HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science



DAILY REPORT #5050



PERIOD COVERED: 5am March 10 - 5am March 11, 2010 (DOY 069/10:00z-070/10:00z)



OBSERVATIONS SCHEDULED



ACS/WFC 11995



CCD Daily Monitor (Part 2)



This program comprises basic tests for measuring the read noise and dark

current of the ACS WFC and for tracking the growth of hot pixels. The

recorded frames are used to create bias and dark reference images for

science data reduction and calibration. This program will be executed

four days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To

facilitate scheduling, this program is split into three proposals. This

proposal covers 320 orbits (20 weeks) from 1 February 2010 to 20 June

2010.



NIC2 11148



High Contrast Imaging of Dusty White Dwarfs



For the past 18 years, only one white dwarf with a circumstellar dust

disk was known to exist. In the last two years, six new disks have been

discovered. Since all material inwards of a few AU should be scoured

clean during post main sequence evolution, the primary explanation is

the presence of a planetary system that is perturbing relic

planetesimals into the tidal disruption radius of the white dwarf. Dusty

disks around white dwarfs should be markers for planets and we propose

to use high contrast imaging to search for faint companions down to 6

M_$J$ that may be feeding the disks. White dwarfs are uniquely suited

for planet searches, where the planet/white dwarf contrast is less than

for main sequence stars.



STIS/CC 11845



CCD Dark Monitor Part 2



Monitor the darks for the STIS CCD.



STIS/CC 11847



CCD Bias Monitor-Part 2



Monitor the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1,

and 1x1 at gain = 4, to build up high-S/N superbiases and track the

evolution of hot columns.



STIS/CCD 11999



JWST Calibration from a Consistent Absolute Calibration of Spitzer &

Hubble



Recently, Gordon, Bohlin, et al. submitted a successful Spitzer proposal

for cross calibration of HST and Spitzer. The cross-calibration targets

are stars in three categories: WDs, A-stars, and G-stars. Traditionally,

IR flux standards are extrapolations of stellar models that are tied to

absolute fluxes at shorter wavelengths. HST absolute flux standards are

among the best available with a solid basis that uses pure hydrogen

models of hot WD stars for the SED slopes and is tied to Vega at 5556A

via precise Landolt V-band photometry. Consistently matching models to

our three categories of HST observations along with Spitzer photometry

and the few existing absolute IR flux determinations will provide a

solid basis for JWST flux calibration over its 0.8-30micron range. The

goal of this proposal is to complete the HST observations of the set of

HST/Spitzer cross-calibration stars. Using a variety of standard stars

with three different spectral types will ensure that the final

calibration is not significantly affected by systematic uncertainties.



WFC3/ACS/IR 11142



Revealing the Physical Nature of Infrared Luminous Galaxies at 0.3<z<2.7

Using HST and Spitzer



We aim to determine physical properties of IR luminous galaxies at

0.3<z<2.7 by requesting coordinated HST/NIC2 and MIPS 70um observations

of a unique, 24um flux-limited sample with complete Spitzer mid-IR

spectroscopy. The 150 sources investigated in this program have S(24um)

> 0.8mJy and their mid-IR spectra have already provided the majority

targets with spectroscopic redshifts (0.3<z<2.7). The proposed

150~orbits of NIC2 and 66~hours of MIPS 70um will provide the physical

measurements of the light distribution at the rest-frame ~8000A and

better estimates of the bolometric luminosity. Combining these

parameters together with the rich suite of spectral diagnostics from the

mid-IR spectra, we will (1) measure how common mergers are among LIRGs

and ULIRGs at 0.3<z<2.7, and establish if major mergers are the drivers

of z>1 ULIRGs, as in the local Universe, (2) study the co-evolution of

star formation and blackhole accretion by investigating the relations

between the fraction of starburst/AGN measured from mid-IR spectra vs.

HST morphologies, L(bol) and z, and (3) obtain the current best

estimates of the far-IR emission, thus L(bol) for this sample, and

establish if the relative contribution of mid-to-far IR dust emission is

correlated with morphology (resolved vs. unresolved).



WFC3/IR 11587



Probing Population III Star Formation in a z=7 Galaxy



Population III (Pop III) stars, the first generation, metal-free stars

in the Universe, have been a main focus of the studies of early galaxy

formation and reionization. HeII 1640 emission originates from energetic

ionizing photons beyond 54.4eV, and is an ideal tracer of massive Pop

III star formation with strong far-UV radiation. HeII has not yet been

detected directly in individual galaxies at z<6.3, indicating a small

contribution of Pop III star formation at those redshifts. We propose to

use WFC3 narrow-band imaging to measure the flux of HeII emission in

galaxy IOK-1 (z=6.96), the highest redshift spectroscopically confirmed

galaxy to date. At this redshift, the HeII line is perfectly located in

the WFC3 F130N filter passband. Our deep narrow-band imaging will detect

a HeII flux down to 4x10^-18 erg/s/cm^2 at the 5-sigma level,

corresponding to a star formation rate from massive Pop III stars of ~1

M_sun per year, a factor of ~5 improvement to the best ground-based

results at lower redshift. Strong HeII emission, if detected, will

provide the first direct evidence of significant Pop III formation in

early galaxies at the end of the reionization epoch. We will also carry

out short F125W broad-band observations to measure the rest-frame UV

flux of this galaxy in order to constrain its total star formation rate

and to provide continuum subtraction for narrow-band imaging.



WFC3/IR 11738



SPIDERWEBS AND FLIES: OBSERVING MASSIVE GALAXY FORMATION IN ACTION



Distant luminous radio galaxies are among the brightest known galaxies

in the early Universe, pinpoint likely progenitors of dominant cluster

galaxies and are unique laboratories for studying massive galaxy

formation. Spectacular images with the ACS and NICMOS of one such

object, the "Spiderweb Galaxy" at z = 2.2, show in exquisite detail,

hierarchical merging occurring 11 Gyr ago. By imaging 3 additional

Spiderweb-like galaxies we wish to study this potentially crucial phase

of massive galaxy evolution, when hierarchical merging, galaxy

downsizing and AGN feedback are all likely to be occurring. Properties

of the complete sample of Spiderweb galaxies will be used to (i)

constrain models for the formation and evolution of the most massive

galaxies that dominate rich clusters and (ii) investigate the nature of

chain and tadpole galaxies, a fundamental but poorly understood

constituent of the early Universe.



We shall image rest-frame UV and optical continuum emission from 3 radio

galaxies with 2.4 < z < 3.8 that appear clumpy and large in shallow

WFPC/PC observations. The new observations will typically reach ~2

magnitudes fainter over 20-40 times larger area than previously.

Photometric and morphological parameters will be measured for satellite

galaxies ("flies") in the clumpy massive hosts and for galaxies in ~ 1.5

Mpc x 1.5 Mpc regions of surrounding protoclusters. Locations, sizes,

elongations, clumpiness, masses, and star formation rates of the merging

satellite and protocluster galaxies will be compared with new state of

the art simulations. Combination of ACS and WFC3 images will help

disentangle the properties of the young and old populations.



Specific goals include: (i) investigating star formation histories of

the satellite galaxies and the extended emission,



(ii) studying "downsizing" and merging scenarios and (iii) measuring the

statistics of linear galaxies and relating them to models for the

formation of massive galaxies and to the properties of the important but

enigmatic class of chain/tadpole galaxies in the HUDF.



WFC3/IR 11931



IR Signal Non-Linearity Calibration



These observations will be used to quantify the non-linear signal

behavior of the IR channel, as well as to create the IR channel

non-linearity calibration reference file. The non-linearity behavior of

each pixel in the detector will be investigated through the use of flat

fields, while the photometric behavior of point sources will be studied

using observations of 47 Tuc.



WFC3/IR/S/C 11929



IR Dark Current Monitor



Analyses of ground test data showed that dark current signals are more

reliably removed from science data using darks taken with the same

exposure sequences as the science data, than with a single dark current

image scaled by desired exposure time. Therefore, dark current images

must be collected using all sample sequences that will be used in

science observations. These observations will be used to monitor changes

in the dark current of the WFC3-IR channel on a day-to-day basis, and to

build calibration dark current ramps for each of the sample sequences to

be used by Gos in Cycle 17. For each sample sequence/array size

combination, a median ramp will be created and delivered to the

calibration database system (CDBS).



WFC3/UVIS 11905



WFC3 UVIS CCD Daily Monitor



The behavior of the WFC3 UVIS CCD will be monitored daily with a set of

full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K

subarray biases are acquired at less frequent intervals throughout the

cycle to support subarray science observations. The internals from this

proposal, along with those from the anneal procedure (Proposal 11909),

will be used to generate the necessary superbias and superdark reference

files for the calibration pipeline (CDBS).



WFC3/UVIS 11908



Cycle 17: UVIS Bowtie Monitor



Ground testing revealed an intermittent hysteresis type effect in the

UVIS detector (both CCDs) at the level of ~1%, lasting hours to days.

Initially found via an unexpected bowtie-shaped feature in flatfield

ratios, subsequent lab tests on similar e2v devices have since shown

that it is also present as simply an overall offset across the entire

CCD, i.e., a QE offset without any discernable pattern. These lab tests

have further revealed that overexposing the detector to count levels

several times full well fills the traps and effectively neutralizes the

bowtie. Each visit in this proposal acquires a set of three 3x3 binned

internal flatfields: the first unsaturated image will be used to detect

any bowtie, the second, highly exposed image will neutralize the bowtie

if it is present, and the final image will allow for verification that

the bowtie is gone.



WFC3/UV/IR 11664



The WFC3 Galactic Bulge Treasury Program: Populations, Formation

History, and Planets



Exploiting the full power of the Wide Field Camera 3 (WFC3), we propose

deep panchromatic imaging of four fields in the Galactic bulge. These

data will enable a sensitive dissection of its stellar populations,

using a new set of reddening-free photometric indices we have

constructed from broad-band filters across UV, optical, and near-IR

wavelengths. These indices will provide accurate temperatures and

metallicities for hundreds of thousands of individual bulge stars.

Proper motions of these stars derived from multi-epoch observations will

allow separation of pure bulge samples from foreground disk

contamination. Our catalogs of proper motions and panchromatic

photometry will support a wide range of bulge studies.



Using these photometric and astrometric tools, we will reconstruct the

detailed star-formation history as a function of position within the

bulge, and thus differentiate between rapid- and extended-formation

scenarios. We will also measure the dependence of the stellar mass

function on metallicity, revealing how the characteristic mass of star

formation varies with chemistry. Our sample of bulge stars with accurate

metallicities will include 12 candidate hosts of extrasolar planets.

Planet frequency is correlated with metallicity in the solar

neighborhood; our measurements will extend this knowledge to a remote

environment with a very distinct chemistry.



Our proposal also includes observations of six well-studied globular and

open star clusters; these observations will serve to calibrate our

photometric indices, provide empirical population templates, and

transform the theoretical isochrone libraries into the WFC3 filter

system. Besides enabling our own program, these products will provide

powerful new tools for a host of other stellar-population investigations

with HST/WFC3. We will deliver all of the products from this Treasury

Program to the community in a timely fashion.



WFC3/UVIS/IR 11644



A Dynamical-Compositional Survey of the Kuiper Belt: A New Window Into

the Formation of the Outer Solar System



The eight planets overwhelmingly dominate the solar system by mass, but

their small numbers, coupled with their stochastic pasts, make it

impossible to construct a unique formation history from the dynamical or

compositional characteristics of them alone. In contrast, the huge

numbers of small bodies scattered throughout and even beyond the

planets, while insignificant by mass, provide an almost unlimited number

of probes of the statistical conditions, history, and interactions in

the solar system. To date, attempts to understand the formation and

evolution of the Kuiper Belt have largely been dynamical simulations

where a hypothesized starting condition is evolved under the

gravitational influence of the early giant planets and an attempt is

made to reproduce the current observed populations. With little

compositional information known for the real Kuiper Belt, the test

particles in the simulation are free to have any formation location and

history as long as they end at the correct point. Allowing compositional

information to guide and constrain the formation, thermal, and

collisional histories of these objects would add an entire new dimension

to our understanding of the evolution of the outer solar system. While

ground based compositional studies have hit their flux limits already

with only a few objects sampled, we propose to exploit the new

capabilities of WFC3 to perform the first ever large-scale

dynamical-compositional study of Kuiper Belt Objects (KBOs) and their

progeny to study the chemical, dynamical, and collisional history of the

region of the giant planets. The sensitivity of the WFC3 observations

will allow us to go up to two magnitudes deeper than our ground based

studies, allowing us the capability of optimally selecting a target list

for a large survey rather than simply taking the few objects that can be

measured, as we have had to do to date. We have carefully constructed a

sample of 120 objects which provides both overall breadth, for a general

understanding of these objects, plus a large enough number of objects in

the individual dynamical subclass to allow detailed comparison between

and within these groups. These objects will likely define the core

Kuiper Belt compositional sample for years to come. While we have many

specific results anticipated to come from this survey, as with any

project where the field is rich, our current knowledge level is low, and

a new instrument suddenly appears which can exploit vastly larger

segments of the population, the potential for discovery -- both

anticipated and not -- is extraordinary.



FLIGHT OPERATIONS SUMMARY:



Significant Spacecraft Anomalies: (The following are preliminary reports

of potential non-nominal performance that will be investigated.)



HSTARS:

12214 - GSAcq(2,3,3) scheduled at 070/00:55:05 -01:01:54 had failed to

RGA Hold (gyro control) due to search radius limit exceeded on FGS-2.



Observations affected: WFC3 98 - 108, Proposal ID#11664, STIS 54

Proposal ID#11845.



COMPLETED OPS REQUEST:

18822-0 - Clear GENSLEW Slot-8 for COS proposal 11639 @ 069/2214z



COMPLETED OPS NOTES: (None)



SCHEDULED SUCCESSFUL

FGS GSAcq 6 5

FGS REAcq 9 9

OBAD with Maneuver 6 5



SIGNIFICANT EVENTS: (None)