View Single Post
  #1  
Old August 30th 10, 06:18 PM posted to sci.astro.hubble
Cooper, Joe
external usenet poster
 
Posts: 568
Default Daily Report #5170

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5170

PERIOD COVERED: 5am August 27 - 5am August 30, 2010 (DOY 239/09:00z-242/09:00z)

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

12365 - GSAcq(1,2,1) at 240/23:21:19z took 2 attempts to acquire Fine
Lock.

Observations possibly affected: WFC3 204 Proposal ID#11908, WFC3
205-206 & ACS 44-47 Proposal ID#11613, STIS 45 Proposal ID#11845, STIS
46-47 Proposal ID#11847.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES:

2066-0 - Update CCS SOI after COS FSW 4.11 installation @ 241/2345z
2061-0 - HST486/NSSC-1 SOI Configuration -- PRD 7.3 (closed) @
241/2359z
2067-0 - COS EEPROM & Exec SOIs out of synch between install & active
(closed) @ 242/0001z

SCHEDULED SUCCESSFUL
FGS GSAcq 19 19
FGS REAcq 28 28
OBAD with Maneuver 16 16

SIGNIFICANT EVENTS:

Flash Report: COS FSW 4.11 installation complete

COS successfully transition down to boot and back-up to Operate (COS
CS FSW 4.11 was active at 242/02:50z).


OBSERVATIONS SCHEDULED:

S/C 12046

COS FUV DCE Memory Dump

Whenever the FUV detector high voltage is on, count rate and current
draw information is collected, monitored, and saved to DCE memory.
Every 10 msec the detector samples the currents from the HV power
supplies (HVIA, HVIB) and the AUX power supply (AUXI). The last 1000
samples are saved in memory, along with a histogram of the number of
occurrences of each current value.

In the case of a HV transient (known as a "crackle" on FUSE), where
one of these currents exceeds a preset threshold for a persistence
time, the HV will shut down, and the DCE memory will be dumped and
examined as part of the recovery procedure. However, if the current
exceeds the threshold for less than the persistence time (a
"mini-crackle" in FUSE parlance), there is no way to know without
dumping DCE memory. By dumping and examining the histograms regularly,
we will be able to monitor any changes in the rate of "mini-crackles"
and thus learn something about the state of the detector.

COS/NUV 12042

COS-GTO: Pluto

We seek to measure Pluto's albedo below 2100, to better constrain
surface composition. COS observations will provide a substantial
improvement in the S/N of Pluto spectra from 1800 to 2100.
Accumulation of past HST/FOS spectra yields extremely low S/N below
2000 (S/N of only 1-3 in 100 bins; Krasnopolsky 2001). We expect to
achieve S/N=5 at 1950 with 10 binning. In addition to spectrally broad
albedo measurements, these observations could reveal line or molecular
band emission, such as C I 1931 or CO 1993.

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.

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 11922

UVIS Fringing

Multiple pointing observations of the globular cluster Omega Centauri
(NGC 5139) in the narrow band filters F656N and F953N will be used to
verify the fringing model developed during various tests (TV3) and its
impact on photometric accuracy. By measuring the relative changes in
brightness of a star at different positions on the detector, we will
determine the local variations induced by the fringing pattern.

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 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).

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.

STIS/CCD 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD.

WFC3/IR 11738

SPIDERWEBS AND FLIES: OBSERVING MASSIVE GALAXY FORMATION IN ACTION

Distant luminous radio galaxies are among the brightest known galaxies
in the early Universe, pinpoint likely progenitors of dominant cluster
galaxies and are unique laboratories for studying massive galaxy
formation. Spectacular images with the ACS and NICMOS of one such
object, the "Spiderweb Galaxy" at z = 2.2, show in exquisite detail,
hierarchical merging occurring 11 Gyr ago. By imaging 3 additional
Spiderweb-like galaxies we wish to study this potentially crucial
phase of massive galaxy evolution, when hierarchical merging, galaxy
downsizing and AGN feedback are all likely to be occurring. Properties
of the complete sample of Spiderweb galaxies will be used to (i)
constrain models for the formation and evolution of the most massive
galaxies that dominate rich clusters and (ii) investigate the nature
of chain and tadpole galaxies, a fundamental but poorly understood
constituent of the early Universe.

We shall image rest-frame UV and optical continuum emission from 3
radio galaxies with 2.4 z 3.8 that appear clumpy and large in
shallow WFPC/PC observations. The new observations will typically
reach ~2 magnitudes fainter over 20-40 times larger area than
previously. Photometric and morphological parameters will be measured
for satellite galaxies ("flies") in the clumpy massive hosts and for
galaxies in ~ 1.5 Mpc x 1.5 Mpc regions of surrounding protoclusters.
Locations, sizes, elongations, clumpiness, masses, and star formation
rates of the merging satellite and protocluster galaxies will be
compared with new state of the art simulations. Combination of ACS and
WFC3 images will help disentangle the properties of the young and old
populations.

Specific goals include: (i) investigating star formation histories of
the satellite galaxies and the extended emission, (ii) studying
"downsizing" and merging scenarios and (iii) measuring the statistics
of linear galaxies and relating them to models for the formation of
massive galaxies and to the properties of the important but enigmatic
class of chain/tadpole galaxies in the HUDF.

STIS/CCD/MA1 11737

The Distance Dependence of the Interstellar N/O Abundance Ratio: A
Gould Belt Influence?

The degree of elemental abundance homogeneity in the interstellar
medium is a function of the enrichment and mixing processes that
govern galactic chemical evolution. Observations of young stars and
the interstellar gas within ~500 pc of the Sun have revealed a local
ISM that is so well-mixed it is having an impact on ideas regarding
the formation of extrasolar planets. However, the situation just
beyond the local ISM is not so clear. Sensitive UV absorption line
measurements have recently revealed a pattern of inhomogeneities in
the interstellar O, N, and Kr gas-phase abundances at distances of
~500 pc and beyond that appear nucleosynthetic in origin rather than
due to dust depletion. In particular, based on a sample of 13
sightlines, Knauth et al. (2006) have found that the nearby stars (d
500 pc) exhibit a mean interstellar N/O abundance ratio that is
significantly higher (0.18 dex) than that toward the more distant
stars. Interestingly, all of their sightlines lie in the sky vicinity
of the Gould Belt of OB associations, molecular clouds, and diffuse
gas encircling the Sun at a distance of ~400 pc. Is it possible that
mixing processes have not yet smoothed out the recent ISM enrichment
by massive stars in the young Belt region? By measuring the
interstellar N/O ratios in a strategic new sample of sightlines with
STIS, we propose to test the apparent N/O homogeneity inside the Gould
Belt and determine if the apparent decline in the N/O ratio with
distance is robust and associated with the Belt region.

ACS/WFC3 11734

The Hosts of High Redshift Gamma-Ray Bursts

Gamma-ray bursts are the most luminous explosive events known, acting
as beacons to the high redshift universe. Long duration GRBs have
their origin in the collapse of massive stars and thus select star
forming galaxies across a wide range of redshift. Due to their bright
afterglows we can study the details of GRB host galaxies via
absorption spectroscopy, providing redshifts, column densities and
metallicities for galaxies far too faint to be accessible directly
with current technology. We have already obtained deep ground based
observations for many hosts and here propose ACS/WFC3 and WFC3
observations of the fields of bursts at z3 which are undetected in
deep ground based images. These observations will study the hosts in
emission, providing luminosities and morphologies and will enable the
construction of a sample of high-z galaxies with more detailed
physical properties than has ever been possible before.

WFC3/IR 11708

Determining the Sub-stellar IMF in the Most Massive Young Milky Way
Cluster, Westerlund 1

Despite over 50 years of active research, a key question in galactic
astronomy remains unanswered: is the initial mass function (IMF) of
stars and sub-stellar objects universal, or does it depend on initial
conditions? The answer has profound consequences for the evolution of
galaxies as well as a predictive theory of star formation. Work to
date suggests that certain environments (high densities, e.g.
Elmegreen 2004; low metallicity, e.g. Larson 2005) should produce a
top-heavy IMF, and there are hints from unresolved star-bursts that
this might be the case. Yet, there is no clear evidence for an IMF
that differs from that characterizing the Galactic field stars in a
resolved stellar population down to one solar mass. Westerlund 1 is
the most massive young star cluster known in the Milky Way. With an
estimated mass of 5x10^4 Msun, an age of 3-5 Myr, and located at a
distance of 3-4 kpc, it presents a unique opportunity to test whether
the IMF in such a cluster deviates from the norm well down into the
brown dwarf regime. We propose WFC3 near-IR imaging to probe the IMF
down to 40 Jupiter masses. The data will enable use to: 1) provide a
stringent test of the universality of the IMF under conditions
approximating those of star-bursts; 2) search for primordial or
dynamic mass segregation in the clusters; and 3) assess whether the
cluster is likely to remain bound (as a massive open cluster) or
disperse into the field. We will obtain images in the F125W, F160W,
and F139M filters. The F139M filter covers a strong water absorption
feature and the color F125W/F139M is a powerful temperature diagnostic
in the range 2800-4000 K. This information will enable us to: a)
confirm membership for low mass stars suspected on the basis of their
position in the color-magnitude diagram; b) place the members in the
HR diagram; and c) estimate the masses and ages of cluster members for
low-mass stars and sub-stellar objects. This new capability offered
with the WFC3 (through a novel combination of filter complement, high
spatial resolution, and large field of view) will enable us to make a
fundamental test of whether the IMF is universal on a unique resolved
stellar population, as well as assess the clusters structure,
dynamics, and ultimate fate.

WFC3/IR 11694

Mapping the Interaction Between High-Redshift Galaxies and the
Intergalactic Environment

With the commissioning of the high-throughput large-area camera
WFC3/IR, it is possible for the first time to undertake an efficient
survey of the rest-frame optical morphologies of galaxies at the peak
epoch of star formation in the universe. We therefore propose deep
WFC3/IR imaging of over 320 spectroscopically confirmed galaxies
between redshift 1.6 z 3.4 in well-studied fields which lie along
the line of sight to bright background QSOs. The spectra of these
bright QSOs probe the IGM in the vicinity of each of the foreground
galaxies along the line of sight, providing detailed information on
the physical state of the gas at large galactocentric radii. In
combination with our densely sampled UV/IR spectroscopy, stellar
population models, and kinematic data in these fields, WFC3/IR imaging
data will permit us to construct a comprehensive picture of the
structure, dynamics, and star formation properties of a large
population of galaxies in the early universe and their effect upon
their cosmological environment.

WFC3/UV/IR 11664

The WFC3 Galactic Bulge Treasury Program: Populations, Formation
History, and Planets

Exploiting the full power of the Wide Field Camera 3 (WFC3), we
propose deep panchromatic imaging of four fields in the Galactic
bulge. These data will enable a sensitive dissection of its stellar
populations, using a new set of reddening-free photometric indices we
have constructed from broad-band filters across UV, optical, and
near-IR wavelengths. These indices will provide accurate temperatures
and metallicities for hundreds of thousands of individual bulge stars.
Proper motions of these stars derived from multi-epoch observations
will allow separation of pure bulge samples from foreground disk
contamination. Our catalogs of proper motions and panchromatic
photometry will support a wide range of bulge studies.

Using these photometric and astrometric tools, we will reconstruct the
detailed star-formation history as a function of position within the
bulge, and thus differentiate between rapid- and extended-formation
scenarios. We will also measure the dependence of the stellar mass
function on metallicity, revealing how the characteristic mass of star
formation varies with chemistry. Our sample of bulge stars with
accurate metallicities will include 12 candidate hosts of extrasolar
planets. Planet frequency is correlated with metallicity in the solar
neighborhood; our measurements will extend this knowledge to a remote
environment with a very distinct chemistry.

Our proposal also includes observations of six well-studied globular
and open star clusters; these observations will serve to calibrate our
photometric indices, provide empirical population templates, and
transform the theoretical isochrone libraries into the WFC3 filter
system. Besides enabling our own program, these products will provide
powerful new tools for a host of other stellar-population
investigations with HST/WFC3. We will deliver all of the products from
this Treasury Program to the community in a timely fashion.

WFC3/UVIS 11630

Monitoring 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 and months, as we
have been doing for the past seven years. Previous Hubble Space
Telescope observations (including previous Snapshot programs 8634,
10170, 10534, and 11156), together with near-IR images obtained using
adaptive optics on the Keck Telescope, reveal both planets to be
dynamic worlds which change on time scales ranging from hours to
(terrestrial) years. Uranus equinox occurred in December 2007, and the
northern hemisphere is becoming fully visible for the first time since
the early 1960s. HST observations during the past several years
(Hammel et al. 2005, Icarus 175, 284 and references therein) have
revealed strongly wavelength-dependent latitudinal structure, the
presence of numerous visible-wavelength cloud features in the northern
hemisphere, at least one very long-lived discrete cloud in the
southern hemisphere, and in 2006 the first clearly defined dark spot
seen on Uranus. Long term ground-based observations (Lockwood and
Jerzekiewicz, 2006, Icarus 180, 442; Hammel and Lockwood 2007, Icarus
186, 291) reveal seasonal brightness changes that seem to demand the
appearance of a bright northern polar cap within the next few years.
Recent HST and Keck observations of Neptune (Sromovsky et al. 2003,
Icarus 163, 256 and references therein) show a general increase in
activity at south temperate latitudes until 2004, when Neptune
returned to a rather Voyager-like appearance with discrete bright
spots rather than active latitude bands. 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 features.

STIS/CCD/MA1/MA2 11616

The Disks, Accretion, and Outflows (DAO) of T Tau Stars

Classical T Tauri stars undergo magnetospheric accretion, power
outflows, and possess the physical and chemical conditions in their
disks to give rise to planet formation. Existing high resolution FUV
spectra verify that this spectral region offers unique diagnostics of
these processes, which have the potential to significantly advance our
understanding of the interaction of a star and its accretion disk. To
date the limited results are intriguing, with dramatic differences in
kinematic structure in lines ranging from C IV to H2 among the few
stars that have been observed. We propose to use HST/COS to survey the
disks, outflows, and accretion (the DAO) of 26 CTTS and 6 WTTS in the
FUV at high spectral resolution. A survey of this size is essential to
establish how properties of accretion shocks, winds and disk
irradiation depend on disk accretion rate. Specifically, our goals are
to (1) measure the radiation from and understand the physical
properties of the gas very near the accretion shock as a function of
accretion rate using emission line profiles of hot lines (C IV, Si IV,
N V, and He II); (2) measure the opacity, velocity, and temperature at
the base of the outflow to constrain outflow models using wind
absorption features; and (3) characterize the radiation incident on
disks and protoplanetary atmospheres using H2 line and continuum
emission and reconstructed bright Ly-alpha line emission.

WFC3/ACS/UVIS 11613

GHOSTS: Stellar Outskirts of Massive Spiral Galaxies

We propose to continue our highly successful GHOSTS HST survey of the
resolved stellar populations of nearby, massive disk galaxies using
SNAPs. These observations provide star counts and color-magnitude
diagrams 2-3 magnitudes below the tip of the Red Giant Branch of the
outer disk and halo of each galaxy. We will measure the metallicity
distribution functions and stellar density profiles from star counts
down to very low average surface brightnesses, equivalent to ~32 V-mag
per square arcsec.

This proposal will substantially improve our unique sampling of galaxy
outskirts. Our targets cover a range in galaxy mass, luminosity,
inclination, and morphology. As a function of these galaxy properties,
this survey provides: - the most extensive, systematic measurement of
radial light profiles and axial ratios of the diffuse stellar halos
and outer disks of spiral galaxies; - a comprehensive analysis of halo
metallicity distributions as function of galaxy type and position
within the galaxy; - an unprecedented study of the stellar metallicity
and age distribution in the outer disk regions where the disk
truncations occur; - the first comparative study of globular clusters
and their field stellar populations.

We will use these fossil records of the galaxy assembly process to
test halo formation models within the hierarchical galaxy formation
scheme.

ACS/WFC3 11604

The Nuclear Structure of OH Megamaser Galaxies

We propose a snapshot survey of a complete sample of 80 OH megamaser
galaxies. Each galaxy will be imaged with the ACS/WFC through F814W
and a linear ramp filter (FR656N or FR716N or FR782N or FR853N)
allowing us to study both the spheroid and the gas morphology in
Halpha + [N II]. We will use the 9% ramps FR647M (5370-7570 angstroms)
centered at 7000 angstroms and FR914M (7570-10, 719 angstroms) 8000
angstroms for continuum subtraction for the high and low z objects
respectively. OH megamaser galaxies (OHMG) form an important class of
ultraluminous IR-galaxies (ULIRGs) whose maser lines emit QSO-like
luminosities. ULIRGs in general are associated with recent mergers but
it is often unclear whether their power output is dominated by
starbursts or a hidden QSO because of the high absorbing columns which
hide their nuclei even at X-ray wavelengths. In contrast, OHMG exhibit
strong evidence for the presence of an energetically important and
recently triggered active nucleus. In particular it is clear that much
of the gas must have already collapsed to form a nuclear disk which
may be the progenitor of a circum-nuclear torus, a key element of the
unified scheme of AGN. A great advantage of studying OHMG systems over
the general ULIRG population, is that the circum-nuclear disks are
effectively "fixed" at an inner, edge on, orientation, eliminating
varying inclination as a nuisance parameter. We will use the HST
observations in conjunction with existing maser and spectroscopic data
to construct a detailed picture of the circum-nuclear regions of a
hitherto relatively neglected class of galaxy that may hold the key to
understanding the relationship between galaxy mergers, nuclear star-
formation, and the growth of massive black holes and the triggering of
nuclear activity.

Ads