HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4658
PERIOD COVERED: 5am July 22 - 5am July 23, 2008 (DOY 204/0900z-205/0900z)
OBSERVATIONS SCHEDULED
FGS 11212
Filling the Period Gap for Massive Binaries
The current census of binaries among the massive O-type stars is
seriously incomplete for systems in the period range from years to
millennia because the radial velocity variations are too small and the
angular separations too close for easy detection. Here we propose to
discover binaries in this observational gap through a Faint Guidance
Sensor SNAP survey of relatively bright targets listed in the Galactic O
Star Catalog. Our primary goal is to determine the binary frequency
among those in the cluster/association, field, and runaway groups. The
results will help us assess the role of binaries in massive star
formation and in the processes that lead to the ejection of massive
stars from their natal clusters. The program will also lead to the
identification of new, close binaries that will be targets of long term
spectroscopic and high angular resolution observations to determine
their masses and distances. The results will also be important for the
interpretation of the spectra of suspected and newly identified binary
and multiple systems.
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 i
mages. Each observation will need its own CRMAP, as different SAA
passages leave different imprints on the NICMOS detectors.
NIC2 11135
Extreme Makeovers: Tracing the Transformation of Massive Galaxies at
z~2.5
To obtain a full spectroscopic census of the universe at z~2.5 we have
conducted a near-infrared spectroscopic survey for K-selected galaxies.
We found that, in contrast to the local universe, massive high-redshift
galaxies span a wide range of properties, varying from (dusty) star
burst to "red and dead" galaxies. This may imply that massive
galaxies
transform from star-forming to quiescent galaxies in the targeted
redshift range. To understand whether the 9 quiescent galaxies in our
sample are the progenitors of local elliptical, we are observing them in
the current cycle with NIC2. For cycle 16 we propose to complete our
sample of massive z~2.5 galaxies and image the remaining 10 galaxies,
which all have emission lines. Based on emission-line diagnostics, 6 of
these galaxies are identified as star-forming objects and 4 harbor an
active galactic nucleus. The goals are to 1) determine whether star
formation in massive z~2.5 galaxies takes place in disks or is triggered
by merger activity, 2) derive the contribution of AGNs to the rest-frame
optical emission, and 3) test whether the morphologies are consistent
with the idea that the star-forming galaxies, AGNs, and quiescent
galaxies represent subsequent phases of an evolutionary sequence. The
combination of both programs will provide the first morphological study
of a spectroscopically confirmed massive galaxy sample at z~2.5.
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 programs,
numerous approved and planned ground-based spectroscopic observations,
and state-of-the-art modeling. We expect to substantially increase the
numbers of massive stars known in the Galaxy, including main sequence
stars and post-main sequence stars in the Red Supergiant, Luminous Blue
Variable and Wolf-Rayet stages. Ultimately, this program 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 11113
Binaries in the Kuiper Belt: Probes of Solar System Formation and
Evolution
The discovery of binaries in the Kuiper Belt and related small body
populations is powering a revolutionary step forward in the study of
this remote region. Three quarters of the known binaries in the Kuiper
Belt have been discovered with HST, most by our snapshot surveys. The
statistics derived from this work are beginning to yield surprising and
unexpected results. We have found a strong concentration of binaries
among low-inclination Classicals, a possible size cutoff to binaries
among the Centaurs, an apparent preference for nearly equal mass
binaries, and a strong increase in the number of binaries at small
separations. We propose to continue this successful program in Cycle 16;
we expect to discover at least 13 new binary systems, targeted to
subgroups where these discoveries can have the greatest impact.
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
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
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 11218
Snapshot Survey for Planetary Nebulae in Globular Clusters of the Local
Group
Planetary nebulae {PNe} in globular clusters {GCs} raise a number of
interesting issues related to stellar and galactic evolution. The number
of PNe known in Milky Way GCs, 4, is surprisingly low if one assumes
that all stars pass through a PN stage. However, it is likely that the
remnants of stars now evolving in Galactic GCs leave the AGB so slowly
that any ejected nebula dissipates long before the star becomes hot
enough to ionize it. Thus there should not be ANY PNe in Milky Way
GCs--but there are four! It has been suggested that these PNe are the
result of mergers of binary stars within GCs, i.e., that they are
descendants of blue stragglers. The frequency of occurrence of PNe in
external galaxies poses more questions, because it shows a range of
almost an order of magnitude. I propose a Snapshot survey aimed at
discovering PNe in the GC systems of Local Group galaxies more distant
than the Magellanic Clouds. These clusters, some of which may be much
younger than their counterparts in the Milky Way, might contain many
more PNe than those of our own galaxy. I will use the standard technique
of emission-line and continuum imaging, which easily discloses PNe.
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/NIC3/ACS/SBC 11144
Building on the Significant NICMOS Investment in GOODS: A Bright,
Wide-Area Search for z>=7 Galaxies
One of the most exciting frontiers in observational cosmology has been
to trace the buildup and evolution of galaxies from very early times.
While hierarchical theory teaches us that the star formation rate in
galaxies likely starts out small and builds up gradually, only recently
has it been possible to see evidence for this observationally through
the evolution of the LF from z~6 to z~3. Establishing that this build up
occurs from even earlier times {z~7-8} has been difficult, however, due
to the small size of current high-redshift z~7-8 samples -- now
numbering in the range of ~4-10 sources. Expanding the size of these
samples is absolutely essential, if we are to push current studies of
galaxy buildup back to even earlier times. Fortunately, we should soon
be able to do so, thanks to ~50 arcmin**2 of deep {26.9 AB mag at 5
sigma} NICMOS 1.6 micron data that will be available over the two ACS
GOODS fields as a result of one recent 180-orbit ACS backup program and
a smaller program. These data will nearly triple the deep near-IR
imaging currently available and represent a significant resource for
finding and characterizing the brightest high-redshift sources -- since
high-redshift candidates can be easily identified in these data from
their red z-H colors. Unfortunately, the red z-H colors of these
candidates are not sufficient to determine that these sources are at
z>=7, and it is important also to have deep photometry at 1.1 microns.
To obtain this crucial information, we propose to follow up each of
these z-H dropouts with NICMOS at 1.1 microns to determine which are at
high redshift and thus significantly expand our sample of luminous, z>=7
galaxies. Since preliminary studies indicate that these candidates occur
in only 30% of the NIC3 fields, our follow-up strategy is ~3 times as
efficient as without this pre-selection and 9 times as efficient as a
search in a field with no pre- existing data. In total, we expect to
identify ~8 luminous z-dropouts and possibly ~2 z~10 J- dropouts as a
result of this program, more than tripling the number currently known.
The increased sample sizes are important if we are to solidify current
conclusions about galaxy buildup and the evolution of the LF from z~8.
In addition to the high redshift science, these deep 1.1 micron data
would have significant value for many diverse endeavors, including {1}
improving our constraints on the stellar mass density at z~7-10 and {2}
doubling the number of galaxies at z~6 for which we can estimate dust
obscuration.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports
of potential non-nominal performance that will be investigated.)
HSTARS:
11404 Loss of Lock in level 2 SAA @ 204/1237z.
Following a successful
REACQ(1,3,1) at 11:57:01z, there was a loss of
lock @12:37:55z while in SAA2
with QF3STOPF and QSTOP flags set & take
data flag went down. TERM EXP scheduled
@12:58:20z. Observation
affected: NICMOS #30, proposal
08795.
11405 REACQ(2,1,2) fine lock backup on FGS 2 only during LOS @ 204/1650z.
QF1STOPF and QSTOP flags set on
FGS 1. Observation affected: WFPC
75 TO 76, ACS 2, NICMOS 32;
proposal 11144
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS GSacq
7
7
FGS REacq
7
7
OBAD with Maneuver 28
28
SIGNIFICANT EVENTS: (None)