NASA Hubble Space Telescope Daily Report # 4534
HUBBLE SPACE TELESCOPE DAILY REPORT # 4534
Continuing to collect World Class Science
PERIOD COVERED: UT January 25,26,27, 2007 (DOY 025,026,027)
OBSERVATIONS SCHEDULED
NIC1/NIC2/NIC3 8795
NICMOS Post-SAA calibration – CR Persistence Part 6
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=3Ddate/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 i mages. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.
WFPC2 11289
SL2S: The Strong Lensing Legacy Survey
Recent systematic surveys of strong galaxy-galaxy lenses {CLASS, SLACS, GOODS, etc.} are producing spectacular results for galaxy masses roughly below a transition mass M~10^13 Mo. The observed lens properties and their evolution up to z~0.2, consistent with numerical simulations, can be described by isothermal elliptical potentials. In contrast, modeling of giant arcs in X-ray luminous clusters {halo masses M >~10^13 Mo} favors NFW mass profiles, suggesting that dark matter halos are not significantly affected by baryon cooling. Until recently, lensing surveys were neither deep nor extended enough to probe the intermediate mass density regime, which is fundamental for understanding the assembly of structures. The CFHT Legacy Survey now covers 125 square degrees, and thus offers a large reservoir of strong lenses probing a large range of mass densities up to z~1. We have extracted a list of 150 strong lenses using the most recent CFHTLS data release via automated procedures. Following our first SNAPSHOT proposal in cycle 15, we propose to continue the Hubble follow-up targeting a larger list of 130 lensing candidates. These are intermediate mass range candidates {between galaxies and clusters} that are selected in the redshift range of 0.2-1 with no a priori X-ray selection. The HST resolution is necessary for confirming the lensing candidates, accurate modeling of the lenses, and probing the total mass concentration in galaxy groups up to z~1 with the largest unbiased sample available to date.
NIC3 11236
Did Rare, Large Escape-Fraction Galaxies Reionize the Universe?
Lyman continuum photons produced in massive starbursts may have played a dominant role in the reionization of the Universe. Starbursts are important contributors to the ionizing metagalactic background at lower redshifts as well. However, their contribution to the background depends upon the fraction of ionizing radiation that escapes from the intrinsic opacity of galaxies below the Lyman limit. Current surveys suggest that the escape fraction is close to zero in most galaxies, even among young starbursts, but is large in 15-25% of them. Non-uniform escape fractions are expected as a result of violent events creating clear paths in small parts of galaxies. The number of galaxies observed with high escape fraction will result from the combination of the intrinsic number with clear lines of sight and their orientation with respect to the observer. We propose to measure the fraction of escaping Lyman continuum radiation in a large sample (47) of z~0.7 starbursts in the COSMOS field. These compact UV-lumnious galaxies are good analogs to high redshift LBGs. Using the SBC/PR130L we can quickly (1-4 orbits) detect relative escape fractions (f_LC/f_1500) of 25% or more. This will be the first measurement of the escape fraction in sources between z=3D1 and the = local universe. We expect ~10 detections. Stacking will set limits of <4% on the relative escape fraction in the rest. We will correlate the LC detections with the properties of the galaxies. By targetting z~0.7 in COSMOS, we will have tremendous ancillary information on those sources. A non-detection in all sources would be significant (99% confidence). This would imply that QSOs provide the overwhelming majority of ionizing radtion at z<1, requiring substantial evolution in the processes within Lyman break galaxies which allow large escape fractions at high redshift.
ACS/SBC 11220
Mapping the FUV Evolution of Type IIn Supernovae
We will use the PR110L prism on the SBC of ACS to map the FUV evolution of Type IIn supernovae {SNe}. The main goal of this proposal is to measure the FUV continuum, Ly-a emission line flux, and their evolution to {1} quantify and interpret Type IIn SN transient event detections at high redshift and {2} dramatically improve current high redshift Type IIn selection criteria. We show that the inherent properties of Type IIn SNe facilitate high redshift detection. We will observe the rest-frame FUV of a sample of eight 0.02 < z < 0.33 Type IIn SNe to directly measure the survival of Ly-alpha photons in low to intermediate redshift Type IIn SNe environments and extrapolate the results to high redshift. We will calibrate relationships such as FUV luminosity vs. emission line flux and measure emission line evolution vs. FUV light evolution. The intent is to categorize and improve the utility of Type IIn SNe.
FGS 11211
An Astrometric Calibration of Population II Distance Indicators
In 2002 HST produced a highly precise parallax for RR Lyrae. That measurement resulted in an absolute magnitude, M{V}=3D 0.61+/-0.11, a useful result, judged by the over ten refereed citations each year since. It is, however, unsatisfactory to have the direct, parallax-based, distance scale of Population II variables based on a single star. We propose, therefore, to obtain the parallaxes of four additional RR Lyrae stars and two Population II Cepheids, or W Vir stars. The Population II Cepheids lie with the RR Lyrae stars on a common K-band Period-Luminosity relation. Using these parallaxes to inform that relationship, we anticipate a zero-point error of 0.04 magnitude. This result should greatly strengthen confidence in the Population II distance scale and increase our understanding of RR Lyrae star and Pop II Cepheid astrophysics.
FGS 11210
The Architecture of Exoplanetary Systems
Are all planetary systems coplanar? Concordance cosmogony makes that prediction. It is, however, a prediction of extrasolar planetary system architecture as yet untested by direct observation for main sequence stars other than the Sun. To provide such a test, we propose to carry out FGS astrometric studies on four stars hosting seven companions. Our understanding of the planet formation process will grow as we match not only system architecture, but formed planet mass and true distance from the primary with host star characteristics for a wide variety of host stars and exoplanet masses. We propose that a series of FGS astrometric observations with demonstrated 1 millisecond of arc per-observation precision can establish the degree of coplanarity and component true masses for four extrasolar systems: HD 202206 {brown dwarf+planet}; HD 128311 {planet+planet}, HD 160691 =3D mu Arae {planet+planet}, and HD 222404AB =3D gamma Cephei {planet+star}. In each case the companion is identified as such by assuming that the minimum mass is the actual mass. For the last target, a known stellar binary system, the companion orbit is stable only if coplanar with the AB binary orbit.
WFPC2 11202
The Structure of Early-type Galaxies: 0.1-100 Effective Radii
The structure, formation and evolution of early-type galaxies is still largely an open problem in cosmology: how does the Universe evolve from large linear scales dominated by dark matter to the highly non-linear scales of galaxies, where baryons and dark matter both play important, interacting, roles? To understand the complex physical processes involved in their formation scenario, and why they have the tight scaling relations that we observe today {e.g. the Fundamental Plane}, it is critically important not only to understand their stellar structure, but also their dark-matter distribution from the smallest to the largest scales. Over the last three years the SLACS collaboration has developed a toolbox to tackle these issues in a unique and encompassing way by combining new non-parametric strong lensing techniques, stellar dynamics, and most recently weak gravitational lensing, with high-quality Hubble Space Telescope imaging and VLT/Keck spectroscopic data of early-type lens systems. This allows us to break degeneracies that are inherent to each of these techniques separately and probe the mass structure of early-type galaxies from 0.1 to 100 effective radii. The large dynamic range to which lensing is sensitive allows us both to probe the clumpy substructure of these galaxies, as well as their low-density outer haloes. These methods have convincingly been demonstrated, by our team, using smaller pilot-samples of SLACS lens systems with HST data. In this proposal, we request observing time with WFPC2 and NICMOS to observe 53 strong lens systems from SLACS, to obtain complete multi-color imaging for each system. This would bring the total number of SLACS lens systems to 87 with completed HST imaging and effectively doubles the known number of galaxy-scale strong lenses. The deep HST images enable us to fully exploit our new techniques, beat down low-number statistics, and probe the structure and evolution of early-type galaxies, not only with a uniform data-set an order of magnitude larger than what is available now, but also with a fully coherent and self-consistent methodological approach!
S/C 11163
Accreting Pulsating White Dwarfs in Cataclysmic Variables
Recent ground-based observations have increased the number of known pulsating white dwarfs in close binaries with active mass transfer {cataclysmic variables} from 5 to 11 systems. Our past Cycles 8 and 11 STIS observations of the first 2 known, followed by our Cycle 13 SBC observations of the next 3 discovered, revealed the clear presence of the white dwarf and increased amplitude of the pulsations in the UV compared to the optical. The temperatures derived from the UV spectra show 4 systems are much hotter than non-interacting pulsating white dwarfs. A larger sample is needed to sort out the nature of the instability strip in accreting pulsators i.e. whether effects of composition and rotation due to accretion result in a well- defined instability strip as a function of Teff.
NIC2/WFPC2 11142
Revealing the Physical Nature of Infrared Luminous Galaxies at 0.3
We aim to determine physical properties of IR luminous galaxies at 0.3 WFPC2 11077 HST/WFPC2 1-gyro On-orbit Checkout The goal of this program is to verify the performance of the HST under One Gyro operation. As in previous Two Gyro Testing and Orbital Verification programs the analysis will be done by characterizing the Point Spread Function (PSF) of PC1 in the F555W filter. Two Primary issues addressed by this proposal: – PSF structure and repeatibility – Pointing, stability, and offset accuracy. PSF will be characterized as a function of – exposure time – guide star brightness – sky position For the Pointing we will characterize: – repeatability of small offsets – stability within visibility period – stability across occultations. as a function of the guide star brightness The Program requires fifteen orbits: (7 for the main target, 1 for the secondary target) for two gyro mode, then for 1-gyro mode. The structure of the visits is identical to the visits executed as part of the program 10458 “ACS and WFPC2 TGSMOV Two-Gyro PSF, Pointing, and Dither Test” with the only exception of the NICMOS parallel that have been removed. The target selection is based on the visibility in the mid January to mid February 2008 timeframe. Final target selection will be confirmed after the analysis of the guide star availability. WFPC2 11038 Narrow Band and Ramp Filter Closeout These observations are to improve calibration of narrow band and ramp filters. We also test for changes in the filter properties during WFPC2’s 14 years on-board HST. WFPC2 11032 CTE Extended Targets Closeout Measuring the charge transfer efficiency {CTE} of an astronomical CCD camera is crucial to determining the CCD’s photometric fidelity across the field of view. WFPC2’s CTE has degraded steadily over the last 13 years because of continuous exposure to trapped particles in HST’s radiation environment. The fraction of photometric signal lost from WFPC2’s CTI {change transfer inefficiency} is a function of WFPC2’s time in orbit, the integrated signal in the image, the location of the image on the CCD, and the background signal. Routine monitoring of WFPC2’s degrading CTE over the last 13 years has primarily concerned the effects of CTI on point-source photometry. However, most of the sources imaged by WFPC2 are extended rather than point- like. This program aims to characterize the effects of CTI on the photometry and morphology of extended sources near the end of WFPC2’s functional life. Images of a standard field within the rich galaxy cluster Abell 1689 are recorded with each WFPC2 camera using the F606W and F814W filters. These images will be compared with contemporaneous images of Abell 1689 recorded with the field rotated by approximately 180 degrees to assess differences between extended sources imaged near and far from the serial register. The images will also be compared with similar images recorded in Cycle 8 {Program 8456} to characterize the rate of CTE degradation over the lifetime of WFPC2. WFPC2 10905 The Dynamic State of the Dwarf Galaxy Rich Canes Venatici I Region With accurate distances, the nearest groups of galaxies can be resolved in 3 dimensions and the radial component of the motions of galaxies due to local density perturbations can be distinguished from cosmological expansion components. Currently, with the ACS, galaxy distances within 8 Mpc can be measured effectively and efficiently by detecting the tip of the red giant branch {TRGB}. Of four principal groups at high galactic latitude in this domain, the Canes Venatici I Group {a} is the least studied, {b} is the most populated, though overwhelmingly by dwarf galaxies, and {c} is likely the least dynamically evolved. It is speculated that galaxies in low mass groups may fail to retain baryons as effectively as those in high mass groups, resulting in significantly higher mass-to-light ratios. The CVn I Group is suspected to lie in the mass regime where the speculated astrophysical processes that affect baryon retention are becoming important. 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) SIGNIFICANT EVENTS: (None)
SCHEDULED SUCCESSFUL
FGS GSacq 23 23
FGS REacq 19 19
OBAD with Maneuver 84 84
