NICMOS has played a key role in probing the deep near infrared regime for a decade. It has been the only instrument available to observe faint objects in the near infrared that are not observable from the ground. However, the calibration of NICMOS has turned out to be difficult in the low-count-rate regime. The NICMOS calibration team has extrapolated a power-law to describe the apparent non-linearity in the NICMOS detectors from measurements at ~50-5000 ADU/s to flux counts around 0.1-1 ADU/s. Precise measurements of faint objects (such as SNe Ia at high redshift) require us to reduce the uncertainties from this extrapolation. Here we propose to determine the absolute zeropoint for faint objects by cross-calibrating the WFC3 and NICMOS detectors in observations of early type galaxies at redshifts z>1.

Calibration program to determine zeropoints of NICMOS/WFC3 cameras for faint objects COSMOLOGY 0 false 0.0 0.0 false false false false false false SUPPORTED CALIBRATION DETECTOR LINEARITY TEST PHOTOMETRIC z=0.98 J2000 12 29 28.5000 +01 51 50.00 J2000 CALIBRATION DETECTOR LINEARITY TEST PHOTOMETRIC z=1.23 J2000 12 52 54.4000 -29 27 15.00 J2000 CALIBRATION DETECTOR LINEARITY TEST PHOTOMETRIC z=1.24 J2000 14 34 29.3000 +34 26 40.00 J2000 CALIBRATION DETECTOR LINEARITY TEST PHOTOMETRIC z=1.39 J2000 22 35 21.5000 -25 57 25.00 J2000 CALIBRATION DETECTOR LINEARITY TEST PHOTOMETRIC z=0.98 J2000 12 29 28.1700 +01 52 8.98 J2000 WFC3/IR Imaging No No F105W WFC3/IR Imaging No No F110W WFC3/IR Imaging No No F125W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F105W WFC3/IR Imaging No No F110W WFC3/IR Imaging No No F125W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F105W WFC3/IR Imaging No No F110W WFC3/IR Imaging No No F125W WFC3/IR Imaging No No F160W WFC3/IR Imaging No No F105W WFC3/IR Imaging No No F110W WFC3/IR Imaging No No F125W WFC3/IR Imaging No No F160W NIC2 Imaging No No F110W POS-TARG DITHER DITHER 1.5375 NIC-XSTRIP-DITH false false 7 0.0 POS-TARG NIC-SPIRAL-DITH 0.0 1 false POS-TARG DITHER 4.576 LINE 2.92 false false 74.653 4 18.528 WFC3-IR-DITHER-BOX-MIN 2 false The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12051 :visit-id "01" :proposal-version -1 :trans-version "20090702" :date "27-Jan-2010 13:28:50.0" :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 3830000 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12051 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12051 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2836 :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 3236 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12051 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2936 :al-overhead-at-end 0 :internal-dur-at-end 611 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3236 :pcs-gap 0 ) true 2 0 Please adjust NSAMP to fill time allocated to orbit The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12051 :visit-id "02" :proposal-version -1 :trans-version "20090702" :date "02-Feb-2010 11:40:01.0" :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 3830000 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12051 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12051 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2836 :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 3267 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12051 :visit-id "02" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2936 :al-overhead-at-end 0 :internal-dur-at-end 592 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3267 :pcs-gap 0 ) true 2 0 Please adjust NSAMP to fill time allocated to orbit The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. 1265747940000 274.210233205224 (Tic-Visit :proposal-id 12051 :visit-id "03" :proposal-version -1 :trans-version "20090702" :date "27-Jan-2010 13:28:21.0" :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 3969264 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12051 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12051 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2936 :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 3283 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12051 :visit-id "03" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3036 :al-overhead-at-end 0 :internal-dur-at-end 611 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3283 :pcs-gap 0 ) true 2 0 Please adjust NSAMP to fill time allocated to orbit The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12051 :visit-id "04" :proposal-version -1 :trans-version "20090702" :date "02-Feb-2010 11:41:17.0" :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 3830000 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12051 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12051 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2836 :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 3267 :pcs-gap 0 ) (Tic-Orbit :proposal-id 12051 :visit-id "04" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2936 :al-overhead-at-end 0 :internal-dur-at-end 592 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3267 :pcs-gap 0 ) true 2 0 Please adjust NSAMP to fill time allocated to orbit The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 12051 :visit-id "05" :proposal-version -1 :trans-version "20100218" :date "24-Feb-2010 06:33:21.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "23" :si-bright-earth-limb-angle 20.0 :data-volume 200976 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 12051 :visit-id "05" :obset-id "05" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 12051 :visit-id "05" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2879 :al-overhead-at-end 0 :internal-dur-at-end 56 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3234 :pcs-gap 0 ) false 1 0 Please adjust NSAMP to fill time allocated to orbit