Daily 3753

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 3753

PERIOD COVERED: DOY 344

OBSERVATIONS SCHEDULED

ACS/HRC 10137

Cluster Archeology: The Origin of Ultra-compact Dwarf Galaxies

Ultra-compact dwarf {UCD} galaxies are a new type of galaxy we have
discovered in the central regions of the Fornax and Virgo galaxy
clusters. Our most recent observations in the Fornax Cluster show that
UCDs outnumber normal galaxies in the centre of that cluster. Here we
propose snapshot imaging of UCDs in the Fornax and Virgo clusters to
test theories of how these fascinating objects formed. In particular
we wish to image Virgo cluster UCDs for which we have ground-based
Keck spectroscopy to test predictions that they formed more recently
than the Fornax UCDs.

ACS/HRC 10199

The Most Massive Galaxies in the Universe: Double Trouble?

We are proposing an HST snapshot survey of 70 objects with velocity
dispersion larger than 350 km/s, selected from the Sloan Digital Sky
Survey. Potentially this sample contains the most massive galaxies in
the Universe. Some of these objects may be superpositions; HST imaging
is the key to determining if they are single and massive or if they
are two objects in projection. The objects which HST imaging shows to
be single objects are interesting because they potentially harbor the
most massive black holes, and because their existence places strong
constraints on galaxy formation models. When combined with ground
based data already in hand, the objects which HST imaging shows are
superpositions provide valuable information about interaction rates of
early- type galaxies as well as their dust content. They also
constrain the allowed parameter space for models of binary
gravitational lenses {such models are currently invoked to explain
discrepancies in the distribution of lensed image flux ratios and
separations}.

ACS/HRC 10377

ACS Earth Flats

High signal sky flats will be obtained by observing the bright Earth
with the HRC and WFC. These observations will be used to verify the
accuracy of the flats currently used by the pipeline and will provide
a comparison with flats derived via other techniques: L- flats from
stellar observations, sky flats from stacked GO observations, and
internal flats using the calibration lamps. Weekly coronagraphic
monitoring is required to assess the changing position of the spots.

ACS/HRC 10398

Transcending Voyager: A Deeper Look at Neptune's Ring-Moon System

We will use the High Resolution Channel {HRC} of ACS to study the
inner rings, arcs and moons of Neptune with a sensitivity that exceeds
that achieved by Voyager 2 during its 1989 flyby. Our study will
reveal any moons down to V magnitude 25.5, to address a peculiar
truncation in the size distribution of inner moons and to look for the
"shepherds" and source bodies for Neptune's dusty rings. {For
comparison, Neptune's smallest known moon is Naiad, at magnitude
23.9}. Recent ground-based studies show that the mysterious arcs in
the Adams Ring continue to shift and change, and may be fading away
entirely. We will obtain the visual-band data uniquely necessary to
determine whether the arcs are fading. Long-term monitoring of the
arcs at high resolution and sensitivity will reveal their gradual
changes more clearly and enable us to assess the role of Galatea,
whose resonances are widely believed to confine the arcs.

ACS/WFC 10216

Co-evolution of spheroids and black holes

The masses of the giant black holes in galaxies are correlated with
the luminosities, masses, and velocity dispersions of their host
spheroids. This empirical connection of phenomena on widely different
scales {from sub-parsec to kiloparsec} suggests that the evolution of
a galaxy and its central black hole are closely linked. We propose to
test various unified formation models, by measuring the cosmic
evolution of the black hole/spheroid relations, back to z=0.37 {a
lookback time of 4 Gyrs}. We will obtain 1-orbit ACS images of a
sample of 20 Seyfert 1 galaxies, for which we already have extensive
new ground-based measures of the black hole masses and the stellar
velocity dispersions. HST resolution is required for accurate
measurement of the nonstellar AGN continuum, and the luminosity and
effective radius of the bulge of each host galaxy. This will complete
the set of observables needed to map the co-evolution of spheroids and
black-holes. The proposed sample is the minimum required to make the
first measure of the black hole mass/bulge correlation and of the
fundamental plane for active galaxies outside the local Universe.

ACS/WFC 10326

The Morphological, Photometric, and Spectroscopic Properties of
Intermediate Redshift Cluster Galaxies

We will use the ACS/WFC to image 8 fields in the outskirts of the
kT=5.8keV, X-ray cluster RX J0152-13 at z=0.83, for which we obtained
imaging in four central fields during Cycle 11. The resulting
wide-field mosaic of RX J0152-13 will enable direct study of the
population of galaxies falling into this cluster and will provide a
much needed comparison to our on-going wide-field study of the more
massive, 10.5keV cluster MS1054-03 at the same redshift. Imaging RX
J0152-13 to twice its viral radius enables us to: {1} trace the
transformation of infalling field spirals into cluster early-types
using, e.g., the morphology-density relation to large radii and very
low local densities; {2} determine the importance of galaxy-galaxy
interactions, i.e., whether the frequency of such encounters in the
infall region is as unexpectedly high as found in MS1054-03; and {3}
study in detail the star-formation histories of the most recently
accreted members via accurate colors and morphologies. A comparison of
RX J0152-13 with MS1054-03 will also allow us to directly probe the
dependence of galaxy evolution on cluster mass. Only by pairing the
wide-field ACS mosaic of RX J0152-13 with multi-object spectroscopy
from the Magellan, Keck, and VLT telescopes can we test predictions
from galaxy formation models, understand how field spirals evolve into
early-type cluster members, and better constrain the formation of
galaxies in general.

ACS/WFC/HRC 9895

The Role of Groups in the Evolution of Galaxies at Intermediate
Redshifts

Groups are the most common environment experienced by galaxies, yet
they remain the least studied. The tidal fields and dynamical friction
encountered by galaxies in groups probably holds the key to
understanding the role of environment in driving the evolution of
galaxies since z ~ 1. To study the evolution of galaxies in the group
environment, we propose the first unbiased HST study of groups at
moderate redshifts. Unlike previous HST group samples, that relied on
radio or X-ray properties, our kinematically selected sample is drawn
from a large redshift survey and is not biased towards unusually dense
groups. HST imaging is essential to determine the morphology of
galaxies in these systems and contrast this with the properties of
galaxies in denser and more evolved groups and rich clusters at these
epochs. HST data are also required to adequately compare the
properties of groups at intermediate redshifts with local group
samples derived from the 2df and Sloan surveys. We will combine the
HST images with deep ground-based observations to study how
morphologies and stellar populations of galaxies in groups have
evolved in time. These observations are key to understanding the
decline in the volume averaged star formation rate in the universe.

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration - CR Persistence Part 5

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 9780

NIC3 Imaging of z~6 Candidates in a Deep ACS Parallel Field: Finding
the reionizing population and their LF

A fundamental cosmological question is when and how the universe was
reionized. It is now generally believed that the reionization ended by
z=6. There is evidence that QSO/AGN cannot provide enough photons to
keep the universe ionized at that epoch. In Yan et al. {2003}, we
presented a first statistically significant sample of 6.0z6.5 galaxy
candidates, 30 objects in total found in a deep ACS/WFC parallel field
by using the "drop-out" technique, and argued that the contamination
due to possible contaminators was minimal. We concluded that young,
star-forming galaxies did exist in large number as expected from our
earlier work {Yan et al. 2002}, and that they could have contributed
most of the reionizing photons. The candidates in our sample have a
median magnitude of AB=27.4 mag, beyond the spectroscopic capability
of any existing facilities. Any effort of acquiring a large sample of
galaxies around z=6 will have the vast majority of candidates at such
a faint brightness level. Thus near-IR imaging is the only practical
way to further confirm the nature and the redshifts of these
candidates until the launch of the JWST in 2010. Here we propose to
use the NIC3 of the NICMOS to image 43% of our sample in the F110W and
F160W bands to unambiguously confirm their nature. We will image 13-14
of our candidates with two NIC3 fields, and request 16 orbits of
observation in total. With this data set, we will be able to determine
the surface density of galaxies at the crucial epoch around z=6, and
derive photometric redshift for our candidates. Our result will set
stringent limits to the faint-end slope of the luminosity function
{LF} and the star formation rate at z=6, and thus provide essential
constraints to a series of questions regarding the reionization of the
universe.

NIC3 9846

The Origins of Sub-stellar Masses: Searching for the End of the IMF

Is there a preferred scale that defines the end of the IMF? We propose
to test this hypothesis by conducting a deep spectroscopic survey of
extremely low mass objects in the embedded young cluster associated
with NGC1333. At a distance of only 300pc, this cluster is one of the
nearest examples of a dense young cluster. We will be able to obtain
R=200 spectra and photometry for 40-60 cluster members with masses
between 5-40 Jupiter masses at an age of 1 Myr observed through
A{v}10 mag. This will enable us to estimate temperatures and
luminosities for all sources detected in the survey. We will compare
their positions in an H-R diagram to PMS evolutionary tracks in order
to estimate their ages and masses. For a solar metallicity cloud at a
temperature of 10 K, the minimum mass for fragmentation is thought to
be 10 Jupiter masses. A statistically significant sample of objects
detected below this limit would challenge the role of hierarchical
fragmentation in limiting substellar masses. The proximity of this
cluster combined with the unique sensitivity, wavelength coverage, and
multi-object spectroscopic capability of NICMOS on HST make this
experiment possible.

WFPC2 10356

WFPC2 Cycle 13 Decontaminations and Associated Observations

This proposal is for the monthly WFPC2 decons. Also included are
instrument monitors tied to decons: photometric stability check, focus
monitor, pre- and post-decon internals {bias, intflats, kspots, &
darks}, UV throughput check, VISFLAT sweep, and internal UV flat
check.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.) None

COMPLETED OPS REQs:
17338-2 Payload Safing Sequence Modification @ 344/14:56z
17348-2 Quick Update to SGI Ops Strings A, G, C @ 344/15:51z
17337-0 Enable STIS CEB @ 18:11z
17345-1 RMGA Calibration for December 2004 @ 344/19:35z

OPS NOTES EXECUTED: None

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS Gsacq 07 07
FGS Reacq 07 07
FHST Update 09 09
LOSS of LOCK


SIGNIFICANT EVENTS:

The STIS CEB test was successfully executed today (OPS Request 17337)
over one orbit (start 344/16:32- end 344/1813) to ensure STIS can
still support future battery capacity testing. The current draw was as
expected (~0.7 amps).