HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science
 
DAILY REPORT #5147
 
PERIOD COVERED: 5am July 27 - 5am July 28, 2010 (DOY 208/09:00z-209/09:00z)
 
FLIGHT OPERATIONS SUMMARY:
 
Significant Spacecraft Anomalies: (The following are preliminary reports
of potential non-nominal performance that will be investigated.)
 
HSTARS:
12342 - REAcq(2,1,1) at 209/06:54:02z resulted in a "scan step limit exceeded"
           error in FGS2 on the first attempt. The REAcq went on to succeed on the
           second attempt.      
 
           Observations possibly affected WFC 73-75, Proposal ID#11700; COS 45,
           Proposal ID#11598
 
 
COMPLETED OPS REQUEST: (None)
 
COMPLETED OPS NOTES: (None)
 
                     SCHEDULED SUCCESSFUL
FGS GSAcq               7              7    
FGS REAcq               8              8
OBAD with Maneuver 4              4
 
SIGNIFICANT EVENTS: (None)
 
 
OBSERVATIONS SCHEDULED:
 
COS/NUV/FUV 11598
 
How Galaxies Acquire their Gas: A Map of Multiphase Accretion and
Feedback in Gaseous Galaxy Halos
 
We propose to address two of the biggest open questions in galaxy
formation - how galaxies acquire their gas and how they return it to the
IGM - with a concentrated COS survey of diffuse multiphase gas in the
halos of SDSS galaxies at z = 0.15 - 0.35. Our chief science goal is to
establish a basic set of observational facts about the physical state,
metallicity, and kinematics of halo gas, including the sky covering
fraction of hot and cold material, the metallicity of infall and
outflow, and correlations with galaxy stellar mass, type, and color -
all as a function of impact parameter from 10 - 150 kpc. Theory suggests
that the bimodality of galaxy colors, the shape of the luminosity
function, and the mass-metallicity relation are all influenced at a
fundamental level by accretion and feedback, yet these gas processes are
poorly understood and cannot be predicted robustly from first
principles. We lack even a basic observational assessment of the
multiphase gaseous content of galaxy halos on 100 kpc scales, and we do
not know how these processes vary with galaxy properties. This ignorance
is presently one of the key impediments to understanding galaxy
formation in general. We propose to use the high-resolution gratings
G130M and G160M on the Cosmic Origins Spectrograph to obtain sensitive
column density measurements of a comprehensive suite of multiphase ions
in the spectra of 43 z < 1 QSOs lying behind 43 galaxies selected from
the Sloan Digital Sky Survey. In aggregate, these sightlines will
constitute a statistically sound map of the physical state and
metallicity of gaseous halos, and subsets of the data with cuts on
galaxy mass, color, and SFR will seek out predicted variations of gas
properties with galaxy properties. Our interpretation of these data will
be aided by state-of-the-art hydrodynamic simulations of accretion and
feedback, in turn providing information to refine and test such models.
We will also use Keck, MMT, and Magellan (as needed) to obtain optical
spectra of the QSOs to measure cold gas with Mg II, and optical spectra
of the galaxies to measure SFRs and to look for outflows. In addition to
our other science goals, these observations will help place the Milky
Way's population of multiphase, accreting High Velocity Clouds (HVCs)
into a global context by identifying analogous structures around other
galaxies. Our program is designed to make optimal use of the unique
capabilities of COS to address our science goals and also generate a
rich dataset of other absorption-line systems.
 
ACS/WFC3 11670
 
The Host Environments of Type Ia Supernovae in the SDSS Survey
 
The Sloan Digital Sky Survey Supernova Survey has discovered nearly 500
type Ia supernovae and created a large, unique, and uniform sample of
these cosmological tools. As part of a comprehensive study of the
supernova hosts, we propose to obtain Hubble ACS images of a large
fraction of these galaxies. Integrated colors and spectra will be
measured from the ground, but we require high-resolution HST imaging to
provide accurate morphologies and color information at the site of the
explosion. This information is essential in determining the systematic
effects of population age on type Ia supernova luminosities and
improving their reliability in measuring dark energy. Recent studies
suggest two populations of type Ia supernovae: a class that explodes
promptly after star-formation and one that is delayed by billions of
years. Measuring the star-formation rate at the site of the supernova
from colors in the HST images may be the best way to differentiate
between these classes.
 
COS/NUV/S/C/FUV 12082
 
Extending COS/G130M Coverage Down to 905A With Two New Central
Wavelengths.
 
These exploratory observations will provide sensitivity, wavelength
range, and resolution measurements for two new COS FUV G130M central
wavelength settings. These new settings will extend COS/G130M coverage
down to 905? in two new bandpasses; 1021-1171? (BLUE) and 905-1055?
(Ultra-BLUE). The modes are chosen to provide continuous coverage from
905? to the existing coverage in the G130M/1291? setting with
approximately 30? of overlap in each mode for cross-calibration
purposes. No focus adjustments will be made for these settings, as this
is deemed an unnecessary risk to COS.
 
These new modes have the potential to provide greater than FUSE
sensitivity at moderate (3, 000-5, 000) resolution.
 
Three WD targets are defined;
 
1) GD50 (GSC-04717-00588; a well observed standard WD) 2) WD0320-539
(GSC-08493-00891, one of the targets used in exploring the G140L
sensitivity), 3) REJ0503-289 (WD-5001-289 = GSC-04717-00588, a hot EUVE
bright WD)
 
But only target 2) is used at this time.
 
In the observations section, G130M/1291A is a placeholder for the BLUE
and Super-BLUE settings.
 
STIS/CC 11845
 
CCD Dark Monitor Part 2
 
Monitor the darks for the STIS CCD.
 
STIS/CC 11847
 
CCD Bias Monitor-Part 2
 
Monitor the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1,
and 1x1 at gain = 4, to build up high-S/N superbiases and track the
evolution of hot columns.
 
WFC3/IR 11933
 
IR Rate Dependent Non-linearity
 
The NICMOS non-linearity known as the Bohlin Effect has revealed that
the apparent flux of a source observed by NICMOS is not a simple, linear
function of count rate. The effect has been characterized by
observations of star clusters observed with and without additional
background from the internal lamps. As WFC3 lacks internal lamps which
can be used to add background, we will rely on the bright Earth limb to
provide additional background. We will observe a star cluster, 47 Tuc,
repeatedly throughout a complete HST orbit which has been chosen to put
the closest approach to the bright Earth to be 13.5 degrees, the closest
approach allowed while retaining FGS guiding. Another set will be done
with the BE limb closest approach of 15.5 degrees. The observations will
be done with the two most commonly used filters, F110W and F160W and at
two different bright Earth limb angles to test the linearity of the
non-linearity. We have also included an orbit on NGC 1850 to repeat the
NICMOS field for which the linearity of the field has been established.
 
WFC3/IR/S/C 11929
 
IR Dark Current Monitor
 
Analyses of ground test data showed that dark current signals are more
reliably removed from science data using darks taken with the same
exposure sequences as the science data, than with a single dark current
image scaled by desired exposure time. Therefore, dark current images
must be collected using all sample sequences that will be used in
science observations. These observations will be used to monitor changes
in the dark current of the WFC3-IR channel on a day-to-day basis, and to
build calibration dark current ramps for each of the sample sequences to
be used by Gos in Cycle 17. For each sample sequence/array size
combination, a median ramp will be created and delivered to the
calibration database system (CDBS).
 
WFC3/UV/ACS/WFC/IR 12055
 
A Panchromatic Hubble Andromeda Treasury - I
 
We propose to image the north east quadrant of M31 to deep limits in the
UV, optical, and near-IR. HST imaging should resolve the galaxy into
more than 100 million stars, all with common distances and foreground
extinctions. UV through NIR stellar photometry (F275W, F336W with
WFC3/UVIS, F475W and F814W with ACS/WFC, and F110W and F160W with
WFC3/NIR) will provide effective temperatures for a wide range of
spectral types, while simultaneously mapping M31's extinction. Our
central science drivers are to: understand high-mass variations in the
stellar IMF as a function of SFR intensity and metallicity; capture the
spatially-resolved star formation history of M31; study a vast sample of
stellar clusters with a range of ages and metallicities. These are
central to understanding stellar evolution and clustered star formation;
constraining ISM energetics; and understanding the counterparts and
environments of transient objects (novae, SNe, variable stars, x-ray
sources, etc.). As its legacy, this survey adds M31 to the Milky Way and
Magellanic Clouds as a fundamental calibrator of stellar evolution and
star-formation processes for understanding the stellar populations of
distant galaxies. Effective exposure times are 977s in F275W, 1368s in
F336W, 4040s in F475W, 4042s in F814W, 699s in F110W, and 1796s in
F160W, including short exposures to avoid saturation of bright sources.
These depths will produce photon-limited images in the UV. Images will
be crowding-limited in the optical and NIR, but will reach below the red
clump at all radii. The images will reach the Nyquist sampling limit in
F160W, F475W, and F814W.
 
WFC3/UVIS 11905
 
WFC3 UVIS CCD Daily Monitor
 
The behavior of the WFC3 UVIS CCD will be monitored daily with a set of
full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K
subarray biases are acquired at less frequent intervals throughout the
cycle to support subarray science observations. The internals from this
proposal, along with those from the anneal procedure (Proposal 11909),
will be used to generate the necessary superbias and superdark reference
files for the calibration pipeline (CDBS).
 
WFC3/UVIS/IR 11700
 
Bright Galaxies at z>7.5 with a WFC3 Pure Parallel Survey
 
The epoch of reionization represents a special moment in the history of
the Universe as it is during this era that the first galaxies and star
clusters are formed. Reionization also profoundly affects the
environment where subsequent generations of galaxies evolve. Our
overarching goal is to test the hypothesis that galaxies are responsible
for reionizing neutral hydrogen. To do so we propose to carry out a pure
parallel WFC3 survey to constrain the bright end of the redshift z>7.5
galaxy luminosity function on a total area of 176 arcmin^2 of sky.
Extrapolating the evolution of the luminosity function from z~6, we
expect to detect about 20 Lyman Break Galaxies brighter than M_* at z~8
significantly improving the current sample of only a few galaxies known
at these redshifts. Finding significantly fewer objects than predicted
on the basis of extrapolation from z=6 would set strong limits to the
brightness of M_*, highlighting a fast evolution of the luminosity
function with the possible implication that galaxies alone cannot
reionize the Universe. Our observations will find the best candidates
for spectroscopic confirmation, that is bright z>7.5 objects, which
would be missed by small area deeper surveys. The random pointing nature
of the program is ideal to beat cosmic variance, especially severe for
luminous massive galaxies, which are strongly clustered. In fact our
survey geometry of 38 independent fields will constrain the luminosity
function like a contiguous single field survey with two times more area
at the same depth. Lyman Break Galaxies at z>7.5 down to m_AB=26.85 (5
sigma) in F125W will be selected as F098M dropouts, using three to five
orbits visits that include a total of four filters (F606W, F098M, F125W,
F160W) optimized to remove low-redshift interlopers and cool stars. Our
data will be highly complementary to a deep field search for high- z
galaxies aimed at probing the faint end of the luminosity function,
allowing us to disentangle the degeneracy between faint end slope and
M_* in a Schechter function fit of the luminosity function. We waive
proprietary rights for the data. In addition, we commit to release the
coordinates and properties of our z>7.5 candidates within one month from
the acquisition of each field.