Daily Rpt #4982

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #4982

PERIOD COVERED: 5am November 30 - 5am December 1, 2009 (DOY 334/10:00z-335/10:00z)

OBSERVATIONS SCHEDULED

ACS/WFC3 11604

The Nuclear Structure of OH Megamaser Galaxies

We propose a snapshot survey of a complete sample of 80 OH megamaser
galaxies. Each galaxy will be imaged with the ACS/WFC through F814W
and a linear ramp filter (FR656N or FR716N or FR782N or FR853N)
allowing us to study both the spheroid and the gas morphology in
Halpha + [N II]. We will use the 9% ramps FR647M (5370-7570 angstroms)
centered at 7000 angstroms and FR914M (7570-10, 719 angstroms) 8000
angstroms for continuum subtraction for the high and low z objects
respectively. OH megamaser galaxies (OHMG) form an important class of
ultraluminous IR-galaxies (ULIRGs) whose maser lines emit QSO-like
luminosities. ULIRGs in general are associated with recent mergers but
it is often unclear whether their power output is dominated by
starbursts or a hidden QSO because of the high absorbing columns which
hide their nuclei even at X-ray wavelengths. In contrast, OHMG exhibit
strong evidence for the presence of an energetically important and
recently triggered active nucleus. In particular it is clear that much
of the gas must have already collasped to form a nuclear disk which
may be the progenitor of a circum-nuclear torus, a key element of the
unified scheme of AGN. A great advantage of studying OHMG systems over
the general ULIRG population, is that the circum-nuclear disks are
effectively "fixed" at an inner, edge on, orientation, eliminating
varying inclination as a nuisance parameter. We will use the HST
observations in conjunction with existing maser and spectroscopic data
to construct a detailed picture of the circum-nuclear regions of a
hitherto relatively neglected class of galaxy that may hold the key to
understanding the relationship between galaxy mergers, nuclear
star-formation, and the growth of massive black holes and the
triggering of nuclear activity.

ACS/WFC3 11879

CCD Daily Monitor (Part 1)

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 352 orbits (22 weeks) from 31 August
2009 to 31 January 2010.

COS/FUV 11895

FUV Detector Dark Monitor

The purpose of this proposal is to monitor the FUV detector dark rate
by taking long science exposures without illuminating the detector.
The detector dark rate and spatial distribution of counts will be
compared to pre-launch and SMOV data in order to verify the nominal
operation of the detector. Variations of count rate as a function of
orbital position will be analyzed to find dependence of dark rate on
proximity to the SAA. Dependence of dark rate as function of time will
also be tracked.

COS/NUV 11894

NUV Detector Dark Monitor

The purpose of this proposal is to measure the NUV detector dark rate
by taking long science exposures with no light on the detector. The
detector dark rate and spatial distribution of counts will be compared
to pre-launch and SMOV data in order to verify the nominal operation
of the detector. Variations of count rate as a function of orbital
position will be analyzed to find dependence of dark rate on proximity
to the SAA. Dependence of dark rate as function of time will also be
tracked.

FGS 11704

The Ages of Globular Clusters and the Population II Distance Scale

Globular clusters are the oldest objects in the universe whose age can
be accurately determined. The dominant error in globular cluster age
determinations is the uncertain Population II distance scale. We
propose to use FGS 1R to obtain parallaxes with an accuracy of 0.2
milliarcsecond for 9 main sequence stars with [Fe/H] -1.5. This will
determine the absolute magnitude of these stars with accuracies of
0.04 to 0.06mag. This data will be used to determine the distance to
24 metal-poor globular clusters using main sequence fitting. These
distances (with errors of 0.05 mag) will be used to determine the ages
of globular clusters using the luminosity of the subgiant branch as an
age indicator. This will yield absolute ages with an accuracy of 5%,
about a factor of two improvement over current estimates. Coupled with
existing parallaxes for more metal-rich stars, we will be able to
accurately determine the age for globular clusters over a wide range
of metallicities in order to study the early formation history of the
Milky Way and provide an independent estimate of the age of the
universe.

The Hipparcos database contains only 1 star with [Fe/H] -1.4 and an
absolute magnitude error less than 0.18 mag which is suitable for use
in main sequence fitting. Previous attempts at main sequence fitting
to metal-poor globular clusters have had to rely on theoretical
calibrations of the color of the main sequence. Our HST parallax
program will remove this source of possible systematic error and yield
distances to metal- poor globular clusters which are significantly
more accurate than possible with the current parallax data. The HST
parallax data will have errors which are 10 times smaller than the
current parallax data. Using the HST parallaxes, we will obtain main
sequence fitting distances to 11 globular clusters which contain over
500 RR Lyrae stars. This will allow us to calibrate the absolute
magnitude of RR Lyrae stars, a commonly used Population II distance
indicator.

S/C 12046

COS FUV DCE Memory Dump

Whenever the FUV detector high voltage is on, count rate and current
draw information is collected, monitored, and saved to DCE memory.
Every 10 msec the detector samples the currents from the HV power
supplies (HVIA, HVIB) and the AUX power supply (AUXI). The last 1000
samples are saved in memory, along with a histogram of the number of
occurrences of each current value.

In the case of a HV transient (known as a "crackle" on FUSE), where
one of these currents exceeds a preset threshold for a persistence
time, the HV will shut down, and the DCE memory will be dumped and
examined as part of the recovery procedure. However, if the current
exceeds the threshold for less than the persistence time (a
"mini-crackle" in FUSE parlance), there is no way to know without
dumping DCE memory. By dumping and examining the histograms regularly,
we will be able to monitor any changes in the rate of "mini-crackles"
and thus learn something about the state of the detector.

STIS/CCD 11721

Verifying the Utility of Type Ia Supernovae as Cosmological Probes:
Evolution and Dispersion in the Ultraviolet Spectra

The study of distant type Ia supernova (SNe Ia) offers the most
practical and immediate discriminator between popular models of dark
energy. Yet fundamental questions remain over possible
redshift-dependent trends in their observed and intrinsic properties.
High-quality Keck spectroscopy of a representative sample of 36
intermediate redshift SNe Ia has revealed a surprising, and
unexplained, diversity in their rest-frame UV fluxes. One possible
explanation is hitherto undiscovered variations in the progenitor
metallicity. Unfortunately, this result cannot be compared to local UV
data as only two representative SNe Ia have been studied near maximum
light. Taking advantage of two new `rolling searches' and the
restoration of STIS, we propose a non-disruptive TOO campaign to
create an equivalent comparison local sample. This will allow us to
address possible evolution in the mean UV spectrum and its diversity,
an essential precursor to the study of SNe beyond z~1.

STIS/CCD 11844

CCD Dark Monitor Part 1

The purpose of this proposal is to monitor the darks for the STIS CCD.

STIS/CCD 11846

CCD Bias Monitor-Part 1

The purpose of this proposal is to 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/MA1/MA2 11866

Echelle Grating Blaze Function Zero Points

We will observe the flux standard G191B2B, obtaining echelle spectra
in all primary and intermediate wavelength settings. While this was
done in cycle 10 (8915), the echelle blaze shift has proved to depend
sensitively on side of operation, time and the exact MSM positioning.
We therefore believe it is important to obtain a complete set of post-
repair data at default MSM position to allow a comprehensive solution
for the echelle blaze shifts on a repaired side 2.

WFC3/ACS 11888

ACS Internal Flat Fields

The stability of the CCD flat fields will be monitored using the
calibration lamps and a sub-sample of the filter set. High signal
observations will be used to assess the stability of the
pixel-to-pixel flat field structure and to monitor the position of the
dust motes.

WFC3/IR 11189

Probing the Early Universe with GRBs

Cosmology is beginning to constrain the nature of the earliest stars
and galaxies to form in the Universe, but direct observation of
galaxies at z6 remains highly challenging due to their scarcity,
intrinsically small size, and high luminosity distance. GRB
afterglows, thanks to their extreme luminosities, offer the
possibility of circumventing these normal constraints by providing
redshifts and spectral information which couldn't be obtained through
direct observation of the host galaxies themselves. In addition, the
association of GRBs with massive stars means that they are an
indicator of star formation, and that their hosts are likely
responsible for a large proportion of the ionizing radiation during
that era. Our collaboration is conducting a campaign to rapidly
identify and study candidate very high redshift bursts, bringing to
bear a network of 2, 4 and 8m telescopes with near-IR instrumentation.
Swift has proven capable of detecting faint, distant GRBs, and
reporting accurate positions for many bursts in near real-time. Here
we propose to continue our HST program of targeting GRBs at z~6 and
above. HST is crucial to this endeavor, allowing us (a) to
characterize the basic properties, such as luminosity and color, and
in some cases morphologies, of the hosts, which is essential to
understanding these primordial galaxies and their relationship to
other galaxy populations; and (b) to monitor the late time afterglows
and hence compare them to lower-z bursts and test the use of GRBs as
standard candles.

WFC3/IR 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 WFC3 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!

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).

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

#12111 GSAcq(2,1,1) @334/14:36:43z failed because it as in was in a
continuous FGS Loss of Lock looping

Observations affected: ACS #22-24 Proposal #11604

COMPLETED OPS REQUEST:

#18562-1 CONTINGENCY: Continuous FGS Loss of Lock looping @ 334/15:08z
& 15:15z

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSAcq 5 4
FGS REAcq 10 10
OBAD with Maneuver 4 4

SIGNIFICANT EVENTS: (None)