!__Proposal-Section__ !6124 ! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template ! $Id: 6124,v 4.1 1995/04/27 13:12:42 pepsa Exp $ ! ! Refer to the HST Phase II Proposal Instructions to fill this out ! ! Anything after a "!" is ignored, and may be deleted ! ! All keywords with multiple entries are comma delimited except the ! Visit_Requirements and Special_Requirements keywords which can be ! delimited with carriage returns or semi-colons, but not commas ! ! For help call your Program Coordinator: Christian Ready ! Phone: 410 338-4546 , E-mail: ready@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Date generated: Mon Dec 19 08:28:41 EST 1994 ! Proposal_Information ! Section 4 Title: `Spotting' Iron-Rich SN Ia Remnants in NGC 5253 Proposal_Category: GO Scientific_Category: Interstellar Medium Cycle: 5 Investigators PI_name: Robert Fesen PI_Institution: Dartmouth College CoI_Name: Andrew Hamilton CoI_Institution: University of Colorado Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) We propose to detect 100 -- 1000 yr old Type Ia supernova remnants in the central region of NGC 5253 by means of obscuration spots due to Fe-rich ejecta resonance line absorptions. Absorption line studies of young supernova remnants represent new and potentially powerful tools for exploring the properties of the freely expanding, iron-rich ejecta expected in SN Ia remnants. , We request WFPC2+F255W images of the amorphous starburst galaxy NGC 5253. Two of the brightest historic Type Ia supernovae occurred here, SN 1895B (= Z Cen) and SN 1972E. By imaging NGC 5253 in the rich ultraviolet Fe I + Fe II resonance line region (2300--3000 Angstrom), 100 -- 1000 yr old SN Ia remnants with V_ exp = 5 - 10 * 10^3 km/s located in NGC 5253's facing nuclear region will be detected as 0.05'' - 0.50'' x (D/4 Mpc) diameter dark `spots'. SN 1895B which exploded just 25'' from the center, is a prime candidate for such iron absorption detection. Older and subsequently larger SN Ia remnants which lie in the galaxy's nuclear region will be detected as well. These detections can place strong constraints on the mass and expansion velocity of iron ejecta in Type Ia SNe and this galaxy's SN Ia rate. Questions ! Free format text (please update) Observing_Description: The orbital visibility of NGC 5253 (Dec = --31 deg) is 53 minutes. In order to detect an Fe I/II absorption signal, we need a S/N of at least 4 for the faintest, outer parts of the nuclear region we intend to search for SN Ia absorption spots. SN 1895B lies 25'' off the nucleus and therefore represents the faint end of possible detections and one that we consider a prime SN Ia target for Fe I/II absorption study. We therefore will use it as a basis to calculate the necessary WFPC2 exposure times. For the SN 1895B position, we estimate a NGC 5253 surface brightness of U=20.4 mag/sq. arcsec, from the V surface brightness and B-V and U-B colors of NGC 5253 from Caldwell & Phillips' surface brightness vs. radius plot, and B-V and U-B images. The galaxy is sufficiently blue that it may not be appreciably fainter at 3000 Angstrom\ compared to U (3500 Angstrom). Therefore using m = 20.6 mag, equation 6.1 in the WFPC2 handbook, and intQT dLambda/Lambda = 0.00085 for the F255W filter, we estimate N = 0.013 ct/pixel sec for the region near SN 1895B. In a 600 sec exposurethis means we'll detect 8 e^-. This is comparable to the 0.016 cts dark current at --77 C (Table 4.2; WFPC hdbk) and the 5 e^- of the WFPC's readout noise and means that a 600 sec exposure will then have a S/N = 1.25. To reach a S/N >= 4, requires about 80 cts or ten of these (= 100 minutes). With 53 minutes orbital visibility minus the 12 minutes needed for GS Acquisition, that leaves 41 min for exposures and overhead. We can fit three 10 min exposures plus 8 minutes overhead in this first orbit. In a second and third orbits, which have only a 6 min GS re-acq., we can fit two 18 min CR-SPLIT exposures each with 5 min OH, completely filling the orbit. Thus, in three orbits, the total exposure time will be 30 + 36 + 36 = 102 minutes, enough to give us a S/N = 4 for the SN 1895B and much better than this over the inner 20'' * 40'' nuclear region of the galaxy. Real_Time_Justification: None. We plan U and B CCD images of the NGC 5253 galaxy using the 2.4 m telescope at MDM Observatory, Arizona. We will employ a 1024 x 1024 Tek CCD with 0.25'' pixels with the goal of obtaining deep blue images of the galaxy to compare with the F255W image taken with HST for SN Ia remnant detection. We plan also to examine any archival HST images that may help confirm our detections. Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number: 001 Target_Name:NGC5253 Alternate_Names:HARO10 Description:GALAXY,STARBURST Position:RA=13H 37M 5.25S +/- 0.1S, DEC=-31D 23' 15" +/- 5" ! Most common specification format is ! RA=0H 0M 0.00S +/- 0S, ! DEC=0D 0' 0.0" +/- 0", ! PLATE-ID=0000 Equinox:B1950.0 RV_or_Z: RA_PM: ! Units are seconds of time per year Dec_PM: ! Units are seconds of arc per year Epoch: Annual_Parallax: Flux:SURF(V)=20+/- 2.0 Comments:This galaxy has been classified as an amorphous starburst spiral/irregular. It has had two Type Ia SNe (SN 1895B and SN 1972E). This program consists of three independent images dithered so that we can co-add them to obtain the best S/N and effective resolution. Visits ! Section 6 Visit_Number: 1 Visit_Requirements: ! Section 7.1 On_Hold_Comments: Visit_Comments: Exposure_Number:11 ! Section 6.5 Target_Name:NGC5253 Config:WFPC2 Opmode:IMAGE Aperture:WF3-FIX Sp_Element:F255W Wavelength:2553 Optional_Parameters:CR-SPLIT=NO Number_of_Iterations:1 Time_Per_Exposure:700S Special_Requirements: ! Section 7.2 Exposure_Number:12 ! Section 6.5 Target_Name:NGC5253 Config:WFPC2 Opmode:IMAGE Aperture:WF3-FIX Sp_Element:F255W Wavelength:2553 Optional_Parameters:CR-SPLIT=NO Number_of_Iterations:1 Time_Per_Exposure:700S Special_Requirements: ! Section 7.2 Exposure_Number:13 ! Section 6.5 Target_Name:NGC5253 Config:WFPC2 Opmode:IMAGE Aperture:WF3-FIX Sp_Element:F255W Wavelength:2553 Optional_Parameters:CR-SPLIT=NO Number_of_Iterations:1 Time_Per_Exposure:700S Special_Requirements: ! Section 7.2 Exposure_Number:21 ! Section 6.5 Target_Name:NGC5253 Config:WFPC2 Opmode:IMAGE Aperture:WF3-FIX Sp_Element:F255W Wavelength:2553 Optional_Parameters:CR-SPLIT=NO Number_of_Iterations:1 Time_Per_Exposure:800S Special_Requirements:POS TARG -0.50,0.50 ! Section 7.2 Exposure_Number:22 ! Section 6.5 Target_Name:NGC5253 Config:WFPC2 Opmode:IMAGE Aperture:WF3-FIX Sp_Element:F255W Wavelength:2553 Optional_Parameters:CR-SPLIT=NO Number_of_Iterations:1 Time_Per_Exposure:800S Special_Requirements:POS TARG -0.50,0.50 ! Section 7.2 Exposure_Number:23 ! Section 6.5 Target_Name:NGC5253 Config:WFPC2 Opmode:IMAGE Aperture:WF3-FIX Sp_Element:F255W Wavelength:2553 Optional_Parameters:CR-SPLIT=NO Number_of_Iterations:1 Time_Per_Exposure:800S Special_Requirements:POS TARG -0.50,0.50 ! Section 7.2 Exposure_Number:31 ! Section 6.5 Target_Name:NGC5253 Config:WFPC2 Opmode:IMAGE Aperture:WF3-FIX Sp_Element:F255W Wavelength:2553 Optional_Parameters:CR-SPLIT=NO Number_of_Iterations:1 Time_Per_Exposure:800S Special_Requirements:POS TARG 0.50,0.50 ! Section 7.2 Exposure_Number:32 ! Section 6.5 Target_Name:NGC5253 Config:WFPC2 Opmode:IMAGE Aperture:WF3-FIX Sp_Element:F255W Wavelength:2553 Optional_Parameters:CR-SPLIT=NO Number_of_Iterations:1 Time_Per_Exposure:800S Special_Requirements:POS TARG 0.50,0.50 ! Section 7.2 Exposure_Number:33 ! Section 6.5 Target_Name:NGC5253 Config:WFPC2 Opmode:IMAGE Aperture:WF3-FIX Sp_Element:F255W Wavelength:2553 Optional_Parameters:CR-SPLIT=NO Number_of_Iterations:1 Time_Per_Exposure:800S Special_Requirements:POS TARG 0.50,0.50 ! Section 7.2 Comments: Data_Distribution ! Defaults indicated; change if desired Medium: 8MM ! 8MM or 6250BPI or 1600BPI Blocking_Factor: 10 ! 10 or 1 ! Only astronomers with very old 9- ! track tape drives should consider ! a blocking factor of 1 Ship_To: PI_Address ! STSCI or PI_Address or ! PI Address from Phase I is: ! ! 6127 Wilder Lab, ! Department of Physics and Astr ! onomy, Hanover, NH 03755 ! ! Ship_Via: UPS ! UPS (2-day) or OVERNIGHT ! Overnight shipping done at PI expense Recipient_Email: ! Needed if Ship_To: is not PI_Address !