7455( 3) - 05/20/97 15:36 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7455 Version: 3 Check-in Date: 20-May-1997 15:36:06 1.Proposal Title: The inner region of the starburst galaxy NGC5102. ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle GALAXIES GO 7 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: SYLVIE F. BEAULIEU INSTITUTE OF ASTRONOMY CoI: Kenneth Freeman Mount Stromlo and Siding Spring N Observatories CoI: Colin Norman Johns Hopkins University N ------------------------------------------------------------------------------------ 6. Abstract NGC 5102 is a nearby (3.5 Mpc) galaxy of classical SO appearance which has undergone a recent starburst in its nucleus, bulge and disk. Because it is so close, it provides a unique opportunity to investigate the upper end of the IMF for a typical starburst, the mass of starburst matter relative to the underlying older population, and the effect of the starburst on the largescale structure of this galaxy. We have excellent deep B and V WFPC2 images for this purpose; these images show that the surface brightness distribution follows closely a very steep power law, I(r) \propto r^-1.28, from r = 350 pc in to at least r = 0.15 arcsec = 3 pc. This very steep cusp distribution is steeper than the cusps of any of the ellipticals in the HST sample of Byun et al. (1996). We would like to understand the nature of this steep and extended power law distribution, with later application to its kinematics, including the possibility of a kinematically distinct core and a central black hole in this very steep-cusped bulge. The inner region is affected by dust obscuration, and we are requesting H and K images of NGC 5102 with NICMOS, to make a definitive measurement of the light distribution in its inner regions. The HST is required for its high spatial resolution. The H and K images will also be used to correct our WFPC2 stellar photometry for reddening, with the aid of radiative transfer models for dusty galaxies. This proposal is part of a larger program on this important galaxy, involving extensive groundbased optical and radio observations. ------------------------------------------------------------------------------------ 7455( 3) - 05/20/97 15:36 - [ 2] Observations Description ------------------------ We propose a single pointing with NICMOS/NIC2 centered on the nucleus of NGC 5102. The total exposure time is set by our goal to get adequate K-band surface photometry at full spatial resolution out to a radius of about 5 arcsec. This is required to do the best possible correction of the interstellar reddening by the highly structured dust in the inner regions of NGC 5102. The surface brightness distribution derived from our WFPC2 images indicates that the power law cusp continues in to the center of the galaxy, unresolved at HST resolution. If this is so, we estimate that the peak surface brightness will reach 7.9 K mag arcsec^-2 and 8.0 H mag arcsec^-2 in the central pixel. To avoid saturation, the individual K-band and H-band exposures should not exceed 50 sec and 20 sec respectively. For the K-band observations, we propose an eight-position TWO-CHOP for the first orbit, chopping to sky about 115 arcsec away from the nucleus, along the minor axis of NGC 5102. At each position, we would take 5 * 32 sec exposures to avoid saturation on source, for a total of 640 sec on source in the first orbit. In the second orbit we would do a four- position TWO-CHOP, with 5 * 48 sec exposures at each position. This gives an additional 480 sec on source. This total exposure of 1120 sec gives an adequate S/N of 17 on a 0.2 arcsec scale at a radius of 5 arcsec. We would then use the remainder of the second orbit for the H-band observations. The individual exposures would be 16 sec to avoid saturation, and we would start a series of 3 integrations on the background field followed by a series of 38 integrations on source. This gives 608 sec on source and an excellent S/N of 73 on a 0.2 arcsec scale at a radius of 5 arcsec. We will use MULTIACCUM mode to ensure useful data at the very bright center of the galaxy. Real Time Justification ----------------------- NONE An extensive program of groundbased optical and near-IR imaging and optical spectroscopy of NGC 5102 is well under way, to investigate the structure and kinematics of the young and older populations in this system and the chemical properties of its resolved HII regions. The optical imaging with the SSO 40-inch telescope and 2K CCD is aimed at UBVI surface photometry of the entire galaxy (diameter D_25= 9 arcmin), for the purpose of measuring the distribution of surface brightness and color, and so to constrain the radial distribution of the mass fraction and age of the starburst. The optical surface photometry is complemented by JHK mosaic mapping of the entire galaxy with the SSO 2.3-m telescope. We are also measuring the distribution of Balmer and metallic line strengths in the inner 3 arcmin = 3 kpc of NGC 5102, from deep spectra in several position angles (resolution 1.1 Angstrom). The spectra and the optical and near-IR surface photometry will be used for population synthesis studies: the goal again is to derive the distribution of age and mass fraction of the starburst. The spectra will also be used to measure the kinematics of the bulge, to see if the starburst has any identifiable kinematic signature like a kinematically distinct core. We will also make 21-cm HI synthesis observations of NGC 5102, using the Australia Telescope, with a spatial resolution of 6 arcsec = 100 pc and a velocity resolution of about 7 km s^-1. The goal here is to study the detailed kinematics of the gas responding to galactic winds and supershells resulting from the starburst. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 7455( 3) - 05/20/97 15:36 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 7455( 3) - 05/20/97 15:36 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC5102 GALAXY,STARBURST,GALAXY RA=13H 21M 57.7S +/- 0.15S,DEC=- J2000 V = 454 SURF-BKG(B) = 10.6+/-0.2 ,NUCLEUS 36D 37' 49.5" +/- 2" SURF-BKG(K) = 7.9+/-0.2 H-K = 0.1+/-0.2 E(B-V) = 0.1+/-0.05 2 NGC5102- GALAXY,STARBURST,GALAXY RA=13H 22M 4.5S +/- 0.15S,DEC=- J2000 V = 454 SURF-BKG(B) = 26.0+/-0.5 BKGRD2 ,NUCLEUS 36D 39' 12.5" +/- 2" B-V = -0.2+/-0.1 E(B-V) = 0.1+/-0.05 7455( 3) - 05/20/97 15:36 - [ 5] Visit: 01 Visit Requirements: PCS MODE FINE 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 NGC5102 NIC2 MULTIAC NIC2 F222M PATTERN=TWO-CHOP,CHOP-SIZE=115, 5 DEF CUM PATTERN-ORIENT=47,NUM-POS=8, OFFSET=SAM,SAMP-SEQ=STEP32, NSAMP=8 ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC5102 NIC2 MULTIAC NIC2 F222M PATTERN=TWO-CHOP,CHOP-SIZE=115, 6 DEF CUM PATTERN-ORIENT=47,NUM-POS=4, OFFSET=SAM,SAMP-SEQ=STEP32, NSAMP=8 ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC5102-BKG NIC2 MULTIAC NIC2 F160W PATTERN=NONE,SAMP-SEQ=STEP32, 3 DEF RD2 CUM NSAMP=6 ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC5102 NIC2 MULTIAC NIC2 F160W PATTERN=NONE,SAMP-SEQ=STEP32, 63 DEF CUM NSAMP=6 ------------------------------------------------------------------------------------------------------------------------------------ 7455( 3) - 05/20/97 15:36 - [ 6] Summary Form for Proposal 7455 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations NIC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes MULTIACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters PATTERN=TWO-CHOP CHOP-SIZE=115 PATTERN-ORIENT=47 NUM-POS=8 OFFSET=SAM SAMP-SEQ=STEP32 NSAMP=8 NUM-POS=4 NSAMP=6 PATTERN=NONE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category GALAXIES ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PCS MODE FINE ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F222M F160W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC5102 NGC5102-BKGRD2 ------------------------------------------------------------------------------------------------------------------------------------