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Daily Report #5027



 
 
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Old February 5th 10, 04:04 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #5027

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5027

PERIOD COVERED: 5am February 4 - 5am February 5, 2010 (DOY 035/10:00z-036/10:00z)

OBSERVATIONS SCHEDULED

COS/NUV 11894

NUV Detector Dark Monitor

The purpose of this proposal is to measure the NUV detector dark rate
by taking long science exposures with no light on 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 11896

NUV Spectroscopic Sensitivity Monitoring

The purpose of this proposal is to monitor sensitivity of each NUV
grating mode to detect any changes due to contamination or other
causes.

NIC3/WFC3/IR 11153

The Physical Nature and Age of Lyman Alpha Galaxies

In the simplest scenario, strong Lyman alpha emission from high
redshift galaxies would indicate that stellar populations younger than
10 Myrs dominate the UV. This does not, however, constrain the stellar
populations older than 100 Myrs, which do not contribute to UV light.
Also, the Lyman alpha line can be boosted if the interstellar medium
is both clumpy and dusty. Different studies with small samples have
reached different conclusions about the presence of dust and old
stellar populations in Lyman alpha emitters. We propose HST-NICMOS and
Spitzer-IRAC photometry of 35 Lyman-alpha galaxies at redshift
4.5z6.5, in order to determine their spectral energy distribution
(SED) extending through rest-frame optical. This will allow us to
measure accurately (1) The total stellar mass in these objects,
including old stars which may have formed at redshifts (z 8) not
easily probed by any other means. (2) The dust extinction in the rest-
frame UV, and therefore a correction to their present star-formation
rates. Taken together, these two quantities will yield the
star-formation histories of Lyman alpha galaxies, which form fully
half of the known galaxies at z=4-6. They will tell us whether these
are young or old galaxies by straddling the 4000A break. Data from
NICMOS is essential for these compact and faint (i=25- 26th magnitude
AB) high redshift galaxies, which are too faint for good near-IR
photometry from the ground.

STIS/CC/MA 11516

COS-GTO: Cold ISM

With the COS, we will be able to observe interstellar spectra in a new
regime, translucent clouds, for atomic, ionic, and molecular lines and
bands, and extinction curves. The COS will allow us to observe stars
with total visual extinctions up to 10 magnitudes, and the grain size
indicator Rv up to 4.5. In translucent clouds we expect to see the
transition from neutral and ionized carbon to mostly C I, and then
from there, we should expect to see carbon increasingly locked up in
molecular form, as CO. Other species are expected to make similar
transitions, so we should find detectable abundances of molecules such
as H2O, OH, CS, CH2, SiO, and others; also, lower ionization fractions
of the metallic elements - and higher depletions of those elements as
well. Given that we expect to find higher depletions, we should see an
altered grain size distribution, which may show up in the extinction
curves, probably as lower far-UV extinction than in diffuse clouds.
Finally, we will search for neutral PAHs in absorption, as diffuse
bands in the UV, paralleling the optical DIBs (which are thought by
some scientists to be formed by singly-ionized PAHs). In translucent
clouds, models show that the PAHs will be neutral, not in cationic
form.

STIS/CC/MA 11608

How Far Does H2 Go: Constraining FUV Variability in the Gaseous Inner
Holes of Protoplanetary Disks

By studying the innermost, planet-forming regions of circumstellar
disks around low-mass pre-main sequence stars we can refine theories
of planet formation and develop timescales for the evolution of disks
and their planets. Spitzer infrared observations of T Tauri stars have
given us an unprecedented look at dust evolution in young objects,
particularly the transitional disks. However, despite this ground
breaking progress in studying the dust in young disks, the
relationship between the dust and gas properties in the inner disk
remains essentially unknown. Using STIS on HST, we propose to quantify
the variability of H2 emission originating within the inner holes of
transitional disks and explore its implications on dust distribution
and planet formation.

STIS/CCD 11606

Dynamical Hypermassive Black Hole Masses

We will use STIS spectra to derive the masses of 5 hypermassive black
holes (HMBHs). From the observed scaling relations defined by less
massive spheroids, these objects are expected to reside at the nuclei
of host galaxies with stellar velocity dispersions greater than 320
km/s. These 5 targets have confirmed regular gas distributions on the
scales of the black hole sphere of influence. It is essential that the
sphere of influence is resolved for accurate determinations of black
hole mass (0.1"). These scales cannot be effectively observed from the
ground. Only two HMBHs have had their masses modeled so far; it is
impossible to draw any general conclusions about the connections
between HMBH mass and their massive host galaxies. With these 5
targets we will determine whether these HMBHs deviate from the scaling
relations defined by less massive spheroids. A larger sample will
allow us to firmly anchor the high mass end of the correlation between
black hole mass and stellar velocity dispersion, and other scaling
relations. Therefore we are also conducting a SNAPshot program with
which we expect to detect a further 24 HMBH candidates for STIS
observation in future cycles. At the completion of this project we
will have populated the high mass end of the scaling relations with
the sample sizes enjoyed by less massive spheroids.

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/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.

STIS/CCD/MA2 11568

A SNAPSHOT Survey of the Local Interstellar Medium: New NUV
Observations of Stars with Archived FUV Observations

We propose to obtain high-resolution STIS E230H SNAP observations of
MgII and FeII interstellar absorption lines toward stars within 100
parsecs that already have moderate or high-resolution far-UV (FUV),
900-1700 A, observations available in the MAST Archive. Fundamental
properties, such as temperature, turbulence, ionization, abundances,
and depletions of gas in the local interstellar medium (LISM) can be
measured by coupling such observations. Due to the wide spectral range
of STIS, observations to study nearby stars also contain important
data about the LISM embedded within their spectra. However, unlocking
this information from the intrinsically broad and often saturated FUV
absorption lines of low-mass ions, (DI, CII, NI, OI), requires first
understanding the kinematic structure of the gas along the line of
sight. This can be achieved with high resolution spectra of high-mass
ions, (FeII, MgII), which have narrow absorption lines, and can
resolve each individual velocity component (interstellar cloud). By
obtaining short (~10 minute) E230H observations of FeII and MgII, for
stars that already have moderate or high- resolution FUV spectra, we
can increase the sample of LISM measurements, and thereby expand our
knowledge of the physical properties of the gas in our galactic
neighborhood. STIS is the only instrument capable of obtaining the
required high resolution data now or in the foreseeable future.

STIS/MA1/MA2 11857

STIS Cycle 17 MAMA Dark Monitor

This proposal monitors the behavior of the dark current in each of the
MAMA detectors.

The basic monitor takes two 1380s ACCUM darks each week with each
detector. However, starting Oct 5, pairs are only included for weeks
that the LRP has external MAMA observations planned. The weekly pairs
of exposures for each detector are linked so that they are taken at
opposite ends of the same SAA free interval. This pairing of exposures
will make it easier to separate long and short term temporal
variability from temperature dependent changes.

For both detectors, additional blocks of exposures are taken once
every six months. These are groups of five 1314s FUV-MAMA Time-Tag
darks or five 3x315s NUV ACCUM darks distributed over a single
SAA-free interval. This will give more information on the brightness
of the FUV MAMA dark current as a function of the amount of time that
the HV has been on, and for the NUV MAMA will give a better measure of
the short term temperature dependence.

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 11909

UVIS Hot Pixel Anneal

The on-orbit radiation environment of WFC3 will continually generate
new hot pixels. This proposal performs the procedure required for
repairing those hot pixels in the UVIS CCDs. During an anneal, the
two-stage thermo-electric cooler (TEC) is turned off and the
four-stage TEC is used as a heater to bring the UVIS CCDs up to ~20
deg. C. As a result of the CCD warmup, a majority of the hot pixels
will be fixed; previous instruments such as WFPC2 and ACS have seen
repair rates of about 80%. Internal UVIS exposures are taken before
and after each anneal, to allow an assessment of the procedure's
effectiveness in WFC3, provide a check of bias, global dark current,
and hot pixel levels, as well as support hysteresis (bowtie)
monitoring and CDBS reference file generation. One IR dark is taken
after each anneal, to provide a check of the IR detector.

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 08 08
FGS REAcq 06 06
OBAD with Maneuver 05 05

SIGNIFICANT EVENTS: (None)


 




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