8677( 7) - 05/10/01 13:18 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8677 Version: 7 Check-in Date: 10-May-2001 13:18:05 1.Proposal Title: Extragalactic Novae: the Maximum Magnitude - Rate of Decline Relation in NGC 4472 ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 9 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Laura Ferrarese Rutgers the State University of New Jersey CoI: Dr. Patrick C\^ote California Institute of Technology N ------------------------------------------------------------------------------------ 5. Abstract The two goals of this proposal are: (1) to provide the first homogeneous observational constraints on theoretical models for novae outbursts; and (2) to assess the reliability of novae as standard candles. We propose to accomplish these goals by using WFPC2 to collect well sampled light curves for 20-50 novae in the supergiant elliptical galaxy NGC 4472, the brightest galaxy within 30 Mpc. Both the length of the observing window and the temporal sampling of the observations are specifically designed to ensure that the novae peak magnitudes and decline rates are measured accurately. These data will be used to construct the first `Maximum Magnitude versus Rate of Decline' (MMRD) relation for a galaxy beyond the Local Group. This relation is not only a potentially powerful standard candle, but its shape and dispersion are directly linked to physical parameters which govern the physics of novae outbursts such as the white dwarf mass, temperature and mass accretion rate. At present, it is impossible to investigate the universality of the MMRD relation since there exist no more than 30 extra-galactic novae with well sampled light curves (most in M31 and the LMC). Our short survey will therefore double the sample of novae light curves accumulated during the past century, and will provide the first strong observational constraints on theoretical models of novae production and outburst. ------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 2] Observations Description ------------------------ In planning these observations, we must take into account two major issues: (1) the temporal spacing of the observations must be optimized so that the novae light curves are well sampled; and (2) the exposure times must be chosen so that the light curves can be followed for at least two magnitudes after maximum in order to construct a MMRD relation. Furthermore, it is important that the field: (1) be observed without changing the telescope roll angle; and (2) is located where the largest number of novae will be found, yet at the same time has a background level faint enough to allow detection of the faintest novae two magnitudes below maximum. The time taken by novae to decline by two magnitudes after maximum can vary between a couple of days to about 100 days. Based on the observational data of Duerbeck (1987, see also Figure 1), we expect most of the novae to have a decline time <= 60 days. The maximum length of time HST can observe the same field without changing the roll angle (a critical requirement for our program) is about 60 days, which would allow us to follow 20\ of the 20-day novae for two magnitudes after maximum. A must in defining the MMRD relation is to obtain good estimates of the maximum magnitude. For each galaxy, we propose to use the F555W filter at 19 epochs, the first 12 very finely spaced (2 days apart), and the last 7 obtained 5 days apart. At epochs 13 to 17 we propose to obtain F814W images as well as F555W. We will use this color information to constrain the magnitude at maximum for the novae which outburst during the less finely sampled period, following the procedure used by Ferrarese et al. (1996). This procedure is based on the observation that the color of novae at maximum is close to zero; extrapolating the novae color along the light curve will aid in estimating the time of outburst and, as a result, the maximum magnitude. We expect ~ 12 outbursts in the 20 days sampled at 2-day intervals, all of which will have a very well determined maxima (i.e., to within 0.1 mag). The high-quality light curves of these novae will then be used to build templates which will aid in the analysis of the light-curves for those novae which undergo outburst during the less finely sampled period, or for which the ~ 60-day window ends before the light curve can be followed down by two magnitudes. In this scheme, the total observing window will be 57 days. The reason for placing the finely sampled epochs at the beginning of the observing sequence is to assure that all of the novae observed in this period will have a light curve covering at least two magnitudes. The Cepheid distance modulus to Virgo is 31.04 mag (Ferrarese Etal 1999b). V magnitudes of novae at maximum range from -9 to -7 (Figure 1), and the nova light curves need to be followed down for at least two magnitudes after maximum in order to derive the decline rate. This suggests that we must optimize our observations for the detection of objects with V magnitudes between ~ 22 and ~ 26. At the faint end, the limiting magnitude for detection of an object against a background depends, of course, on the background brightness. Figure 4 shows the recovery rate for a randomly distributed sample of stars with V magnitudes between 23 and 29 as a function of the background brightness, using the WFPC2/F555W and a 2200 second exposure (roughly 1 orbit once overhead is accounted for). This figure demonstrates that, in order to achieve a recovery rate of at least 50\ background no brighter than Mu_V = 18 mag arcsec^-2. A Digitized Sky Survey image of NGC 4472 is shown in Figure 5. By placing the center of the pyramid at the center of the galaxy, we will be able to maximize the total magnitude enclosed by the WFPC2 field and thereby detect 20-50 novae in our observing window. This calculation excludes the central region of the galaxy where the surface brightness exceeds Mu_V = 18 mag arcsec^-2. Note that the above estimate for the number of detected novae is most likely a lower limit: even against a background of 18 V mag arcsec^-2, we will still be able to detect 50\ and therefore derive complete light curves for all but the faintest objects. Discovering and monitoring novae in NGC 4472 should not present any technical challenge as far as the photometric analysis is concerned: observations of Cepheid variables as far as the Virgo and Fornax clusters are now routine (see Silbermann et al. Etal 1999 and Ferrarese Etal 1996 for specific examples), and novae at peak are brighter than Cepheids (and are the most luminous objects in elliptical galaxies). In summary, one orbit of HST time is needed in both the F555W and F814W filters at each epoch. Given the fact that we propose to observe NGC 4472 at 19 epochs (five of which in both V and I), we request a total of 24 orbits. Real Time Justification ----------------------- While the observations are not time-critical, once they have begun, they should be carried out in the exact sequence outlined in the previous section, without interruption or omission, to ensure optimum coverage of the novae light curves. All observations should also be carried out at the same roll angle. No supporting or coordinated observations required. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4472 GALAXY, Elliptical RA=12H 29M 48.00S +/- 0.25S, J2000 V=+983 V = 8.41+/-0.06 DEC=07D 59' 43.2" +/- 3.75" B-V = 0.96+/-0.09 Coordinate Source: OTHER_SOURCE 8677( 7) - 05/10/01 13:18 - [ 4] Visit: 01 Visit Priority: Visit Requirements: ORIENT 130D TO 135D 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 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 5] Visit: 02 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 2D TO 2.1D 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 ------------------------------------------------------------------------------------------------------------------------------------ 20 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG 0.6, 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 6] Visit: 03 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 4D TO 4.1D 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 ------------------------------------------------------------------------------------------------------------------------------------ 30 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG 0.6, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 7] Visit: 04 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 6D TO 6.1D 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 ------------------------------------------------------------------------------------------------------------------------------------ 40 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG 0.0, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 8] Visit: 05 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 8D TO 8.1D 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 ------------------------------------------------------------------------------------------------------------------------------------ 50 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG -0.6, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 9] Visit: 06 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 10D TO 10.12D 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 ------------------------------------------------------------------------------------------------------------------------------------ 70 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG -0.6, 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 10] Visit: 07 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 12D TO 12.12D 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 ------------------------------------------------------------------------------------------------------------------------------------ 70 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG -0.6,-0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 11] Visit: 08 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 14D TO 14.2D 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 ------------------------------------------------------------------------------------------------------------------------------------ 80 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG 0.0,-0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 12] Visit: 09 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 16D TO 16.2D 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 ------------------------------------------------------------------------------------------------------------------------------------ 90 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG 0.6,-0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 13] Visit: 10 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 18D TO 18.2D 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 ------------------------------------------------------------------------------------------------------------------------------------ 100 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 14] Visit: 11 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 55D TO 57D 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 ------------------------------------------------------------------------------------------------------------------------------------ 110 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG 0.6, 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 15] Visit: 12 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 22D TO 22.2D 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 ------------------------------------------------------------------------------------------------------------------------------------ 120 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG 0.6, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 16] Visit: 13 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 24D TO 24.2D 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 ------------------------------------------------------------------------------------------------------------------------------------ 130 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG 0.0, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 17] Visit: 14 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 26D TO 26.2D 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 ------------------------------------------------------------------------------------------------------------------------------------ 140 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG -0.6, 0.6 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 18] Visit: 15 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 31D TO 31.2D 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 ------------------------------------------------------------------------------------------------------------------------------------ 150 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG -0.6, 0.0 ------------------------------------------------------------------------------------------------------------------------------------ 151 NGC4472 WFPC2 IMAGE PC1-FIX F814W 7921 CR-SPLIT=DEF 1 2600 S SAME POS AS 150 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 19] Visit: 16 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 36D TO 36.2D 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 ------------------------------------------------------------------------------------------------------------------------------------ 160 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG -0.6,-0.6 ------------------------------------------------------------------------------------------------------------------------------------ 161 NGC4472 WFPC2 IMAGE PC1-FIX F814W 7921 CR-SPLIT=DEF 1 2600 S SAME POS AS 160 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 20] Visit: 17 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 41D TO 41.2D 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 ------------------------------------------------------------------------------------------------------------------------------------ 170 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG 0.0,-0.6 ------------------------------------------------------------------------------------------------------------------------------------ 171 NGC4472 WFPC2 IMAGE PC1-FIX F814W 7921 CR-SPLIT=DEF 1 2600 S SAME POS AS 170 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 21] Visit: 18 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 46D TO 46.2D 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 ------------------------------------------------------------------------------------------------------------------------------------ 180 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S POS TARG 0.6,-0.6 ------------------------------------------------------------------------------------------------------------------------------------ 181 NGC4472 WFPC2 IMAGE PC1-FIX F814W 7921 CR-SPLIT=DEF 1 2600 S SAME POS AS 180 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 22] Visit: 19 Visit Priority: Visit Requirements: SAME ORIENT AS 1; AFTER 1 BY 51D TO 51.2D 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 ------------------------------------------------------------------------------------------------------------------------------------ 190 NGC4472 WFPC2 IMAGE PC1-FIX F555W 5398 CR-SPLIT=DEF 1 2400 S ------------------------------------------------------------------------------------------------------------------------------------ 191 NGC4472 WFPC2 IMAGE PC1-FIX F814W 7921 CR-SPLIT=DEF 1 2600 S SAME POS AS 190 ------------------------------------------------------------------------------------------------------------------------------------ 8677( 7) - 05/10/01 13:18 - [ 23] Summary Form for Proposal 8677 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1-FIX ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 130D TO 135D SAME ORIENT AS 1; AFTER 1 BY 2D TO 2.1D POS TARG 0.6, 0.0 SAME ORIENT AS 1; AFTER 1 BY 4D TO 4.1D POS TARG 0.6, 0.6 SAME ORIENT AS 1; AFTER 1 BY 6D TO 6.1D POS TARG 0.0, 0.6 SAME ORIENT AS 1; AFTER 1 BY 8D TO 8.1D POS TARG -0.6, 0.6 SAME ORIENT AS 1; AFTER 1 BY 10D TO 10.12D POS TARG -0.6, 0.0 SAME ORIENT AS 1; AFTER 1 BY 12D TO 12.12D POS TARG -0.6,-0.6 SAME ORIENT AS 1; AFTER 1 BY 14D TO 14.2D POS TARG 0.0,-0.6 SAME ORIENT AS 1; AFTER 1 BY 16D TO 16.2D POS TARG 0.6,-0.6 SAME ORIENT AS 1; AFTER 1 BY 18D TO 18.2D SAME ORIENT AS 1; AFTER 1 BY 55D TO 57D SAME ORIENT AS 1; AFTER 1 BY 22D TO 22.2D SAME ORIENT AS 1; AFTER 1 BY 24D TO 24.2D SAME ORIENT AS 1; AFTER 1 BY 26D TO 26.2D SAME ORIENT AS 1; AFTER 1 BY 31D TO 31.2D SAME POS AS 150 SAME ORIENT AS 1; AFTER 1 BY 36D TO 36.2D SAME POS AS 160 SAME ORIENT AS 1; AFTER 1 BY 41D TO 41.2D SAME POS AS 170 SAME ORIENT AS 1; AFTER 1 BY 46D TO 46.2D SAME POS AS 180 SAME ORIENT AS 1; AFTER 1 BY 51D TO 51.2D SAME POS AS 190 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC4472 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 5398 7921 ------------------------------------------------------------------------------------------------------------------------------------