Daily Report #4783

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT***** #4782

PERIOD COVERED: 5am January 30 - 5am February 02, 2009 (DOY
*************************** 030/1000z-033/1000z)

OBSERVATIONS SCHEDULED

WFPC2 11966

The Recent Star Formation History of SINGS Galaxies

The Spitzer Legacy project SINGS provided a unique view of the current
state of star formation and dust in a sample of galaxies of all Hubble
types. This multi-wavelength view allowed the team to create current
star formation diagnostics that are independent of the dust content
and increased our understanding of the dust in galaxies. Even so,
using the SINGS data alone we can only make rough estimates of the
recent star formation history of these galaxies. The lack of high
resolution observations (especially U-band and H-alpha) means that it
is impossible to estimate the ages of young clusters. In addition, the
low resolution of the Spitzer and ground-based observations means that
what appear to be individual Spitzer sources can actually be composed
of many individual clusters with varying ages. We need to know the
ages, star formation histories, and extinction of these individual
clusters to understand how these clusters form and age and thus
influence the evolution of the galaxy. In this proposal we address
this missing area of SINGS by obtaining high-resolution WFPC2 UBVI &
H-alpha observations to not only accurately locate and determine the
ages of the young stellar clusters in the actively star forming SINGS
galaxies but to also address a variety of other scientific issues.
Over 500 HST orbits and 500 hours of Spitzter observing time have been
dedicated to observations of the SINGS sample. But the HST
observations have not been systematic. By adding a relatively small
fraction of this time for these requested observations, we will
greatly enhance the legacy value of the SINGS observations by creating
a uniform high resolution multi-wavelength HST archive that matches
the quality of the lower resolution SINGS archive.

WFPC2 11962

A New Supernova in the Antennae; Narrowing in on the Hubble Constant
and Dark Energy

A measurement of the Hubble constant to a precision of a few percent
would be a powerful aid to the investigation of the nature of dark
energy and a potent "end-to-end" test of the present cosmological
model. In Cycle 15 we constructed a new, streamlined distance ladder
utilizing high-quality type Ia supernova data and observations of
Cepheids with HST in the near-IR to minimize the dominant sources of
systematic uncertainty in past measurements of the Hubble constant and
reduce its total uncertainty to a little under 5%. Here we propose to
exploit this new route with a rare opportunity to begin reducing the
remaining uncertainty. SN 2007sr in the Antennae (NGC 4038/9) is the
rare SN Ia which is suitable for increasing the precision of small
calibration sample of SNe Ia. Even rarer is that it is close enough
that it's Cepheids are within range of observing with WFPC2 (and
NICMOS, should it return to life). But we need to act fast as the
window of long visibility and fixed orient runs from mid-early
December 2008 to early March 2009. We request 34 orbits with WFPC2 to
find the Cepheids in the SN host. We also request 16 orbits to observe
the Cepheids we find with Camera 2, F160W if NICMOS becomes available
by April 2009 . (If NICMOS does not return we would forgo these
observations and ask the TTRB to let us make them with our own WFC3-IR
allocation, though we much prefer the smaller pixel size of NIC2).

WFPC2 11956

Hubble Heritage: Side B

We propose a program of 39 orbits to observe 6 targets with WFPC2
following a successful return to science using side B electronics.
These observations will be used for Hubble Heritage releases in the
months leading up to servicing mission 4. Because of launch delays,
our reserve of releasable images is growing dangerously slim. We are
proposing here to replenish one of our important lines of
communication with the public.

We have carefully chosen targets that can efficiently use single
pointings of WFPC2 to obtain images of visually striking and
astrophysically interesting targets. Observations will reach high S/N
and will be dithered and subsampled to improve the resolution and
pixel scale to near ACS/WFC3 quality at a modest cost in exposure
time. Most of the observations will schedule in the interim between a
return to science and the availability of new science proposals that
may be selected in response to an interim call for proposals.

WFPC2 11944/11943

Binaries at the Extremes of the H-R Diagram

We propose to use HST/Fine Guidance Sensor 1r to survey for binaries
among some of the most massive, least massive, and oldest stars in our
part of the Galaxy. FGS allows us to spatially resolve binary systems
that are too faint to observe using ground-based, speckle or optical
long baseline interferometry, and too close to resolve with AO. We
propose a SNAP-style program of single orbit FGS TRANS mode
observations of very massive stars in the cluster NGC 3603, luminous
blue variables, nearby low mass main sequence stars, cool subdwarf
stars, and white dwarfs. These observations will help us to (1)
identify systems suitable for follow up studies for mass
determination, (2) study the role of binaries in stellar birth and in
advanced evolutionary states, (3) explore the fundamental properties
of stars near the main sequence-brown dwarf boundary, (4) understand
the role of binaries for X-ray bright systems, (5) find binaries among
ancient and nearby subdwarf stars, and (6) help calibrate the white
dwarf mass - radius relation.

FGS 11942

Increasing the Accuracy of HST Astrometry with FGS1R

We propose to observe six exoplanetary system host stars and two
planetary nebulae central stars with FGS1r. All objects have been
previously observed under proposals GO-09233, -09969, -10989, and
-11210. These observations will significantly extend the time
baseline, permitting improvements in the determination of proper
motion. This systematic motion must be removed to get at the
perturbation of interest, either due to exoplanetary companions or the
orbital motion of the Earth (parallax). In most cases the perturbation
orbits will also improve. We improve either companion mass or PN
parallax. For one target, GJ 876, theoretical dynamical modelers have
proposed an inclination closer to 50 degrees, while FGS3 measurements
indicated an inclination closer to 84 degrees. These new data, once
combined with our older FGS3 data, will permit an independent
remeasurement of the inclination of the outermost companion, and a
re-evaluation of widely used dynamical algorithms.

WFPC2 11797

Supplemental WFPC2 CYCLE 16 Intflat Linearity Check and Filter
Rotation Anomaly Monitor

Supplemental observations to 11029, to cover period from Aug 08 to
SM4. 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 11022 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.

Note: These are supplemental observations to cover June to SM4 (Oct 8
'08) + 6 months.

WFPC2 11794

Cycle 16 Visible Earth Flats

This proposal monitors flatfield stability. This proposal obtains
sequences of Earth streak flats to construct high quality flat fields
for the WFPC2 filter set. These flat fields will allow mapping of the
OTA illumination pattern and will be used in conjunction with previous
internal and external flats to generate new pipeline superflats. These
Earth flats will complement the Earth flat data obtained during cycles
4-15.

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.

ACS/SBC 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-luminous 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=1 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 targeting 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 radiation at z1, requiring substantial evolution
in the processes within Lyman break galaxies which allow large escape
fractions at high redshift.

WFPC2 11103

A Snapshot Survey of The Most Massive Clusters of Galaxies

We propose the continuation of our highly successful SNAPshot survey
of a sample of 125 very X-ray luminous clusters in the redshift range
0.3-0.7. As demonstrated by the 25 snapshots obtained so far in
Cycle14 and Cycle15 these systems frequently exhibit strong
gravitational lensing as well as spectacular examples of violent
galaxy interactions. 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.
All of our primary science goals require only the detection and
characterization of high-surface-brightness features and are thus
achievable even at the reduced sensitivity of WFPC2. Because of their
high redshift and thus compact angular scale our target clusters are
less adversely affected by the smaller field of view of WFPC2 than
more nearby systems. Acknowledging the broad community interest in
this sample we waive our data rights for these observations.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

11657 - GSacq(2,3,3) scheduled at 031/17:18:18 failed to RGA control
at 17:21:28 with QF2STOPF and QSTOP flags set.

Observations affected: Astrometry FGS1,Proposal ID #11944

11658 - GSacq(1,2,2) scheduled at 031/19:11:36 failed to RGA control.
At AOS stop flags QF1STOPF and QSTOP flags were set.

REacq(1,2,2) scheduled at 031/20:40:22 failed to RGA control at
20:43:18 with stop flags QF1STOPF and QSTOP flags set.

Upon acquisition of signal at 031/23:43:46, REacq (1,2,2) scheduled at
031/22:16:20 failed to RGA Hold.

Observations affected: WFPC 107 and 112, Proposal ID#11956.

11659 - REacq(1,2,2) scheduled at 032/00:05:42 - 00:13:47 failed to
RGA Hold (Gyro Control).

Observation affected: WFPC 113 Proposal ID#11956

COMPLETED OPS REQUEST:

18370-2 Adjust NCS CPL Setpoint 3 times (down to 10º C)

COMPLETED OPS NOTES: (None)

*********************** SCHEDULED***** SUCCESSFUL

FGS GSacq************** 15****************** 13
FGS REacq************** 18****************** 15
OBAD with Maneuver **** 65****************** 65

SIGNIFICANT EVENTS: (None)