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Daily 3740
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 3740 PERIOD COVERED: DOY 323 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 10239 A Multiwavelength Study of POX 52, a Dwarf Seyfert Galaxy with an Intermediate-Mass Black Hole We propose a comprehensive optical, UV, and X-ray investigation of the unique galaxy POX 52. POX 52 is a Seyfert 1 galaxy with unprecedented properties: its host galaxy appears to be a dwarf elliptical, and its stellar velocity dispersion is only 36 km/s. The stellar velocity dispersion and the broad emission-line widths both suggest a black hole mass of order 10^5 solar masses, placing POX 52 in a region of AGN parameter space that is almost completely unexplored at present. We request ACS/HRC imaging to perform a definitive measurement of the host galaxy structure; STIS UV and optical spectroscopy to study the nonstellar continuum and the structure of the broad-line region; and Chandra ACS imaging to detect the X-ray emission from the nucleus and investigate its spectral and variability properties. The results of this program will give a detailed understanding of the host galaxy and accretion properties of one of the very few known black holes in the mass range around 10^5 solar masses. ACS/HRC/NIC1/WFC 10190 The Star Formation History and Metallicity Evolution of M33: A Comprehensive Study of Disk Evolution We will obtain deep, panchromatic imaging photometry of stellar populations in four fields ranging from 0.5 to 4 scale lengths across the disk of the Local Group spiral M33. The observations are designed to detect the oldest main-sequence turnoffs in three outer disk fields, and to reach the crowding limit in the innermost field. We will combine the photometry data with information we already have in-hand on abundances from stars and H II regions in M33 to derive the star formation history and metallicity evolution of the M33 disk. The information from our four fields will allow us to obtain {1} the ages of the oldest disk stars and the radial variation of their ages; {2} the radial variation of the star formation history and its nature {e.g., constant, declining, or bursting}; and {3} the metallicity distribution in each field and the time evolution of the metallicity gradient. Our team, an experienced mix of photometrists, spectroscopists, and galaxy evolution theorists, will use the results from this program to construct a comprehensive chemo- dynamical model for the M33 disk. This detailed study of M33 will be a key in developing an understanding of the formation and evolution of disks that can be applied to studies of disks at both low and high redshift, and will also yield a wealth of information on stellar populations, chemical evolution, and star clusters that will be of great value to future investigators. 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 Einsteining 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. NIC/NIC3 10226 The NICMOS Grism Parallel Survey We propose to continue managing the NICMOS pure parallel program. Based on our experience, we are well prepared to make optimal use of the parallel opportunities. The improved sensitivity and efficiency of our observations will substantially increase the number of line-emitting galaxies detected. As our previous work has demonstrated, the most frequently detected line is Halpha at 0.7z1.9, which provides an excellent measure of current star formation rate. We will also detect star-forming and active galaxies in other redshift ranges using other emission lines. The grism observations will produce by far the best available Halpha luminosity functions over the crucial--but poorly observed--redshift range where galaxies appear to have assembled most of their stellar mass. This key process of galaxy evolution needs to be studied with IR data; we found that observations at shorter wavelengths appear to have missed a large fraction of the star-formation in galaxies, due to dust reddening. We will also obtain deep F110W and F160W images, to examine the space densities and morphologies of faint red galaxies. In addition to carrying out the public parallels, we will make the fully reduced and calibrated images and spectra available on-line, with some ground-based data for the deepest parallel fields included. 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. NIC2 10173 Infrared Snapshots of 3CR Radio Galaxies Radio galaxies are an important class of extragalactic objects: they are one of the most energetic astrophysical phenomena and they provide an exceptional probe of the evolving Universe, lying typically in high density regions but well-represented across a wide redshift range. In earlier Cycles we carried out extensive HST observations of the 3CR sources in order to acquire a complete and quantitative inventory of the structure, contents and evolution of these important objects. Amongst the results, we discovered new optical jets, dust lanes, face-on disks with optical jets, and revealed point-like nuclei whose properties support FR-I/BL Lac unified schemes. Here, we propose to obtain NICMOS infrared images of 3CR sources with z0.3 as a major enhancement to an already superb dataset. We aim to deshroud dusty galaxies, study the underlying host galaxy free from the distorting effects of dust, locate hidden regions of star formation and establish the physical characteristics of the dust itself. We will measure frequency and spectral energy distributions of point-like nuclei, expected to be stronger and more prevalent in the IR, seek spectral turnovers in known synchrotron jets and find new jets. We will strongly test unified AGN schemes and merge these data with existing X-ray to radio observations. The resulting database will be an incredibly valuable resource to the astronomical community for years to come. 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 10359 WFPC2 CYCLE 13 Standard Darks This dark calibration program obtains dark frames every week in order to provide data for the ongoing calibration of the CCD dark current rate, and to monitor and characterize the evolution of hot pixels. Over an extended period these data will also provide a monitor of radiation damage to the CCDs. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) None COMPLETED OPS REQs: None OPS NOTES EXECUTED: None SCHEDULED SUCCESSFUL FAILURE TIMES FGS Gsacq 08 08 FGS Reacq 08 08 FHST Update 16 16 LOSS of LOCK SIGNIFICANT EVENTS: None |
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