Hubble Status Report - October 2003
The report of the HST-JWST Transition Panel, chaired by John Bahcall, was issued before schedule in mid-August. It recommended three options to NASA, one of them including two further servicing missions to the Observatory: SM4, carrying WFC3 and COS, around 2005 and a new SM5 around 2010 aimed towards maximising the scientific productivity of HST - but only after the proposed science was successful in an open peer-reviewed competition with other new space astrophysics proposals. Whichever of the three options is chosen, it will be necessary to fit a propulsion module to the spacecraft in order to allow a controlled re-entry at the end of its operational life.
The Cycle 12 time allocation process for HST took place in Baltimore in late March this year and resulted in the allocation of 3154 primary orbits from a total of 19674 requested. These were distributed over the five instruments currently available, with 53.7% going to ACS, 27.8% to STIS, 14.5% to NICMOS, 7.4% to WFPC2 and 2.2% to the FGS. PIs from ESA member states were awarded 16.8% of the accepted proposals and 10.2% of the accepted primary orbits. The Cycle 13 call for proposals was issued in early October 2003.
Of particular interest is the use of the ACS grism mode to obtain spectra of supernovae discovered using the split-epoch ACS observing strategy. This mode, with calibration and extraction software developed at the ST-ECF, provides probably the most sensitive optical spectroscopic capability for point sources available to astronomers at the moment. This is currently being exploited by a GO programme to follow up the GOODS discoveries. The aim is to confirm the SN Ia classification and provide the redshift for SN cosmology studies (Omega Lambda and equation of state of dark energy). A spectacular example is provided by SN2002fw which has a redshift of 1.3. An ACS grism spectrum was obtained in 15ks and is the spectrum of the highest z SN to date.
As part of the complementary groundbased observing programmes, ESO is currently releasing the optical spectroscopy of approximately 500 colour-selected sources in the CDF-S obtained with the red-optimised FORS2 instrument on the VLT.