Date: January 5th 2007

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4272

PERIOD COVERED: UT January 04, 2007 (DOY 004)

OBSERVATIONS SCHEDULED

ACS/WFC 10798

Dark Halos and Substructure from Arcs & Einstein Rings

The surface brightness distribution of extended gravitationally lensed arcs and Einstein rings contains super-resolved information about the lensed object, and, more excitingly, about the smooth and clumpy mass distribution of the lens galaxies The source and lens information can non-parametrically be separated, resulting in a direct "gravitational image" of the inner mass- distribution of cosmologically-distant galaxies {Koopmans 2005; Koopmans et al 2006 [astro- ph/0601628]} With this goal in mind, we propose deep HST ACS-F555W/F814W and NICMOS- F160W WFC imaging of 20 new gravitational-lens systems with spatially resolved lensed sources, of the 35 new lens systems discovered by the Sloan Lens ACS Survey {Bolton et al 2005} so far, 15 of which are being imaged in Cycle-14 Each system has been selected from the SDSS and confirmed in two time-efficient HST-ACS snapshot programs {cycle 13&14} High- fidelity multi-color HST images are required {not delivered by the 420s snapshots} to isolate these lensed images {properly cleaned, dithered and extinction-corrected} from the lens galaxy surface brightness distribution, and apply our "gravitational maging" technique Our sample of 35 early-type lens galaxies to date is by far the largest, still growing, and most uniformly selected This minimizes selection biases and small-number statistics, compared to smaller, often serendipitously discovered, samples Moreover, using the WFC provides information on the field around the lens, higher S/N and a better understood PSF, compared with the HRC, and one retains high spatial resolution through drizzling The sample of galaxy mass distributions - determined through this method from the arcs and Einstein ring HST images - will be studied to: {i} measure the smooth mass distribution of the lens galaxies {dark and luminous mass are separated using the HST images and the stellar M/L values derived from a joint stellar-dynamical analysis of each system}; {ii} quantify statistically and individually the incidence of mass- substructure {with or without obvious luminous counter-parts such as dwarf galaxies} Since dark-matter substructure could be more prevalent at higher redshift, both results provide a direct test of this prediction of the CDM hierarchical structure-formation model

ACS/WFC 10918

Reducing Systematic Errors on the Hubble Constant: Metallicity Calibration of the Cepheid PL Relation

Reducing the systematic errors on the Hubble constant is still of significance and of immediate importance to modern cosmology One of the largest remaining uncertainties in the Cepheid- based distance scale {which itself is at the foundation of the HST Key Project determination of H_o} which can now be addressed directly by HST, is the effect of metallicity on the Cepheid Period-Luminosity relation Three chemically distinct regions in M101 will be used to directly measure and thereby calibrate the change in zero point of the Cepheid PL relation over a range of metallicities that run from SMC-like, through Solar, to metallicities as high as the most metal- enriched galaxies in the pure Hubble flow ACS for the first time offers the opportunity to make a precise calibration of this effect which currently accounts for at least a third of the total systematic uncertainty on Ho The calibration will be made in the V and I bandpasses so as to be immediately and directly applicable to the entire HST Cepheid-based distance scale sample, and most especially to the highest-metallicity galaxies that were hosts to the Type Ia supernovae, which were then used to extend the the distance scale calibration out to cosmologically significant distances

ACS/WFC/HRC 10920

High-Resolution Imaging of Nearby Lyman Break Galaxy Analogs in the GALEX All-Sky Survey

We have used the ultraviolet all-sky imaging survey currently being conducted by the Galaxy Evolution Explorer {GALEX} to identify for the first time a rare population of low-redshift starbursts with properties remarkably similar to high-redshift Lyman Break Galaxies These compact UV luminous galaxies {UVLGs} resemble Lyman Break Galaxies in terms of size, UV luminosity, star-formation rate, surface brightness, mass, metallicity, kinematics, dust content, and color They have characteristic ``ages'' {stellar mass/SFR} of only a few hundred Myr This population of galaxies is thus worthy of study in its own right and as a sample of local analogs of Lyman Break Galaxies We propose to image a sample of the 9 nearest and brightest compact UVLGs in the near-ultraviolet, near-infrared, and H-alpha using ACS With these images we will 1} characterize their structure and morphology, 2} look for signs of interactions and mergers, 3} investigate the distribution and propogation of star formation over varying time scales, and 4} quantify the stellar populations and star formation history, in order to determine whether a previous generation of stars formed long before the current burst These data will perfectly complement our existing Spitzer, GALEX, and SDSS data, and will provide important information on star-formation in the present-day universe as well as shed light on the earliest major episodes of star formation in high-redshift galaxies

ACS/WFC/WFPC2 10890

Morphologies of the Most Extreme High-Redshift Mid-IR-Luminous Galaxies

The formative phase of the most massive galaxies may be extremely luminous, characterized by intense star- and AGN-formation Till now, few such galaxies have been unambiguously identified at high redshift, restricting us to the study of low-redshift ultraluminous infrared galaxies as possible analogs We have recently discovered a sample of objects which may indeed represent this early phase in galaxy formation, and are undertaking an extensive multiwavelength study of this population These objects are bright at mid-IR wavelengths {F[24um]>0 8mJy}, but deep ground based imaging suggests extremely faint {and in some cases extended} optical counterparts {R~24-27} Deep K-band images show barely resolved galaxies Mid-infrared spectroscopy with Spitzer/IRS reveals that they have redshifts z ~ 2-2 5, suggesting bolometric luminosities ~10^{13-14}Lsun! We propose to obtain deep ACS F814W and NIC2 F160W images of these sources and their environs in order to determine kpc-scale morphologies and surface photometry for these galaxies The proposed observations will help us determine whether these extreme objects are merging systems, massive obscured starbursts {with obscuration on kpc scales!} or very reddened {locally obscured} AGN hosted by intrinsically low-luminosity galaxies

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 10906

The Fundamental Plane of Massive Gas-Rich Mergers: II The QUEST QSOs

We propose deep NICMOS H-band imaging of a carefully selected sample of 23 local QSOs This program is the last critical element of a comprehensive investigation of the most luminous mergers in the nearby universe, the ultraluminous infrared galaxies {ULIRGs} and the quasars This effort is called QUEST: Quasar / ULIRG Evolutionary STudy The high-resolution HST images of the QUEST QSOs will complement an identical set of images on the ULIRG sample obtained during Cycle 12, an extensive set of ground-based data that include long-slit NIR spectra from a Large VLT Program, and a large set of mid-infrared spectra from a Cycle 1 medium-size program with Spitzer This unique dataset will allow us to derive with unprecedented precision structual, kinematic, and activity parameters for a large unbiased sample of objects spanning the entire ULIRG/QSO luminosity function These data will refine the fundamental plane of massive gas-rich mergers and enable us to answer the following quesitons: {1} Do ultraluminous mergers form elliptical galaxies, and in particular, giant ellipticals? {2} Do ULIRGs evolve into optical bright QSOs? The results from this detailed study of massive mergers in the local universe will be relevant to understanding the basic physical processes involved in creating massive early-type host on the one hand, and growing/feeding embedded massive black holes on the other, in major galaxy mergers This is an important question since 50% of cosmic star formation at high-z and most of the big BHs appear to be formed in this process

NIC2, ACS/WFC 10802

SHOES-Supernovae, HO, for the Equation of State of Dark energy

The present uncertainty in the value of the Hubble constant {resulting in an uncertainty in Omega_M} and the paucity of Type Ia supernovae at redshifts exceeding 1 are now the leading obstacles to determining the nature of dark energy We propose a single, integrated set of observations for Cycle 15 that will provide a 40% improvement in constraints on dark energy This program will observe known Cepheids in six reliable hosts of Type Ia supernovae with NICMOS, reducing the uncertainty in H_0 by a factor of two because of the smaller dispersion along the instability strip, the diminished extinction, and the weaker metallicity dependence in the infrared In parallel with ACS, at the same time the NICMOS observations are underway, we will discover and follow a sample of Type Ia supernovae at z > 1 Together, these measurements, along with prior constraints from WMAP, will provide a great improvement in HST's ability to distinguish between a static, cosmological constant and dynamical dark energy The Hubble Space Telescope is the only instrument in the world that can make these IR measurements of Cepheids beyond the Local Group, and it is the only telescope in the world that can be used to find and follow supernovae at z > 1 Our program exploits both of these unique capabilities of HST to learn more about one of the greatest mysteries in science

FLIGHT OPERATIONS SUMMARY:

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

HSTARS: 10595 - GSAcq(2,1,2) failed due to Scan Step limit exceeded on FGS 2 Upon acquisition at 004/16:01:30z the GSAcq (2,1,2) scheduled at 004/15:52:00 failed due to scan step limit exceeded Previous OBAD RSS was 17 26 a/s Post acq MAP RSS was 13 85 a/s

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                      SCHEDULED      SUCCESSFUL

FGS GSacq 10 09 FGS REacq 05 05 OBAD with Maneuver 30 30

SIGNIFICANT EVENTS: (None)

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