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 (z>5) 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 (D<3.5Mpc) 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)