Status Report

NASA Hubble Space Telescope Daily Report #3908

By SpaceRef Editor
July 25, 2005
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science


PERIOD COVERED: UT July 22-24, 2005 (DOY 203-205)


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/HRC 10623

HST Optical Snapshot Survey of Intermediate Redshift Ultraluminous
Infrared Galaxies

Ultraluminous infrared galaxies {ULIGs} are commonly believed to be a
transitory phase in the evolution of disk galaxy mergers into QSOs.
However, a recently reported discrepancy between the morphological and
structural properties of z < 0.13 ULIGs and z = 0.12-0.25 QSOs with M{V} < -23.5 has cast doubt on their evolutionary connection. We propose an ACS snapshot survey of a sample of 39 ULIGs with z = 0.35-1.0. These galaxies are the best suited for comparison with luminous z=0.12-0.25 QSOs because {1} they are at larger lookback times than local ULIGs, and thus are likely representative of the systems that evolve into lower redshift luminous QSOs, {2} they have luminosities comparable to luminous QSOs and, {3} they are selected in a manner that biases the sample towards harboring imbedded AGN, and thus are the most likely precursors to optical QSOs. High resolution HST ACS images will allow a determination of galaxy morphology and reveal the presence of bright AGN. The 2-D profile of each galaxy will be modeled using GALFIT, with the AGN comprising one component of the fit where applicable to better characterize the underlying galaxy. Fundamental parameters {effective radius and surface brightness, and F814W-band magnitude} of the underlying galaxy will thus be measured and compared with the host galaxies of the luminous QSO sample. This imaging campaign will consume a modest amount of HST time, but will provide for the first time a statistically significant view of ULIGs at look-back times of 30-65% the age of the universe, and sufficient resolution and sensitivity to conduct a meaningful comparison with z=0.12-0.25 QSOs, as well as with local {z < 0.3} IRAS- detected and distant {z > 2} SCUBA-detected ULIGs.

WFPC2 10534

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, months, and
years. Uranus is rapidly approaching equinox in 2007, with another 4
degrees of latitude becoming visible every year. Recent HST
observations during this epoch {including 6818: Hammel, Lockwood, and
Rages; 8680: Hammel, Rages, Lockwood, and Marley; 8634: Rages, Hammel,
Lockwood, Marley, and McKay; and 10170: Rages, Hammel, Lockwood, and
Marley} have revealed strongly wavelength-dependent latitudinal
structure and the presence of numerous visible-wavelength cloud
features in the northern hemisphere. Long-term ground-based
observations {Lockwood and Thompson 1999} show seasonal brightness
changes whose origins are not well understood. Recent near-IR images
of Neptune obtained using adaptive optics on the Keck Telesccope
together with images from our Cycle 9 Snapshot program {8634} show a
general increase in activity at south temperate latitudes as well as
the possible development of another Great Dark Spot. 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


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 a
Snapshot program using the ACS/HRC that has a potential discovery
efficiency an order of magnitude higher than the HST observations that
have already discovered the majority of known transneptunian binaries.
By more than doubling the number of observed objects in dynamically
hot and cold subpopulations we will be able to answer, with
statistical significance, the question of whether these groups differ
in the abundance of binaries as a result 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.


Life Before the Fall: Morphological Evolution of Galaxies in Groups
Prior to Cluster Assembly at z=0.37

We propose to obtain a deep ACS/WFC mosaic of a protocluster comprised
of 4 distinct galaxy groups that are gravitationally bound to each
other at z=0.37. The galaxy groups have a total combined mass
comparable to the Coma cluster and already have twice as many
absorption line galaxies as the field. The SG1120 complex thus
provides an unprecedented opportunity for determining whether
“pre-processing” in the group environment is responsible for the bulk
of observed diffences between galaxies in nearby clusters and those in
the field. High resolution imaging with HST is needed to
morphologically classify the group members and measure their
structural parameters. By combining the early-type fraction and
morphology-density relation in SG1120 with results from our wide-field
spectroscopic survey, we will test whether spectral and morphological
transformation timescales are decoupled on group scales and isolate
the environmental mechanisms responsible for such evolution. We will
also measure the Fundamental Plane and M/L ratios of the early-type
members to constrain their formation epoch and how their stellar
populations have evolved. Observations of the multiple galaxy groups
in SG1120 provide a unique dataset to the community and will aid our
understanding of how galaxies evolve in the still poorly studied group

ACS/HRC 10498

Detecting the progenitors of core-collapse supernovae

Modern supernovae searches in the nearby Universe are discovering
large numbers of SNe which have massive star progenitors {Types II, Ib
and Ic}. The extensive HST image archives within ~20Mpc enables their
indvidual bright stellar content to be resolved. As massive, evolved
stars are the most luminous single objects in a galaxy, the progenitos
of core-collapse SNe should be directly detectable on pre-explosion
images. Two recent highlights of our ongoing HST programme are that we
have detected the first red supergiant progenitor of a normal type II
supernova and shown that SN1993J came from a binary system by
detecting the companion star at the position of the SN. We have
detected a further two progenitor stars of normal type II-P
supernovae, set mass limits on a further 7 and suggest that faint type
II supernovae are unlikely to come from the collapse of very massive
stars which form black holes. These discoveries are providing strong
constraints on theoretical models of pre- supernova evolution and the
origin of the supernova types. We request time to continue this
successful project and require ACS observations of future SNe which
are discovered in galaxies closer than 20Mpc which have pre-explosion
HST archive images available. This will allow the SNe to be precisely
positioned on the pre-explosion images. We have set a final goal for
this project of determining masses and types, or setting restrictive
mass-limits for 30 supernovae.

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.

ACS/WFC 10407

When did M31’s disk form?

The recent discovery of THIN disk globular clusters in M31 provides a
unique opportunity to determine the age of M31’s disk. The globular
cluster kinematics imply that the disk has not been significantly
heated or destroyed by a merger since they were formed. Thus the
cluster ages provide a lower limit to the disk age. This limit will
complement the high-redshift data, where few disk galaxies are
currently known because of their relatively low surface brighness. We
propose to obtain BV ACS imaging of seven disk clusters to below the
level of the horizontal branch {HB} to determine the distribution of
evolved stars in the color-magnitude diagram. The contribution of
evolved stars, particularly blue HB stars, is crucial to estimating
the age of the globular cluster from both color-magnitude diagrams and
the high S/N integrated spectra which we will obtain from the ground.


Unravelling NGC 3125-1: The Most Extreme Wolf-Rayet Star Cluster Known
in the Local Universe

Based on cycle 10 STIS UV spectroscopy, we have recently discovered a
star cluster, NGC 3125-1, which has the strongest known He II 1640
emission {of stellar origin} in the local universe. The number of
implied WR stars is more than an order of magnitude higher than for
any other well-studied giant HII region. Because strong He II 1640
emission has been discovered in the composite spectra of redshift 3
Lyman Break Galaxies, NGC 3125-1 potentially provides a unique
opportunity to study a nearby object with direct implications for the
stellar populations observed in the early universe. In order to
understand the origin of this anomalously strong WR feature, we
propose to obtain the first high resolution imaging of NGC 3125-1, at
wavelengths from the far ultraviolet through the near infrared. This
will allow us to simultaneously place it in the context of more
familiar objects, such as R136 in 30 Doradus, while also unravelling
the physics responsible for the observed UV spectral signature.


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.

NIC2 10176

Coronagraphic Survey for Giant Planets Around Nearby Young Stars

A systematic imaging search for extra-solar Jovian planets is now
possible thanks to recent progress in identifying “young stars near
Earth”. For most of the proposed young {<~ 30 Myrs} and nearby {<~ 60 pc} targets, we can detect a few Jupiter-mass planets as close as a few tens of AUs from the primary stars. This represents the first time that potential analogs of our solar system - that is planetary systems with giant planets having semi-major axes comparable to those of the four giant planets of the Solar System - come within the grasp of existing instrumentation. Our proposed targets have not been observed for planets with the Hubble Space Telescope previously. Considering the very successful earlier NICMOS observations of low mass brown dwarfs and planetary disks among members of the TW Hydrae Association, a fair fraction of our targets should also turn out to posses low mass brown dwarfs, giant planets, or dusty planetary disks because our targets are similar to {or even better than} the TW Hydrae stars in terms of youth and proximity to Earth. Should HST time be awarded and planetary mass candidates be found, proper motion follow-up of candidate planets will be done with ground-based AOs.


Mid-Ultraviolet Spectral Templates for Old Stellar Systems

We propose a three-year program to provide both observational and
theoretical mid- ultraviolet {2300A — 3100A} spectral templates for
interpreting the age and metallicity of globular clusters and
elliptical galaxies from spectra of their integrated light. The mid-UV
is the region most directly influenced by stellar age, and is observed
directly in optical and infrared studies of high-redshift quiescent
systems. The reliability of age and metallicity determinations remains
questionable until non-solar metallicities and abundance ratios are
considered, and stars spanning the color-magnitude diagram are
included, as we propose here. With archival HST STIS spectra we have
improved the list of mid-UV atomic line parameters, then calculated
spectra from first principles which match observed spectra of standard
stars up to one- fourth solar metallicity. We will extend both
observations and calculations to stars of solar metallicity and
beyond, and to those in short-lived stages hotter than the
main-sequence turnoff, stars not currently well-represented in
empirical libraries. The necessary line-list improvements will come
from new high-resolution mid-UV spectra of nine field stars. A key
application of the results of this program will be to the old systems
now being discovered as `Extremely Red Objects’ at high redshifts.
Reliable age-dating of these places constraints on the epoch when
large structures first formed in the universe.


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


#9899 – GSacq(2,1,2) resulted in fine lock backup (2,0,2) @
205/18:26:57z GSacq(2,1,2) scheduled at 205/18:26:57 resulted in
finelock backup during zoe. At AOS there were no flags. The Map at
18:34:31 showed vehicle axis errors 27.276, -6.146, -3.727.

#9900 – GSacq(1,2,2) results in finelock backup (1,0,1) scan step lmt
exc on FGS-2 @ 206/07:35z The GSacq(1,2,2) scheduled at 206/07:35:06 –
07:43:08 Z resulted in finelock backup (1,0,1) using FGS-1, due to
scan step limit exceeded on FGS-2 durng acquisition walkdown.



               SCHEDULED     SUCCESSFUL 
 FGS Gsacq        22             22 
 FGS Reacq        24             24 
 FHST Update      39             39 


SpaceRef staff editor.