HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science
DAILY REPORT #5148
PERIOD COVERED: 5am July 28 - 5am July 29, 2010 (DOY 209/09:00z-210/09:00z)
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports
of potential non-nominal performance that will be investigated.)
HSTARS: (None)
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSAcq 6 6
FGS REAcq 8 8
OBAD with Maneuver 3 3
SIGNIFICANT EVENTS: (None)
OBSERVATIONS SCHEDULED:
ACS/WFC 11996
CCD Daily Monitor (Part 3)
This program comprises basic tests for measuring the read noise and dark
current of the ACS WFC and for tracking the growth of hot pixels. The
recorded frames are used to create bias and dark reference images for
science data reduction and calibration. This program will be executed
four days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To
facilitate scheduling, this program is split into three proposals. This
proposal covers 308 orbits (19.25 weeks) from 21 June 2010 to 1 November
2010.
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.
COS/NUV/FUV 11728
The Impact of Starbursts on the Gaseous Halos of Galaxies
Perhaps the most important (yet uncertain) aspects of galaxy evolution
are the processes by which galaxies accrete gas and by which the
resulting star formation and black hole growth affects this accreting
gas. It is believed that both the form of the accretion and the nature
of the feedback change as a function of the galaxy mass. At low mass the
gas comes in cold and the feedback is provided by massive stars. At high
mass, the gas comes in hot, and the feedback is from an AGN. The
changeover occurs near the mass where the galaxy population transitions
from star-forming galaxies to red and dead ones. The population of red
and dead galaxies is building with cosmic time, and it is believed that
feedback plays an important role in this process: shutting down star
formation by heating and/or expelling the reservoir of cold halo gas. To
investigate these ideas, we propose to use COS far-UV spectra of
background QSOs to measure the properties of the halo gas in a sample of
galaxies near the transition mass that have undergone starbursts within
the past 100 Myr to 1 Gyr. The galactic wind associated with the
starburst is predicted to have affected the properties of the gaseous
halo. To test this, we will compare the properties of the halos of the
post-starburst galaxies to those of a control sample of galaxies matched
in mass and QSO impact parameter. Do the halos of the post-starburst
galaxies show a higher incidence rate of Ly-Alpha and metal
absorption-lines? Are the kinematics of the halo gas more disturbed in
the post-starbursts? Has the wind affected the ionization state and/or
the metallicity of the halo? These data will provide fresh new insights
into the role of feedback from massive stars on the evolution of
galaxies, and may also offer clues about the properties of the QSO metal
absorption-line systems at high-redshift .
COS/NUV/FUV 12086
Generation of 1-D Fixed Pattern Templates
Tests have shown that application of a 1-D fixed pattern template to a
COS spectrum can reduce the fixed pattern noise in G130M or G160M
spectra to an equivalent S/N of about 30/1. For this to be occur, the
template must be derived from data for the same grating and nearly the
same central wavelength as the observation. This is because each grating
has a different cross dispersion profile, and different central
wavelengths fall at different cross dispersion detector locations. As a
result, spectra obtained at each grating and central wavelength setting
are derived from different regions of the detectors -- each with their
own, unique detector features and grid wire shadows.
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 11696
Infrared Survey of Star Formation Across Cosmic Time
We propose to use the unique power of WFC3 slitless spectroscopy to
measure the evolution of cosmic star formation from the end of the
reionization epoch at z>6 to the close of the galaxy- building era at
z~0.3.Pure parallel observations with the grisms have proven to be
efficient for identifying line emission from galaxies across a broad
range of redshifts. The G102 grism on WFC3 was designed to extend this
capability to search for Ly-alpha emission from the first galaxies.
Using up to 250 orbits of pure parallel WFC3 spectroscopy, we will
observe about 40 deep (4-5 orbit) fields with the combination of G102
and G141, and about 20 shallow (2-3 orbit) fields with G141 alone.
Our primary science goals at the highest redshifts are: (1) Detect Lya
in ~100 galaxies with z>5.6 and measure the evolution of the Lya
luminosity function, independent of of cosmic variance; 2) Determine the
connection between emission line selected and continuum-break selected
galaxies at these high redshifts, and 3) Search for the proposed
signature of neutral hydrogen absorption at re-ionization. At
intermediate redshifts we will (4) Detect more than 1000 galaxies in
Halpha at 0.5<z<1.8 to measure the evolution of the extinction-corrected
star formation density across the peak epoch of star formation. This is
over an order-of-magnitude improvement in the current statistics, from
the NICMOS Parallel grism survey. (5) Trace ``cosmic downsizing" from
0.5<z<2.2; and (6) Estimate the evolution in reddening and metallicty in
star- forming galaxies and measure the evolution of the Seyfert
population. For hundreds of spectra we will be able to measure one or
even two line pair ratios -- in particular, the Balmer decrement and
[OII]/[OIII] are sensitive to gas reddening and metallicity. As a bonus,
the G102 grism offers the possibility of detecting Lya emission at
z=7-8.8.
To identify single-line Lya emitters, we will exploit the wide
0.8--1.9um wavelength coverage of the combined G102+G141 spectra. All
[OII] and [OIII] interlopers detected in G102 will be reliably separated
from true LAEs by the detection of at least one strong line in the G141
spectrum, without the need for any ancillary data. We waive all
proprietary rights to our data and will make high-level data products
available through the ST/ECF.
WFC3/IR 11915
IR Internal Flat Fields
This program is the same as 11433 (SMOV) and depends on the completion
of the IR initial alignment (Program 11425). This version contains three
instances of 37 internal orbits: to be scheduled early, middle, and near
the end of Cycle 17, in order to use the entire 110-orbit allocation.
In this test, we will study the stability and structure of the IR
channel flat field images through all filter elements in the WFC3-IR
channel. Flats will be monitored, i.e. to capture any temporal trends in
the flat fields and delta flats produced. High signal observations will
provide a map of the pixel-to-pixel flat field structure, as well as
identify the positions of any dust particles.
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 11908
Cycle 17: UVIS Bowtie Monitor
Ground testing revealed an intermittent hysteresis type effect in the
UVIS detector (both CCDs) at the level of ~1%, lasting hours to days.
Initially found via an unexpected bowtie-shaped feature in flatfield
ratios, subsequent lab tests on similar e2v devices have since shown
that it is also present as simply an overall offset across the entire
CCD, i.e., a QE offset without any discernable pattern. These lab tests
have further revealed that overexposing the detector to count levels
several times full well fills the traps and effectively neutralizes the
bowtie. Each visit in this proposal acquires a set of three 3x3 binned
internal flatfields: the first unsaturated image will be used to detect
any bowtie, the second, highly exposed image will neutralize the bowtie
if it is present, and the final image will allow for verification that
the bowtie is gone.
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.
_________________________
David Cottle
UBB Owner & Administrator