Daily Report #4655

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT*** #4655

PERIOD COVERED: 5am July 17 - 5am July 18, 2008 (DOY
199/0900z-200/0900z)

OBSERVATIONS SCHEDULED

ACS/SBC 11151

Evaluating the Role of Photoevaporation of Protoplanetary Disk
Dispersal

Emission produced by accretion onto the central star leads to
photoevaporation, which may play a fundamental role in disk dispersal.
Models of disk photoevaporation by the central star are challenged by
two potential problems: the emission produced by accretion will be
substantially weaker for low-mass stars, and photoevaporation must
continue as accretion slows. Existing FUV spectra of CTTSs are biased
to solar-mass stars with high accretion rates, and are therefore
insufficient to address these problems. We propose use HST/ACS SBC
PR130L to obtain FUV spectra of WTTSs and of CTTSs at low masses and
mass accretion rates to provide crucial data to evaluate
photoevaporation models. We will estimate the FUV and EUV luminosities
of low-mass CTTSs with small mass accretion rates, CTTSs with
transition disks and slowed accretion, and of magnetically-active
WTTSs.

NIC1/NIC2 11172

Defining Classes of Long Period Variable Stars in M31

We propose a thrifty but information-packed investigation {1440
exposures total} with NICMOS F205W, F160W and F110W providing crucial
information about Long Period Variables in M31, at a level of detail
that has recently allowed the discovery of new variable star classes
in the Magellanic Clouds, a very different stellar population. These
observations are buttressed by an extensive map of the same fields
with ACS and WFPC2 exposures in F555W and F814W, and a massive
ground-based imaging patrol producing well-sampled light curves for
more than 400,000 variable stars. Our primary goal is to collect
sufficient NIR data in order to analyze and classify the huge number
of long-period variables in our catalog {see below} through
Period-Luminosity {P/L} diagrams. We will produce accurate P/L
diagrams for both the bulge and a progression of locations throughout
the disk of M31. These diagrams will be similar in quality to those
currently in the Magellanic Clouds, with their lower metallicity,
radically different star formation history, and larger spread in
distance to the variables. M31 offers an excellent chance to study
more typical disk populations, in a manner which might be extended to
more distant galaxies where such variables are still visible, probing
a much more evenly spread progenitor age distribution than cepheids
{and perhaps useful as a distance scale alternative or cross-check}.
Our data will also provide a massive and unique color-magnitude
dataset, and allow us to confirm the microlensing nature of a large
sample of candidate lensed sources in M31. We expect that this study
will produce several important results, among them a better
understanding of P/L and P/L-color relations for pulsating variables
which are essential to the extragalactic distance ladder, will view
these variables at a common distance over a range of metallicities
{eliminating the distance-error vs. metallicity ambiguity between the
LMC and SMC}, allow further insight into possible faint-variable
mass-loss for higher metallicities, and in general produce a sample
more typical of giant disk galaxies predominant in many studies.

NIC1/NIC2/NIC3 8795

NICMOS Post-SAA Calibration - CR Persistence Part 6

A new procedure proposed to alleviate the CR-persistence problem of
NICMOS. Dark frames will be obtained immediately upon exiting the SAA
contour 23, and every time a NICMOS exposure is scheduled within 50
minutes of coming out of the SAA. The darks will be obtained in
parallel in all three NICMOS Cameras. The POST-SAA darks will be
non-standard reference files available to users with a USEAFTER
date/time mark. The keyword 'USEAFTER=date/time' will also be added to
the header of each POST-SAA DARK frame. The keyword must be populated
with the time, in addition to the date, because HST crosses the SAA ~8
times per day so each POST-SAA DARK will need to have the appropriate
time specified, for users to identify the ones they need. Both the raw
and processed images will be archived as POST-SAA DARKSs. Generally we
expect that all NICMOS science/calibration observations started within
50 minutes of leaving an SAA will need such maps to remove the CR
persistence from the science images. Each observation will need its
own CRMAP, as different SAA passages leave different imprints on the
NICMOS detectors.

NIC3 11545

A NICMOS Survey of Newly-Discovered Young Massive Clusters

We are on the cusp of a revolution in massive star research triggered
by 2MASS and Spitzer/GLIMPSE, and now is the ideal time to capitalize
on these projects by performing the first survey of massive stars in
young stellar clusters throughout the Galactic plane. A search of the
2MASS and GLIMPSE surveys has produced over 450 newly-identified
massive stellar cluster candidates in the Galactic plane which are
hidden from our view at optical wavelengths due to extinction. Here we
propose a program of 29 orbits to image the most promising candidate
clusters in broad and narrow band filters using HST/NICMOS. We will be
complementing these observations with approved Spitzer and Chandra
programmes, numerous approved and planned ground-based spectroscopic
observations, and state-of-the-art modelling. We expect to
substantially increase the numbers of massive stars known in the
Galaxy, including main sequence OB stars and post-main sequence stars
in the Red Supergiant, Luminous Blue Variable and Wolf-Rayet stages.
Ultimately, this programme will address many of the fundamental topics
in astrophysics: the slope to the initial mass function (IMF), an
upper-limit to the masses of stars, the formation and evolution of the
most massive stars, gamma-ray burst (GRB) progenitors, the chemical
enrichment of the interstellar medium, and nature of the first stars
in the Universe.

WFPC2 11156

Monitoring Active Atmospheres on Uranus and Neptune

We propose Snapshot observations of Uranus and Neptune to monitor
changes in their atmospheres on time scales of weeks and months.
Uranus equinox is only months away, in December 2007. Hubble Space
Telescope observations during the past several years {Hammel et al.
2005, Icarus 175, 284 and references therein} have revealed strongly
wavelength-dependent latitudinal structure, the presence of numerous
visible-wavelength cloud features in the northern hemisphere, at least
one very long-lived discrete cloud in the southern hemisphere, and in
2006 the first dark spot ever seen on Uranus. Long-term ground-based
observations {Lockwood and Jerzekiewicz, 2006, Icarus 180, 442; Hammel
and Lockwood 2007, Icarus 186, 291} reveal seasonal brightness changes
whose origins are not well understood. Recent near-IR images of
Neptune obtained using adaptive optics on the Keck Telescope, together
with HST observations {Sromovsky et al. 2003, Icarus 163, 256 and
references therein} which include previous Snapshot programs {GO 8634,
10170, 10534} show a general increase in activity at south temperate
latitudes until 2004, when Neptune returned to a rather Voyager-like
appearance. Further Snapshot observations of these two dynamic planets
will elucidate the nature of long-term changes in their zonal
atmospheric bands and clarify the processes of formation, evolution,
and dissipation of discrete albedo features.

WFPC2 11235

HST NICMOS Survey of the Nuclear Regions of Luminous Infrared Galaxies
in the Local Universe

At luminosities above 10^11.4 L_sun, the space density of far-infrared
selected galaxies exceeds that of optically selected galaxies. These
`luminous infrared galaxies' {LIRGs} are primarily interacting or
merging disk galaxies undergoing enhanced star formation and Active
Galactic Nuclei {AGN} activity, possibly triggered as the objects
transform into massive S0 and elliptical merger remnants. We propose
NICMOS NIC2 imaging of the nuclear regions of a complete sample of 88
L_IR 10^11.4 L_sun luminous infrared galaxies in the IRAS Revised
Bright Galaxy Sample {RBGS: i.e., 60 micron flux density 5.24 Jy}.
This sample is ideal not only in its completeness and sample size, but
also in the proximity and brightness of the galaxies. The superb
sensitivity and resolution of NICMOS NIC2 on HST enables a unique
opportunity to study the detailed structure of the nuclear regions,
where dust obscuration may mask star clusters, AGN and additional
nuclei from optical view, with a resolution significantly higher than
possible with Spitzer IRAC. This survey thus provides a crucial
component to our study of the dynamics and evolution of IR galaxies
presently underway with Wide-Field, HST ACS/WFC and Spitzer IRAC
observations of these 88 galaxies. Imaging will be done with the F160W
filter {H-band} to examine as a function of both luminosity and merger
stage {i} the luminosity and distribution of embedded star clusters,
{ii} the presence of optically obscured AGN and nuclei, {iii} the
correlation between the distribution of 1.6 micron emission and the
mid-IR emission as detected by Spitzer IRAC, {iv} the evidence of bars
or bridges that may funnel fuel into the nuclear region, and {v} the
ages of star clusters for which photometry is available via ACS/WFC
observations. The NICMOS data, combined with the HST ACS, Spitzer, and
GALEX observations of this sample, will result in the most
comprehensive study of merging and interacting galaxies to date.

WFPC2 11800

Hubble Heritage imaging of NGC 3324 in the Carina Nebula

An ACS H-alpha mosaic of NGC 3324 already exists (HST proposal 10475,
PI Nathan Smith). This program will use WFPC2 to obtain two more
filters for this field.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

#11402 GSAcq (1,2,1) failed to RGA Hold due to QF1STOPF Flag on FGS1
during LOS@ 199/16:07:01z.

The 199/15:32:20z GSAcq (1,2,1) and 199/17:50:16z REAcq (1,2,1) failed
to RGA hold due to QF1STOPF flag on FGS 1. Received 486 ESB messages
1808 (TxG FHST Sanity Check Failed) and 1805 (FHST Moving Target
Detected).

Possible observations affected: WFPC #120 127 Proposal 11800; and
NICMOS #110 Proposal # 8795.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

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

FGS GSacq********************** 8******************* 7
FGS REacq********************** 7******************* 6
OBAD with Maneuver******* ***** 28***************** 28

SIGNIFICANT EVENTS: (None)