Status Report

NASA Hubble Space Telescope Daily Report #4270

By SpaceRef Editor

January 3, 2007

Filed under Hubble Space Telescope, Space Telescope Science Institute, US

HUBBLE SPACE TELESCOPE DAILY REPORT # 4270

– Continuing to collect World Class Science

PERIOD COVERED: UT December 29,30,31, 2006-Jan 01,02, 2007 (DOY 29,30,31,01,02)

OBSERVATIONS SCHEDULED

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 11068

NICMOS A-Star Spectrophotometric Observations

Now that the Cohen A-star fluxes have been verified in the IR by the four cycle 14 NICMOS grism observations from program 10754, verification of four more of these Cohen SEDs will be done in Cycle 15. All 8 stars are selected from the Spitzer IRAC photometric calibration target lists, {Tables 1-2} in Reach et al. 2005, PASP, 117,978; and all 8 A-stars are near the north ecliptic pole, ie near the JWST continuous viewing zone. The baseline plan for JWST NIRSpec calibration is to use the Cohen modeled flux beyond the 2.5micron NICMOS limit. Because of intrinsic variation within the same spectral type there is some statistical scatter expected in the precision of the Cohen flux extrapolation that is based on models. Thus, the ensemble JWST flux calibration based on an average over 8 stars should be sqrt{8} more accurate than a sensitivity based on just one A-star. In addition to JWST calibration, this program supports spectrophotometric cross calibration of HST and Spitzer. The targets are chosen to be faint enough for unsaturated observations with JWST NIRSpec, yet still bright enough for high signal to noise in relatively short observations with HST+NICMOS and with Spitzer+IRAC.

ACS/HRC 11041

ACS CCDs daily monitor

This program consists of a set of basic tests to monitor, the read noise, the development of hot pixels and test for any source of noise in ACS CCD detectors. The files, biases and dark will be used to create reference files for science calibration. This programme will be for the entire lifetime of ACS. For cycle 15 the program will cover 18 months 12.1.06->05.31.08 and it has been divied into three different proposal each covering six months. The three proposals are 11041-11042-11043.

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.

WFPC2 10915

ACS Nearby Galaxy Survey

Existing HST observations of nearby galaxies comprise a sparse and highly non-uniform archive, making comprehensive comparative studies among galaxies essentially impossible. We propose to secure HST’s lasting impact on the study of nearby galaxies by undertaking a systematic, complete, and carefully crafted imaging survey of ALL galaxies in the Local Universe outside the Local Group. The resulting images will allow unprecedented measurements of: {1} the star formation history {SFH} of a >100 Mpc^3 volume of the Universe with a time resolution of Delta[log{t}]=0.25; {2} correlations between spatially resolved SFHs and environment; {3} the structure and properties of thick disks and stellar halos; and {4} the color distributions, sizes, and specific frequencies of globular and disk clusters as a function of galaxy mass and environment. To reach these goals, we will use a combination of wide-field tiling and pointed deep imaging to obtain uniform data on all 72 galaxies within a volume-limited sample extending to ~3.5 Mpc, with an extension to the M81 group. For each galaxy, the wide-field imaging will cover out to ~1.5 times the optical radius and will reach photometric depths of at least 2 magnitudes below the tip of the red giant branch throughout the limits of the survey volume. One additional deep pointing per galaxy will reach SNR~10 for red clump stars, sufficient to recover the ancient SFH from the color-magnitude diagram. This proposal will produce photometric information for ~100 million stars {comparable to the number in the SDSS survey} and uniform multi-color images of half a square degree of sky. The resulting archive will establish the fundamental optical database for nearby galaxies, in preparation for the shift of high-resolution imaging to the near-infrared.

ACS/HRC 10910

HST / Chandra Monitoring of a Dramatic Flare in the M87 Jet

As the nearest galaxy with an optical jet, M87 affords an unparalleled opportunity to study extragalactic jet phenomena at the highest resolution. During 2002, HST and Chandra monitoring of the M87 jet detected a dramatic flare in knot HST-1 located ~1″ from the nucleus. Its optical brightness eventually increased seventy-fold and peaked in 2005; the X-rays show a similarly dramatic outburst. In both bands HST-1 is still extremely bright and greatly outshines the galaxy nucleus. To our knowledge this is the first incidence of an optical or X-ray outburst from a jet region which is spatially distinct from the core source — this presents an unprecedented opportunity to study the processes responsible for non-thermal variability and the X-ray emission. We propose five epochs of HST/ACS flux monitoring during Cycle 15, as well as seven epochs of Chandra/ACIS observation {5ksec each, five Chandra epochs contemporary with HST}. At two of the HST/ACS epochs we also gather spectral information and map the magnetic field structure. The results of this investigation are of key importance not only for understanding the nature of the X-ray emission of the M87 jet, but also for understanding flares in blazar jets, which are highly variable, but where we have never before been able to resolve the flaring region in the optical or X-rays. These observations will allow us to test synchrotron emission models for the X-ray outburst, constrain particle acceleration and loss timescales, and study the jet dynamics associated with this flaring component.

ACS/HRC/WFC 10896

An Efficient ACS Coronagraphic Survey for Debris Disks around Nearby Stars

We propose to finish our Cycle 11 optical survey for nearby debris disks using the ACS/HRC coronagraph. Out of 43 orbits originally proposed for the survey, 23 orbits were allocated, leading to a survey of 22 stars, from which two new debris disks were imaged for the first time. Our analysis of the initial survey gives an empirical estimate for the detection rate of debris disks relative to heliocentric distance and dust optical depth. Our target list for Cycle 15 is now optimized to yield more frequent disk detections. Likewise our observing strategy is improved to maximize sensitivity per telescope orbit allocated. Therefore we present the most efficient survey possible. The scientific motivation is to obtain scattered light images of previously unresolved debris disks to determine their viewing geometry and physical architecture, both of which may characterize the underlying planetary system. We choose 25 debris disk targets for which we predict a detection rate of 25% ? 5%. Four targets have extrasolar planets from which the viewing geometry revealed by a disk detection will resolve the v sin{i} ambiguity in the planet masses. These targets present the remarkable opportunity of finally seeing a debris disk in system with known planets.

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.

ACS/WFC 10882

Emission Line 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. We discovered new optical jets, dust lanes, and revealed point-like nuclei whose properties support AGN unified schemes. Here, we propose to obtain ACS emission line images at low and high excitation of 3CR sources with z<0.3, both low- and classical high- power radio galaxies, as a major enhancement to an already superb dataset. We aim to probe fundamental relationships between warm optical line-emitting gas, radio source structure {jets and lobes} and X-ray coronal halos. We will combine our existing UV images with new emission- line images to establish quantitative star formation characteristics and their relation to dust and merging, and with emission-line excitation maps, test theories on ionization beam patterns and luminosities from active nuclei. We will seek jet induced star formation and knowing optical emission-line physics, investigate quantitative jet physics. The nuclear emission line properties of the galaxies will themselves be established and used as ingredients in continuing tests of unified AGN theories. The resulting database will be an incredibly valuable resource to the astronomical community for years to come.

ACS/WFC 10881

The Ultimate Gravitational Lensing Survey of Cluster Mass and Substructure

We propose a systematic and detailed investigation of the mass, substructure, and thermodynamics of one hundred X-ray luminous galaxy clusters at 0.151} cluster samples. For this ultimate cluster survey, we request ACS SNAPSHOTS through the F606W filter drawn from a target list of 143 clusters.

ACS/WFC 10875

A Snapshot Survey of The Most Massive Clusters of Galaxies

We propose the continuation of our highly successful Cycle14 snapshot survey of a sample of 123 very X-ray luminous clusters in the redshift range 0.3-0.7. As demonstrated by the 21 snapshots obtained so far in Cycle14 these systems frequently exhibit strong gravitational lensing as well as spectacular examples of violent galaxy evolution. The proposed observations will provide important constraints on the cluster mass distributions, the physical nature of galaxy-galaxy and galaxy-gas interactions in cluster cores, and a set of optically bright, lensed galaxies for further 8-10m spectroscopy. Acknowledging the broad community interest in this sample we waive our data rights for these observations.

ACS/HRC/WFPC2/NIC3 10842

A Cepheid Distance to the Coma Cluster

We propose to use the Advanced Camera for Surveys to search for Cepheid variables in two spiral galaxies in the core of the Coma cluster. A direct application of the canonical primary distance indicator at 100 Mpc will measure the far-field Hubble constant free of many of the systematic uncertainties which beset current determinations relying on secondary indicators. Establishing the far-field H_o with Cepheids will provide one of the strongest links in the extragalactic distance scale and will directly calibrate the fiducial fundamental plane of elliptical galaxies in Coma. With ACS/HRC, S/N=5 to 10 or better can be reached for Cepheids with periods of 40d to 70d at mean light in 5 orbits with the F606W filter if H_o=72 km/s/Mpc. Efficient detection and phasing can be done with twelve epochs optimally spaced for periods of 40-70d.

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.

ACS/WFC 10605

Quantifying Star Formation and Feedback: The M81 Group Dwarf Galaxies

Studies of the impact of star formation via stellar winds and supernovae {‘feedback’} on the properties of a galaxy are of fundamental importance to understanding galaxy evolution. One crucial aspect in these studies is a precise census of the recent star formation in a galaxy. The aim of this proposal is to obtain spatially resolved star formation histories with a time resolution of roughly 30 Myr over the last 500 Myr in a carefully designed sample using the absolutely unique capabilities of the ACS. Our sample comprises 10 galaxies in the M81 group which is host to a wide diversity of dwarf star forming galaxies. They span ranges of 6 magnitudes in luminosity, 1000 in current star formation rate, and 0.5 dex in metallicity. The ACS observations will allow us to directly observe the strength and spatial relationships of all of the star formation in these galaxies in the last 500 Myr. We can then quantify the star formation and measure {1} the fraction of star formation that is triggered by feedback, {2} the fraction of star formation that occurs in clusters and associations, and {3} to what degree future star formation is governed by the feedback from previous star formation. The ACS observations will be complemented with high-quality ancillary data collected by our team for all galaxies {e.g., Spitzer, UV/optical/NIR, VLA HI}. We will calculate the energy created by star formation events and compare it to the estimated energy deposited into the local ISM. This will enable us to construct prescriptions of how star formation and feedback depend on metallicity, size, gas content, and current star formation rates in galaxies. Our resolved star formation maps will be compared with star formation rates inferred from H-alpha, UV, and IR observations – allowing an independent calibration of these techniques. Recent ACS imaging by us of one galaxy in the same group clearly demonstrates the feasibility of the proposed program. Most of the sample galaxies are located in the CVZ, making this an extremely efficient program.

ACS/WFC/WFPC2 10584

The link between X-ray source and stellar populations in M81

We propose to perform a deep v~26-27.0 HST-ACS survey of the nearby {3.6 Mpc} spiral galaxy M~81 in order to study the nature of its X-ray source populations detected with Chandra. For the first time in a galaxy other than the Milky-Way or the Magelanic Clouds, we will classify X-ray sources as High-Mass and Low-Mass X-ray binaries {HMXBs, LMXBs} and investigate how these populations depend on their galactic environment. The classification will be performed {a} by finding and classifying unique optical counterparts for the X-ray sources and {b} studying the stellar populations in their vicinity. Both tasks require the <0.1'' resolution of HST-ACS which matches well the positional accuracy of Chandra. Finally we will use these results together with X-ray binary evolution synthesis models in order to constrain X-ray binary {XRB} evolution channels. These data will also be a great resource for studies of the star-formation and star- cluster populations in one of the prototypical spiral galaxies.

ACS/HRC 10878

An ACS Prism Snapshot Survey for z~2 Lyman Limit Systems

We propose to conduct a spectroscopic survey of Lyman limit absorbers at redshifts 1.7 < z < 2.2, using ACS/HRC and the PR200L prism. We have selected 100 quasars at 2.3 < z < 2.6 from the Sloan Digital Sky Survey Spectroscopic Quasar sample, for which no BAL signature is found at the QSO redshift and no strong metal absorption lines are present at z > 2.3 along the lines of sight. The survey has three main observational goals. First, we will determine the redshift frequency dN/dz of the LLS over the column density range 16.3

ACS/HRC 11041

ACS CCDs daily monitor

ACS/WFC 10882

Emission Line Snapshots of 3CR Radio Galaxies

ACS/WFC 10918

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

ACS/WFC 11024

WFPC2 CYCLE 15 INTERNAL MONITOR

This calibration proposal is the Cycle 15 routine internal monitor for WFPC2, to be run weekly to monitor the health of the cameras. A variety of internal exposures are obtained in order to provide a monitor of the integrity of the CCD camera electronics in both bays {both gain 7 and gain 15 — to test stability of gains and bias levels}, a test for quantum efficiency in the CCDs, and a monitor for possible buildup of contaminants on the CCD windows. These also provide raw data for generating annual super-bias reference files for the calibration pipeline.

ACS/WFC 11046

CCD Hot Pixel Annealing

Hot pixel annealing will continue to be performed once every 4 weeks. The CCD TECs will be turned off and heaters will be activated to bring the detector temperatures to about +20C. This state will be held for approximately 6 hours, after which the heaters are turned off, the TECs turned on, and the CCDs returned to normal operating condition. To assess the effectiveness of the annealing, a bias and four dark images will be taken before and after the annealing procedure for both WFC and HRC. The HRC darks are taken in parallel with the WFC darks. The charge transfer efficiency {CTE} of the ACS CCD detectors declines as damage due to on-orbit radiation exposure accumulates. This degradation has been closely monitored at regular intervals, because it is likely to determine the useful lifetime of the CCDs. We combine the annealling activity with the charge transfer efficiency monitoring and also merge into the routine dark image collection. To this end, the CTE monitoring exposures have been moved into this proposal . All the data for this program is acquired using internal targets {lamps} only, so all of the exposures should be taken during Earth occultation time {but not during SAA passages}. This program emulates the ACS pre-flight ground calibration and post-launch SMOV testing {program 8948}, so that results from each epoch can be directly compared. Extended Pixel Edge Response {EPER} and First Pixel Response {FPR} data will be obtained over a range of signal levels for both the Wide Field Channel {WFC}, and the High Resolution Channel {HRC}.

ACS/WFC/WFPC2 10890

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

FGS 10610

Astrometric Masses of Extrasolar Planets and Brown Dwarfs

We propose observations with HST/FGS to estimate the astrometric elements {perturbation orbit semi-major axis and inclination} of extra-solar planets orbiting six stars. These companions were originally detected by radial velocity techniques. We have demonstrated that FGS astrometry of even a short segment of reflex motion, when combined with extensive radial velocity information, can yield useful inclination information {McArthur et al. 2004}, allowing us to determine companion masses. Extrasolar planet masses assist in two ongoing research frontiers. First, they provide useful boundary conditions for models of planetary formation and evolution of planetary systems. Second, knowing that a star in fact has a plantary mass companion, increases the value of that system to future extrasolar planet observation missions such as SIM PlanetQuest, TPF, and GAIA.

NIC2, ACS/WFC 10802

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

NIC3 10792

Quasars at Redshift z=6 and Early Star Formation History

We propose to observe four high-redshift quasars {z=6} in the NIR in order to estimate relative Fe/Mg abundances and the central black hole mass. The results of this study will critically constrain models of joint quasar and galaxy formation, early star formation, and the growth of supermassive black holes. Different time scales and yields for alpha-elements {like O or Mg} and for iron result into an iron enrichment delay of ~0.3 to 0.6 Gyr. Hence, despite the well-known complexity of the FeII emission line spectrum, the ratio iron/alpha – element is a potentially useful cosmological clock. The central black hole mass will be estimated based on a recently revised back hole mass – luminosity relationship. The time delay of the iron enrichment and the time required to form a supermassive black hole {logM>8 Msol, tau ~0.5Gyr} as evidenced by quasar activity will be used to date the beginning of the first intense star formation, marking the formation of the first massive galaxies that host luminous quasars, and to constrain the epoch when supermassive black holes start to grow by accretion.

WFPC2 10915

ACS Nearby Galaxy Survey

WFPC2 11023

WFPC2 CYCLE 15 Standard Darks – part 1

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.

WFPC2 11029

WFPC2 CYCLE 15 Intflat Linearity Check and Filter Rotation Anomaly Monitor

Intflat observations will be taken to provide a linearity check: the linearity test consists of a series of intflats in F555W, in each gain and each shutter. A combination of intflats, visflats, and earthflats will be used to check the repeatability of filter wheel motions. {Intflat sequences tied to decons, visits 1-18 in prop 10363, have been moved to the cycle 15 decon proposal xxxx for easier scheduling.} Note: long-exposure WFPC2 intflats must be scheduled during ACS anneals to prevent stray light from the WFPC2 lamps from contaminating long ACS external exposures.

ACS/WFC 10835

Probing The Globular Cluster / Low Mass X-ray Binary Connection in Early-type Galaxies At Low X-ray

Combined high-resolution imaging from Hubble and Chandra {CXO} has revolutionized our understanding of extragalactic low-mass X-ray binaries {LMXBs} and globular clusters {GCs}, yet their connection in early-type galaxies has remained unstudied at the luminosities of the Galactic LMXBs in GCs. NGC 4278 and 3379 will be the first two prototypical elliptical galaxies with deep CXO observations enabling the study of LMXBs at lower luminosities. We propose mosaic ACS observations of both galaxies {5 fields per galaxy} that will provide the most comprehensive view into the connection between GCs and LMXBs in early-type galaxies. We will detect ~860 and ~270 GCs in all of NGC 4278 and NGC 3379, respectively. These two galaxies will have among the greatest number of detected GC-LMXBs to date {~130 & 50} and will include the faintest GC-LMXBs in a normal early-type galaxy. We will measure the fraction of GCs which contain LMXBs, as a function of X-ray luminosity, galactocentric distance, color, and GC half-light radius. Using the radial profiles of optical light, GCs, and LMXBs, we will determine the percentage of field LMXBs which may have originated in GCs. We will use the measured GC properties over the entire extent of both galaxies to constrain theories of GC formation and evolution.

ACS/WFC 10886

The Sloan Lens ACS Survey: Towards 100 New Strong Lenses

As a continuation of the highly successful Sloan Lens ACS {SLACS} Survey for new strong gravitational lenses, we propose one orbit of ACS-WFC F814W imaging for each of 50 high- probability strong galaxy-galaxy lens candidates. These observations will confirm new lens systems and permit immediate and accurate photometry, shape measurement, and mass modeling of the lens galaxies. The lenses delivered by the SLACS Survey all show extended source structure, furnishing more constraints on the projected lens potential than lensed-quasar image positions. In addition, SLACS lenses have lens galaxies that are much brighter than their lensed sources, facilitating detailed photometric and dynamical observation of the former. When confirmed lenses from this proposal are combined with lenses discovered by SLACS in Cycles 13 and 14, we expect the final SLACS lens sample to number 80–100: an approximate doubling of the number of known galaxy-scale strong gravitational lenses and an order-of-magnitude increase in the number of optical Einstein rings. By virtue of its homogeneous selection and sheer size, the SLACS sample will allow an unprecedented exploration of the mass structure of the early-type galaxy population as a function of all other observable quantities. This new sample will be a valuable resource to the astronomical community by enabling qualitatively new strong lensing science, and as such we will waive all but a short {3-month} proprietary period on the observations.

ACS/WFC 11046

CCD Hot Pixel Annealing

FGS 10928

Calibrating Cosmological Chronometers: White Dwarf Masses

We propose to use HST/FGS1R to determine White Dwarf {WD} masses. The unmatched resolving power of HST/FGS1R will be utilized to follow up four selected WD binary pairs. This high precision obtained with HST/FGS1R simply cannot be equaled by any ground based technique. This proposed effort complements that done by CoI Nelan in which a sample of WDs is being observed with HST/FGS1R. This proposal will dramatically increase the number of WDs for which dynamical mass measurements are possible, enabling a better calibration of the WD mass-radius relation, cooling curves, initial to final mass relations, and ultimately giving important clues to the star formation history of our Galaxy and the age of its disk as well as in other galaxies.

NIC1/NIC2/NIC3 11060

NICMOS Photometric Stability Monitoring

This NICMOS calibration proposal carries out photometric monitoring observations during Cycle 15. The format is the same as the Cycle 14 version of the program {10725}, but a few modifications were made with respect to the Cycle 12 program 9995 and Cycle 13 program 10381. Provisions had to be made to adopt to 2-gyro mode {G191B2B was added as extra target to provide target visibility through most of the year}. Where before 4 or 7 dithers were made in a filter before we moved to the next filter, now we observe all filters at one position before moving to the next dither position. While the previous method was chosen to minimize the effect of persistence, we now realize that persistence may be connected to charge trapping and by moving through the filter such that the count rate increases, we reach equilibrium more quickly between charge being trapped and released. We have also increased exposure times where possible to reduce the charge trapping non-linearity effects.

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration – CR Persistence Part 5

NIC2 10849

Imaging Scattered Light from Debris Disks Discovered by the Spitzer Space Telescope around 21 Sun-like Stars

We propose to use the high-contrast capability of the NICMOS coronagraph to image a sample of newly discovered circumstellar disks associated with Sun-like stars. These systems were identified by their strong thermal infrared {IR} emission with the Spitzer Space Telescope as part of the Spitzer Legacy Science program titled “The Formation and Evolution of Planetary Systems” {FEPS, P.I.: M.Meyer}. Modeling of the thermal excess emission from the spectral energy distributions alone cannot distinguish between narrowly confined high-opacity disks and broadly distributed, low-opacity disks. By resolving light scattered by the circumstellar material, our proposed NICMOS observations can break this degeneracy, thus revealing the conditions under which planet formation processes are occuring or have occured. For three of our IR-excess stars that have known radial-velocity planets, resolved imaging of the circumstellar debris disks may further offer an unprecedented view of planet-disk interactions in an extrasolar planetary system. Even non-detections of the light scattered by the circumstellar material will place strong constraints on the disk geometries, ruling out disk models with high optical depth. Unlike previous disk imaging programs, our program contains a well-defined sample of ~1 solar mass stars covering a range of ages from 3 Myr to 3 Gyr, thus allowing us to study the evolution of disks from primordial to debris for the first time. The results from our program will greatly improve our understanding of the architecture of debris disks around Sun-like stars, and will create a morphological context for the existence of our own solar system. This proposal is for a continuation of an approved Cycle 14 program {GO/10527, P.I.: D. Hines}.

NIC2 10852

Coronagraphic Polarimetry with NICMOS: Dust grain evolution in T Tauri stars

The formation of planetary systems is intimately linked to the dust population in circumstellar disks, thus understanding dust grain evolution is essential to advancing our understanding of how planets form. By combining {1} the coronagraphic polarimetry capabilities of NICMOS, {2} powerful 3-D radiative transfer codes, and {3} observations of objects known to span the Class II-III stellar evolutionary phases, we will gain crucial insight into dust grain growth. By observing objects representative of a known evolutionary sequence of YSOs, we will be able to investigate how the dust population evolves in size and distribution during the crucial transition from a star+disk system to a system containing planetesimals. When combine with our previous study on dust grain evolution in the Class I-II phase, the proposed study will help to establish the fundamental time scales for the depletion of ISM-like grains: the first step in understanding the transformation from small submicron sized dust grains, to large millimeter sized grains, and untimely to planetary bodies.

NIC2/NIC1 11000

Evaporating Disks

Evaporation in the vicinity of an O star disrupts protoplanetary disks, as seen in the Orion proplyds. We have found a number of evaporating disks with Spitzer, which are in some ways more dramatic and better oriented for detailed study than the proplyds ? they have cometary tails extending up to 0.1 pc from the evaporation working surface. We will use Spitzer/IRS and HST/NICMOS to investigate these systems in more detail. We want to explore the excitation condition in the gas, both in the head and in the tail where possible. We will measure the effects of evaporation on the characteristic emission features of the dust. We also will use NICMOS to image them in detail, including mapping complex structures resolved in their tails at 24 microns

WFPC2 10915

ACS Nearby Galaxy Survey

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10584 – GSAcq (1,3,1) failed due to Search Radius Limit Exceeded on FGS GSAcq (1,3,1) scheduled at 364/11:24:12-11:31:15 failed due to Search Radius Limit Exceeded on FGS 3. Received 486 ESB (4) 1805 “FHST moving target detected” and a05 “Exceeded SRL”. OBAD #1 RSS: 2262.82 a-s OBAD #2 RSS: 9.00 a-s OBAD MAP RSS: 186.20 a-s

10585 – Gsacq(2,1,2) failed to RGA control During LOS GSacq(2,1,2) scheduled at 365/10:08:03 failed. At AOS 10:55:00 stop flag QF2STOPF was observed. The OBAD2 showed errors of V1=-6.31, V2=8.39, V3=-1.73, and RSS=10.64. The Map at 11:00:13 show erros of V1=-48.74, V2=-1542.65, V3= -28.42 and RSS=1543.68.

10586 – GSAcq(1,2,1) resulted in Fine Lock Backup GSAcq (1,2,1) scheduled at 365/14:30:20-14:37:40 resulted in fine lock backup (1,0,1) using FGS 1 with QF2STOPF and QSTOP flags set on FGS 2. No other flags were noted. OBAD #1: V1 -2997.81, V2 2075.95, V3 1384.19, RSS 3900.30. OBAD #2: V1 -4.58, V2 -7.67, V3 -17.56, RSS 19.70. OBAD MAP: V1 2.17, V2 -4.03, V3 -0.51, RSS 4.60

10587 – GSAcq(1,2,1) resulted in Fine Lock Backup (1,0,1) At AOS 365/16:43:19 GSAcq (1,2,1) scheduled 365/16:06:10-16:13:34 had resulted in Fine Lock Backup (1,0,1) using FGS 1 with QSTOP flag set on FGS 2. OBAD # 1 & 2 unavailable due to LOS. OBAD MAP: V1 1.05, V2 -3.88, V3 -7.39, RSS 8.41

Also displaying QF2STOPF flag. OBAD Information should read: OBAD #1 unavailable due to LOS OBAD #2: V1 1.05, V2 -3.88, V3 -7.39, RSS 8.41 OBAD MAP: V1 -190.09, V2 -1827.32, V3 -83.13, RSS 1839.06

10588 – GSAcq(2,3 ,3) failed to RGA control At AOS 365/19:39:17 GSAcq (2,3,3) scheduled from 365/19:18:04-19:25:24 had failed to RGA control with QF2STOPF and QSTOP flags set on FGS 2. No other flags or ESB’s noted. OBAD #1: V1 -396.98, V2 -1864.00, V3 67.07, RSS 1906.98 OBAD #2: V1 0.91, V2 -3.74, V3 4.58, RSS 5.98 OBAD MAP: V1 -1.59, V2 12.59, V3 -1.25, RSS 12.75

10591 – GSacq(2,1,2,) failed to RGA control. During LOS GSacq(2,1,2) scheduled at 001/08:30:04 failed. At AOS 09:11:30 flags were set indicating the GSacq failed due to receiving stop flags QF2STOPF and QSTOP on FGS2. OBAD1: V1=2568.75, V2=-3040.31, V3=229.32, RSS=3986.80 OBAD2: V1=2.81, V2=1.56, V3=-6.35, RSS=7.12.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                            SCHEDULED      SUCCESSFUL
FGS GSacq                 44                     40
FGS REacq                 25                      25
OBAD with Maneuver  138                     138

SIGNIFICANT EVENTS: (None)

SpaceRef Editor

SpaceRef staff editor.

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