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Daily 3753
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 3753 PERIOD COVERED: DOY 344 OBSERVATIONS SCHEDULED ACS/HRC 10137 Cluster Archeology: The Origin of Ultra-compact Dwarf Galaxies Ultra-compact dwarf {UCD} galaxies are a new type of galaxy we have discovered in the central regions of the Fornax and Virgo galaxy clusters. Our most recent observations in the Fornax Cluster show that UCDs outnumber normal galaxies in the centre of that cluster. Here we propose snapshot imaging of UCDs in the Fornax and Virgo clusters to test theories of how these fascinating objects formed. In particular we wish to image Virgo cluster UCDs for which we have ground-based Keck spectroscopy to test predictions that they formed more recently than the Fornax UCDs. ACS/HRC 10199 The Most Massive Galaxies in the Universe: Double Trouble? We are proposing an HST snapshot survey of 70 objects with velocity dispersion larger than 350 km/s, selected from the Sloan Digital Sky Survey. Potentially this sample contains the most massive galaxies in the Universe. Some of these objects may be superpositions; HST imaging is the key to determining if they are single and massive or if they are two objects in projection. The objects which HST imaging shows to be single objects are interesting because they potentially harbor the most massive black holes, and because their existence places strong constraints on galaxy formation models. When combined with ground based data already in hand, the objects which HST imaging shows are superpositions provide valuable information about interaction rates of early- type galaxies as well as their dust content. They also constrain the allowed parameter space for models of binary gravitational lenses {such models are currently invoked to explain discrepancies in the distribution of lensed image flux ratios and separations}. ACS/HRC 10377 ACS Earth Flats High signal sky flats will be obtained by observing the bright Earth with the HRC and WFC. These observations will be used to verify the accuracy of the flats currently used by the pipeline and will provide a comparison with flats derived via other techniques: L- flats from stellar observations, sky flats from stacked GO observations, and internal flats using the calibration lamps. Weekly coronagraphic monitoring is required to assess the changing position of the spots. ACS/HRC 10398 Transcending Voyager: A Deeper Look at Neptune's Ring-Moon System We will use the High Resolution Channel {HRC} of ACS to study the inner rings, arcs and moons of Neptune with a sensitivity that exceeds that achieved by Voyager 2 during its 1989 flyby. Our study will reveal any moons down to V magnitude 25.5, to address a peculiar truncation in the size distribution of inner moons and to look for the "shepherds" and source bodies for Neptune's dusty rings. {For comparison, Neptune's smallest known moon is Naiad, at magnitude 23.9}. Recent ground-based studies show that the mysterious arcs in the Adams Ring continue to shift and change, and may be fading away entirely. We will obtain the visual-band data uniquely necessary to determine whether the arcs are fading. Long-term monitoring of the arcs at high resolution and sensitivity will reveal their gradual changes more clearly and enable us to assess the role of Galatea, whose resonances are widely believed to confine the arcs. ACS/WFC 10216 Co-evolution of spheroids and black holes The masses of the giant black holes in galaxies are correlated with the luminosities, masses, and velocity dispersions of their host spheroids. This empirical connection of phenomena on widely different scales {from sub-parsec to kiloparsec} suggests that the evolution of a galaxy and its central black hole are closely linked. We propose to test various unified formation models, by measuring the cosmic evolution of the black hole/spheroid relations, back to z=0.37 {a lookback time of 4 Gyrs}. We will obtain 1-orbit ACS images of a sample of 20 Seyfert 1 galaxies, for which we already have extensive new ground-based measures of the black hole masses and the stellar velocity dispersions. HST resolution is required for accurate measurement of the nonstellar AGN continuum, and the luminosity and effective radius of the bulge of each host galaxy. This will complete the set of observables needed to map the co-evolution of spheroids and black-holes. The proposed sample is the minimum required to make the first measure of the black hole mass/bulge correlation and of the fundamental plane for active galaxies outside the local Universe. ACS/WFC 10326 The Morphological, Photometric, and Spectroscopic Properties of Intermediate Redshift Cluster Galaxies We will use the ACS/WFC to image 8 fields in the outskirts of the kT=5.8keV, X-ray cluster RX J0152-13 at z=0.83, for which we obtained imaging in four central fields during Cycle 11. The resulting wide-field mosaic of RX J0152-13 will enable direct study of the population of galaxies falling into this cluster and will provide a much needed comparison to our on-going wide-field study of the more massive, 10.5keV cluster MS1054-03 at the same redshift. Imaging RX J0152-13 to twice its viral radius enables us to: {1} trace the transformation of infalling field spirals into cluster early-types using, e.g., the morphology-density relation to large radii and very low local densities; {2} determine the importance of galaxy-galaxy interactions, i.e., whether the frequency of such encounters in the infall region is as unexpectedly high as found in MS1054-03; and {3} study in detail the star-formation histories of the most recently accreted members via accurate colors and morphologies. A comparison of RX J0152-13 with MS1054-03 will also allow us to directly probe the dependence of galaxy evolution on cluster mass. Only by pairing the wide-field ACS mosaic of RX J0152-13 with multi-object spectroscopy from the Magellan, Keck, and VLT telescopes can we test predictions from galaxy formation models, understand how field spirals evolve into early-type cluster members, and better constrain the formation of galaxies in general. ACS/WFC/HRC 9895 The Role of Groups in the Evolution of Galaxies at Intermediate Redshifts Groups are the most common environment experienced by galaxies, yet they remain the least studied. The tidal fields and dynamical friction encountered by galaxies in groups probably holds the key to understanding the role of environment in driving the evolution of galaxies since z ~ 1. To study the evolution of galaxies in the group environment, we propose the first unbiased HST study of groups at moderate redshifts. Unlike previous HST group samples, that relied on radio or X-ray properties, our kinematically selected sample is drawn from a large redshift survey and is not biased towards unusually dense groups. HST imaging is essential to determine the morphology of galaxies in these systems and contrast this with the properties of galaxies in denser and more evolved groups and rich clusters at these epochs. HST data are also required to adequately compare the properties of groups at intermediate redshifts with local group samples derived from the 2df and Sloan surveys. We will combine the HST images with deep ground-based observations to study how morphologies and stellar populations of galaxies in groups have evolved in time. These observations are key to understanding the decline in the volume averaged star formation rate in the universe. NIC1/NIC2/NIC3 8794 NICMOS Post-SAA calibration - CR Persistence Part 5 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. NIC3 9780 NIC3 Imaging of z~6 Candidates in a Deep ACS Parallel Field: Finding the reionizing population and their LF A fundamental cosmological question is when and how the universe was reionized. It is now generally believed that the reionization ended by z=6. There is evidence that QSO/AGN cannot provide enough photons to keep the universe ionized at that epoch. In Yan et al. {2003}, we presented a first statistically significant sample of 6.0z6.5 galaxy candidates, 30 objects in total found in a deep ACS/WFC parallel field by using the "drop-out" technique, and argued that the contamination due to possible contaminators was minimal. We concluded that young, star-forming galaxies did exist in large number as expected from our earlier work {Yan et al. 2002}, and that they could have contributed most of the reionizing photons. The candidates in our sample have a median magnitude of AB=27.4 mag, beyond the spectroscopic capability of any existing facilities. Any effort of acquiring a large sample of galaxies around z=6 will have the vast majority of candidates at such a faint brightness level. Thus near-IR imaging is the only practical way to further confirm the nature and the redshifts of these candidates until the launch of the JWST in 2010. Here we propose to use the NIC3 of the NICMOS to image 43% of our sample in the F110W and F160W bands to unambiguously confirm their nature. We will image 13-14 of our candidates with two NIC3 fields, and request 16 orbits of observation in total. With this data set, we will be able to determine the surface density of galaxies at the crucial epoch around z=6, and derive photometric redshift for our candidates. Our result will set stringent limits to the faint-end slope of the luminosity function {LF} and the star formation rate at z=6, and thus provide essential constraints to a series of questions regarding the reionization of the universe. NIC3 9846 The Origins of Sub-stellar Masses: Searching for the End of the IMF Is there a preferred scale that defines the end of the IMF? We propose to test this hypothesis by conducting a deep spectroscopic survey of extremely low mass objects in the embedded young cluster associated with NGC1333. At a distance of only 300pc, this cluster is one of the nearest examples of a dense young cluster. We will be able to obtain R=200 spectra and photometry for 40-60 cluster members with masses between 5-40 Jupiter masses at an age of 1 Myr observed through A{v}10 mag. This will enable us to estimate temperatures and luminosities for all sources detected in the survey. We will compare their positions in an H-R diagram to PMS evolutionary tracks in order to estimate their ages and masses. For a solar metallicity cloud at a temperature of 10 K, the minimum mass for fragmentation is thought to be 10 Jupiter masses. A statistically significant sample of objects detected below this limit would challenge the role of hierarchical fragmentation in limiting substellar masses. The proximity of this cluster combined with the unique sensitivity, wavelength coverage, and multi-object spectroscopic capability of NICMOS on HST make this experiment possible. WFPC2 10356 WFPC2 Cycle 13 Decontaminations and Associated Observations This proposal is for the monthly WFPC2 decons. Also included are instrument monitors tied to decons: photometric stability check, focus monitor, pre- and post-decon internals {bias, intflats, kspots, & darks}, UV throughput check, VISFLAT sweep, and internal UV flat check. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) None COMPLETED OPS REQs: 17338-2 Payload Safing Sequence Modification @ 344/14:56z 17348-2 Quick Update to SGI Ops Strings A, G, C @ 344/15:51z 17337-0 Enable STIS CEB @ 18:11z 17345-1 RMGA Calibration for December 2004 @ 344/19:35z OPS NOTES EXECUTED: None SCHEDULED SUCCESSFUL FAILURE TIMES FGS Gsacq 07 07 FGS Reacq 07 07 FHST Update 09 09 LOSS of LOCK SIGNIFICANT EVENTS: The STIS CEB test was successfully executed today (OPS Request 17337) over one orbit (start 344/16:32- end 344/1813) to ensure STIS can still support future battery capacity testing. The current draw was as expected (~0.7 amps). |
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