5933( 4) - 11/21/95 21:13 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5933 Version: 4 Check-in Date: ********** 1.Proposal Title: UV Spectroscopy of the Starburst Regions in Arp 299 ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Galaxies & Clusters GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Susan Neff NASA/GSFC CoI: Adam Stanford JPL Y CoI: Bill Vacca UC-Berkeley N CoI: Marshall Joy NASA/MSFC N ------------------------------------------------------------------------------------ 6. Abstract We propose to obtain FOS UV spectroscopy of the main starburst regions in the interacting galaxy system Arp 299 (=NGG3690/IC694). In Cycle 2 we obtained FOC UV images to locate the brightest UV knots in this pair of colliding galaxies, which many other wavelength regimes show to be the site of intense star formation. We will use spatially- resolved UV spectra of the starburst knots to place constraints on the ages, duration, and upper mass cut-off of the bursts. The relationship of these ages to the kinematics of the collision will be used to investigate the way the dynamics of a collision controls the location, strength and timing of starbursts in interacting galaxies. ------------------------------------------------------------------------------------ 5933( 4) - 11/21/95 21:13 - [ 2] Observations Description ------------------------ For each of 7 starburst regions we want to obtain a ~one hour exposure with the G160L grating on the FOS blue side with the 1.0 aperture. The aperture size is dictated by the separation of the emission regions, each of which is nearly a point source but only several arcsec apart. With the 1.0 aperture the observation will get nearly all of the flux from one region without including light from any other region. The G160L grating on the blue side was selected because it covers the necessary wavelength range for measuring the important aborption and emission lines produced by massive stars including Si iv Lambda 1400, C iv Lambda 1550, He ii Lambda 1640, and C iii Lambda 1909. The resulting wavelength resolution of ~6.5 Angstrom is sufficiently high to achieve our scientific goals. The ~one hour exposures will result in S/N=15 per diode on average for each starburst region at Lambda 1500 Angstrom. This exposure time was calculated based on the flux measured for each starburst region in our FOC UV images, and the curve shown in Figure 1.2.3 of the FOS Handbook for the G160L grating. For example, for region B1, the measured flux in a 0.9 arcsec aperture is 25 counts/s, which is equivalent to ~5.5 * 10^-16 erg s^-1 ang^-1 cm^-2. This value must be corrected by a factor of ~3 for the pre-COSTAR PSF, which brings the flux density in region B1 to ~1.6 * 10^-15 erg s^-1 ang^-1 cm^-2. The curve for the G160L grating in Figure 1.2.3 shows a count rate of ~0.4 per diode for F_Lambda= 1 * 10^-14 erg s^-1 ang^-1 cm^- 2. So the predicted count rate for B1 is 0.065 per diode, and to reach S/N=15 per diode a 57 minute exposure is required. The FOC UV image in Figure 1 shows the main knots of UV emission in the two galaxies of the Arp 299 system. We intend to obtain an UV spectrum of each of the 5 main knots, plus two smaller knots in region C, to achieve our scientific goal of mapping the progression of starbursts relative to the dynamics of the galaxy collision. Note that the observations will be very efficient (80%) because of the location of Arp 299 in the CVZ , and because they can be done as one visit. The total time required is 6 orbits, based on an average exposure time of 65 minutes per exposure for 7 knots, 9 minutes of ACQ/BINARY for each knot, 6 minutes of overhead per exposure for the ACCUM mode, and 12 minutes for the initial GS acquisition. Real Time Justification ----------------------- The position of Arp 299 places it in a CVZ, which we want to take advantage of for efficiency. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 5933( 4) - 11/21/95 21:13 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5933( 4) - 11/21/95 21:13 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC3690- GALAXY, INTERACTING RA=11H 28M 29.92S +/- 0.05S, 2000 V = V = 17.0 +/- 0.3 B-V = 0.3 +/- 0.1 E(B- OFFSET GALAXY, STARBURST DEC=58D 33' 40.1" +/- 0.5" +3150 V) = 0.2 +/- 0.02 F(2000) = 1.2 +/- 0.3 E-15 Comments: V mag is within 1 arcsec aperture 2 NGC3690-B1 GALAXY, INTERACTING RA-OFF = +1.00S +/- 0.05S, DEC- 2000 V = V = 16.9 +/- 0.3 B-V = 0.3 +/- 0.1 E(B- GALAXY, STARBURST OFF = +0.1" +/- 0.1", FROM 1 +3150 V) = 0.22 +/- 0.02 F(2000) = 1.6 +/- 0.3 E-15 3 NGC3690-B2 GALAXY, INTERACTING RA-OFF = +0.89S +/- 0.05S, DEC- 2000 V = V = 16.9 +/- 0.3 B-V = 0.3 +/- 0.1 E(B- GALAXY, STARBURST OFF = +2.7" +/- 0.1", FROM 1 +3150 V) = 0.22 +/- 0.02 F(2000) = 1.6 +/- 0.3 E-15 4 NGC3690-B3 GALAXY, INTERACTING RA-OFF = +0.97S +/- 0.05S, DEC- 2000 V = V = 16.7 +/- 0.3 B-V = 0.3 +/- 0.1 E(B- GALAXY, STARBURST OFF = +4.6" +/- 0.1", FROM 1 +3150 V) = 0.22 +/- 0.02 F(2000) = 1.6 +/- 0.3 E-15 5 NGC3690-C1 GALAXY, INTERACTING RA-OFF = +0.73S +/- 0.05S, DEC- 2000 V = V = 17.9 +/- 0.3 B-V = 0.2 +/- 0.1 E(B- GALAXY, STARBURST OFF = +8.6" +/- 0.1", FROM 1 +3150 V) = 0.24 +/- 0.02 F(2000) = 1.0 +/- 0.2 E-15 6 NGC3690-A GALAXY, INTERACTING RA-OFF = +3.29S +/- 0.05S, DEC- 2000 V = V = 17.2 +/- 0.3 B-V = 0.3 +/- 0.1 E(B- GALAXY, STARBURST OFF = +2.9" +/- 0.1", FROM 1 +3150 V) = 0.42 +/- 0.02 F(2000) = 0.6 +/- 0.1 E-15 5933( 4) - 11/21/95 21:13 - [ 5] Visit: 01 Visit Requirements: CVZ 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 NGC3690- FOS/BL ACQ/BIN 4.3 MIRROR 1 54S ONBOARD ACQ FOR 2 OFFSET ARY ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC3690- FOS/BL ACCUM 1.0- G160L 1150- STEP- 1 5000S OFFSET PAIR-A 2510 PATT=SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC3690-B1 FOS/BL ACCUM 1.0- G160L 1150- STEP- 1 3500S PAIR-A 2510 PATT=SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC3690-B2 FOS/BL ACCUM 1.0- G160L 1150- STEP- 1 3500S PAIR-A 2510 PATT=SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC3690-B3 FOS/BL ACCUM 1.0- G160L 1150- STEP- 1 3500S PAIR-A 2510 PATT=SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC3690-C1 FOS/BL ACCUM 1.0- G160L 1150- STEP- 1 5600S PAIR-A 2510 PATT=SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 7 NGC3690-A FOS/BL ACCUM 1.0- G160L 1150- STEP- 1 7610S PAIR-A 2510 PATT=SINGLE ------------------------------------------------------------------------------------------------------------------------------------ 5933( 4) - 11/21/95 21:13 - [ 6] Summary Form for Proposal 5933 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/BINARY ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters STEP-PATT=SINGLE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Galaxies & Clusters ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements CVZ ONBOARD ACQ FOR 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G160L ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC3690-OFFSET NGC3690-B1 NGC3690-B2 NGC3690-B3 NGC3690-C1 NGC3690-A ------------------------------------------------------------------------------------------------------------------------------------