! +====================+ ! | PED OUTPUT PRODUCT | ! +====================+ ! ! /spectre/data1/aroman/proposals/6021.prop ! Generated by PREPROCESSOR, version 2.0 ! Date: Wed Sep 27 09:25:15 EDT 1995 Proposal_Information Title: A Test for Abundance Enrichment by Massive Stars in the Wolf-Rayet Galaxy NGC 5253 Proposal_Category: GO Scientific_Category: Interstellar Medium Cycle: 5 Investigators PI_Name: Henry A. Kobulnicky PI_Institution: University of Minnesota CoI_Name: Evan Skillman CoI_Institution: University of Minnesota Contact: Abstract: We propose to obtain UV and optical spectra with the FOS to measure nebular abundances in NGC 5253, a Wolf-Rayet starburst galaxy that exhibits anomalous N/O ratios attributed to pollution from massive star winds. The primary focus of this program is to measure the relative carbon, nitrogen, and oxygen abundances in NGC 5253. We seek to establish the extent of short-term, localized abundance enhancements due to massive star populations, and evaluate C abundance measurements as a new tool for probing the chemical evolution history of starburst galaxies. Multiple FOS spectra over the wavelength range from 1600Angstrom\ to 6800Angstrom\ obtained through the same aperture will allow us to measure several ionization species and minimize uncertainties caused by unknown interstellar reddening and ionization correction factors that have plagued other UV spectroscopic studies. Specifically, we will measure the UV lines O III LambdaLambda1661 -- 1666, C III LambdaLambda1907 -- 1909, and N III LambdaLambda1748 -- 1754 simultaneously, which will enable us to measure the N^++/O^++, and C^++/O^++ ratios with very little uncertainty. This will allow us to confirm the N/O enhancement by measuring the favored ionic species of nitrogen (N^++), and test the claim that C is also enhanced in this region. Questions Observing_Description: Adequate ground-based spectra exist for NGC5253 which can be used to determine the electron densities, temperatures, nitrogen abundances, and crude line ratios for exposure time estimates. To minimize error introduced by applying extinction corrections and temperature estimates from ground- based spectra which employed different slit size and placement, we intend to obtain spectra using four gratings covering the range 1600Angstrom\\ to 6800Angstrom . G190H contains the crucial O III LambdaLambda1661 -- 1666, N III LambdaLambda1748 -- 1754 and C III LambdaLambda1907 -- 1909 lines used to determine the N^++/O^++ and C^++/O^++ ratios virtually unaffected by reddening uncertainties. The G270H grating contains the C II Lambda2326 line useful for constraining the ionization correction factor (ICF) carbon. Grating G400H contains the higher Balmer series lines for one determination of the reddening and the O II Lambda3727 line for determining the oxygen ICF. Grating G570H contains HAlpha and HBeta for establishing the reddening correction, and O III Lambda4959 and O III Lambda5007 lines to be used in determining the oxygen abundance. (An electron temperature from ground based Lambda4363 measurements will be assumed.) centerlineTable 1 centerlineLine Flux and Integration Time Estimates begintabbing XXXXXXXXXXLine \\= XXXXXXF (erg s^-1 cm^-2 arcsec^-1 \\= XXXXGrating \\= XXXXExp. Time (s) Line \\> F (erg s^-1 cm^-2 arcsec^-1) \\> Grating \\> Exp. Time (s) , HBeta Lambda4861 \\> 4times10^-13 \\> G570H \\> 300 , N III Lambda1750 \\> 4times10^-15 \\> G190H \\> 3600 , C II Lambda2326 \\> 7times10^-15 \\> G270H \\> 900 , O II Lambda3727 \\> 4times10^-13 \\> G400H \\> 300 , O III Lambda4959 \\> 6times10^-13 \\> G570H \\> 300 , endtabbing Exposure times have been estimated using theoretical emissivities relative to HBeta, or, where possible, the ground-based spectroscopy of Walsh & Roy (1989). We estimate exposure times of 3600 sec (2 orbits) to detect N III Lambda1750 at the 5Sigma level. Previous attempts to measure this line (Garnett Etal\\ 1994) achieved only upper limits, but if the N enhancements derived from optical data are accurate, we will detect this line. Exposure times for the other gratings were chosen to obtain at least a signal to noise of 5:1 for the weakest crucial lines in each grating: C II Lambda2326 for the G270 grating, O II Lambda3727 for G400H. Exposure times for G570H were selected with the goal of measuring the O III Lambda4959 and Lambda5007 lines in order to have a secondary estimate of the oxygen abundance in addition to the UV Lambda1661, Lambda1666 lines. This duplication will enable a strong check on the amount of reddening in the UV. HST UV images of NGC 5253 already exist in the archives and will facilitate target acquisition and aperture placement. Real_Time_Justification: None None Calibration_Justification: Additional_Comments: Should be scheduled in cooperation with a related proposal, proposal number 6001 (Roy etal), for best efficiency. This file is intended to be merged with 6001 to achieve a 12-orbit, 2-visit schedule file. Targets list in this file is same as 6001, for completeness, though not all targes are observed in this visit. Fixed_Targets Target_Number: 1 Target_Name: STAR-OFFSET Alternate_Names: Description: STAR Position: RA=13H 39M 51.945S +/- 0.01S,DEC=-31D 39' 02.94" +/- 0.1" Equinox: J2000 RV_or_Z: RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: V = 14.5+/-0.5 B-V = 0.5+/-0.5 Comments: Target_Number: 2 Target_Name: NGC5253-UV1 Alternate_Names: Description: EXT-MEDIUM, HII REGION Position: RA-OFF=4.03S+/- 0.01S,DEC-OFF=35.93"+/- 0.1",FROM 1 Equinox: J2000 RV_or_Z: V = +400 RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: SURF(V) = 18.4+/-0.2 B-V = 0.0+/-0 A(V) = 0.9+/-0 Comments: Object in the galaxy is a stellar cluster Target_Number: 3 Target_Name: NGC5253-UV2 Alternate_Names: Description: EXT-MEDIUM, HII REGION Position: RA-OFF=4.08S+/- 0.01S,DEC-OFF=31.54"+/- 0.1",FROM 1 Equinox: J2000 RV_or_Z: V = +400 RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: SURF(V) = 18.8+/-0.2 B-V = 0.0+/-0 A(V) = 0.9+/-0 Comments: Object in the galaxy is a stellar cluster Target_Number: 4 Target_Name: NGC5253-UV3 Alternate_Names: Description: EXT-MEDIUM, HII REGION Position: RA-OFF=3.63S+/- 0.01S,DEC-OFF=33.70"+/- 0.1",FROM 1 Equinox: J2000 RV_or_Z: V = +400 RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: SURF(V) = 18.4+/-0.2 B-V = 0.0+/-0 A(V) = 0.9+/-0 Comments: Object in the galaxy is a stellar cluster Target_Number: 5 Target_Name: NGC5253-HII-1 Alternate_Names: Description: EXT-MEDIUM,HII REGION, Position: RA-OFF=4.061S+/- 0.01S,DEC-OFF=37.31"+/- 0.1",FROM 1 Equinox: J2000 RV_or_Z: V = 400 RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: SURF(V) = 18.4+/-0.2 B-V = 0.0+/-0 A(V) = 0.9+/-0 Comments: Object in the galaxy is location in an HII region suspected to be N enriched Target_Number: 6 Target_Name: NGC5253-HII-2 Alternate_Names: Description: EXT-MEDIUM,HII REGION, Position: RA-OFF=4.007S+/- 0.01S,DEC-OFF=39.13"+/- 0.1",FROM 1 Equinox: J2000 RV_or_Z: V = 400 RA_PM: 0.0 Dec_PM: 0.0 Epoch: Annual_Parallax: 0.0 Flux: SURF(V) = 18.4+/-0.2 B-V = 0.0+/-0 A(V) = 0.9+/-0 Comments: Object in the galaxy is location in an HII region far from the N enriched location Solar_System_Targets Generic_Targets Scan_Data Visits Visit_Number: 02 Visit_Requirements: PCS MODE FINE On_Hold_Comments: Visit_Comments: To be merged into same visit with Roy etal (6001) NGC 5253 observations to get centered on to offset star without peak up exposures. From there, continue with offsets to the two targets in HII region. Entire visit is on FOS/RD. Exposure_Number: 51 Target_Name: NGC5253-HII-1 Config: FOS/RD Opmode: ACCUM Aperture: 1.0 Sp_Element: G190H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 3600S Special_Requirements: MIN DUR 90% MAX DUR 110% Comments: Exposure_Number: 52 Target_Name: NGC5253-HII-1 Config: FOS/RD Opmode: ACCUM Aperture: 1.0 Sp_Element: G400H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 300S Special_Requirements: MIN DUR 90% MAX DUR 110% Comments: Exposure_Number: 53 Target_Name: NGC5253-HII-1 Config: FOS/RD Opmode: ACCUM Aperture: 1.0 Sp_Element: G570H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 400S Special_Requirements: MIN DUR 90% MAX DUR 110% Comments: Exposure_Number: 54 Target_Name: NGC5253-HII-2 Config: FOS/RD Opmode: ACQ Aperture: 4.3 Sp_Element: MIRROR Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 60S Special_Requirements: MIN DUR 90% MAX DUR 100% Comments: Exposure_Number: 61 Target_Name: NGC5253-HII-2 Config: FOS/RD Opmode: ACCUM Aperture: 1.0 Sp_Element: G190H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 2500S Special_Requirements: Comments: Exposure_Number: 62 Target_Name: NGC5253-HII-2 Config: FOS/RD Opmode: ACCUM Aperture: 1.0 Sp_Element: G400H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 300S Special_Requirements: Comments: Exposure_Number: 63 Target_Name: NGC5253-HII-2 Config: FOS/RD Opmode: ACCUM Aperture: 1.0 Sp_Element: G570H Wavelength: Optional_Parameters: Number_of_Iterations: 1 Time_Per_Exposure: 300S Special_Requirements: Comments: Data_Distribution ! 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