! $Id: 5434,v 7.1 1994/07/27 17:55:28 pepsa Exp $ coverpage: title_1: THE STELLAR POPULATION AND STAR FORMING HISTORY OF IZW18 title_2: CYCLE4 MEDIUM sci_cat: GALAXIES & CLUSTERS sci_subcat: STELLAR POPULATIONS proposal_for: GO pi_fname: REGINALD pi_mi: J. pi_lname: DUFOUR pi_inst: RICE UNIVERSITY pi_country: USA pi_phone: (713)527-4939 hours_pri: 12.43 num_pri: 3 wf_pc: Y fos: Y off_fname: G. ANTHONY off_lname: GORRY off_title: V.P. FOR RESEARCH off_inst: 3240 off_addr_1: OFFICE OF SPONSORED RESEARCH off_addr_2: RICE UNIVERSITY off_addr_3: 6100 MAIN ST. off_city: HOUSTON off_state: TX off_zip: 77251 off_country: USA off_phone: 713 527 6054 ! end of coverpage abstract: line_1: We propose to obtain deep planetary and wide-field camera imagery of IZw18 line_2: --the dwarf galaxy which has the lowest known O/H abundance among the several line_3: hundred star-forming irregular and blue-compact galaxies studied spectro- line_4: scopically during the past decade. Deep imagery with the wide field camera line_5: through blue, visual, and red filters of the main body and several components line_6: will be used to characterize its stellar population and star formation history. line_7: Planetary camera imagery of its "star-bursting" main body will be used to line_8: resolve the dense OB associations in its core that are responsible for exciting line_9: the ionized gas and its blue-compact nature. Imagery with the wide field line_10: camera through Halpha and [OIII] 5007A filters will permit detailed study of line_11: the morphology and ionization of the ionized gas surrounding the main body of line_12: the galaxy. Since IZw18 is the most extreme example of super metal-poor line_13: star-forming dwarf irregular galaxies, and has been used to set the primordial line_14: helium abundance, study with the HST should have a significant impact on our line_15: understanding of such relatively rare systems which may be the closest thing to line_16: a nearby "Holy Grail" of galaxy formation and evolution ! ! end of abstract general_form_proposers: lname: DUFOUR fname: REGINALD mi: J. inst: 3240 country: USA ! lname: GARNETT fname: DONALD mi: R. inst: 2710 country: USA ! lname: SHIELDS fname: GREGORY mi: A. inst: 3550 country: USA ! lname: SKILLMAN fname: EVAN mi: D. inst: 2710 country: USA ! ! end of general_form_proposers block general_form_text: question: 3 section: 1 line_1: Four groups of observations of IZw18 are proposed for Cycle 4: line_3: 1. WFPC2 (WFC) BVR imagery with the "wide-B" (F450W), "old-V" (F555W), and line_4: "wide-R" F702W filters. The "main body" of IZw18 will be centered in the WF3 line_5: CCD and the observations should be scheduled at a time when either WF2 or WF4 line_6: will have an orientation along PA=312deg relative to WF3. This will enable line_7: imagery of components A-C-D-E in two WFC CCDs along the PA=312deg (or 132deg) line_8: axis. The imagery will be CR-SPLIT deep (two 2400sec - "half orbit") exposures line_9: in order to reach V=28 stars with a S/N of about 10 (see next question). Since line_10: the distance of IZw18 is about 10Mpc, corresponding to a distance modulus of line_11: (m-M)=30.0, and is essentially unreddened, the brightest stars (Mv=-7 OB stars) line_12: are expected to be near V=23 apparent magnitude. line_14: 2. WFPC2 (WFC) Halpha and [OIII]5007 imagery with the F658N and F502N filters. line_15: HI and Fabry-Perot observations indicate that the gas in and around IZw18 is line_16: redshifted by about 750 (+/-70) km/sec. For +750 km/sec the 6562.8A Halpha line line_17: will be at 6579.2 (thus a good match for the F658N filter) and the 5006.8A line_18: [OIII] line will be at 5019.3A (still in the high transmission part of the F502N line_19: filter). This imagery will be used to obtain high resolution maps of the line_20: ionized gas in the main body of IZw18 (which extends out over 25 arcsec from the line_21: main body in the NE and SW directions). An [OIII]/Halpha ratio map will be line_22: constructed which will enable charaterization of the ionization level and line_23: sources of this extended emission. As for (1) above, we plan to take two ! question: 3 section: 2 line_1: "CR-SPLIT" 2400sec exposures through each filter, hopefully at a time when the line_2: corners of the PC are along PA=312 so as to have the longest part of the PC line_3: follow the elongations of the galaxy components. line_5: 3. WFPC2 (PC) BVR imagery of the main body of IZw18 through the F439W, F555W, line_6: and F675W filters. The region to be centered in PC1 is the brightest core of line_7: the two main body associations (which are separated by 5.5"). The objective line_8: here is to reap the maximum spatial resolution of HST at some sacrifice of line_9: limiting magnitude in order to separate OB stars in IZw18 as much as possible. line_10: (CoI Garnett notes that a proprietory Cycle 2 WFC F220W image shows very dense line_11: clustering of OB stars in the NW component and we need maximum resolution to line_12: resolve these stars). We further choose F439W instead of F450W to supress the line_13: surrounding nebulosity as much as possible (a similar argument holds for F555W line_14: compared to F606W). We use F675W for R because it is the best calibrated. line_16: 4. FOS/RD spectra with G190H and G570H gratings with the 1.0-PAIR-B aperture line_17: in order to obtain and accurate measurement of the CIII]1909, SiIII]1883,92, line_18: OIII]1660,66 UV lines and optical tie-in with Halpha for exactly the same line_19: aperture. This, in conjunction with our optical spectra, will enable very line_20: accurate ratios of C:N:O:Si:H to be determined in this most metal-poor of line_21: star forming galaxies known. Our exposures are based on a previous G190H line_22: spectrum of IZw18 (3200sec) for which the aperture (1" circle) slightly line_23: missed the best postion. We expect to attain a S/N of about 6 for CIII]. ! question: 4 section: 1 line_1: The proposed observations make fundamental use of the recovered high line_2: resolution image quality of the HST expected to be available for Cycle 4. In line_3: the section 2 discussion we noted the multi-component nature of IZw18 and the line_4: ever more interesting structures that become apparent with increasing line_5: sub-arcsecond resolution. For an assumed distance of 10Mpc for IZw18 (based on line_6: a mean Vr=+759 km/sec and Ho=75), 1 arcsecond corresponds to 48pc and (m-M)=30 line_7: suggests that the most luminous O stars will have V=23 (just at the limit of line_8: ground-based imagery). Therefore, using HST (limiting V~28 and resolution line_9: <0.1") we would expect to be able to study the brightest stars and surrounding line_10: emission nebulosities in the main body and possibly also the brightest stars and line_11: resolve the Halpha emission "knot" in component C to the NW. Our proposed WFC line_12: BVR imagery should detect stars as faint as about 28.5 (Mv=-1.5) corresponding line_13: to intermediate mass stars on the red-giant "tip" of evolution -thus enabling line_14: some evaluation of the existence of an intermediate or older age population in line_15: this chemically youngest of the star-forming galaxies known. The proposers have line_16: a demonstrated history of imagery and spectroscopy work on IZw18 in spectroscopy line_17: with the IUE (UV), McDonald, and MMT telescopes. We have published emission- line_18: line Halpha-[OIII]-[SII] imagery from Palomar, unpublished UBVRI imagery from line_19: McDonald, and unpublished Fabry-Perot imaging spectroscopy from CFHT available line_20: for enhanced use and interpretation of the HST imagery and spectroscopic line_21: observations proposed here. VLA HI maps of the galaxy have also been published line_22: for comparison with the optical-HST results. ! question: 4 section: 2 line_1: We propose using the F450W, F555W, and F702W filters with the WFC in order line_2: to reach the faintest stars possible for investment in spacecraft time. We line_3: performed calculations for V=23.0 (Mv=-7) and V=28.0 (Mv=-2) B0 stars in IZw18 line_4: using the instructions and data in the 1993 March WFPC2 Instrument Handbook. line_5: The signal-to-noise calculated for a single 2400sec "half-orbit" integration for line_6: the V=23 star was found to be (B,V,R) = (850,670,430) [Assuming a 23.3 line_7: mag/arcsec2 sky background and 7e-/pixel readout noise]. For a V=28.0 B0 star, line_8: the S/N expected on a 2400sec exposure is about (B,V,R) = (8,7,4) [But note that line_9: the S/N on the B (F450W) drastically drops for redder stars, such as G-K-M line_10: giants and supergiants]. A CR-SPLIT PAIR of 2400sec exposures would therefore line_11: result in quite accurate BVR color-magnitude diagrams down to V=28+ --which is line_12: necessary to characterize the stellar population and ages in IZw18. Given the line_13: discovery of a very concentrated cluster of stars in the main body NW "core", line_14: result in quite accurate BVR color-magnitude diagrams down to V=28+ --which is line_15: necessary to characterize the stellar population and ages in IZw18. Given the line_16: discovery of a very concentrated cluster of stars in the main body NW "core", line_17: we propose taking CR-SPLIT PAIRED 1200sec eposures with PC1 of WFPC2 of this line_18: region through the F439W ("B" - but avoiding the high transmission of the F450W line_19: filter at Hbeta-[OIII] around 4800-5100A from the bright core nebulosity), F555W line_20: (the narrower "V" F569W transmits the same as F555W at Halpha), and F702W "R". line_21: Compared to the WFC imagery above, we loose about a factor of 3-4 in photons line_22: detected, but gain a factor of 2 in spatial resolution--which may be essential line_23: to resolving the "core cluster" stars. Nonetheless, calculations suggest for a ! question: 4 section: 3 line_1: V=27.0 B0 star, the S/N on a 1200sec exposure will be about >5 in all passbands line_2: (the limiting factor will be background and crowding confusion around the core). line_4: Imagery of diffuse Halpha and [OIII]5007 (redshifted) emission poses a line_5: different set of problems. From Dufour & Hester (1990) and our higher- line_6: resolution CFHT imagery, the brightest knot in the main body of IZw18 has line_7: a measured surface brightness of 1.53E-14 ergs/cm-2/sec/arcsec2 and a line_8: 5007/6563 ratio of 0.6. From the WFPC2 manual, the F658N+OTA throughput line_9: at 6580.3A is 0.105 and for F502N+OTA at 5020.2A is 0.038. Correspondingly, line_10: the number of detected photons per sec per square arcsec is expected to be line_11: 24 for Halpha and 3.9 for [OIII]. These will be distributed (in an unknown line_12: fashion) in some 100 WFC2 pixels. Correspondingly, in a 2400sec exposure line_13: we would expect to have about 57,000 photoelectrons (or 8200 DN) detected line_14: at Halpha and about 9,400 (1340 DN) detected in [OIII] in a 10X10 pixel area. line_15: For the case of a very concentrated semi-stellar source, we correspondingly line_16: would have a high S/N of >100 for Halpha and >30 for [OIII]. ! question: 4 section: 4 line_1: Finally, we note that as part of line_2: the Cycle 2 program GO-3840, we obtained a 3200sec G190H/RD FOS spectrum of a line_3: position near the NW core of IZw18. This spectrum shows CIII]1909A and line_4: possibly SiIII]1883-92A lines but the offset position missed the brightest line_5: NW HII region core. Therefore, the S/N is lower than expected and we have line_6: received permission from STScI to "re-attempt" to take this spectrum with line_7: the 1" square aperture and an improved astrometric position. In addition, we line_8: propose to take a G570H spectrum for precise UV-optical tie-in for the location line_9: corresponding to the highest surface brightness HII region in IZw18. ! question: 5 section: 1 line_1: We would like to schedule the WFC2 imagery to occur at a date such that the line_2: position angle of the centers of WF2 or WF4 is 312 (+/- 10) degrees -or 122 (+/- line_3: 10) degrees relative to the center of WFC3 (where the main body of the galaxy line_4: will be centered). Any of these four possible orientations will permit the more line_5: distant components (C-D-E) across the boundary of the WFC3 CCD into the field of line_6: WFC2 or WFC4 CCD. Each of these four orientations occur about 3 months apart line_7: and have about 20-day windows in time, so scheduling such would likely not be line_8: too tight. ! question: 6 section: 1 line_1: None are anticipated to be needed. ! ! ! ! question: 8 section: 1 line_1: None. ! question: 9 section: 1 line_1: Program GO-2416: "Imagery and Spectroscopy of Super Metal Poor Galaxies" line_2: PI: Dufour; CoIs common to this proposal: Skillman line_3: Program GO-3589: "High Resolution Parallel Imagery of Diffuse Objects in line_4: the Magellanic Clouds"; CoI common to this proposal: Garnett line_5: Program GO-3591: "Massive Stars in Starburst Galaxies"; CoI common to this line_6: proposal: Garnett line_7: Program GO-3840: "The Abundances and Time Evolution of Carbon, Nitrogen, line_8: and Oxygen in Star Forming Galaxies"; PI: Skillman; CoIs common to this line_9: proposal: Dufour, Garnett line_10: Program GO-4276: "The Abundance and Evolution of Carbon in the Spiral line_11: Galaxy NGC 2403: Cycle 3 Medium"; PI: Garnett; CoIs common to this proposal: line_12: Dufour, Skillman line_13: Program GO-4382: "HST Imagery and Spectroscopy of the Dusty SMC H II Region line_14: N88A: Cycle 3 High"; PI: Dufour; CoIs common to this proposal: Garnett, line_15: Skillman line_16: Program GO-4383: "UV Spectroscopy of Two Very C-Poor Halo Planetary line_17: Nebulae: Cycle 3 Medium"; CoI common to this proposal: Dufour line_18: Program GO-4385: "Ultra-Violet Spectroscopy of the Orion Nebula: Cycle 3 line_19: High"; Co-I common to this proposal: Dufour line_20: Program GO-4497: "High Resolution Parallel Imagery of Diffuse Objects in line_21: the Magellanic Clouds"; CoI common to this proposal: Garnett ! question: 9 section: 2 line_1: GO-2416: An imaging and spectroscopic study of the nearby extreme low-mass line_2: dwarf irregular galaxy GR 8 (DDO 155), to study the stellar population and line_3: the morphology and composition of the ionized gas. WFC (F336W, F439W, F555W, line_4: F702W, F785LP, F502N, & F656N) and FOC/48 (F150W) images of the nearby low line_5: luminosity irregular galaxy GR8 were successfully obtained during Cycle 1. line_6: The wide-band WFC and FOC imagery came out very well, resolving numerous OB and line_7: red supergiants throughout GR8 for the first time (compared to previous ground- line_8: based studies). Broad-band photometry of the visible stars as faint as R=24.5 line_9: revealed a pattern of migrating star formation across this galaxy. The FOC line_10: imagery indicated that the two brightest stars "in GR8" are likely foreground line_11: objects. The FOS spectroscopy of one of the faint H II regions (obtained in line_12: 1993 February) displayed weak C III] emission and little else. Two poster line_13: papers on these results have been presented at AAS meetings and two at the 1993 line_14: March "Tex-Mex IV" meeting in Austin (for which summary papers will be published line_15: in Revista Mex. de Astron. y Astrof. in late 1993). Dufour is currently line_16: preparing a paper on the WFC photometry results for submission to the line_17: Astronomical Journal. line_19: "The Star Formation History of GR8 From HST Imagery," R.J. Wyatt and R.J. line_20: Dufour, Rev. Mex. Astr. Ap., 23, in press. line_21: "HST FOC/48 UV Imagery of GR8," B. Patterson, R.J. Wyatt, and R.J.Dufour, line_22: Rev. Mex. Astr. Ap., 23, in press. ! question: 10 section: 1 line_1: Dufour has in place at Rice a 19inch color Sparcstation 2GX with 64MBy of line_2: memory, 3GBy of hard disks, a 5GBy exabyte 8mm tape drive, and CD-rom reader. line_3: Installed on this machine and others in the department is a full IRAF-STDAS line_4: implimentation and other software such as DAOPHOT, SUPERMONGO, MATHEMATICA, etc. line_5: for astronomical data analysis. The university cost-shared in the purchase of line_6: much of this equipment. There also a color X-station etherneted to the line_7: Sparcstation for 2nd-party color graphics. Our department has another 7 UNIX line_8: and VMS based modern workstations and a color/B&W 35mm hardcopy camera system line_9: etherneted to these machines. The PI also has a 2nd year graduate student line_10: pursuing his M.S. thesis study on HST-related programs (Orion Nebula and SMC HII line_11: regions) as well as a postdoctoral fellow, Dr. Don Walter. The university cost line_12: shares in graduate student support. line_14: Skillman and Garnett have comparable color workstations and software in line_15: place at the University of Minnesota for the analysis of HST imagery and line_16: spectroscopy data and nebular model analysis. Shields has a variety of line_17: computational facilities at UT-Austin for his theoretical nebular modeling and line_18: analysis studies ! !end of general form text general_form_address: lname: DUFOUR fname: REGINALD mi: J. category: PI inst: 3240 addr_1: SPACE PHYSICS AND ASTRONOMY addr_2: RICE UNIVERSITY addr_3: P. O. BOX 1892 city: HOUSTON state: TX zip: 77251 country: USA phone: 713 527 4944 telex: RJD@RICE.EDU ! lname: category: CON ! ! end of general_form_address records fixed_targets: targnum: 1 name_1: IZW18-MAINBODY name_2: MARK116 descr_1: E,307 pos_1: RA = 09H 34M 02.04S +/- 0.05S, pos_2: DEC = +55D 14' 28.01" +/- 0.1" equinox: J2000 rv_or_z: V = +759 comment_1: THIS IS A DWARF IRREGULAR GALAXY comment_2: BRIGHTEST STARS ARE AT V=23 fluxnum_1: 1 fluxval_1: V=28.0, TYPE=B0V, E(B-V)=0.1 fluxnum_2: 2 fluxval_2: SURF-LINE(6563) = 1.5 E-14 fluxnum_3: 3 fluxval_3: SURF-LINE(5007) = 9.0 E-15 ! targnum: 2 name_1: IZW18-NWHIIR name_2: MARK116 descr_1: H,503 pos_1: RA-OFF = -4.25S +/- 0.03S, pos_2: DEC-OFF = -9.5" +/- 0.5", pos_3: FROM 3 equinox: J2000 rv_or_z: V = +759 acqpr_1: EXT acqpr_2: BKG comment_1: THIS IS THE BRIGHTEST HALPHA BLOB comment_2: CIRCULAR WITH FWHM APPROX 0.5" fluxnum_1: 1 fluxval_1: SURF-LINE(6563) = 1.5 E-14 fluxnum_2: 2 fluxval_2: SURF-LINE(5007) = 9.0 E-15 fluxnum_3: 3 fluxval_3: SURF-LINE(1909) = 2.1 E-15 ! targnum: 3 name_1: OFFSET-STAR descr_1: A,138 pos_1: RA = 09H 34M 06.29S +/- 0.03S, pos_2: DEC = +55D 14' 37.5" +/- 0.5" equinox: J2000 rv_or_z: V = 0 comment_1: THIS IS THE OFFSET STAR FOR comment_2: THE IZW18-NWHIIR FOS SPECTRA comment_3: PROPER MOTION UNKNOWN fluxnum_1: 1 fluxval_1: V=15.4, B-V=+0.6, TYPE=G2V ! ! end of fixed targets ! No solar system records found ! No generic target records found exposure_logsheet: linenum: 1.000 targname: IZW18-MAINBODY config: WFPC2 opmode: IMAGE aperture: WF3-FIX sp_element: F702W num_exp: 1 time_per_exp: 1800S s_to_n: 4 fluxnum_1: 1 priority: 1 param_1: CR-SPLIT=NO req_1: CYCLE 4; req_2: ORIENT 267D +/- 10D / 1.0-1.2; req_3: SEQ 1.0-1.2 NO GAP comment_1: ORIENTATION FOR MB CENTERED IN WF3 comment_2: GALAXY EXTENSIONS AT PA=312D IN WF2 comment_3: THREE OTHER ORIENTATIONS POSSIBLE: comment_4: -ORIENT=357D PUTS EXTENSIONS IN WF4 comment_5: -ORIENT=87D WITH MAINBODY IN WF2 OK comment_6: -ORIENT=177D WITH MAINBODY IN WF4 OK ! linenum: 1.100 targname: IZW18-MAINBODY config: WFPC2 opmode: IMAGE aperture: WF3-FIX sp_element: F450W num_exp: 2 time_per_exp: 2300S s_to_n: 8 fluxnum_1: 1 priority: 1 param_1: CR-SPLIT=NO req_1: CYCLE 4 comment_1: ORIENTATION FOR MB CENTERED IN WF3 comment_2: GALAXY EXTENSIONS AT PA=312D IN WF2 comment_3: THREE OTHER ORIENTATIONS POSSIBLE: comment_4: -ORIENT=357D PUTS EXTENSIONS IN WF4 comment_5: -ORIENT=87D WITH MAINBODY IN WF2 OK comment_6: -ORIENT=177D WITH MAINBODY IN WF4 OK ! linenum: 1.200 targname: IZW18-MAINBODY config: WFPC2 opmode: IMAGE aperture: WF3-FIX sp_element: F555W num_exp: 2 time_per_exp: 2300S s_to_n: 7 fluxnum_1: 1 priority: 1 param_1: CR-SPLIT=NO req_1: CYCLE 4 comment_1: ORIENTATION FOR MB CENTERED IN WF3 comment_2: GALAXY EXTENSIONS AT PA=312D IN WF2 comment_3: THREE OTHER ORIENTATIONS POSSIBLE: comment_4: -ORIENT=357D PUTS EXTENSIONS IN WF4 comment_5: -ORIENT=87D WITH MAINBODY IN WF2 OK comment_6: -ORIENT=177D WITH MAINBODY IN WF4 OK ! linenum: 1.300 targname: IZW18-MAINBODY config: WFPC2 opmode: IMAGE aperture: WF3-FIX sp_element: F702W num_exp: 2 time_per_exp: 1800S s_to_n: 4 fluxnum_1: 1 priority: 1 param_1: CR-SPLIT=NO req_1: CYCLE 4; req_2: ORIENT 267D +/- 10D / 1.3-1.5; req_3: SEQ 1.3-1.5 NO GAP comment_1: ORIENTATION FOR MB CENTERED IN WF3 comment_2: GALAXY EXTENSIONS AT PA=312D IN WF2 comment_3: THREE OTHER ORIENTATIONS POSSIBLE: comment_4: -ORIENT=357D PUTS EXTENSIONS IN WF4 comment_5: -ORIENT=87D WITH MAINBODY IN WF2 OK comment_6: -ORIENT=177D WITH MAINBODY IN WF4 OK ! linenum: 1.400 targname: IZW18-MAINBODY config: WFPC2 opmode: IMAGE aperture: WF3-FIX sp_element: F502N num_exp: 2 time_per_exp: 2300S s_to_n: 1 fluxnum_1: 3 priority: 1 param_1: CR-SPLIT=NO req_1: CYCLE 4 comment_1: ORIENTATION FOR MB CENTERED IN WF3 comment_2: GALAXY EXTENSIONS AT PA=312D IN WF2 comment_3: THREE OTHER ORIENTATIONS POSSIBLE: comment_4: -ORIENT=357D PUTS EXTENSIONS IN WF4 comment_5: -ORIENT=87D WITH MAINBODY IN WF2 OK comment_6: -ORIENT=177D WITH MAINBODY IN WF4 OK ! linenum: 1.500 targname: IZW18-MAINBODY config: WFPC2 opmode: IMAGE aperture: WF3-FIX sp_element: F658N num_exp: 2 time_per_exp: 2300S s_to_n: 2 fluxnum_1: 2 priority: 1 param_1: CR-SPLIT=NO req_1: CYCLE 4 comment_1: ORIENTATION FOR MB CENTERED IN WF3 comment_2: GALAXY EXTENSIONS AT PA=312D IN WF2 comment_3: THREE OTHER ORIENTATIONS POSSIBLE: comment_4: -ORIENT=357D PUTS EXTENSIONS IN WF4 comment_5: -ORIENT=87D WITH MAINBODY IN WF2 OK comment_6: -ORIENT=177D WITH MAINBODY IN WF4 OK ! linenum: 2.100 targname: IZW18-MAINBODY config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F555W num_exp: 2 time_per_exp: 600S s_to_n: 3 fluxnum_1: 1 priority: 2 param_1: CR-SPLIT=NO req_1: CYCLE 4; req_2: ORIENT 132D +/- 20D / 2.1-2.3; req_3: SEQ 2.1-2.3 NO GAP; req_4: NON-INT comment_1: ORIENTATION FOR MB CENTERED IN PC1 comment_2: GALAXY EXTENSIONS AT PA=312D IN WF3 ! linenum: 2.200 targname: IZW18-MAINBODY config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F439W num_exp: 2 time_per_exp: 1000S s_to_n: 3 fluxnum_1: 1 priority: 2 param_1: CR-SPLIT=NO req_1: CYCLE 4; req_2: NON-INT comment_1: ORIENTATION FOR MB CENTERED IN PC1 comment_2: GALAXY EXTENSIONS AT PA=312D IN WF3 ! linenum: 2.300 targname: IZW18-MAINBODY config: WFPC2 opmode: IMAGE aperture: PC1-FIX sp_element: F675W num_exp: 2 time_per_exp: 1000S s_to_n: 2 fluxnum_1: 1 priority: 2 param_1: CR-SPLIT=NO req_1: CYCLE 4; req_2: NON-INT comment_1: ORIENTATION FOR MB CENTERED IN PC1 comment_2: GALAXY EXTENSIONS AT PA=312D IN WF3 ! linenum: 3.000 targname: OFFSET-STAR config: FOS/RD opmode: ACQ/BINARY aperture: 4.3 sp_element: MIRROR num_exp: 1 time_per_exp: 18.8S s_to_n: 10 fluxnum_1: 1 priority: 3 req_1: CYCLE 4; req_2: GROUP 3.0,3.1,3.2 NO GAP; req_3: ONBOARD ACQ FOR 3.1-3.2 comment_1: THIS IS THE V=15.4 OFFSET STAR comment_2: FIELD IS CLEAR OF NEBULOSITY comment_3: NO COMPARABLY BRIGHT STARS NEARBY ! linenum: 3.100 targname: IZW18-NWHIIR config: FOS/RD opmode: ACCUM aperture: 1.0-PAIR-B sp_element: G570H num_exp: 1 time_per_exp: 300S s_to_n: 15 fluxnum_1: 1 priority: 3 param_1: STEP-PATT=SINGLE req_1: CYCLE 4; req_2: GROUP 3.0,3.1,3.2 NO GAP comment_1: THIS IS THE BRIGHTEST HII BLOB IN comment_2: THE GALAXY, FWHM=0.5" comment_3: SINGLE SPECTRUM TO BE TAKEN IN 1.0" comment_4: SQUARE APERTURE "B" ! linenum: 3.200 targname: IZW18-NWHIIR config: FOS/RD opmode: ACCUM aperture: 1.0-PAIR-B sp_element: G190H num_exp: 1 time_per_exp: 3600S s_to_n: 6 fluxnum_1: 3 priority: 3 param_1: STEP-PATT=SINGLE req_1: CYCLE 4; req_2: GROUP 3.0,3.1,3.2 NO GAP comment_1: THIS IS THE BRIGHTEST HII BLOB IN comment_2: THE GALAXY, FWHM=0.5" comment_3: SINGLE SPECTRUM TO BE TAKEN IN 1.0" comment_4: SQUARE APERTURE "B" ! ! end of exposure logsheet ! No scan data records found