE 512X512 F430W 1 460S 3 1 2 ------------------------------------------------------------------------------------------------------------------------------------ 17 NGC5846 FOC/48 IMAGE 512X512 F342W 1 240S 3 1 2 ------------------------------------------------------------------------------------------------------------------------------------ 18 NGC5846 FOC/48 IMAGE 512X512 F175W 1 2040S 3 1 2 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 2295c [ 6] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOC/96 FOC/48 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 4.50 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES & CLUSTERS ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category NUCLEI/CORES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CYCLE 1 / 1-18 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F480LP,F1ND,F2ND F342W,F1ND F175W F430W F342W F480LP ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC1316 NGC3998 NGC4382 NGC4636 IC4296 NGC5846 ------------------------------------------------------------------------------------------------------------------------------------