9739( 6) - 08/21/03 10:26 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9739 Version: 6 Check-in Date: 21-Aug-2003 10:24:28 1.Proposal Title: Are We Missing the Dominant Sites of Star Formation in Local UV-Bright Starbursts? ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 12 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Dr. Rupali Chandar Space Telescope Science Institute CoI: Dr. Claus Leitherer Space Telescope Science Institute N CoI: Dr. Daniela Calzetti Space Telescope Science Institute N ------------------------------------------------------------------------------------ 5. Abstract We propose to explore the ages, extinctions, and masses of young stellar clusters in four nearby dwarf starburst galaxies (He 2-10, NGC 5253, NGC 4214, and IIZw40). We will combine available archival data with new, high resolution HST observations from the ultraviolet to the infrared. All four galaxies are known from ground based radio/infrared observations to contain highly obscured, massive stellar clusters, which dominate the far infrared flux. Despite the fact that almost all of the infrared flux comes from regions which are obscured at UV and optical wavelengths, these galaxies are consistent with the well known correlation between the UV slope (beta) and the ratio of far infrared flux to ultraviolet flux at 1600 Angstroms. Because the UV and IR fluxes are decoupled, this observation implies that a simple foreground screen model, where UV photons from hot stars are reprocessed into the infrared by local dust, is not the proper interpretation for why these galaxies follow the beta relation. We propose to investigate the underlying mechanisms responsible for this observed correlation in these UV bright galaxies, and explore the implication for high redshift starbursts. ------------------------------------------------------------------------------------ 9739( 6) - 08/21/03 10:26 - [ 2] Observations Description ------------------------ STIS observations: We give calculated exposure times based on He2-10 (one of the more distant galaxies in our sample) as a n example. Our requirement that we reach the faintest clusters observed in available optical archival WFPC2 V band images with a S/N > 30 is achieved in 1500 s with the NUV+F25QTZ, according to the STIS exposure time calculator. The available V-I colors ofr these optically bright clusters is consistent with all of them having formed coevally. We also checked that older clusters visible in the optical images can be reached by our calculated exposure time of 1500 s. The ages of these older objects will help us construct the cluster formation history of the galaxies. In the FUV+F25QTZ, to reach comparable faint young stellar populationss requires about 60 minutes. We note that based on exposure times calculated from STIS FUV spectra from our program GO9036, the very luminous cluster in NGC4214 just exceeds the MAMA brightness limits. Thus for this object, we use the narrower STIS NUV filters. NICMOS: For He2-10 and NGC 4214, each NICMOS observation will consist of Paschen alpha, continuum, and J-H-K broadband imaging. II Zw40 only requires J and K imaging. Our previous experience shows that the extra time spent obtaining a narrowband exposure for the underlying continuum provides a much more reliable continuum subtraction and Paschen alpha photometry and better spatial PSF matching relative to using the F160W filter for continuum subtraction. We give exposure times for NIC2 (which gives an optimal compromise between angular resolution and field of view). Each set of exposures will be taken with a 4-position dither to maximize recovery of spatial information and rejection of cosmic rays and CR-persistence. From the SNAP-9360 images, the typical Paschen alpha line surface brightness of our galaxies is 4.5x10^-5 Jy/arcsec^2 and the H band continuum surface brightness is 5x10^-5 Jy/arcsec^-2. The NICMOS ETC shows that 4 exposures of 500 s each in F187N and in F190N will achieve S/N=8-10 per resolution element for the continuum subtracted line emission. For each of the J, H, and K band imaging, we have based our exposure times on available ground based fluxes; however the poor resolution available for these images makes it difficult to know exactly the level of individual sources in each of these filters. Our best estimates show that we can reach J_AB, H_AB=24.3 and K_AB=21.8 in 4x250s in J and K, and 4x200 s in H. At the distance of He2-10, this corresponds to, for example, J_abs=-6.3, which should allow us to reach the young embedded clusters in this galaxy, and provide the first high resolution IR view of these dwarf starbursts. ACS: IIZW40 is the only galaxy in our sample which does not have available optical HST Halpha, V and I band imaging. He2-10, which is located at the same distance as IIZw40 does have Halpha imaging available, and we use these observations to determine the exposure time needed. Accounting for a factor 3 difference in QE between WFPC2 and ACS at this wavelength, we need 20 minutes exposure in Halpha. Similarly, approximately 10 minutes in V and I filters should be sufficient to reach the clusters with a minimum S/N of 30. Real Time Justification ----------------------- Calibration Justification ------------------------- 9739( 6) - 08/21/03 10:26 - [ 3] Additional Comments ------------------- ------------------------------------------------------------------------------------ 9739( 6) - 08/21/03 10:26 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HE210 GALAXY, STARBURST RA=08H36M15.0S +/- 0.1", DEC=- J2000 V = 12.45 26D24'34.0" +/- 0.1", PLATE- ID=05XX Coordinate Source: HST_IMAGE 2 NGC5253 GALAXY, STARBURST RA=13H39M56.0S +/- 0.1", DEC=- J2000 V = 10.87 31D38'25.0" +/- 0.1", PLATE- ID=02IZ Coordinate Source: HST_IMAGE 3 NGC4214 GALAXY, STARBURST RA=12H15M39.8S +/- 0.1", J2000 V = 10.24 DEC=+36D19'34.0" +/- 0.1", PLATE-ID=00Y2 Coordinate Source: HST_IMAGE 4 IIZW40 GALAXY, STARBURST RA=05H55M42.63S +/- 0.1", J2000 V = 15.48 DEC=+03D23'31.8" +/- 0.1", PLATE-ID=04YQ Coordinate Source: GUIDE_STAR_CATALOG 9739( 6) - 08/21/03 10:26 - [ 5] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type STIS-MAMA-BOX Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.275 Coordinate_Frame POS-TARG Pattern_Orient 26.6 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type NIC-SPIRAL-DITH Pattern_Purpose DITHER Number_Of_Points 4 Point_Spacing 0.8 Coordinate_Frame POS-TARG Pattern_Orient 0.0 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type LINE Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.246 Coordinate_Frame POS-TARG Pattern_Orient 0.0 Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 9739( 6) - 08/21/03 10:26 - [ 6] Visit: 01 Visit Priority: Visit Requirements: 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 HE210 STIS/F ACCUM F25QTZ MIRROR 1 1400 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 2 HE210 STIS/N ACCUM F25CN27 MIRROR 1 500 S UV-MAM 0 A ------------------------------------------------------------------------------------------------------------------------------------ 3 HE210 STIS/N ACCUM F25CN27 MIRROR 1 500 S POS TARG 0.246, 0 UV-MAM 0 A ------------------------------------------------------------------------------------------------------------------------------------ 4 HE210 STIS/F ACCUM F25QTZ MIRROR 1 950 S POS TARG 0.246, 0 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 5 HE210 STIS/F ACCUM F25QTZ MIRROR 1 950 S POS TARG -0.246, 0 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 6 HE210 STIS/N ACCUM F25CN27 MIRROR 1 500 S POS TARG -0.246, 0 UV-MAM 0 A ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Visit Id| Exp Id |Primary |Secondary |Iteration |CR-SPLIT |Orbit Num |Duration | |Pattern Pos |Pattern Pos |Num |Num | | ------------------------------------------------------------------------------------------------------------------------------------ 01 1 none none none none 1 tbd 01 2 none none none none 1 tbd 01 3 none none none none 1 tbd 01 4 none none none none 2 tbd 01 5 none none none none 2 tbd 01 6 none none none none 2 tbd 9739( 6) - 08/21/03 10:26 - [ 7] Visit: 02 Visit Priority: Visit Requirements: 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 HE210 NIC2 ACCUM NIC2-FI F110W 1 250 S PATTERN 2 1-5 X ------------------------------------------------------------------------------------------------------------------------------------ 2 HE210 NIC2 ACCUM NIC2-FI F160W 1 200 S X ------------------------------------------------------------------------------------------------------------------------------------ 3 HE210 NIC2 ACCUM NIC2-FI F222M 1 250 S X ------------------------------------------------------------------------------------------------------------------------------------ 4 HE210 NIC2 ACCUM NIC2-FI F187N 1 500 S X ------------------------------------------------------------------------------------------------------------------------------------ 5 HE210 NIC2 ACCUM NIC2-FI F190N 1 500 S X ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Visit Id| Exp Id |Primary |Secondary |Iteration |CR-SPLIT |Orbit Num |Duration | |Pattern Pos |Pattern Pos |Num |Num | | ------------------------------------------------------------------------------------------------------------------------------------ 02 1 1 none none none 1 300.0 02 1 2 none none none 1 300.0 02 1 3 none none none 2 360.0 02 1 4 none none none 3 360.0 02 2 1 none none none 1 250.0 02 2 2 none none none 1 250.0 02 2 3 none none none 2 320.0 02 2 4 none none none 3 310.0 02 3 1 none none none 1 310.0 02 3 2 none none none 1 320.0 02 3 3 none none none 2 360.0 02 3 4 none none none 3 360.0 02 4 1 none none none 1 tbd 02 4 2 none none none 2 600.0 02 4 3 none none none 2 600.0 02 4 4 none none none 3 600.0 02 5 1 none none none 1 tbd 02 5 2 none none none 2 600.0 02 5 3 none none none 3 600.0 02 5 4 none none none 3 600.0 9739( 6) - 08/21/03 10:26 - [ 8] Visit: 03 Visit Priority: Visit Requirements: 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 NGC5253 STIS/F ACCUM F25QTZ MIRROR 1 1400 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC5253 STIS/N ACCUM F25CN27 MIRROR 1 500 S UV-MAM 0 A ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC5253 STIS/N ACCUM F25CN27 MIRROR 1 500 S POS TARG 0.246, 0 UV-MAM 0 A ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC5253 STIS/F ACCUM F25QTZ MIRROR 1 950 S POS TARG 0.246, 0 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC5253 STIS/F ACCUM F25QTZ MIRROR 1 950 S POS TARG -0.246, 0 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 6 NGC5253 STIS/N ACCUM F25CN27 MIRROR 1 500 S POS TARG -0.246, 0 UV-MAM 0 A ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Visit Id| Exp Id |Primary |Secondary |Iteration |CR-SPLIT |Orbit Num |Duration | |Pattern Pos |Pattern Pos |Num |Num | | ------------------------------------------------------------------------------------------------------------------------------------ 03 1 none none none none 1 tbd 03 2 none none none none 1 tbd 03 3 none none none none 1 tbd 03 4 none none none none 2 tbd 03 5 none none none none 2 tbd 03 6 none none none none 2 tbd 9739( 6) - 08/21/03 10:26 - [ 9] Visit: 04 Visit Priority: Visit Requirements: 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 IIZW40 STIS/F ACCUM F25QTZ MIRROR 1 1400 S UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 2 IIZW40 STIS/N ACCUM F25CN27 MIRROR 1 500 S UV-MAM 0 A ------------------------------------------------------------------------------------------------------------------------------------ 3 IIZW40 STIS/N ACCUM F25CN27 MIRROR 1 500 S POS TARG 0.246, 0 UV-MAM 0 A ------------------------------------------------------------------------------------------------------------------------------------ 4 IIZW40 STIS/F ACCUM F25QTZ MIRROR 1 950 S POS TARG 0.246, 0 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 5 IIZW40 STIS/F ACCUM F25QTZ MIRROR 1 950 S POS TARG -0.246, 0 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 6 IIZW40 STIS/N ACCUM F25CN27 MIRROR 1 500 S POS TARG -0.246, 0 UV-MAM 0 A ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Visit Id| Exp Id |Primary |Secondary |Iteration |CR-SPLIT |Orbit Num |Duration | |Pattern Pos |Pattern Pos |Num |Num | | ------------------------------------------------------------------------------------------------------------------------------------ 04 1 none none none none 1 tbd 04 2 none none none none 1 tbd 04 3 none none none none 1 tbd 04 4 none none none none 2 tbd 04 5 none none none none 2 tbd 04 6 none none none none 2 tbd 9739( 6) - 08/21/03 10:26 - [ 10] Visit: 05 Visit Priority: Visit Requirements: 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 IIZW40 ACS/HR ACCUM HRC F658N CR-SPLIT=2 1 1200 S C ------------------------------------------------------------------------------------------------------------------------------------ 2 IIZW40 ACS/HR ACCUM HRC-FIX F555W CR-SPLIT=2 1 600 S C ------------------------------------------------------------------------------------------------------------------------------------ 3 IIZW40 ACS/HR ACCUM HRC-FIX F814W CR-SPLIT=2 1 580 S C ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Visit Id| Exp Id |Primary |Secondary |Iteration |CR-SPLIT |Orbit Num |Duration | |Pattern Pos |Pattern Pos |Num |Num | | ------------------------------------------------------------------------------------------------------------------------------------ 05 1 none none none 1 1 tbd 05 1 none none none 2 1 tbd 05 2 none none none 1 1 tbd 05 2 none none none 2 1 tbd 05 3 none none none 1 1 tbd 05 3 none none none 2 1 tbd 9739( 6) - 08/21/03 10:26 - [ 11] Visit: 06 Visit Priority: Visit Requirements: 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 HE210 NIC2 ACCUM NIC2-FI F110W 1 330 S PATTERN 2 1-2 X ------------------------------------------------------------------------------------------------------------------------------------ 2 HE210 NIC2 ACCUM NIC2-FI F222M 1 335 S X ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Visit Id| Exp Id |Primary |Secondary |Iteration |CR-SPLIT |Orbit Num |Duration | |Pattern Pos |Pattern Pos |Num |Num | | ------------------------------------------------------------------------------------------------------------------------------------ 06 1 1 none none none 1 tbd 06 1 2 none none none 1 tbd 06 1 3 none none none 1 tbd 06 1 4 none none none 1 tbd 06 2 1 none none none 1 tbd 06 2 2 none none none 1 tbd 06 2 3 none none none 1 tbd 06 2 4 none none none 1 tbd 9739( 6) - 08/21/03 10:26 - [ 12] Visit: 07 Visit Priority: Visit Requirements: 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 NGC4214 NIC2 ACCUM NIC2-FI F110W 1 250 S PATTERN 2 1-5 X ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4214 NIC2 ACCUM NIC2-FI F160W 1 200 S X ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4214 NIC2 ACCUM NIC2-FI F222M 1 250 S X ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC4214 NIC2 ACCUM NIC2-FI F187N 1 500 S X ------------------------------------------------------------------------------------------------------------------------------------ 5 NGC4214 NIC2 ACCUM NIC2-FI F190N 1 500 S X ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Visit Id| Exp Id |Primary |Secondary |Iteration |CR-SPLIT |Orbit Num |Duration | |Pattern Pos |Pattern Pos |Num |Num | | ------------------------------------------------------------------------------------------------------------------------------------ 07 1 1 none none none 1 300.0 07 1 2 none none none 1 300.0 07 1 3 none none none 2 360.0 07 1 4 none none none 3 360.0 07 2 1 none none none 1 260.0 07 2 2 none none none 1 260.0 07 2 3 none none none 2 320.0 07 2 4 none none none 3 310.0 07 3 1 none none none 1 310.0 07 3 2 none none none 1 320.0 07 3 3 none none none 2 370.0 07 3 4 none none none 3 370.0 07 4 1 none none none 1 tbd 07 4 2 none none none 2 620.0 07 4 3 none none none 2 620.0 07 4 4 none none none 3 620.0 07 5 1 none none none 1 tbd 07 5 2 none none none 2 600.0 07 5 3 none none none 3 600.0 07 5 4 none none none 3 600.0 9739( 6) - 08/21/03 10:26 - [ 13] Visit: 08 Visit Priority: Visit Requirements: 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 NGC4214 STIS/N ACCUM F25CN27 MIRROR 1 620 S UV-MAM 0 A ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC4214 STIS/N ACCUM F25CN27 MIRROR 1 620 S POS TARG 0.246, 0 UV-MAM 0 A ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC4214 STIS/N ACCUM F25CN18 MIRROR 1 640 S UV-MAM 2 A ------------------------------------------------------------------------------------------------------------------------------------ 4 NGC4214 STIS/N ACCUM F25CN18 MIRROR 1 640 S POS TARG 0.246, 0 UV-MAM 2 A ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Visit Id| Exp Id |Primary |Secondary |Iteration |CR-SPLIT |Orbit Num |Duration | |Pattern Pos |Pattern Pos |Num |Num | | ------------------------------------------------------------------------------------------------------------------------------------ 08 1 none none none none 1 tbd 08 2 none none none none 1 tbd 08 3 none none none none 1 tbd 08 4 none none none none 1 tbd 9739( 6) - 08/21/03 10:26 - [ 14] Summary Form for Proposal 9739 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F25QTZ F25CN270 NIC2-FIX HRC HRC-FIX F25CN182 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/FUV-MAMA STIS/NUV-MAMA NIC2 ACS/HRC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=2 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements POS TARG 0.246, 0 POS TARG -0.246, 0 PATTERN 2 1-5 PATTERN 2 1-2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR F110W F160W F222M F187N F190N F658N F555W F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names HE210 NGC5253 IIZW40 NGC4214 ------------------------------------------------------------------------------------------------------------------------------------