HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science <br /><br />DAILY REPORT #3911 <br /><br />PERIOD COVERED: UT July 27, 2005 [DOY 208] <br /><br />OBSERVATIONS SCHEDULED <br /><br />ACS/HRC 10435 <br /><br />Merger-Induced Populations in Early-Type Galaxy Cores <br /><br />Hierarchical formation models predict that early-type galaxies are built<br />up over an extended period from mergers of smaller systems, a process<br />which should leave long- lived signatures in their light profiles and<br />stellar population colors. Merger events should have continued up to<br />relatively recent times {the last 1-5 Gyr}, and many ellipticals and S0<br />bulges should therefore show evidence of multiple, discrete,<br />intermediate-age populations. Although there is substantial<br />observational support for a dissipational merger origin for some<br />early-type galaxies, most do not exhibit the expected anomalies in<br />either their light profiles or color distributions. However, existing<br />searches {mainly in the V and I bands} have not probed very deeply. Here<br />we propose high resolution, broad-band, near-ultraviolet {2500-3400 A}<br />imaging of the cores of bright early-type galaxies. This is the most<br />sensitive probe available for the detection of spatially-segregated,<br />multiple population components with ages in the range 1-5 Gyr. Our<br />sample consists of dust- and AGN-free systems with both normal and<br />mildly anomalous central light profiles. There is very little existing<br />information on the near-UV structure of early-type galaxies, and our<br />program would effectively explore new terrain. <br /><br />ACS/HRC/WFC 10389 <br /><br />ACS CCDs daily monitor - Cycle 13 - Part 2 <br /><br />This program consists of a set of basic tests to monitor, the read<br />noise, the development of hot pixels and test for any source of noise in<br />ACS CCD detectors. The files, biases and dark will be used to create<br />reference files for science calibration. This program will be for the<br />entire lifetime of ACS. <br /><br />ACS/HRC/WFC 10400 <br /><br />Unravelling NGC 3125-1: The Most Extreme Wolf-Rayet Star Cluster Known<br />in the Local Universe <br /><br />Based on cycle 10 STIS UV spectroscopy, we have recently discovered a<br />star cluster, NGC 3125-1, which has the strongest known He II 1640<br />emission {of stellar origin} in the local universe. The number of<br />implied WR stars is more than an order of magnitude higher than for any<br />other well-studied giant HII region. Because strong He II 1640 emission<br />has been discovered in the composite spectra of redshift 3 Lyman Break<br />Galaxies, NGC 3125-1 potentially provides a unique opportunity to study<br />a nearby object with direct implications for the stellar populations<br />observed in the early universe. In order to understand the origin of<br />this anomalously strong WR feature, we propose to obtain the first high<br />resolution imaging of NGC 3125-1, at wavelengths from the far<br />ultraviolet through the near infrared. This will allow us to<br />simultaneously place it in the context of more familiar objects, such as<br />R136 in 30 Doradus, while also unravelling the physics responsible for<br />the observed UV spectral signature. <br /><br />ACS/HRC/WFC/WFPC2 10384 <br /><br />Focus Monitor <br /><br />The focus of HST is measured from WFPC2/PC and ACS/HRC images of stars.<br />Multiple exposures are taken in parallel over an orbit to determine the<br />influence of breathing on the derived mean focus. Observations are taken<br />of clusters with suitable orientations to ensure stars appear in all<br />fields. <br /><br />ACS/WFC/WFPC2 10499 <br /><br />Life Before the Fall: Morphological Evolution of Galaxies in Groups<br />Prior to Cluster Assembly at z=0.37 <br /><br />We propose to obtain a deep ACS/WFC mosaic of a protocluster comprised<br />of 4 distinct galaxy groups that are gravitationally bound to each other<br />at z=0.37. The galaxy groups have a total combined mass comparable to<br />the Coma cluster and already have twice as many absorption line galaxies<br />as the field. The SG1120 complex thus provides an unprecedented<br />opportunity for determining whether "pre-processing" in the group<br />environment is responsible for the bulk of observed diffences between<br />galaxies in nearby clusters and those in the field. High resolution<br />imaging with HST is needed to morphologically classify the group members<br />and measure their structural parameters. By combining the early-type<br />fraction and morphology-density relation in SG1120 with results from our<br />wide-field spectroscopic survey, we will test whether spectral and<br />morphological transformation timescales are decoupled on group scales<br />and isolate the environmental mechanisms responsible for such evolution.<br />We will also measure the Fundamental Plane and M/L ratios of the<br />early-type members to constrain their formation epoch and how their<br />stellar populations have evolved. Observations of the multiple galaxy<br />groups in SG1120 provide a unique dataset to the community and will aid<br />our understanding of how galaxies evolve in the still poorly studied<br />group regime. <br /><br />NIC1/NIC2/NIC3 8793 <br /><br />NICMOS Post-SAA calibration - CR Persistence Part 4 <br /><br />A new procedure proposed to alleviate the CR-persistence problem of<br />NICMOS. Dark frames will be obtained immediately upon exiting the SAA<br />contour 23, and every time a NICMOS exposure is scheduled within 50<br />minutes of coming out of the SAA. The darks will be obtained in parallel<br />in all three NICMOS Cameras. The POST-SAA darks will be non-standard<br />reference files available to users with a USEAFTER date/time mark. The<br />keyword 'USEAFTER=date/time' will also be added to the header of each<br />POST-SAA DARK frame. The keyword must be populated with the time, in<br />addition to the date, because HST crosses the SAA ~8 times per day so<br />each POST-SAA DARK will need to have the appropriate time specified, for<br />users to identify the ones they need. Both the raw and processed images<br />will be archived as POST-SAA DARKSs. Generally we expect that all NICMOS<br />science/calibration observations started within 50 minutes of leaving an<br />SAA will need such maps to remove the CR persistence from the science<br />images. Each observation will need its own CRMAP, as different SAA<br />passages leave different imprints on the NICMOS detectors. <br /><br />NIC2 10428 <br /><br />The colours of QSO host galaxies at z=2 and the evolution of their<br />stellar masses <br /><br />We propose to use NICMOS imaging to measure the rest-frame optical/UV<br />colours of a complete sample of 10 QSO host galaxies at redshifts<br />between z=1.5 and z=2. From our cycle 11 HST observations {the GEMS<br />project} we know that QSO host galaxies at redshifts of z~1 show blue<br />colors despite having early-type morphologies. This is in excellent<br />agreement with recent SDSS results on low-z AGN hosts, suggesting that<br />QSO- type activity in galaxies correlates strongly with the presence of<br />a young stellar population. Our proposed NICMOS observations will allow<br />us to test the validity of this hypothesis out to z~2, by relating the<br />observed QSO host colours to those of normal galaxies at similar<br />redshifts taken from GOODS. We have already established within GEMS that<br />the QSO hosts in our sample possess substantial UV luminosities, most<br />likely originating from young stars. Knowing rest-frame colors, we can<br />estimate stellar ages and stellar masses. For the first time will it be<br />possible to determine the evolution of stellar masses in QSO host<br />galaxies from z=2, the epoch of maximum QSO activity, to the present.<br />Our results will shed light on the relation between nuclear activity and<br />the star formation history of galaxies, and how these processes may<br />jointly drive the cosmic evolution of QSOs and galaxies. <br /><br />FLIGHT OPERATIONS SUMMARY: <br /><br />Significant Spacecraft Anomalies: [The following are preliminary reports<br />of potential non-nominal performance that will be investigated.] <br /><br />HSTARS: [None] <br /><br />COMPLETED OPS REQUEST:<br />#17482-1: FSW 2.8A EEPROM Installation @ 208/1457z<br /><br />COMPLETED OPS NOTES: [None] <br /><br /> SCHEDULED SUCCESSFUL <br />FGS Gsacq 04 04 <br />FGS Reacq 10 10 <br />FHST Update 08 08 <br /><br />SIGNIFICANT EVENTS:<br />FSW 2.8 Release A was successfully installed in HST486 EEPROM at<br />208/14:54:53z. The 2.8A EEPROM load was completed at 208/13:34:26z. The<br />baseline EEPROM memory dump was completed at 208/14:47:29z and verified<br />by FSW.<br /><br />Lynn F. Bassford<br />CHAMP HST Missions Operations Manager<br />Lockheed Martin Technical Operations<br />GSFC PH#: 301-286-2876<br />STScI PH#: 410-338-4895 [shared]<br /><br />"The Hubble Space Telescope is the Babe Ruth of astronomical observatories, the Muhammad Ali of cosmic photography " - Robert Roy Britt, space.com 7-14-4<br />..............................................................