Daily Report #4797

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT****** #4797

PERIOD COVERED: 5am February 23 - 5am February 24, 2009 (DOY
*************************** 054/1000z-055/1000z)

OBSERVATIONS SCHEDULED

WFPC2 11302

WFPC2 CYCLE 16 Standard Darks - Part III

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 11316

HST Cycle 16 & Pre-SM4 Optical Monitor

This is a continuation of the Cycle 15 & pre-SM4 Optical Monitor,
11020. Please see that proposal for a more complete description of the
observing strategy. The 6 visits comprising this proposal observe two
single standard stars with WFPC2/PC in order to establish overall OTA
focal length for the purposes of focus maintenance. The goal of this
monitoring before SM4 is to establish a best estimate of the OTA focus
entering SMOV.

WFPC2 11603

A Comprehensive Study of Dust Formation in Type II Supernovae with
HST, Spitzer and Gemini

The recent discovery of three extremely bright Type II SNe, (2007it,
2007oc, 2007od) gives us a unique opportunity to combine observations
with HST, Spitzer and Gemini to study the little understood dust
formation process in Type II SNe. Priority 1 Spitzer Cycle 5 and band
1 Gemini 2008A time has already been approved for this project. Since
late-time Type II SNe are faint and tend to be in crowded fields, we
need the high sensitivity and high spatial resolution of ACS/HRC and
NICMOS/NIC2 for these observations. This project is motivated by the
recent detection of large amounts of dust in high redshift galaxies.
The dust in these high-z galaxies must come from young, massive stars
so Type II SNe could be potential sources. The mechanism and the
efficiency of dust condensation in Type II SN ejecta are not well
understood, largely due to the lack of observational data. We plan to
produce a unique dataset, combining spectroscopy and imaging in the
visible, near- and mid-IR covering the key phase, 400-700 days after
maximum when dust is known to form in the SN ejecta. Therefore, we are
proposing for coordinated HST/NOAO observations (HST ACS/HRC,
NICMOS/NIC2 & Gemini/GMOS and TReCS) which will be combined with our
Spitzer Cycle 5 data to study these new bright SNe. The results of
this program will place strong constraints on the formation of dust
seen in young high redshift (z5) galaxies.

WFPC2 11793

WFPC2 Cycle 16 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.

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 11974

High-resolution Imaging for 9 Very Bright, Spectroscopically
Confirmed, Group-scale Lenses

There are large samples of strong lenses that probe small (galaxy)
scale masses (e.g., SLACS, SQLS, COSMOS). There are also large samples
of strong lenses that probe large (rich cluster) scale masses (e.g.,
various rich Abell clusters, the Hennawi et al. 2008 SDSS sample). The
sample of strong lenses that probe intermediate (group/cluster-core)
scale masses, however, is sparse, and so any significant additions to
this sample are important. Here we present a sample of strong lenses
that not only probe these intermediate scales but are also quite
bright, since the sample is based almost entirely upon data from the
SDSS, a relatively shallow and poor-resolution survey, at least in
comparison to most other strong lens hunting grounds, such as COSMOS
and CFHTLS. What we lack are the high-resolution imaging data needed
to construct detailed lensing models, to probe the mass and light
profiles of the lensing galaxies and their environments, and to
characterize the morphologies of the lensed (source) galaxies. Only
HST can provide these data, and so we are proposing here for 81 orbits
of deep WFPC2 F450W, F606W and F814W imaging, for 9 of our best and
brightest intermediate-scale lensing systems with known spectroscopic
redshifts and with Einstein radii between 4 and 8 arcsec.

WFPC2 11986

Completing HST's Local Volume Legacy

Nearby galaxies offer one of the few laboratories within which stellar
populations can be tied to multi-wavelength observations. They are
thus essential for calibrating and interpreting key astrophysical
observables, such as broad-band luminosities, durations and energy
input from starbursts, and timescales of UV, H-alpha, and FIR
emission. The study of stellar populations in nearby galaxies requires
high-resolution observations with HST, but HST's legacy for this
limited set of galaxies remains incomplete.

As a first attempt to establish this legacy, The ACS Nearby Galaxy
Survey Treasury (ANGST) began observations in late 2006. ANGST was
designed to carry out a uniform multi-color survey of a volume-limited
sample of ~70 nearby galaxies that could be used for systematic
studies of resolved stellar populations. The resulting data provide
nuanced constraints on the processes which govern star formation and
galaxy evolution, for a well-defined population of galaxies. All
photometry for the survey has been publicly released.

However, the failure of ACS 4.5 months after ANGST began taking data
led to a drastic reduction in the planned survey. The loss is
two-fold. First, the goals of completeness and uniformity were greatly
compromised, impacting global comparison studies. Second, the variety
of observed star formation histories was reduced. Given that we have
never found two galaxies with identical star formation histories, and
fully sampling the population allows us to catch those few systems
whose star formation rates and metallicities place the strongest
constraints on key astrophysical processes.

Here we propose WFPC2 observations of all remaining galaxies within
the Local Volume (D3.5Mpc) for which current HST observations are
insufficient for meaningful stellar population studies. We will use
these observations for research on the star formation histories of
individual galaxies and the Local Volume, detailed calibrations of
star formation rate indicators, and the durations of starbursts. We
will also make them publicly available through the ANGST archive to
support future research. The proposed observations will finally
complete a lasting legacy of HST

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

11696 - REAcq (1,0,1) scheduled at 054/10:30:59 failed to RGA control
at 10:34:50. Stop flags QF1STOPF and QSTOP were received for FGS 1.

REAcq (1,0,1) at 054/12:06:52z was successful.

Observations affected: WFPC 18 - 29, Proposal ID# 11793.

11697 - GSAcq (1,2,2) scheduled from 054/13:46:40 - 13:53:54 failed to
RGA Hold due to QF1STOPF and QSTOP flags on FGS-1.

Observations affected: WFPC 31 - 32, Proposal ID# 11956.

11698 - GSAcq (1,2,2) at 054/22:03:29 failed to RGA control at
22:07:28 with QF1STOPF and QSTOP flags set.

REAcq (1,2,2) at 054/23:27:42 also failed at 23:31:20.

REAcq (1,2,2) at 055/01:03:36 was successful.

Observations affected: WFPC 62 to 72, Proposal ID# 11603.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

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

FGS GSacq************** 06*************** 04
FGS REacq************** 09*************** 07
OBAD with Maneuver **** 30*************** 30

SIGNIFICANT EVENTS: (None)