- Phase II 9981
STIS Scientific Rationale:
STIS UDF parallels are being obtained in 50CCD + MIRROR (imaging) and 50CCD + G750L (slitless spectroscopy). The principal science is to obtain low-resolution (R~500) spectra in the optical to near-IR (524-1027 nm) for a sample of galaxies in the GEMS fields. These spectra may be useful for determining galaxy morphologies and redshifts.
For both pairs of STIS parallel fields, the two paired fields only barely overlap each other on one edge. All four STIS parallel fields fall outside the GOODS field but within the GEMS fields surrounding GOODS.
The pointings for these two pairs of overlapping fields are essentially as follows, with the coordinates representing the approximate center and 50CCD aperture reference location:
Epoch 1, ORIENT 310 RA (J2000)= 03 32 34.5 DEC (J2000)= -27 36 19.0 ~center Epoch 1, ORIENT 314 RA (J2000)= 03 32 38.0 DEC (J2000)= -27 36 16.15 ~center Epoch 2, ORIENT 40 RA (J2000)= 03 33 29.5 DEC (J2000)= -27 46 28.1 ~center Epoch 2, ORIENT 44 RA (J2000)= 03 33 29.7 DEC (J2000)= -27 47 15.2 ~center
50CCD + MIRROR imaging, 50CCD + G750L slitless spectroscopy
Although we could not a priori know exactly the amount of exposure time we would receive at either ORIENT, nor the combined exposure time in the overlap region of both pairs of fields, we could estimate some depths which we hoped to achieve based on a given number of orbits and exposure time.
The STIS ETC claims that we reach ABMAG=20 in 280000 sec at S/N=10 with CR-SPLIT=300. But this seems too bright, so this issue is still under some investigation.
All data for both Epochs have been obtained.