Daily Report #5103

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5103

PERIOD COVERED: 5am May 24 - 5am May 25, 2010 (DOY 144/09:00z-145/09:00z)

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)

SCHEDULED SUCCESSFUL
FGS GSAcq 07 07
FGS REAcq 09 09
OBAD with Maneuver 04 04

SIGNIFICANT EVENTS: (None)


OBSERVATIONS SCHEDULED:

ACS/WFC 11591

Are Low-Luminosity Galaxies Responsible for Cosmic Reionization?

Our group has demonstrated that massive clusters, acting as powerful
cosmic lenses, can constrain the abundance and properties of
low-luminosity star-forming sources beyond z~6; such sources are
thought to be responsible for ending cosmic reionization. The large
magnification possible in the critical regions of well-constrained
clusters brings sources into view that lie at or beyond the limits of
conventional exposures such as the UDF. We have shown that the
combination of HST and Spitzer is particularly effective in delivering
the physical properties of these distant sources, constraining their
mass, age and past star formation history. Indirectly, we therefore
gain a valuable glimpse to yet earlier epochs. Recognizing the result
(and limitations) of blank field surveys, we propose a systematic
search through 10 lensing clusters with ACS/F814W and
WFC3/[F110W+F160W] (in conjunction with existing deep IRAC data). Our
goal is to measure with great accuracy the luminosity function at z~7
over a range of at least 3 magnitude, based on the identification of
about 50 lensed galaxies at 6.5z8. Our survey will mitigate cosmic
variance and extend the search both to lower luminosities and, by
virtue of the WFC3/IRAC combination, to higher redshift. Thanks to the
lensing amplification spectroscopic follow-up will be possible and
make our findings the most robust prior to the era of JWST and the
ELTs.

ACS/WFC/WFC3/IR 11142

Revealing the Physical Nature of Infrared Luminous Galaxies at
0.3z2.7 Using HST and Spitzer

We aim to determine physical properties of IR luminous galaxies at
0.3z2.7 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
(0.3z2.7). 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 0.3z2.7, and establish
if major mergers are the drivers of z1 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. (3) obtain the current best estimates of the far-IR
emission, thus L(bol) for this sample, and establish if the relative
contribtuion of mid-to-far IR dust emission is correlated with
morphology (resolved vs. unresolved).

ACS/WFC/WFC3/IR 11663

Formation and Evolution of Massive Galaxies in the Richest
Environments at 1.5 z 2.0

We propose to image seven 1.5z2 clusters and groups from the IRAC
Shallow Cluster Survey with WFC3 and ACS in order to study the
formation and evolution of massive galaxies in the richest
environments in the Universe in this important redshift range. We will
measure the evolution of the sizes and morphologies of massive cluster
galaxies, as a function of redshift, richness, radius and local
density. In combination with allocated Keck spectroscopy, we will
directly measure the dry merger fraction in these clusters, as well as
the evolution of Brightest Cluster Galaxies (BCGs) over this redshift
range where clear model predictions can be confronted. Finally we will
measure both the epoch of formation of the stellar populations and the
assembly history of that stellar mass, the two key parameters in the
modern galaxy formation paradigm.

COS/FUV/COS/NUV 11741

Probing Warm-Hot Intergalactic Gas at 0.5 z 1.3 with a Blind
Survey for O VI, Ne VIII, Mg X, and Si XII Absorption Systems

Currently we can only account for half of the baryons (or less)
expected to be found in the nearby universe based on D/H and CMB
observations. This "missing baryons problem" is one of the
highest-priority challenges in observational extragalatic astronomy.
Cosmological simulations suggest that the baryons are hidden in
low-density, shock-heated intergalactic gas in the log T = 5 - 7
range, but intensive UV and X-ray surveys using O VI, O VII, and O
VIII absorption lines have not yet confirmed this prediction. We
propose to use COS to carry out a sensitive survey for Ne VIII and Mg
X absorption in the spectra of nine QSOs at z(QSO) 0.89. For the
three highest-redshift QSOs, we will also search for Si XII. This
survey will provide more robust constraints on the quantity of baryons
in warm-hot intergalactic gas at 0.5 z 1.3, and the data will
provide rich constraints on the metal enrichment, physical conditions,
and nature of a wide variety of QSO absorbers in addition to the
warm-hot systems. By comparing the results to other surveys at lower
redshifts (with STIS, FUSE, and from the COS GTO programs), the
project will also enable the first study of how these absorbers evolve
with redshift at z 1. By combining the program with follow-up galaxy
redshift surveys, we will also push the study of galaxy-absorber
relationships to higher redshifts, with an emphasis on the
distribution of the WHIM with respect to the large-scale matter
distribution of the universe..

FGS 11789

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)= 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.

S/C/WFC3/IR 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).

STIS/CCD 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD.

STIS/CCD 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/MA1 12079

STIS PtCr/Ne Lamp Ratios

We will provide improved information on the ratio of the STIS
wavelength calibration lamps at all wavelengths. The LINE & HITM1
lamps have faded by a factor of several since launch, and at the
shortest wavelengths the fading is enough to have significantly
impacted the S/N of the wavecals. The FUV flux of the HITM2 lamp has
not been checked since 1997, and so a detailed comparison of all three
lamps is needed to support a proper wavelength calibration for GO
proposals.

WFC3/IR 11702

Search for Very High-z Galaxies with WFC3 Pure Parallel

WFC3 will provide an unprecedented probe to the early universe beyond
the current redshift frontier. Here we propose a pure parallel program
using this new instrument to search for Lyman-break galaxies at
6.5z8.8 and to probe the epoch of reionization, a hallmark event in
the history of the early universe. We request 200 orbits, spreading
over 30 ~ 50 high Galactic latitude visits (|b|20deg) that last for 4
orbits and longer, resulting a total survey area of about 140~230
square arcminute. Based on our understanding of the new HST parallel
observation scheduling process, we believe that the total number of
long-duration pure parallel visits in Cycle 17 should be sufficient to
accommodate our program. We waive all proprietary rights to our data,
and will also make the enhanced data products public in a timely
manner. (1) We will use both the UVIS and the IR channels, and do not
need to seek optical data from elsewhere. (2) Our program will likely
triple the size of the probable candidate samples at z~7 and z~8, and
will complement other targeted programs aiming at the similar redshift
range. (3) Being a pure parallel program, our survey will only make
very limited demand on the scarce HST resources. More importantly, as
the pure parallel pointings will be at random sight-lines, our program
will be least affected by the bias due to the large scale structure
("cosmic variance"). (4) We aim at the most luminous LBG population,
and will address the bright-end of the luminosity function at z~8 and
z~7. We will constrain the value of L* in particular, which is
critical for understanding the star formation process and the stellar
mass assembly history in the first few hundred million years of the
universe. (5) The candidates from our survey, most of which will be
the brightest ones that any surveys would be able to find, will have
the best chance to be spectroscopically confirmed at the current
8--10m telescopes. (6) We will also find a large number of extremely
red, old galaxies at intermediate redshifts, and the fine spatial
resolution offered by the WFC3 will enable us constrain their
formation history based on the study of their morphology, and hence
shed light on their connection to the very early galaxies in the
universe.

WFC3/UVI 11556

Investigations of the Pluto System

We propose a set of high SNR observations of the Pluto system that
will provide improved lightcurves, orbits, and photometric properties
of Nix and Hydra. The key photometric result for Nix and Hydra will be
a vastly improved lightcurve shape and rotation period to test if the
objects are in synchronous rotation or not. A second goal of this
program will be to retrieve a new epoch of albedo map for the surface
of Pluto. These observations will also improve masses and in some case
densities for the bodies in the Pluto system.

WFC3/UVI 11702

Search for Very High-z Galaxies with WFC3 Pure Parallel

WFC3 will provide an unprecedented probe to the early universe beyond
the current redshift frontier. Here we propose a pure parallel program
using this new instrument to search for Lyman-break galaxies at
6.5z8.8 and to probe the epoch of reionization, a hallmark event in
the history of the early universe. We request 200 orbits, spreading
over 30 ~ 50 high Galactic latitude visits (|b|20deg) that last for 4
orbits and longer, resulting a total survey area of about 140~230
square arcminute. Based on our understanding of the new HST parallel
observation scheduling process, we believe that the total number of
long-duration pure parallel visits in Cycle 17 should be sufficient to
accommodate our program. We waive all proprietary rights to our data,
and will also make the enhanced data products public in a timely
manner. (1) We will use both the UVIS and the IR channels, and do not
need to seek optical data from elsewhere. (2) Our program will likely
triple the size of the probable candidate samples at z~7 and z~8, and
will complement other targeted programs aiming at the similar redshift
range. (3) Being a pure parallel program, our survey will only make
very limited demand on the scarce HST resources. More importantly, as
the pure parallel pointings will be at random sight-lines, our program
will be least affected by the bias due to the large scale structure
("cosmic variance"). (4) We aim at the most luminous LBG population,
and will address the bright-end of the luminosity function at z~8 and
z~7. We will constrain the value of L* in particular, which is
critical for understanding the star formation process and the stellar
mass assembly history in the first few hundred million years of the
universe. (5) The candidates from our survey, most of which will be
the brightest ones that any surveys would be able to find, will have
the best chance to be spectroscopically confirmed at the current
8--10m telescopes. (6) We will also find a large number of extremely
red, old galaxies at intermediate redshifts, and the fine spatial
resolution offered by the WFC3 will enable us constrain their
formation history based on the study of their morphology, and hence
shed light on their connection to the very early galaxies in the
universe.

WFC3/UVI 11730

Continued Proper Motions of the Magellanic Clouds: Orbits, Internal
Kinematics, and Distance

In Cycles 11 and 13 we obtained two epochs of ACS/HRC data for fields
in the Magellanic Clouds centered on background quasars. We used these
data to determine the proper motions of the LMC and SMC to better than
5% and 15% respectively. The results had a number of unexpected
implications for the Milky Way-LMC-SMC system and received
considerable attention in the literature and in the press. The implied
three-dimensional velocities are larger than previously believed and
close to the escape velocity in a standard 10^12 solar mass Milky Way
dark halo. Our orbit calculations suggest the Clouds may not be bound
to the Milky Way or may just be on their first passage, both of which
are unexpected in view of traditional interpretations of the
Magellanic Stream. Alternatively, the Milky Way dark halo may be a
factor two more massive than previously believed, which would be
surprising in view of other observational constraints. Also, the
relative velocity between the LMC and SMC was larger than expected,
leaving open the possibility that the Clouds may not be bound to each
other. To further verify and refine our results we requested an
additional epoch data in Cycle 16 which is being executed with
WFPC2/PC due to the failure of ACS. A detailed analysis of one LMC
field shows that the field proper motion using all three epochs of
data is consistent within 1-sigma with the two-epoch data, thus
verifying that there are no major systematic effects in our previous
measurements. The random errors, however, are only smaller by a factor
of 1.4 because of the relatively large errors in the WFPC2 data. A
prediction for a fourth epoch with measurement errors similar to
epochs 1 and 2 shows that the uncertainties will improve by a factor
of 3. This will allow us to better address whether the Clouds are
indeed bound to each other and to the Milky Way. It will also allow us
to constrain the internal motions of various populations within the
Clouds, and to determine a distance to the LMC using rotational
parallax. Continuation of this highly successful program is therefore
likely to provide important additional insights. Execution in SNAPshot
mode guarantees maximally efficient use of HST resources.

WFC3/UVI 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 biasBRand dark frames. A smaller set of
2Kx4K subarray biases are acquired at less frequent
intervalsBRthroughout the cycle to support subarray science
observations. The internals from this proposal,BRalong with those
from the anneal procedure (11909), will be used to generate the
necessary superbiasBRand superdark reference files for the
calibration pipeline (CDBS).

WFC3/UVI 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.