Notice: For the foreseeable future, the daily reports may contain
apparent discrepancies between some proposal descriptions and the
listed
instrument usage. This is due to the conversion of previously approved
ACS WFC or HRC observations into WFPC2, or NICMOS observations
subsequent to the loss of ACS CCD science capability in late January.
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT # 4385
PERIOD COVERED: UT June 15,16,17, 2007 (DOY 166,167,168)
OBSERVATIONS SCHEDULED
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.
WFPC2 11084
Probing the Least Luminous Galaxies in the Local Universe
We propose to obtain deep color-magnitude data of eight new Local Group
galaxies which we recently discovered: Andromeda XI, Andromeda XII, and
Andromeda XIII {satellites of M31}; Canes Venatici I, Canes Venatici
II,
Hercules, and Leo IV {satellites of the Milky Way}; and Leo T, a new
"free-floating" Local Group dwarf spheroidal with evidence
for recent
star formation and associated H I gas. These represent the least
luminous galaxies known at *any* redshift, and are the only accessible
laboratories for studying this extreme regime of galaxy formation. With
deep WFPC-2 F606W and F814W pointings at their centers, we will
determine whether these objects contain single or multiple age stellar
populations, as well as whether these objects display a range of
metallicities.
NIC3 11080
Exploring the Scaling Laws of Star Formation
As a variety of surveys of the local and distant Universe are
approaching a full census of galaxy populations, our attention needs to
turn towards understanding and quantifying the physical mechanisms that
trigger and regulate the large-scale star formation rates {SFRs} in
galaxies.
FGS 10998
Exoplanet XO-1b: light curve and parallax
We propose to measure the radius of the recently-discovered transiting
extrasolar planet XO-1b. XO-1b's nominal radius is 1.30 times the
radius
of Jupiter, which is nearly as large as HD 209458b {1.32 R_J}. We will
use two independent methods to measure XO-1b's radius: 1} precision
light curve analysis, and 2} measurement of its trigonometric parallax
combined with its spectroscopically-determined effective temperature
and
its apparent magnitude.
NIC3 10908
Gotcha Using Swift GRBs to Pinpoint the Highest Redshift Galaxies
While there is convincing evidence that the Universe was reionized
between redshifts of 6.5 and 15, the role of galaxies in this process
is
still not understood. Several star-forming galaxies at z~6 have been
identified in recent deep, narrow-field surveys, but the expensive
observations along with cosmic variance and contamination make it
difficult to assess their contribution to reionization, or to
significantly increase the sample. It has now been demonstrated that
gamma-ray bursts {GRBs} exist at z>6, and we have already obtained
HST
and Spitzer observations of the host galaxy of GRB050904 at z=6.295
using our Cycle 14 program. GRBs have the advantage of being an
uncontaminated signpost for star- formation, and their afterglows are
sufficiently bright even at z>6 to allow photometric selection {via
the
Ly-alpha drop out technique} with 2-5 meter telescopes. Spectroscopic
confirmation, including detailed information on the host ISM, is also
likely {as demonstrated in the case of GRB050904}. Using our approved
TOO programs at an extensive range of facilities {2-5 m telescopes up
to
Keck/Magellan/Gemini}, we can rapidly find afterglows at z>6 and
easily
distinguish them from dusty low redshift bursts. This approach is
highly
efficient compared to current techniques, especially at z>7. Our
large
allocation on Keck/Magellan/Gemini will also be used to obtain
spectroscopy of the afterglows and host galaxies. Here we request to
continue our program of imaging GRB-selected z>6 galaxies with NICMOS
{z>6}, ACS {z~6}, and Spitzer/IRAC to characterize their properties
{SFR, age, morphology, extinction}, and begin to address their role in
reionization. These observations are requested as >2 month TOOs,
allowing flexibility of scheduling and at the same time taking a unique
and timely advantage of the exquisite performance of three of NASA's
premier missions.
WFPC2 10902
The Nearest Luminous Blue Compact Galaxies: A Window on Galaxy
Formation
As we move to intermediate and high redshifts, Luminous Blue Compact
Galaxies {LBCGs} become increasingly common. The nearest LBCGs, with
their violent starbursts and rich populations of super star clusters
{SSCs} and globular clusters {GCs}, thus provide ideal laboratories for
studying galaxy evolution. Many LBCGs appear to be involved in mergers
between dwarf galaxies, triggering their starbursts. The starburst
regions in LBCGs consist of numerous young star clusters, whose
populations are both easily measurable with HST and easily modelled.
Studying cluster populations provides a powerful probe of the starburst
and merger history which is possible neither for closer objects {of
which there are too few} or for those at high redshift {which are too
far away}. We have previously studied the closest LBCG with WFPC2 and
found hundreds of bright compact SSCs and GCs. In particular, we found
a
population of intermediate-age {~2 Gyr} GCs, indicating a past event of
massive cluster formation. We now propose a multi-wavelength study of
the three other LBCGs with the highest known number of SSCs. The
extinction is small in these galaxies and age estimates robust. The age
distribution of GCs and SSCs will be used to study the past evolution
of
the galaxies. For each LBCG, we will map its cluster formation history,
unveiling its merger and starburst history, and thereby shed light on
some of the processes involved in galaxy evolution at high redshift.
WFPC2 10890
Morphologies of the Most Extreme High-Redshift Mid-IR-Luminous Galaxies
The formative phase of the most massive galaxies may be extremely
luminous, characterized by intense star- and AGN-formation. Till now,
few such galaxies have been unambiguously identified at high redshift,
restricting us to the study of low-redshift ultraluminous infrared
galaxies as possible analogs. We have recently discovered a sample of
objects which may indeed represent this early phase in galaxy
formation,
and are undertaking an extensive multiwavelength study of this
population. These objects are bright at mid-IR wavelengths
{F[24um]>0.8mJy}, but deep ground based imaging suggests extremely
faint
{and in some cases extended} optical counterparts {R~24-27}. Deep
K-band
images show barely resolved galaxies. Mid-infrared spectroscopy with
Spitzer/IRS reveals that they have redshifts z ~ 2-2.5, suggesting
bolometric luminosities ~10^{13-14}Lsun! We propose to obtain deep ACS
F814W and NIC2 F160W images of these sources and their environs in
order
to determine kpc-scale morphologies and surface photometry for these
galaxies. The proposed observations will help us determine whether
these
extreme objects are merging systems, massive obscured starbursts {with
obscuration on kpc scales!} or very reddened {locally obscured} AGN
hosted by intrinsically low-luminosity galaxies.
WFPC2 10870
The Ring Plane Crossings of Uranus in 2007
The rings of Uranus turn edge-on to Earth in May and August 2007. In
between, we will have a rare opportunity to see the unlit face of the
rings. With the nine optically thick rings essentialy invisible, we
will
observe features and phenomena that are normally lost in their glare.
We
will use this opportunity to search thoroughly for the embedded
"shepherd" moons long believed to confine the edges of the
rings,
setting a mass limit roughly 10 times smaller than that of the smallest
shepherd currently known, Cordelia. We will measure the vertical
thicknesses of the rings and study the faint dust belts only known to
exist from a single Voyager image. We will also study the colors of the
newly-discovered faint, outer rings; recent evidence suggests that one
ring is red and the other blue, implying that each ring is dominated by
a different set of physical processes. We will employ near- edge-on
photometry from 2006 and 2007 to derive the particle filling factor
within the rings, to observe how ring epsilon responds to the
"traffic
jam" as particles pass through its narrowest point, and to test
the
latest models for preserving eccentricities and apse alignment within
the rings. Moreover, this data set will allow us to continue monitoring
the motions of the inner moons, which have been found to show possibly
chaotic orbital variations; by nearly doubling the time span of the
existing ACS astrometry, the details of the variations will become much
clearer.
WFPC2 10841
A Proper Motion Search for Intermediate Mass Black Holes in Globular
Clusters {2nd Epoch Observations}
Establishing the presence or absence of intermediate-mass black holes
{IMBH} in globular clusters is crucial for understanding the evolution
of dense stellar systems. Observationally, this search has been
hampered
by the low number of stars with known velocities in the central few
arcseconds. This limits our knowledge of the velocity dispersion in the
region where the gravitational influence of any IMBH would be felt. In
Cycle 13, we successfully obtained ACS/HRC images of the centers of
five
carefully chosen Galactic globular clusters {GO-10401} for a new proper
motion study. Although the science case was approved and the first
epoch
images obtained, the requested future cycle observations were not
granted {due to a general policy decision based on the strong
uncertainties at the time concerning the immediate future of HST}. We
have now assessed the quality of the first epoch observations. The HRC
resolution reveals many isolated stars in to the very center of each
cluster that remained blended or unresolved in previous WFPC2 data.
Given a two year baseline, we are confident that we can achieve the
proper motion precision required to place strict limits on the presence
of an IMBH. Therefore, we request the second-epoch, follow-up
observations to GO-10401 in order to measure the proper motions of
stars
in our target clusters. These velocity measurements will allow us to:
{i} place constraints on the mass of a central black hole in each
cluster; {ii} derive the internal velocity dispersion as a function of
cluster radius; {iii} verify or reject previous reports of cluster
rotation; and {iv} directly measure velocity anisotropy as a function
of
radius. If no second epoch data are obtained then the observing time
already invested in the first epoch will have been wasted.
WFPC2 10829
Secular Evolution at the End of the Hubble Sequence
The bulgeless disk galaxies at the end of the Hubble Sequence evolve at
a glacial pace relative to their more violent, earlier-type cousins.
The
causes of their internal, or secular evolution are important because
secular evolution represents the future fate of all galaxies in our
accelerating Universe and is a key ingredient to understanding galaxy
evolution in lower-density environments at present. The rate of secular
evolution is largely determined by the stability of the cold ISM
against
collapse, star formation, and the buildup of a central bulge. Key
diagnostics of the ISM's stability are the presence of compact
molecular
clouds and narrow dust lanes. Surprisingly, edge-on, pure disk galaxies
with circular velocities below 120 km/s do not appear to contain such
dust lanes. We propose to obtain ACS/WFC F606W images of a
well-selected
sample of extremely late-type disk galaxies to measure the
characteristic scale size of the cold ISM and determine if they possess
the unstable, cold ISM necessary to drive secular evolution. Our sample
has been carefully constructed to include disk galaxies above and below
the critical circular velocity of 120 km/s where the dust properties of
edge-on disks change so remarkably. We will then use surface brightness
profiles to search for nuclear star clusters and pseudobulges, which
are
early indicators that secular evolution is at work, as well as measure
the pitch angle of the dust lanes as a function of radius to estimate
the central mass concentrations.
WFPC2 10818
Very Young Globular Clusters in M31 ?
We propose to use HST's unique high spatial resolution imaging
capabilities to conclusively confirm or refute the presence of alleged
very young globular clusters in M31. Such young globular clusters with
ages < 3 Gyr are not present in our galaxy, and, if real, would lead
to
a striking difference in the age distribution of the GCs between M31
and
the
in M31 is confirmed through our proposed ACS imaging {now WFPC2
imaging}
with HST, this would suggest major differences in the history of
assembly of the two galaxies, with probable substantial late accretion
into M31 which did not occur in our own galaxy.
NIC2 10802
SHOES-Supernovae, HO, for the Equation of State of Dark energy
The present uncertainty in the value of the Hubble constant {resulting
in an uncertainty in Omega_M} and the paucity of
redshifts exceeding 1 are now the leading obstacles to determining the
nature of dark energy. We propose a single, integrated set of
observations for Cycle 15 that will provide a 40% improvement in
constraints on dark energy. This program will observe known Cepheids in
six reliable hosts of
uncertainty in H_0 by a factor of two because of the smaller dispersion
along the instability strip, the diminished extinction, and the weaker
metallicity dependence in the infrared. In parallel with ACS, at the
same time the NICMOS observations are underway, we will discover and
follow a sample of
measurements, along with prior constraints from WMAP, will provide a
great improvement in HST's ability to distinguish between a static,
cosmological constant and dynamical dark energy. The Hubble Space
Telescope is the only instrument in the world that can make these IR
measurements of Cepheids beyond the Local Group, and it is the only
telescope in the world that can be used to find and follow supernovae
at
z > 1. Our program exploits both of these unique capabilities of HST
to
learn more about one of the greatest mysteries in science.
WFPC2 10800
Kuiper Belt Binaries: Probes of Early Solar System Evolution
Binaries in the Kuiper Belt are a scientific windfall: in them we have
relatively fragile test particles which can be used as tracers of the
early dynamical evolution of the outer Solar System. We propose to
continue a Snapshot program using the ACS/HRC that has a demonstrated
discovery potential an order of magnitude higher than the HST
observations that have already discovered the majority of known
transneptunian binaries. With this continuation we seek to reach the
original goals of this project: to accumulate a sufficiently large
sample in each of the distinct populations collected in the Kuiper Belt
to be able to measure, with statistical significance, how the fraction
of binaries varies as a function of their particular dynamical paths
into the Kuiper Belt. Today's Kuiper Belt bears the imprints of the
final stages of giant-planet building and migration; binaries may offer
some of the best preserved evidence of that long-ago era.
NIC3 10792
Quasars at Redshift z=6 and Early Star Formation History
We propose to observe four high-redshift quasars {z=6} in the NIR in
order to estimate relative Fe/Mg abundances and the central black hole
mass. The results of this study will critically constrain models of
joint quasar and galaxy formation, early star formation, and the growth
of supermassive black holes. Different time scales and yields for
alpha-elements {like O or Mg} and for iron result into an iron
enrichment delay of ~0.3 to 0.6 Gyr. Hence, despite the well-known
complexity of the FeII emission line spectrum, the ratio iron/alpha -
element is a potentially useful cosmological clock. The central black
hole mass will be estimated based on a recently revised back hole mass
-
luminosity relationship. The time delay of the iron enrichment and the
time required to form a supermassive black hole {logM>8 Msol, tau
~0.5Gyr} as evidenced by quasar activity will be used to date the
beginning of the first intense star formation, marking the formation of
the first massive galaxies that host luminous quasars, and to constrain
the epoch when supermassive black holes start to grow by accretion.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary
reports
of potential non-nominal performance that will be investigated.)
HSTARS:
10863 - GSAcq(1,2,1) failed due to Scan Step Limit Exceeded
At AOS 166/18:48:35 GSAcq (1,2,1) scheduled from 166/18:03:57-18:11:18
failed to RGA Hold (Gyro Control) due to Scan Step Limit Exceeded on FGS
1.
OBAD #1: V1 527.16, V2 -696.45, V3 25.60, RSS 873.84
OBAD #2: unavailable due to LOS
OBAD MAP: V1 1.15, V2 7.36, V3 0.79, RSS 7.49
10864 - GSacq(1,3,1) not attempted, open loop timer expired
GSacq(1,3,1) at 167/12:31:55 was not attempted due to open loop timer
expiration.
OBAD prior to GSAcq showed RSS error of 12.24 arcseconds, OBAD map after
GSACQ showed RSS error of 2226.42 arcseconds.
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS GSacq
20
18
FGS REacq
20
20
OBAD with Maneuver 80
80
SIGNIFICANT EVENTS: (None)