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Daily 3878
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 3878 PERIOD COVERED: UT June 09, 2005 (DOY 160) OBSERVATIONS SCHEDULED ACS/WFC 10325 Low Redshift Cluster Gravitational Lensing Survey This proposal has two main scientific goals: to determine the dark matter distribution of massive galaxy clusters, and to observe the high redshift universe using these clusters as powerful cosmic telescopes. Deep, g, r, i, z imaging of a sample of low-z {0.2-0.4} clusters will yield a large sample of lensed background galaxies with reliable photometric redshifts. By combining strong and weak lensing constraints with the photometric redshift information it will be possible to precisely measure the cluster dark matter distribution with an unprecedented combination of high spatial resolution and area coverage, avoiding many of the uncertainties which plague ground-based studies and yielding definitive answers about the structure of massive dark matter haloes. In addition, the cosmological parameters can be constrained in a largely model independent way using the multiply lensed objects due to the dependence of the Einsteinng ring radius on the distance to the source. We can also expect to detect several highly magnified dropout galaxies behind the clusters in the redshift ranges 4-5 5-6 and 7-8, corresponding to a drop in the flux in the g, r, and i bands relative to longer wavelength. We will obtain the best information to date on the giant arcs already known in these clusters, making possible detailed, pixel-by-pixel studies of their star formation rate, dust distribution and structural components, including spiral arms, out to a redshift of around z~2.5 in several passbands. ACS/WFC/NIC2 10189 PANS-Probing Acceleration Now with Supernovae Type Ia supernovae {SNe Ia} provide the most direct evidence for an accelerating Universe, a result widely attributed to dark energy. Using HST in Cycle 11 we extended the Hubble diagram with 6 of the 7 highest-redshift SNe Ia known, all at z1.25, providing conclusive evidence of an earlier epoch of cosmic deceleration. The full sample of 16 new SNe Ia match the cosmic concordance model and are inconsistent with a simple model of evolution or dust as alternatives to dark energy. Understanding dark energy may be the biggest current challenge to cosmology and particle physics. To understand the nature of dark energy, we seek to measure its two most fundamental properties: its evolution {i.e., dw/dz}, and its recent equation of state {i.e., w{z=0}}. SNe Ia at z1, beyond the reach of the ground but squarely within the reach of HST with ACS, are crucial to break the degeneracy in the measurements of these two basic aspects of dark energy. The SNe Ia we have discovered and measured with HST in Cycle 11, now double the precision of our knowledge of both properties. Here we propose to quadruple the sample of SNe Ia at z1 in the next two cycles, complementing on-going surveys from the ground at z1, and again doubling the precision of dark energy constraints. Should the current best fit model prove to be the correct one, the precision expected from the current proposal will suffice to rule out a cosmological constant at the 99% confidence level. Whatever the result, these objects will provide the basis with which to extend our empirical knowledge of this newly discovered and dominant component of the Universe, and will remain one of the most significant legacies of HST. In addition, our survey and follow-up data will greatly enhance the value of the archival data within the target Treasury fields for galaxy studies. ACS/WFC/WFPC2 10402 The Formation and Evolution of Spirals: An ACS and WFPC2 Imaging Survey of Nearby Galaxies Over 50% of galaxies in the local universe are spirals. Yet the star formation histories and evolution of this crucial population remain poorly understood. We propose to combine archival data with new ACS/WFC and WFPC2 observations of 11 galaxies, to tackle a comprehensive investigation of nearby spirals covering the entire spiral sequence. The new observations will fill a serious deficiency in HST's legacy, and maximize the scientific return of existing HST data. The filter combination of UBVI, and Halpha is ideal for studying stellar populations, dust properties, and the ISM. Our immediate scientific objectives a {i} to use the resolved cluster populations, both young massive clusters and ancient globular clusters as a chronometer, to understand how spirals assembled as a function of time; {ii} study the rapid disruption properties of young clusters; and {iii} understand dust distributions in spirals from pc to kpc scales. Each of these goals provides an important step towards charting the evolution of galaxies, and an essential baseline for interpreting the galaxy populations being surveyed in both the early and present universe. The resolution of our survey, which exploits the excellent imaging capabilities of HST's two optical cameras, will enable us to understand the record of star cluster, and galaxy formation in a level of detail which is not possible for more distant systems. Finally, the proposed observations will provide a key to interpret an extensive, multiwavelength archive of space- and ground- based data at lower spatial resolution {SPITZER, CHANDRA, GALEX, NICMOS P alpha and H band imaging} for local spirals. NIC1/NIC2/NIC3 8792 NICMOS Post-SAA calibration - CR Persistence Part 3 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 10428 The colours of QSO host galaxies at z=2 and the evolution of their stellar masses We propose to use NICMOS imaging to measure the rest-frame optical/UV colours of a complete sample of 10 QSO host galaxies at redshifts between z=1.5 and z=2. From our cycle 11 HST observations {the GEMS project} we know that QSO host galaxies at redshifts of z~1 show blue colors despite having early-type morphologies. This is in excellent agreement with recent SDSS results on low-z AGN hosts, suggesting that QSO-type activity in galaxies correlates strongly with the presence of a young stellar population. Our proposed NICMOS observations will allow us to test the validity of this hypothesis out to z~2, by relating the observed QSO host colours to those of normal galaxies at similar redshifts taken from GOODS. We have already established within GEMS that the QSO hosts in our sample possess substantial UV luminosities, most likely originating from young stars. Knowing rest-frame colors, we can estimate stellar ages and stellar masses. For the first time will it be possible to determine the evolution of stellar masses in QSO host galaxies from z=2, the epoch of maximum QSO activity, to the present. Our results will shed light on the relation between nuclear activity and the star formation history of galaxies, and how these processes may jointly drive the cosmic evolution of QSOs and galaxies. 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 FAILURE TIMES FGS Gsacq 6 6 FGS Reacq 9 9 FHST Update 9 9 LOSS of LOCK SIGNIFICANT EVENTS: The ACS FSW CS 4.01 was successfully installed at 160/22:50 into EEPROM using the CCS-D String. After the load was complete, EEPROM memory was dumped and there were no miscompares reported by the Payload FSW Team. ACS will remain under FSW CS4.0 control until Sunday evening when ACS will enter Anneal mode. Upon transition from Anneal to Operate mode the newly installed FSW will be copied from EEPROM to EDAC memory and then be activated. |
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