15092( 2) - 11-Dec-2018 20:03:03 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15092 Version: 2 Check-in Time: 11-Dec-2018 20:03:03 STScI Edit Number: 0 Title Testing Dust Models at Moderate Redshift: Is the z=0.437 DLA toward 3C 196 Rich in Carbonaceous Dust? ------------------------------------------------------------------------------------ Type Cycle GO 25 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Monique C Aller Georgia Southern University Res. & Svc. Y Foundation, Inc CoI: Dr. Varsha Purushottam Kulkarni University of South Carolina Research N Foundation ------------------------------------------------------------------------------------ Abstract Interstellar dust grains play a critical role in the formation of stars, and significantly impact the evolution and appearance of distant galaxies. High redshift studies must account for this dust. Dust grains in the Milky Way are predominately carbonaceous and silicate, each of which produces unique spectral signatures in the extinction curve. In distant galaxies, the composition of dust grains and the relative amount of silicate and carbonaceous dust can be studied using the extinction curves along luminous background quasar sightlines produced by gas-rich foreground absorbers. Our previous work suggests that dust grains in distant galaxies are often more silicate-rich than in the Milky Way, but that the dust may be predominately silicate or carbonaceous along a sightline. We predict that silicate-poor, dusty DLAs should be rich in carbonaceous dust, and exhibit a relatively strong 2175 A bump. To test this hypothesis, we propose G230L/430L STIS spectra covering the 2175 A bump in the dusty z=0.437 DLA toward 3C 196, which is hosted in a barred spiral galaxy with (super-) solar metallicity. We expect to find a significant 2175 A bump in this system, like in the dusty but silicate-poor z=0.524 DLA toward AO 0235+164. Combining the proposed data with archival spectra will yield an extinction curve extending from the FUV to the IR, for comparison with local galaxies. The results of this test will significantly inform our models about the distribution of dust grain populations and the dichotomy between carbonaceous and silicate dust grains, and address whether moderate redshift dust in spiral galaxies does differ from the Milky Way, in preparation for planned JWST studies. ------------------------------------------------------------------------------------ Observations Description ------------------------ We will obtain 5 orbits with the STIS/MAMA/G230L grating and 1 orbit with the STIS/G430L grating to span the spectral range from 1570-5700 Angstroms with a S/N per spectral resolution element of ~10 at the center of the (rest-frame) 2175 Angstrom feature. In the observed frame, this feature in the z=0.437 DLA will be centered at 3125.5 Angstroms. Due to the detrimental effects of CTE in the STIS CCD for the exposure times of 1000 seconds or less, and since we are observing a point source and the full slit length is not needed, we use the 52"x0.2"E1 pseudo-aperture for our G430L observation, to place the target closer to the readout amplifier. For the G230L science exposures, we have used 2-point dither patterns along the slit with step sizes of 1.0", 1.5", 2.0", 2.5", and 3.0", to prevent the spectra in different orbits from falling on the 15092( 2) - 11-Dec-2018 20:03:03 - [ 2] same part of the detector. We have used a 3-point dither pattern with smaller step sizes of 0.5" for the G430L observations, due to our proximity to the slit edge. ------------------------------------------------------------------------------------ 15092( 2) - 11-Dec-2018 20:03:03 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 3C196 GALAXY, LYMAN ALPHA RA=08H13M36.0677S +/- 0.11", J2000 Z = 0.87 V = 17.79 SDSS uAB=18.941 CLOUD, QSO DEC=+48D13'2.75" +/- 0.11" Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. The coordinates were updated using the 2MASS All-Sky Point Source Catalog (PSC). The redshift of the QSO was taken from NED. ------------------------------------------------------------------------------------------------------------------------------------ 15092( 2) - 11-Dec-2018 20:03:03 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 1.5 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 90.0 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 2 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 2.0 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 90.0 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 3 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 2.5 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 90.0 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 4 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 3.0 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 90.0 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 15092( 2) - 11-Dec-2018 20:03:03 - [ 5] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 5 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 2 Point_Spacing 1.0 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 90.0 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 6 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.5 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 90.0 Angle_Between_Sides Center_Pattern NO ------------------------------------------------------------------------------------------------------------------------------------ 15092( 2) - 11-Dec-2018 20:03:03 - [ 6] Visit: 01 (Visit 1 -G230L) Visit Requirements: On Hold Comments: Additional Comments: We have verified, using the BOT, that there are no bright objects (i.e. no objects flagged as health/safety concerns) in the field. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 3C196 STIS/CCD ACQ F28X50LP MIRROR 1 25 S (25 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 3C196 STIS/NUV ACCUM 52X0.2 G230L 2376 1 1100 S PATTERN 1 2 -MAMA see below (2302 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 3C196 STIS/NUV ACCUM 52X0.2 G230L 2376 1 1200 S PATTERN 2 3 -MAMA see below (2850 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 3C196 STIS/NUV ACCUM 52X0.2 G230L 2376 1 1100 S PATTERN 3 4 -MAMA see below (2850 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ 3C196 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A 3C196 2 STIS/NUV ACCUM 52X0.2 G230L 2376 1 none none none 1 1151.0 S -MAMA 3C196 2 STIS/NUV ACCUM 52X0.2 G230L 2376 2 none none none 1 1151.0 S -MAMA 3C196 3 STIS/NUV ACCUM 52X0.2 G230L 2376 1 none none none 2 1425.0 S -MAMA 3C196 3 STIS/NUV ACCUM 52X0.2 G230L 2376 2 none none none 2 1425.0 S -MAMA 3C196 4 STIS/NUV ACCUM 52X0.2 G230L 2376 1 none none none 3 1425.0 S -MAMA 3C196 4 STIS/NUV ACCUM 52X0.2 G230L 2376 2 none none none 3 1425.0 S -MAMA 15092( 2) - 11-Dec-2018 20:03:03 - [ 7] Visit: 02 (Visit 2 -G230L) Visit Requirements: On Hold Comments: Additional Comments: We have verified, using the BOT, that there are no bright objects (i.e. no objects flagged as health/safety concerns) in the field. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 3C196 STIS/CCD ACQ F28X50LP MIRROR 1 25 S (25 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 3C196 STIS/NUV ACCUM 52X0.2 G230L 2376 1 1100 S PATTERN 5 2 -MAMA see below (2302 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 3C196 STIS/NUV ACCUM 52X0.2 G230L 2376 1 1200 S PATTERN 4 3 -MAMA see below (2850 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ 3C196 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A 3C196 2 STIS/NUV ACCUM 52X0.2 G230L 2376 1 none none none 1 1151.0 S -MAMA 3C196 2 STIS/NUV ACCUM 52X0.2 G230L 2376 2 none none none 1 1151.0 S -MAMA 3C196 3 STIS/NUV ACCUM 52X0.2 G230L 2376 1 none none none 2 1425.0 S -MAMA 3C196 3 STIS/NUV ACCUM 52X0.2 G230L 2376 2 none none none 2 1425.0 S -MAMA 15092( 2) - 11-Dec-2018 20:03:03 - [ 8] Visit: 03 (Visit3-G430L) Visit Requirements: On Hold Comments: Additional Comments: We have verified, using the BOT, that there are no bright objects (i.e. no objects flagged as health/safety concerns) in the field. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 3C196 STIS/CCD ACQ F28X50LP MIRROR 1 25 S (25 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 3C196 STIS/CCD ACCUM 52X0.2E1 G430L 4300 CR-SPLIT=NO 1 700 S PATTERN 6 2 see below (2325 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ 3C196 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A 3C196 2 STIS/CCD ACCUM 52X0.2E1 G430L 4300 1 none none none 1 775.0 S 3C196 2 STIS/CCD ACCUM 52X0.2E1 G430L 4300 2 none none none 1 775.0 S 3C196 2 STIS/CCD ACCUM 52X0.2E1 G430L 4300 3 none none none 1 775.0 S 15092( 2) - 11-Dec-2018 20:03:03 - [ 9] Summary Form for Proposal 15092 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.2, 52X0.2E1, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PATTERN 1 2, PATTERN 2 3, PATTERN 3 4, PATTERN 4 3, PATTERN 5 2, PATTERN 6 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G230L, G430L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names 3C196 ------------------------------------------------------------------------------------------------------------------------------------