Added SEQ NON INT to keep orbit structure identical to APT modelling. Requested by CS. ----- Attempting Submission 3 (Mon Dec 12 19:42:36 GMT 2011) ----- Dissecting star formation and extinction in the brightest lensed galaxy Gravitational lensing provides rare chances to study high-redshift galaxies in otherwise unobtainable ways. We propose to study a spectacular lensed galaxy that is not only exceptionally bright, but has redshifted H-alpha and H-beta into narrow-band filters on HST. We have already obtained H-beta and broad-band filters. We originally proposed to map H-alpha with NICMOS, but have submitted a change request to switch to G141 grating observations, to measure the ratio of H gamma to H beta, and its spatial variation, in order to map the extinction over this remarkably bright z=1.7 lensed galaxy.
We are using the WFC3 G141 grism to measure the ratio of Hbeta to Hgamma across this giant (38") lensed arc. As justified in the Program Change Request, 4 orbits gives a simulated signal-to-noise ratio of >50 which is sufficient to measure the extinction to a precision of +-0.12 mag on A_v. We use two different roll angles to minimize crowding from cluster galaxies, and do two dither positions at each roll angle. As the PII instructions request, we here explain how we calculate ORIENT, and ask STScI to check our math, please! We assume the G141 grating disperses along the +X axis on the detector; **PLEASE TELL US** if this false. We measure the sky position angle (E of N) we want to run along the +X axis. We add the value from Table 7.4 of the PIIpI of 225.18 degrees, appropriate for the +X direction of WFC3-IR. This should be ORIENT. UNRESOLVED STELLAR POPULATIONS AND GALAXY STRUCTURE 12 false 0.0 0.0 false false false false SUPPORTED GALAXY EMISSION LINE NEBULA GRAVITATIONAL LENS HIGH REDSHIFT GALAXY J2000 r=19.0 NIC2 Imaging No No F180M The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. /private/var/folders/U7/U7EpVZ9NHJe91f-zXie+mk++4y2/-Tmp-/OPVisit2694434740997605987.xml See comments in Proposal Description for discussion of ORIENT. (Tic-Visit :proposal-id 12726 :visit-id "01" :proposal-version -1 :trans-version "20110509" :date "12-Dec-2011 14:40:12.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 974880 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12726 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12726 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2907 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12726 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3007 :al-overhead-at-end 0 :internal-dur-at-end 578 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) true 2 0 HELP! Manual says to set aperture to G141-REF for direct image, but this is not an option!!!*** HELP! Manual says to set aperture to G141-REF for direct image, but this is not an option!!!*** The scheduling data was generated by CASM 19.3. CASM was run in Phase II mode. /private/var/folders/U7/U7EpVZ9NHJe91f-zXie+mk++4y2/-Tmp-/OPVisit8583367696017275744.xml See comments in Proposal Description for discussion of ORIENT. (Tic-Visit :proposal-id 12726 :visit-id "02" :proposal-version -1 :trans-version "20110509" :date "12-Dec-2011 14:41:04.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 974880 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12726 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12726 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2907 :al-overhead-at-end 0 :internal-dur-at-end 0 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12726 :visit-id "02" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3007 :al-overhead-at-end 0 :internal-dur-at-end 578 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3245 :pcs-gap 0 ) true 2 0 HELP! Manual says to set aperture to G141-REF for direct image, but this is not an option!!!*** HELP! Manual says to set aperture to G141-REF for direct image, but this is not an option!!!***