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Daily Report #5193

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Old October 1st 10, 03:46 PM posted to sci.astro.hubble
Cooper, Joe
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Posts: 568
Default Daily Report #5193

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science


PERIOD COVERED: 8:00pm September 29 - 7:59pm September 30, 2010 (DOY 273/00:00z-273/23:59z)


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


12441 - ACS Suspend at 273/11:51z

Observations affected: ACS #62-65, Proposal #11575

12442 - GSAcq(2,1,1) scheduled at 273/16:44:20z results in fine lock
backup (2,0,2), scan step limit exceeded on FGS-2.

Observations possibly affected: COS 95-100 Proposal ID#12041, WFC3 164
Proposal ID#12348

18931-2 - Dump ACS memory at 273/1312z
18932-1 - Recover ACS from Suspend Mode at 273/2103z


Scheduled Successful
FGS GSAcq 8 8
FGS REAcq 7 7
OBAD with Maneuver 6 6


FLASH REPORT: ACS Suspended at 273/11:51z.

FLASH REPORT: ACS Suspend Recovery Side 1 was successfully completed
at 2010/273/21:03 UTC, returning ACS to its nominal WFHROper state in
readiness to intercept the on-going science timeline.



The Stellar Halo Profiles of Massive Disk Galaxies

Stellar halos surrounding massive galaxies are of prime interest in
hierarchical galaxy formation models: most of the halo is formed by
the very early accretion of small, metal poor satellite galaxies each
with their independent evolution history. As such, halos contain the
fossil remnants of the earliest star formation and accretion phases of
a galaxy in formation. The resulting size, shape, age, and metallicity
of stellar halos provide therefore a direct test of the basic
ingredients (reionization, feedback from star formation, density
fluctuation power spectrum) of hierarchical galaxy formation models.

In our GHOSTS survey we have sampled the principle axes of a sample of
11 nearby galaxies with Vrot100 km/s. Our detection of resolved
stellar halo populations ~1.5 mag below the tip of the Red Giant
Branch has revealed halos that extend as far as 30 kpc around the most
massive galaxies in our sample. Those extended stellar halos seem more
compact than current model predictions, they have unexpectedly high
metallicity up to the last detected point, and have a luminosity that
is more closely related to the bulge luminosity than to the galaxy
mass. We propose to extend the light profiles of 4 massive galaxies
with a range in bulge-to-disk ratio to the background limit at ~70
kpc. This will enable us to:

- confirm the stellar halo shape (compactness) and assess with
confidence any conflict with models using these very extended and
accurate halo profile characterizations;

- establish whether stellar envelopes beyond 30 kpc are still
morphologically connected to inner bulges, or whether a break occurs
at larger radii revealing a distinct new component;

- determine whether every massive galaxy has an old, metal-poor halo
at large radius like the Milky Way and M31; if not, constrain for the
first time the range of stellar metallicity gradients in extended
stellar halos.

ACS/WFC3 11575

The Stellar Origins of Supernovae

Supernovae (SNe) have a profound effect on galaxies, and have been
used recently as precise cosmological probes, resulting in the
discovery of the accelerating Universe. They are clearly very
important events deserving of intense study. Yet, even with nearly
4000 known SNe, we know relatively little about the stars which give
rise to these powerful explosions. The main limitation has been the
lack of spatial resolution in pre-SN imaging data. However, since 1999
our team has been at the vanguard of directly identifying SN
progenitor stars in HST images. From this exciting new line of study,
the emerging trend from 5 detections for Type II- Plateau SNe is that
their progenitors appear to be relatively low mass (8 to 20 Msun) red
supergiants, although more cases are needed. Nonetheless, the nature
of the progenitors of Type Ib/c SNe, a subset of which are associated
with the amazing gamma-ray bursts, remains ambiguous. Furthermore, we
remain in the continually embarrassing situation that we still do not
yet know which progenitor systems explode as Type Ia SNe, which are
currently being used for precision cosmology. In Cycle 16 we have
triggered on the Type Ic SN 2007gr and Type IIb SN 2008ax so far. We
propose to determine the identities of the progenitors of 4 SNe within
17 Mpc, which we expect to occur during Cycle 17, through ToO
observations using ACS/HRC.

COS/FUV 11526

COS-GTO: Sampling the Local ISM with Hot White Dwarfs

We shall use hot white dwarf stars located within 150pc of the Sun to
probe the absorption properties of the interstellar gas associated
with the local cavity. There is still much debate concerning the
ionization state of the local gas, since previously detected highly
ionized lines (such as CIV and SiIV) could be associated with the
circumstellar environments of hot white dwarfs. By using a priori
knowledge of the velocity structure of the interstellar sight-lines to
these targets (gained from high spectral resolution ground-based
observations) in conjunction with the UV absorption data gained with
HST-COS, we shall be able to better determine both the physical and
chemical state of the numerous diffuse interstellar clouds present
within the local cavity.

COS/NUV 12041

COS-GTO: Io Atmosphere/STIS

We will use six HST orbits with COS to observe the disk-integrated
longitudinal distribution of Io's atmosphere, and ten HST orbits with
STIS to provide complementary disk-resolved information at key
locations. We will use the COS G225M grating to observe four SO2
absorption bands, which can be used to determine SO2 atmospheric
density. Disk-integrated 19 micron observations of the atmosphere
indicate that the anti-Jupiter hemisphere of Io has an atmospheric
density roughly ten times greater than the Jupiter-facing side
(Spencer et al. 2005), and mm-wave observations suggest a similar
pattern. However the infrared and mm-wave observations cannot easily
separate atmospheric density from atmospheric temperature, so these
results are model-dependent. Sparse 2100 2300 disk-resolved
observations (McGrath et al. 2000, Jessup et al. 2004) tell a
consistent story, but do not cover enough of Io's surface to provide
full confirmation of the long-wavelength result. We will therefore
observe Io's disk-integrated atmospheric density at six longitudes,
roughly 30, 90, 150, 210, 270, and 330 W, to confirm the 19 micron
results and improve our ability to model the 19-micron data. With
STIS, we plan disk-resolved 2000-3200 spectroscopy of Io's SO2
atmosphere. Our observations will target low-latitude regions away
from active plumes (in contrast to our Cycle 10 observations (Jessup
et al. 2004) which targeted the Prometheus plume), to look for the
effect of plumes on the atmosphere. We will also look at the variation
of low-latitude atmospheric abundance with terrain type, to look for
explanations for the large longitudinal variations in atmospheric
pressure to be studied with COS. Finally, we will look at a variety of
regions at two different times of day to determine the extent of
diurnal variations in the atmosphere, which are expected if the
atmosphere is dominantly supported by frost sublimation.


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 .

STIS/CCD 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD.

STIS/CCD 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 z6 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 a (1) Detect Lya
in ~100 galaxies with z5.6 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 0.5z1.8 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 0.5z2.2; 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 12265

Determining the Physical Nature of a Unique Giant Lya Emitter at

We propose deep WFC3/IR imaging for a giant Lya emitter (LAE) with a
Keck spectroscopic redshift of z=6.595 discovered by extensive
narrow-band imaging with Subaru in the SXDS-UKIDSS/UDS field. This
remarkable object is unique in many respects including its large
stellar mass and luminous nebula which extends over 17 kpc; no
equivalent source has been found in other surveys. The nature of this
rare object is unclear. Fundamental to progress is determining the
origin of star formation in such an early massive object; if the age
of the stellar population is short we are likely witnessing a special
moment in the formation history of a massive galaxy. The heating
source for the nebula is also unclear; options include intense star
formation, the infall of cold gas onto a dark halo or shock heating
from a merger. We will take deep broad-band (F125W and F160W) images
and an intermediate-band (F098M) image which will be analyzed in
conjunction with ultra-deep IRAC 3.6 and 4.5 micron data being taken
by the Spitzer/SEDS project. These data will enable us to constrain
the star formation rate and stellar age. Moreover, the UV continuum
morphology and Lya-line distribution will be investigated for evidence
of a major merger, cold accretion, or hot bubbles associated with
outflows. We will address the physical origin of the remarkable object
observed at an epoch where massive galaxies are thought to begin their

WFC3/IR 12307

A public SNAPSHOT Survey of Gamma-ray Burst Host Galaxies

We propose to conduct a public infrared survey of the host galaxies of
Swift selected gamma-ray bursts (GRBs) at z3. By obtaining deep,
diffraction limited imaging in the IR we will complete detections for
the host galaxies, and in concert with our extensive ground based
afterglow and host programmes will compile a detailed catalog of the
properties of high-z galaxies selected by GRBs. In particular these
observations will enable us to study the colours, luminosities and
morphologies of the galaxies. This in turn informs studies of the
nature of the progenitors and the role of GRBs as probes of star
formation across cosmic history. Ultimately it provides a product of
legacy value which will greatly complement further studies with next
generation facilities such as ALMA and JWST.

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 12348

WFC3/UVIS Charge Injection Test

In preparation for making charge injection (CI) available to
observers, this proposal will 1) confirm that the CI performs on-orbit
as it did on the ground, 2) provide an initial assessment of which CI
mode is most effective (10, 17, 25 line or continuous), and 3) obtain
a baseline calibration for each mode.

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.


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