A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Astronomy and Astrophysics » Hubble
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Daily Report #5002



 
 
Thread Tools Display Modes
  #1  
Old December 30th 09, 06:53 PM posted to sci.astro.hubble
Bassford, Lynn[_2_]
external usenet poster
 
Posts: 91
Default Daily Report #5002

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5002

PERIOD COVERED: 5am December 29 - 5am December 30, 2009 (DOY 363/10:00z-364/10:00z)

OBSERVATIONS SCHEDULED

COS/FUV 11895

FUV Detector Dark Monitor

The purpose of this proposal is to monitor the FUV detector dark rate
by taking long science exposures without illuminating the detector.
The detector dark rate and spatial distribution of counts will be
compared to pre-launch and SMOV data in order to verify the nominal
operation of the detector. Variations of count rate as a function of
orbital position will be analyzed to find dependence of dark rate on
proximity to the SAA. Dependence of dark rate as function of time will
also be tracked.

COS/NUV/FUV 11718

The Stellar Halos of Dwarf Galaxies

The metal-poor stellar halo is the oldest extended structure in the
Galaxy. Such halos are thought to form through hierarchical merging,
and contain stars pulled from accreted subhalos. The diffuse stellar
halo therefore stores information about the prop reties of the
accreted galaxies (i.e., their orbits, stellar masses, and
metallicities). It is therefore unsurprising that stellar halos have
become a popular probe of the early epoch of galaxy formation.

Almost all current work on stellar halos has focused on massive
galaxies, however. We propose to extend the work on stellar halos to
much lower mass scales, by studying the halos of faint dwarf galaxies.
By taking halo studies into the dwarf galaxy regime, we can probe
exceptionally small mass scales for the accreted halos. At these mass
scales the effects of reionization and supernova feedback have the
largest impact on the galaxy population. Stellar halos of dwarf
galaxies are therefore a sensitive probe of the key processes needed
to resolve the lack of substructure observed at low masses.

We are requesting two far-field ACS pointings for the three closest
isolated nearby dwarf irregular galaxies whose inner halos have
already been mapped with the ACS Nearby Galaxy Survey Treasury. These
outer fields will allow us to trace the halo out to roughly half the
virial radius, further than any previous study. We will use the
resulting distribution of halo stars (1) to unambiguously measure the
structure of the stellar halo, with minimal contamination from the
main galaxy; (2) to constrain the flattening of the stellar halo; (3)
to measure the metallicity of halo stars as a function of radius; (4)
to correlate any changes in halo profile with changes in metallicity.
The resulting data will constrain models of halo accretion and the
epoch of reionization.

COS/NUV/FUV 11741

Probing Warm-Hot Intergalactic Gas at 0.5 z 1.3 with a Blind
Survey for O VI, Ne VIII, Mg X, and Si XII Absorption Systems

Currently we can only account for half of the baryons (or less)
expected to be found in the nearby universe based on D/H and CMB
observations. This "missing baryons problem" is one of the
highest-priority challenges in observational extragalatic astronomy.
Cosmological simulations suggest that the baryons are hidden in
low-density, shock-heated intergalactic gas in the log T = 5 - 7
range, but intensive UV and X-ray surveys using O VI, O VII, and O
VIII absorption lines have not yet confirmed this prediction. We
propose to use COS to carry out a sensitive survey for Ne VIII and Mg
X absorption in the spectra of nine QSOs at z(QSO) 0.89. For the
three highest-redshift QSOs, we will also search for Si XII. This
survey will provide more robust constraints on the quantity of baryons
in warm-hot intergalactic gas at 0.5 z 1.3, and the data will
provide rich constraints on the metal enrichment, physical conditions,
and nature of a wide variety of QSO absorbers in addition to the
warm-hot systems. By comparing the results to other surveys at lower
redshifts (with STIS, FUSE, and from the COS GTO programs), the
project will also enable the first study of how these absorbers evolve
with redshift at z 1. By combining the program with follow-up galaxy
redshift surveys, we will also push the study of galaxy-absorber
relationships to higher redshifts, with an emphasis on the
distribution of the WHIM with respect to the large-scale matter
distribution of the universe.

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.

STIS/CCD 11703

The Nature of the Black Hole in a NGC 4472 Globular Cluster and the
Origin of Its Broad [OIII] Emission

We propose to use STIS to obtain optical spectroscopy at high spatial
resolution of the black hole-hosting globular cluster RZ2109 in the
Virgo elliptical NGC 4472. This is motivated by our very recent
discovery broad [OIII] 4959, 5007 emission with a width of several
thousand km/s in this globular cluster. The STIS spectroscopy will
enable us to determine if the very broad [OIII] emission is due to
material driven at high velocity from the central accreting black hole
across the globular cluster, or if the velocity widths are due to
gravitational motions very close to the central black hole. In the
former case, the [OIII] emission should extend over a few-tenths of an
arcsecond and be spatially resolved by HST and STIS, while in the
latter case, the emission lines will be unresolved. Distinguishing
between these two possibilities will allow us to - 1) determine
whether the black hole is of intermediate mass or a stellar mass, and
thereby whether the black hole mass - sigma relation extends to
globular cluster masses, 2) test models of black hole formation and
evolution in dense stellar systems, and 3) address the nature of
accretion in the high luminosity black-hole X-ray source, and
constrain the feedback processes from luminous black holes into their
surrounding medium in dense stellar systems.

STIS/CCD 11844

CCD Dark Monitor Part 1

The purpose of this proposal is to monitor the darks for the STIS CCD.

STIS/CCD 11846

CCD Bias Monitor-Part 1

The purpose of this proposal is to 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/FGS 11848

CCD Read Noise Monitor

This proposal measures the read noise of all the amplifiers (A, B, C,
D) on the STIS CCD using pairs of bias frames. Full-frame and binned
observations are made in both Gain 1 and Gain 4, with binning factors
of 1x1, 1x2, 2x1, and 2x2. All exposures are internals. Pairs of
visits are scheduled monthly for the first four months and then
bi-monthly after that.

WFC3/ACS/UVIS 11803

Observing Cluster Assembly Around the Massive Cluster RXJ0152-13

We request ACS imaging for groups and filaments in the outskirts of
two z=0.8 forming clusters of galaxies. These images will be combined
with an unparalleled dataset of wide-field spectroscopy from Magellan,
with ~2200 confirmed members (~3200 by the summer) of the
superstructures surrounding the two clusters. We will estimate merger
rates and determine the morphological composition of the galaxy
populations within the infalling groups and filaments identified in
our spectroscopic dataset. The HST data are critical to understand how
the early-type galaxy fraction remains constant in cluster centers,
while clusters double in mass through the steady accretion of lower
mass groups. One possibility is that the galaxies in the filaments and
infalling groups already have predominantly early-type morphologies,
while another is that galaxies transform during, and possibly even in
connection with, the process of infall. Our unique dataset of
spectroscopic membership, when combined with the exquisite
high-resolution imaging of ACS and WF3, will enable us to witness the
accretion of galaxies unto massive clusters and how this process
affects their properties.

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 11926

IR Zero Points

We will measure and monitor the zeropoints through the IR filters
using observations of the white dwarf standard stars, GD153, GD71 and
GD191B2B and the solar analog standard star, P330E. Data will be taken
monthly during Cycle 17. Observations of the star cluster, NGC 104,
are made twice to check color transformations. We expect an accuracy
of 2% in the wide filter zeropoints relative to the HST photometric
system, and 5% in the medium- and narrow-band filters.

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/UVIS 11594

A WFC3 Grism Survey for Lyman Limit Absorption at z=2

We propose to conduct a spectroscopic survey of Lyman limit absorbers
at redshifts 1.8 z 2.5, using WFC3 and the G280 grism. This
proposal intends to complete an approved Cycle 15 SNAP program
(10878), which was cut short due to the ACS failure. We have selected
64 quasars at 2.3 z 2.6 from the Sloan Digital Sky Survey
Spectroscopic Quasar Sample, for which no BAL signature is found at
the QSO redshift and no strong metal absorption lines are present at z
2.3 along the lines of sight. The survey has three main

observational goals. First, we will determine the redshift frequency
dn/dz of the LLS over the column density range 16.0 log(NHI) 20.3
cm^-2. Second, we will measure the column density frequency
distribution f(N) for the partial Lyman limit systems (PLLS) over the
column density range 16.0 log(NHI) 17.5 cm^-2. Third, we will
identify those sightlines which could provide a measurement of the
primordial D/H ratio. By carrying out this survey, we can also help
place meaningful constraints on two key quantities of cosmological
relevance. First, we will estimate the amount of metals in the LLS
using the f(N), and ground based observations of metal line
transitions. Second, by determining f(N) of the PLLS, we can constrain
the amplitude of the ionizing UV background at z~2 to a greater
precision. This survey is ideal for a snapshot observing program,
because the on-object integration times are all well below 30 minutes,
and follow-up observations from the ground require minimal telescope
time due to the QSO sample being bright.

WFC3/UVIS 11657

The Population of Compact Planetary Nebulae in the Galactic Disk

We propose to secure narrow- and broad-band images of compact
planetary nebulae (PNe) in the Galactic Disk to study the missing link
of the early phases of post-AGB evolution. Ejected AGB envelopes
become PNe when the gas is ionized. PNe expand, and, when large
enough, can be studied in detail from the ground. In the interim, only
the HST capabilities can resolve their size, morphology, and central
stars. Our proposed observations will be the basis for a systematic
study of the onset of morphology. Dust properties of the proposed
targets will be available through approved Spitzer/IRS spectra, and so
will the abundances of the alpha-elements. We will be able thus to
explore the interconnection of morphology, dust grains, stellar
evolution, and populations. The target selection is suitable to
explore the nebular and stellar properties across the galactic disk,
and to set constraints on the galactic evolutionary models through the
analysis of metallicity and population gradients.

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 z7.5 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 z7.5 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 z7.5 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 z7.5 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 z7.5 candidates within
one month from the acquisition of each field.

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 7 7
FGS REAcq 8 8
OBAD with Maneuver 5 5

SIGNIFICANT EVENTS: (None)
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Daily Report Cooper, Joe Hubble 0 December 22nd 08 06:17 PM
Daily Report # 4429 Cooper, Joe Hubble 0 August 20th 07 02:51 PM
Daily Report # 4428 Cooper, Joe Hubble 0 August 17th 07 03:46 PM
Daily Report [email protected] Hubble 0 October 29th 04 04:59 PM
HST Daily Report 131 George Barbehenn Hubble 0 May 11th 04 02:48 PM


All times are GMT +1. The time now is 07:41 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.