Status Report

NASA Hubble Space Telescope Daily Report #3903

By SpaceRef Editor
July 21, 2005
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science


PERIOD COVERED: UT July 15-17, 2005 (DOY 196-198)


NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration – CR Persistence Part 4

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.

ACS/WFC 10624

Solving the Mystery of the Short-Hard Gamma-Ray Bursts

Eight years after the afterglow detections that revolutionized studies
of the long-soft gamma-ray bursts, not even one afterglow of a
short-hard GRB has been seen, and the nature of these events has
become one of the most important problems in GRB research. The Swift
satellite, expected to be in full operation throughout Cycle 14, will
report few-arcsecond localizations for short-hard bursts in minutes,
enabling prompt, deep optical afterglow searches for the first time.
Discovery and observation of the first short-hard optical afterglows
will answer most of the critical questions about these events: What
are their distances and energies? Do they occur in distant galaxies,
and if so, in which regions of those galaxies? Are they the result of
collimated or quasi- spherical explosions? In combination with an
extensive rapid-response ground-based campaign, we propose to make the
critical high-sensitivity HST TOO observations that will allow us to
answer these questions. If theorists are correct in attributing the
short- hard bursts to binary neutron star coalescence events, then
they will serve as signposts to the primary targeted source population
for ground-based gravitational-wave detectors, and short-hard burst
studies will have a vital role to play in guiding those observations.

ACS/WFC 10588

The Host Galaxies of Post-Starburst Quasars

We propose to use ACS to conduct a snapshot imaging survey of
post-starburst quasars now being discovered in signficant numbers by
the Sloan Digital Sky Survey. Post-starburst quasars are broad-lined
AGN that also possess Balmer jumps and high-n Balmer absorption lines
indicative of luminous stellar populations on order of 100 Myr old.
These objects, representing a few percent of the z < 0.5 quasar population, may be an evolutionary stage in the transition of ultraluminous infrared galaxies into normal quasars, or a type of galaxy interaction that triggers both star formation and nuclear activity. These sources may also illustrate how black hole mass/bulge mass correlations arise. Ground-based imaging of individual poststarburst quasars has revealed merger remnants, binary systems, and single point sources. Our ACS snapshots will enable us to determine morphologies and binary structure on sub-arcsecond scales {surely present in the sample and impossible to do without HST}, as well as basic host galaxy properties. We will be looking for relationships among morphology, particularly separation of double nuclei, the starburst age, the quasar black hole mass and accretion rate, that will lead to an understanding of the triggering activity and mutual evolution. This project will bring quantitative data and statistics to the previously fuzzy and anecdotal topic of the "AGN- starburst connection" and help test the idea that post-starburst quasars are an early evolutionary stage of normal quasars.


What Are Stalled Preplanetary Nebulae? An ACS SNAPshot Survey

Essentially all planetary nebulae {PNs} are aspherical, whereas the
mass-loss envelopes of AGB stars are strikingly spherical. Our
previous SNAPshot surveys of a morphologically unbiased sample of
pre-planetary nebulae {PPNs} — objects in transition between the AGB
and PN evolutionary phases — show that roughly half our observed
targets are resolved, with bipolar or multipolar morphologies.
Spectroscopic observations of our sample confirm that these objects
have not yet evolved into planetary nebulae. Thus, the transformation
from spherical to aspherical geometries has already fully developed by
the time these dying stars have become PPNs. Although our current
studies have yielded exciting results, they are limited in two
important ways — {1} the number of well-resolved objects is still
small {18}, and the variety of morphologies observed relatively
multitudinous, hence no clear trends can yet be established between
morphology and other source properties {e.g., near-IR, far-IR colors,
stellar spectral type, envelope mass}, and {2} the current samples are
strongly biased towards small PPNs, as inferred from their low
60-to-25 micron flux ratios [R{60/25}<1]. However, the prototype of objects with R{60/25}>1, the Frosty Leo Nebula, has a puzzlingly large
post- AGB age {almost 10^4 yr} and a fairly cool central star, very
different from the expectations of single-star stellar evolutionary
models. A proposed, but still speculative, hypothesis for such objects
is that the slow evolution of the central star is due to backflow of
material onto the mass-losing star, retarding its evolution towards
the PN phase. This hypothesis has significant consequences for both
stellar and nebular evolution. We therefore propose a survey of PPNs
with R{60/25}>1 which is heavily weighted towards the discovery of
such “stalled PPNs”. Supporting kinematic observations using long-slit
optical spectroscopy {with the Keck}, millimeter and radio
interferometric observations {with OVRO, VLA & VLBA} are being
undertaken. The results from this survey {together with our previous
work} will allow us to draw general conclusions about the complex
mass-outflow processes affecting late stellar evolution, and will
provide crucial input for theories of post-AGB stellar evolution. Our
survey will produce an archival legacy of long-standing value for
future studies of dying stars.

ACS/WFC 10496

Decelerating and Dustfree: Efficient Dark Energy Studies with
Supernovae and Clusters

We propose a novel HST approach to obtain a dramatically more useful
“dust free” Type Ia supernovae {SNe Ia} dataset than available with
the previous GOODS searches. Moreover, this approach provides a
strikingly more efficient search-and-follow-up that is primarily
pre-scheduled. The resulting dark energy measurements do not share the
major systematic uncertainty at these redshifts, that of the
extinction correction with a prior. By targeting massive galaxy
clusters at z > 1 we obtain a five-times higher efficiency in
detection of Type Ia supernovae in ellipticals, providing a
well-understood host galaxy environment. These same deep cluster
images then also yield fundamental calibrations required for future
weak lensing and Sunyaev-Zel’dovich measurements of dark energy, as
well as an entire program of cluster studies. The data will make
possible a factor of two improvement on supernova constraints on dark
energy time variation, and much larger improvement in systematic
uncertainty. They will provide both a cluster dataset and a SN Ia
dataset that will be a longstanding scientific resource.


The Gas Environment of Comet 9P/Tempel 1 During the Deep Impact

This program consists of a series of observations of periodic comet
9P/Tempel 1 in conjunction with NASA’s Deep Impact mission. This
mission is a spacecraft that will release a 360 kg impactor into the
nucleus of the comet on July 4, 2005. Our primary objective is to
study the generation and evolution of the gaseous coma resulting from
this impact. A secondary objective was to obtain wide-band images of
the visual outburst resulting from the impact. The spectroscopic data
can be obtained using two of the prism modes of the ACS’s HRC/PR200L
and SBC/PR130L.


ACS Coronagraphic Imaging of Herbig Ae/Be Stars

We can indirectly learn about the planet formation process by studying
proto-planetary dust disks. In this proposed observational program, we
focus on Herbig Ae/Be stars which are pre-main sequence intermediate
mass stars {2-10 solar masses} thought to be immediate precursors to
the Vega-excess stars like Beta Pictoris. We propose to take ACS
coronagraphic images in the F606W filter of 6 Herbig Ae/Be stars, all
of which have well constrained spectral energy distributions and are
nearby {<200pc}, suggesting possible disk sizes of 3" or larger in radius. We use the recent ACS coronagraph image of Herbig Ae/Be star, HD 141569, which shows a spectacular circumstellar disk, as a template for observing strategy and exposure time estimates. Our observing program involves contemporaneous comparison stars that will be used to subtract the point spread function. These images will constrain the size and possibly, the morphology of the circumstellar dust that may have disk, envelope or disk+envelope geometries. We will analyze these images quantitatively using 2-Dust, an axisymmetric radiative transfer dust code, to derive basic physical parameters of the dusty circumstellar matter such as mass, size, geometry, inclination angle and grain properties.

NIC2 10418

Morphologies and Color Gradients of Galaxies with the Oldest Stellar
Populations at High Redshifts

We have isolated a sample of 9 luminous {~2L*} galaxies with the very
oldest stellar populations at their respective redshifts. The galaxies
have been found in radio-source fields chosen to be at the key
redshifts z~1.5 and z~2.5, which allow the cleanest separation of old
stellar populations from highly reddened starbursts with colors
derived from standard filter combinations. Ground-based observations
in excellent seeing and with adaptive optics of 3 of these galaxies
indicate that all 3 are dominated by well relaxed disks of old stars,
suggesting that the first large stellar systems to form in the
universe were disks in which star formation proceeded extremely
rapidly and efficiently. In order to test this conjecture, we are
requesting NICMOS2 exposures of our sample to obtain high S/N imaging
in the F160W filter to determine detailed morphologies of the old
stellar population, coupled with either NICMOS2 F110W or ACS F814W
exposures {depending on redshift} to determine color gradients and/or
other systematic color variations that might provide clues to
formation processes.

ACS/WFC 10417

Host Galaxies and Environments of the Most Massive Black Holes in the
Early Universe

The existence of luminous quasars with billion solar mass black holes
at high redshift poses important questions about the relation between
the formation and evolution of the earliest galaxies and quasars in
the universe: how could these high-redshift black holes accrete matter
so quickly and so efficiently? Is the quasar phase connected to the
formation of galactic bulge in the earliest epoch? Was the black
hole-bulge mass relation observed locally already established at
high-redshift? We will use ACS/WFC to obtain rest-frame UV imaging of
five quasars at z~4 with the highest estimated black hole mass, of the
order 10 billion solar masses. The goal of the HST observation is to
directly detect their host galaxies and to probe their galactic
environment. These quasars are likely among the most massive and
luminous host galaxies at high-redshift, providing ideal targets for
direct detection. The rest-frame UV properties measured with HST will
be combined with rest-frame optical, mid to far-IR oberservations of
these quasars to measure the star-formation rate, to estimate the
stellar age and mass of the host galaxy, and to probe the
quasar/starburst connection, quasar triggering mechanism and relation
between black hole and bulge formation at the highest possible
redshift. One of the targets, PSS 2322+1944 {z=4.17}, is a
gravitational lensed quasar with a nearly complete Einstein ring in CO
emission, providing a unique opportunity to study the small scale
structure of a high-redshift quasar host galaxy.


Accurate and Robust Calibration of the Extragalactic Distance Scale
with the Maser Galaxy NGC4258 II

The extragalactic distance scale {EDS} is defined by a comparison of
Cepheid Period- Luminosity {PL} relations for nearby galaxies and the
LMC, whose uncertain distance is thereby the SOLE anchor. Studies of
masers orbiting the central black hole in NGC4258 have provided the
most accurate extragalactic distance ever {7.2+/-0.5 Mpc}, and new
radio data and analysis techniques will reduce the uncertainty to < 3.5% {0.07 mag} by 2005. Since this distance is well determined and based on geometric arguments, NGC4258 can provide a much needed new anchor for the EDS. Ultimately, the combination of an independent measurement of H0 and measurements of CMB fluctuations {e.g., WMAP} can be used to directly constrain cosmological parameters including the equation of state of dark energy. In our Cycle 12 proposal, we defined a program spanning two cycles. The Cycle 12 portion was accepted. We have acquired WFC images and are constructing well sampled PL relations in 3 colors {BVI}. The purpose of the Cycle 13 observations is to address systematic sources of error and is crucial for the success of the entire program. To disentangle the effects of reddening and metallicity, and to characterize the effects of blending, we require 50 orbits to obtain H-band photometry {NICMOS/NIC2} and high resolution images {ACS/HRC}.


Deep imaging of newly discovered globular clusters in the outer halo
of M31

Globular clusters {GCs} are fossil relics with which we can
investigate the processes of galaxy formation and growth. We have
recently discovered a sample of GCs, as part of a very wide area CCD
survey of M31. These clusters span a range in projected galactocentric
distance of 20 – 80 kpc, more than double the radii of the previous
most remote known GC. Here we apply for deep ACS images of 13 GCs,
which will allow us to study their stellar populations, line-of-sight
distances and structural parameters. These will be used to: a}
Investigate the merger history of M31, through an examination of
variations in the RGB and HB morphologies, particularly to obtain
metallicities and check for the presence of any second parameter
effect in the HB. d} Determine, in conjuction with ground-based
spectroscopy, the dynamical mass of M31 at large radius, providing a
direct probe of the mass distribution of its dark halo.


ACS CCDs daily monitor – Cycle 13 – Part 2

This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in ACS CCD detectors. The files, biases and dark will be used to
create reference files for science calibration. This program will be
for the entire lifetime of ACS.


CCD Hot Pixel Annealing

Hot pixel annealing will continue to be performed once every 4 weeks.
The CCD TECs will be turned off and heaters will be activated to bring
the detector temperatures to about +20C. This state will be held for
approximately 12 hours, after which the heaters are turned off, the
TECs turned on, and the CCDs returned to normal operating condition.
To assess the effectiveness of the annealing, a bias and four dark
images will be taken before and after the annealing procedure for both
WFC and HRC. The HRC darks are taken in parallel with the WFC darks.
The charge transfer efficiency {CTE} of the ACS CCD detectors declines
as damage due to on-orbit radiation exposure accumulates. This
degradation has been closely monitored at regular intervals, because
it is likely to determine the useful lifetime of the CCDs. We will now
combine the annealling activity with the charge transfer efficiency
monitoring and also merge into the routine dark image collection. To
this end, the CTE monitoring exposures have been moved into this
proposal . All the data for this program is acquired using internal
targets {lamps} only, so all of the exposures should be taken during
Earth occultation time {but not during SAA passages}. This program
emulates the ACS pre-flight ground calibration and post-launch SMOV
testing {program 8948}, so that results from each epoch can be
directly compared. Extended Pixel Edge Response {EPER} and First Pixel
Response {FPR} data will be obtained over a range of signal levels for
both the Wide Field Channel {WFC}, and the High Resolution Channel


An ACS H-alpha Survey of the Carina Nebula

We propose an H-alpha ACS imaging survey covering 540 square
arcminutes of the Carina Nebula, including an unbiased survey of the
bright core, and several prominent dust pillars in the rich southern
region of the nebula. Carina provides an important link between
well-studied nearby H II regions like Orion, and more distant
mini-starbusts like 30 Doradus. CVZ orbits will allow extremely
efficient use of HST to map a large area of this complex and important
region — more than 95 percent of the proposed survey will be observed
by HST for the first time. This survey will provide a complete census
of microjets, proplyds, and silhouette disks with diameters as small
as 200 AU, enough to spatially resolve disks like those in Orion, and
will provide the first catalog of outflows {jets} from embedded
low-mass stars, thin filamentary shocks, and wind-wind collisions in
Carina. An accurate census of these phenomena is needed to
characterize the star formation activity and gas dynamics as a
function of position in the nebula, and to determine if models for
protoplanetary disk evaporation from Orion are applicable in more
extreme regions. Our previous ground-based optical and IR surveys have
already revealed dozens of candidates for this type of activity — but
this is just the tip of the iceberg. Our proposed HST/ACS survey
promises to be a bonanza for understanding ongoing low-mass star
formation influenced by extremely high-mass stars.

ACS/HRC/NIC3 10182

Towards a Comprehensive Understanding of Type Ia Supernovae: The
Necessity of UV Observations

Type Ia supernovae {SNe Ia} are very important to many diverse areas
of astrophysics, from the chemical evolution of galaxies to
observational cosmology which led to the discovery of dark energy and
the accelerating Universe. However, the utility of SNe Ia as
cosmological probes depends on the degree of our understanding of SN
Ia physics, and various systematic effects such as cosmic chemical
evolution. At present, the progenitors of SNe Ia and the exact
explosion mechanisms are still poorly understood, as are evolutionary
effects on SN Ia peak luminosities. Since early-time UV spectra and
light curves of nearby SNe Ia can directly address these questions, we
propose an approach consisting of two observational components: {1}
Detailed studies of two very bright, young, nearby SNe Ia with HST UV
spectroscopy at 13 epochs within the first 1.5 months after discovery;
and {2} studies of correlations with luminosity for five somewhat more
distant Hubble-flow SNe Ia, for which relative luminosities can be
determined with precision, using 8 epochs of HST UV spectroscopy
and/or broad-band imaging. The HST data, along with extensive
ground-based optical to near-IR observations, will be analyzed with
state-of-the-art models to probe SN Ia explosion physics and constrain
the nature of the progenitors. The results will form the basis for the
next phase of precision cosmology measurements using SNe Ia, allowing
us to more fully capitalize on the substantial past {and future}
investments of time made with HST in observations of high-redshift SNe

NIC2 10173

Infrared Snapshots of 3CR Radio Galaxies

Radio galaxies are an important class of extragalactic objects: they
are one of the most energetic astrophysical phenomena and they provide
an exceptional probe of the evolving Universe, lying typically in high
density regions but well-represented across a wide redshift range. In
earlier Cycles we carried out extensive HST observations of the 3CR
sources in order to acquire a complete and quantitative inventory of
the structure, contents and evolution of these important objects.
Amongst the results, we discovered new optical jets, dust lanes,
face-on disks with optical jets, and revealed point-like nuclei whose
properties support FR-I/BL Lac unified schemes. Here, we propose to
obtain NICMOS infrared images of 3CR sources with z<0.3 as a major enhancement to an already superb dataset. We aim to deshroud dusty galaxies, study the underlying host galaxy free from the distorting effects of dust, locate hidden regions of star formation and establish the physical characteristics of the dust itself. We will measure frequency and spectral energy distributions of point-like nuclei, expected to be stronger and more prevalent in the IR, seek spectral turnovers in known synchrotron jets and find new jets. We will strongly test unified AGN schemes and merge these data with existing X-ray to radio observations. The resulting database will be an incredibly valuable resource to the astronomical community for years to come.

ACS/WFC 10154

Morphology of z ~ 7-10 galaxies viewed through gravitational

The aim of these observations is to obtain deep z/ACS and H/NICMOS
images in the core of two lensing clusters, A1835 and AC114, where a
few z ~ 7-10 galaxy candidates have been selected from our ultra-deep
JHK imaging program with Isaac/VLT. Spectroscopic observations have
allowed to confirm 2 of these candidates thanks to the detection of
faint emission lines identified as Lyman alpha at z=7.2 and 10. Our
HST project is focused on two main goals: {1} the morphological
confirmation of galaxy candidates lying near critical lines, and {2}
the determination of the physical scales involved in star-forming
regions at z ~ 7-10. These goals should have important implications on
our present knowledge of the galaxy formation process in the early

NIC1 10143

Ultracool companions to the nearest L dwarfs

We propose to conduct the most sensitive survey to date for low mass
companions to nearby L dwarfs. We will use NICMOS to image targets
drawn from a volume-complete sample of 70 L dwarfs within 20 parsecs.
The combination of infrared imaging and proximity will allow us to
search for T dwarf companions at separations as small as 1.6 AU. This
is crucial, since no ultracool binaries are currently known with
separations exceeding 15 AU. Only 10 dwarfs in this sample have
previous HST observations primarily at optical wavelengths. With the
increased sensitivity of our survey, we will provide the most
stringent test to date of brown dwarf models which envisage formation
as ejected stellar embryos. In addition, our observations will be
capable of detecting binaries with mass ratios as low as 0.3, and will
therefore also test the apparent preference for equal-mass ultracool
binaries. Finally, our observations offer the best prospect to date of
detecting companions significantly cooler than the coolest t dwarf
currently known.


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


#9890:  GSACQ(2,1,2) fine lock backup, scan step limit exceeded on FGS
2 @196/2133z GSACQ(2,1,2) at 196/21:29:09 ended in fine lock backup on
FGS 2 due to scan step limit exceeded on FGS 2 at 21:32:42.

#9891:  Gsacq(1,2,2)fine lock backup (1,0,1) scan step limit exceeded
on FGS 2 @198/1240z GSacq(1,2,2)@ 198/12:39:41 ended in fine lock
backup on FGS 1 due to scan step limit exceeded on FGS 2 at 12:43:04.

#9892:  Gsacq(3,2,2)fine lock backup (2,0,2) scan step limit exceeded
on FGS 3 @198/1423z GSacq(3,2,2)@ 198/14:18:17 ended in fine lock
backup on FGS 2 due to scan step limit exceeded on FGS 3 at 14:22:55.

#9893:  GSacq(1,2,1) Resulted in Fine Lock Backup (1,0,1) @199/02:50z
GSacq(1,2,1) scheduled at 199/02:49:37 resulted in fine lock backup
(1,0,1) due to scan step limit exceeded on fgs 2.

#17470-0:  FHST Maps DOY 197 @197/0910z


              SCHEDULED     SUCCESSFUL
FGS Gsacq        40           40
FGS Reacq        17           17
FHST Update      37           37


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