NASA Hubble Space Telescope Daily Report # 3373
HUBBLE SPACE TELESCOPE
DAILY REPORT # 3373
PERIOD COVERED: DOY 149
OBSERVATIONS SCHEDULED
STIS/CCD/MA1 9184
A Survey for Missing Baryons in Highly Ionized Intergalactic Gas at Low
Redshift.
The Space Telescope Imaging Spectrograph (CCD and MA1) was used to
observe six
additional low-z QSOs with the STIS FUV E140M echelle mode {7 km s^-1
resolution}. Combined with archival data, this will increase the sample
redshift
path by a factor of ~7 compared to the published data. With the echelle
data, we
will {1} measure the number of O VI absorbers per unit redshift {dN/dz}
and
their minimum cosmological mass density with a limiting equivalent width
of
W_Lambda ~50 mAngstrom , {2} examine whether the O VI absorption arises
in
photoionized, collisionally ionized, or multiphase gas, and {3} study the
dependence of the O VI system properties on environment. In addition to
testing
this prediction regarding the location of the missing baryons, the data
will
have applications to many other topics such as low-z LyAlpha absorbers
and the
physical properties and abundances of gas in the Milky Way halo.
GTO/ACS 9291
Formation of High Redshift Radio Galaxies
This programme uses ACS observations of high redshift radio galaxies
{HzRGs} to
investigate massive galaxy and cluster formation in the early Universe.
By
carrying out deep observations of a few z > 3.8 targets the following
four
questions will be studied: {1} Are HzRGs massive central-cluster galaxies
formed
through hierarchical assembly of Lyman break galaxies? Detailed
brightness
distributions colors and morphologies of HzRG clumps will be measured and
compared with those of Lyman break galaxies. {2} Are HzRGs located in
dense
{proto-} clusters and if so what are the properties of the associated
large-scale structures? Lyman alpha excesses, colors and morphologies of
objects
in field will be used to search for companion galaxies of HzRGs. {3} What
are
the origin and fate of giant gas halos associated with HzRGs and what
role do
they play in the formation of massive galaxies? The morphologies and
locations
of Ly-alpha clumps will be compared with those of continuum clumps. {4}
Is
nuclear activity a source of star formation in the early Universe? The
properties of continuum and Ly-alpha clumps along will be compared in
relation
to the radio jet.
FGS 9329
The Masses and Luminosities of Population II Stars
Very little is currently known concerning the mass-luminosity relation
{MLR} of
Population II stars. However, with the advent of the Hipparcos Catalogue,
improved distances to many spectroscopic binaries known to be Pop II
systems are
now available. After surveying the literature and making reasonable
estimates of
the secondary masses, we find 13 systems whose minimum separation should
be
larger than the resolution limit of FGS1. Because of the expected
magnitude
differences and separations, it is not possible to resolve the systems
from the
ground. We therefore propose FGS observations of the sample. In
combination
with
the known spectroscopic orbits and Hipparcos distances, these
observations will
yield up to 26 precise stellar mass determinations of metal-poor stars,
if all
systems are resolved and the relative orbits are determined. A
combination of
FGS data and ground-based observations will lead to component
luminosities and
effective temperatures. This program will allow for a significantly
better
understanding of the Pop II main sequence, which in turn will lead to
better
ages and distances of the galactic globular clusters, and a Pop II MLR
will be
constructed for the first time.
ACS 9400
ARE THERE YOUNG GALAXIES IN THE LOCAL UNIVERSE: THE AGE OF THE BLUE
COMPACT
DWARF GALAXY I ZW 18
The question of whether there exists young galaxies in the local universe
is
important for cosmology. Cold Dark matter models predict that low-mass
galaxies
could still be forming at the present epoch. In the hierarchical model of
galaxy
formation, large galaxies result from the merging of smaller structures.
These
primordial building-block galaxies are too faint and small to be studied
at
high
redshifts, while we stand a much better chance of understanding them if
we can
find some local examples. One of the best candidates for being a young
nearby
galaxy forming stars for the first time at the present epoch, is the blue
compact dwarf {BCD} galaxy I Zw 18 because of its extremely low heavy
element
content {2% that of the Sun}. We propose to obtain deep $V$ and $I$ ACS
images
of I Zw 18. Our goal is to detect or put limits on the red giant branch
{RGB}
stellar population in this galaxy. If RGB stars are not detected, then we
can
set an upper limit for the age of I Zw 18 to be less than 1 Gyr. If they
are
detected, I Zw 18 is not young, and the RGB tip can be used to derive its
distance and set limits on the metallicity of the pregalactic gas.
ACS/WFC 9419
The Complete IMF of a Massive Young Cluster
We propose to use the large improvement in sensitivity and wide-field
resolution
provided by ACS to obtain for the first time the complete ~ 0.1 M_Sun to
~ 100
M_Sun IMF of a single massive young cluster. We will obtain BVI + nebular
deep
{V ~ 27} WFC photometry of six cluster and one background pointings and
we will
use the auto-parallel capacity of ACS to simultaneously acquire deep
NUV+U+V
photometry of selected regions in the cluster. Special care has been
taken to
treat all the complications which arise in the reduction of data for the
purpose
of calculating the IMF of a young cluster. We have chosen as our object
of
study
N11 in the LMC because it arguably provides the best combination of
stellar
mass
range {> 40 O stars, with several O3 stars}, spatial resolution {1 WFC
pixel =
0.0125 pc}, low extinction {E{B-V} ~ 0.1}, crowding, background
confusion, and
nebular contamination in comparison to other Galactic and Local Group
clusters.
It also has the advantage of having two separate regions, one which has
already
stopped forming stars and another one which is still forming them, thus
allowing
us to search for differences in the IMF between those two cases. The ACS
data
will be complemented with IR ground-based observations obtained using
Gemini
South, for which we already have been awarded time.
ACS 9454
The Nature of the UV Continuum in LINERs: A Variability Test
LINERs may be the most common AGNs, and the signposts of accretion onto
the
massive black holes present in most galaxies. However, the LINER spectrum
is the
result of UV excitation, and, in at least some LINERs, a nuclear cluster
of hot
stars, rather than an AGN, dominates the energetics in the UV. Thus, it
is
still
unknown if the UV continuum, or the optical emission lines it excites,
have
anything to do with an AGN. The demographics and accretion physics of
low-luminosity AGNs hinge on this question. We propose to search for
variability
in a sample of 17 LINERs with compact UV nuclei. Variability can reveal
an AGN
component in the UV continuum, even when its light is not dominant. We
will
test
systematically the handful of non-definitive reports of UV variability,
and
potentially quantify the AGN contribution to the UV emission. Variability
in all
or most objects will be strong evidence that LINERs mark dormant AGNs in
most
galaxies. Alternatively, a general null detection of variability will
suggest
that, even in LINERs with additional AGN signatures, the UV continuum is
stellar
in origin. Contemporaneous monitoring with the VLA/VLBA of 11 objects
which
have
radio cores {five of which we already know are radio-variable} will
reveal the
relations between UV and radio variations. The UV-variable objects will
be
targeted for future, better-sampled, monitoring.
ACS 9468
ACS Grism Parallel Survey of Emission- line Galaxies at Redshift z pl 7
We propose an ACS grism parallel survey to search for emission-line
galaxies
toward 50 random lines of sight over the redshift interval 0 < z pl 7. We
request ACS parallel observations of duration more than one orbit at high
galactic latitude to identify ~ 300 HAlpha emission-line galaxies at
0.2 pl
z pl
0.5, ~ 720 O IILambda3727 emission-line galaxies at 0.3 pl z pl 1.68, and
pg
1000 Ly-alpha emission-line galaxies at 3 pl z pl 7 with total emission
line
flux f pg 2* 10^-17 ergs s^-1 cm^-2 over 578 arcmin^2. We will obtain
direct
images with the F814W and F606W filters and dispersed images with the
WFC/G800L
grism at each position. The direct images will serve to provide a zeroth
order
model both for wavelength calibration of the extracted 1D spectra and for
determining extraction apertures of the corresponding dispersed images.
The
primary scientific objectives are as follows: {1} We will establish a
uniform
sample of HAlpha and O II emission-line galaxies at z<1.7 in order to
obtain
accurate measurements of co-moving star formation rate density versus
redshift
over this redshift range. {2} We will study the spatial and statistical
distribution of star formation rate intensity in individual galaxies
using the
spatially resolved emission-line morphology in the grism images. And {3}
we
will
study high-redshift universe using Ly-alpha emitting galaxies identified
at z
pl 7 in the survey. The data will be available to the community
immediately as
they are obtained.
ACS 9480
Cosmic Shear With ACS Pure Parallels
Small distortions in the shapes of background galaxies by foreground mass
provide a powerful method of directly measuring the amount and
distribution of
dark matter. Several groups have recently detected this weak lensing by
large-scale structure, also called cosmic shear. The high resolution and
sensitivity of HST/ACS provide a unique opportunity to measure cosmic
shear
accurately on small scales. Using 260 parallel orbits in Sloan textiti
{F775W}
we will measure for the first time: beginlistosetlength sep0cm
setlengthemsep0cm
setlength opsep0cm em the cosmic shear variance on scales <0.7 arcmin, em
the
skewness of the shear distribution, and em the magnification effect.
endlist Our
measurements will determine the amplitude of the mass power spectrum
sigma_8Omega_m^0.5, with signal-to-noise {s/n} ~ 20, and the mass density
Omega_m with s/n=4. They will be done at small angular scales where
non-linear
effects dominate the power spectrum, providing a test of the
gravitational
instability paradigm for structure formation. Measurements on these
scales are
not possible from the ground, because of the systematic effects induced
by PSF
smearing from seeing. Having many independent lines of sight reduces the
uncertainty due to cosmic variance, making parallel observations ideal.
NICMOS 9484
The NICMOS Parallel Observing Program
We propose to manage the default set of pure parallels with NICMOS. Our
experience with both our GO NICMOS parallel program and the public
parallel
NICMOS programs in cycle 7 prepared us to make optimal use of the
parallel
opportunities. The NICMOS G141 grism remains the most powerful survey
tool for
HAlpha emission-line galaxies at cosmologically interesting redshifts. It
is
particularly well suited to addressing two key uncertainties regarding
the
global history of star formation: the peak rate of star formation in the
relatively unexplored but critical 1<= z <= 2 epoch, and the amount of
star
formation missing from UV continuum-based estimates due to high
extinction. Our
proposed deep G141 exposures will increase the sample of known HAlpha
emission-
line objects at z ~ 1.3 by roughly an order of magnitude. We will also
obtain a
mix of F110W and F160W images along random sight-lines to examine the
space
density and morphologies of the reddest galaxies. The nature of the
extremely
red galaxies remains unclear and our program of imaging and grism
spectroscopy
provides unique information
regarding both the incidence of obscured star bursts and the build up of
stellar
mass at intermediate redshifts. In addition to carrying out the parallel
program
we will populate a public database with calibrated spectra and images,
and
provide limited ground- based optical and near-IR data for the deepest
parallel
fields.
WFPC2 9595
WFPC2 CYCLE 11 SUPPLEMENTAL DARKS pt3/3
This dark calibration program obtains 3 dark frames every day to provide
data
for monitoring and characterizing the evolution of hot pixels.
STIS 9606
CCD Dark Monitor-Part 2
Monitor the darks for the STIS CCD.
STIS 9608
CCD Bias Monitor – Part 2
Monitor the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1,
and 1×1
at gain = 4, to build up high-S/N superbiases and track the evolution of
hot
columns.
STIS 9633
STIS parallel archive proposal – Nearby Galaxies – Imaging and
Spectroscopy
Using parallel opportunities with STIS which were not allocated by the
TAC, we
propose to obtain deep STIS imagery with both the Clear {50CCD} and
Long-Pass
{F28X50LP} filters in order to make color-magnitude diagrams and
luminosity
functions for nearby galaxies. For local group galaxies, we also include
G750L
slitless spectroscopy to search for e.g., Carbon stars, late M giants and
S-type
stars. This survey will be useful to study the star formation histories,
chemical evolution, and distances to these galaxies. These data will be
placed
immediately into the Hubble Data Archive.
ACS 9658
ACS Earth Flats
This program will obtain sequences of flat field images by observing the
bright
Earth. Several UV filters from the interim calibration program {9564}
require
additional exposures to obtain the required illumination. A few UV
filters from
this program will be repeated to monitor for changes in the flat fields
and to
verify the interim results. Since no streaks are observed in the UV, the
wavelength coverage is extended to longer wavelengths in order to explore
the
severity of streaks in the flats from clouds in the FOV. We have added
exposures
for the HRC in the visible filters to verify the results derived from the
L-flat
campaign and to explore the severity of streaks. We have also added
exposures on
WFC using the minimum exposure time and using filters which will not
saturate
the brightest WFC pixel by more than 10 times the full well.
ACS 9674
CCD Daily Monitor
This program consists of basic tests to monitor, the read noise, the
development
of hot pixels and test for any source of noise in ACS CCD detectors. This
programme will be executed once a day for the entire lifetime of ACS.
STIS 9708
STIS Pure Parallel Imaging Program: Cycle 11
This is the default archival pure parallel program for STIS during cycle
11.
WFPC2 9709
POMS Test Proposal: WFII parallel archive proposal
This is the generic target version of the WFPC2 Archival Pure Parallel
program.
The program will be used to take parallel images of random areas of the
sky,
following the recommendations of the 2002 Parallels Working Group.
WFPC2 9710
POMS Test Proposal: WFII backup parallel archive proposal
This is a POMS test proposal designed to simulate scientific plans.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports
of
potential non-nominal performance that will be investigated.)
COMPLETED OPS REQs:
16979-0 PN format for MSS and FHST high rate data @ 149/18:50z
OPS NOTES EXECUTED: NONE
SCHEDULED SUCCESSFUL FAILURE TIMES FGS GSacq 07 07 FGS REacq 10 10 FHST Update 15 15 LOSS of LOCK
SIGNIFICANT EVENTS:
Successfully completed FSW 2.3c RAM installation and back out and EEPROM
installation and MACRO validation testing 148/10:05Z – 149/00:27Z and
149/09:50Z – 150/00:16Z. All test objectives were met.
HST "C" String Aft Flight Deck Internal Command Test scheduled 150/11:00Z
–
21:00Z
with GDOC, SOC, HITT, and CCS using CCS "B" String with CCS Release
4.0.2.2
and PRD S07102. The purpose of this testing is to dry run Aft Flight
Deck
commands to validate CCS verifiers.
