NASA Hubble Space Telescope Daily Report #4139

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science DAILY REPORT # 4139

PERIOD COVERED: UT June 20, 2006 (DOY 171)

OBSERVATIONS SCHEDULED

NIC3 10632

Searching for galaxies at z>6.5 in the Hubble Ultra Deep Field

We propose to obtain deep ACS {F606W, F775W, F850LP} imaging in the area of the original Hubble Ultra Deep Field NICMOS parallel fields and – through simultaneous parallel observations – deep NICMOS {F110W, F160W} imaging of the ACS UDF area. Matching the extreme imaging depth in the optical and near-IR bands will result in seven fields with sufficiently sensitive multiband data to detect the expected typical galaxies at z=7 and 8. Presently no such a field exist. Our combined optical and near-IR ultradeep fields will be in three areas separated by about 20 comoving Mpc at z=7. This will allow us to give a first assessment of the degree of cosmic variance. If reionization is a process extending over a large redshift interval and the luminosity function doesn’t evolve strongly beyond z=6, these data will allow us to identify of the order of a dozen galaxies at 6.5 < z <8.5 - using the Lyman break technique - and to place a first constrain on the luminosity function at z>6.5. Conversely, finding fewer objects would be an indication that the bulk of reionization is done by galaxies at z=6. By spending 204 orbits of prime HST time we will capitalize on the investment of 544 prime orbits already made on the Hubble Ultra Deep Field {UDF}. We have verified that the program as proposed is schedulable and that it will remain so even if forced to execute in the 2-gyro mode. The data will be non-proprietary and the reduced images will be made public within 2 months from the completion of the observations.

NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration – CR Persistence Part 4

A new procedure proposed to alleviate the CR-persistence problem of NICMOS. Dark frames will be obtained immediately upon exiting the SAA contour 23, and every time a NICMOS exposure is scheduled within 50 minutes of coming out of the SAA. The darks will be obtained in parallel in all three NICMOS Cameras. The POST-SAA darks will be non-standard reference files available to users with a USEAFTER date/time mark. The keyword ‘USEAFTER=date/time’ will also be added to the header of each POST-SAA DARK frame. The keyword must be populated with the time, in addition to the date, because HST crosses the SAA ~8 times per day so each POST-SAA DARK will need to have the appropriate time specified, for users to identify the ones they need. Both the raw and processed images will be archived as POST-SAA DARKSs. Generally we expect that all NICMOS science/calibration observations started within 50 minutes of leaving an SAA will need such maps to remove the CR persistence from the science images. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.

NIC2 10755

Photometric Standard Clusters for Cross-Observatory Calibration

The goal of this program is to obtain NICMOS photometry of selected solar analog stars in selected Galactic clusters that will be used as on-orbit photometric standard star fields for JWST-NIRCAM. The availability of such fields at JWST launch will facilitate rapid photometric calibration of NIRCAM. The NIRCAM team plans to observe the chosen clusters with Spitzer- IRAC.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)

HSTARS: (None)

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                         SCHEDULED      SUCCESSFUL 
FGS GSacq               13                    13 
FGS REacq               02                     02 
OBAD with Maneuver  30                     30 

SIGNIFICANT EVENTS:

Flash Report: Status Briefing – ACS Suspend Status Update

A follow-up briefing was held at 1 pm on June 20, 2006 to review the status of the analysis on the ACS suspend event.

Discussion/Agreements:

The preliminary data analysis of the event was presented as well as a review of the data collection process and the A/D FIFO Error handling. The forward plan for the STScI regarding the present SMS and near-term SMSs was discussed. It was agreed to intercept the science timeline with an SMS without ACS effective 8am EDT Thursday and to develop next week’s SMS without ACS activities. The STScI will be ready to provide an intercept SMS with ACS observations when needed. The options for on-orbit tests to troubleshoot side 1 were also discussed.

It was agreed to reconvene on Thursday at 1pm to review the hardware assessment and the options for on-orbit activities.