Status Report

NASA Hubble Space Telescope Daily Report # 3424

By SpaceRef Editor
August 13, 2003
Filed under , ,

HUBBLE SPACE TELESCOPE

DAILY REPORT # 3424

PERIOD COVERED: DOY 223

OBSERVATIONS SCHEDULED

WFPC2 9592

WFPC2 CYCLE 11 Standard Darks

This dark calibration program obtains dark frames every week in order to
provide
data for the ongoing calibration of the CCD dark current rate, and to
monitor
and characterize the evolution of hot pixels. Over an extended period these
data
will also provide a monitor of radiation damage to the CCDs.

WFPC2 9595

WFPC2 CYCLE 11 SUPPLEMENTAL DARKS pt3/3

This dark calibration program obtains 3 dark frames every day to provide
data
for monitoring and characterizing the evolution of hot pixels.

STIS 9606

CCD Dark Monitor-Part 2

Monitor the darks for the STIS CCD.

STIS 9608

CCD Bias Monitor – Part 2

Monitor the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1, and
1×1
at gain = 4, to build up high-S/N superbiases and track the evolution of hot
columns.

STIS 9615

Cycle 11 MAMA Dark Monitor

This test performs the routine monitoring of the MAMA detector dark noise.
This
proposal will provide the primary means of checking on health of the MAMA
detectors systems through frequent monitoring of the background count rate.
The
purpose is to look for evidence of change in dark indicative of detector
problem
developing.

ACS 9675

CCD Daily Monitor

This program consists of basic tests to monitor, the read noise, the
development
of hot pixels and test for any source of noise in ACS CCD detectors. This
programme will be executed once a day for the entire lifetime of ACS.

STIS 9708

STIS Pure Parallel Imaging Program: Cycle 11

This is the default archival pure parallel program for STIS during cycle 11.

WFPC2 9709

POMS Test Proposal: WFII parallel archive proposal

This is the generic target version of the WFPC2 Archival Pure Parallel
program.
The program will be used to take parallel images of random areas of the sky,
following the recommendations of the 2002 Parallels Working Group.

WFPC2 9710

POMS Test Proposal: WFII backup parallel archive proposal

This is a POMS test proposal designed to simulate scientific plans.

STIS/CCD/MA1/MA2 9732

Detecting the hottest white dwarf in a dwarf nova: V446 Her as a laboratory
for
irradiated accretion discs

V446 Her {Nova Her 1960} is an object with very unique combination of
properties: it experienced 40 years ago a nova eruption and started regular
dwarf nova outburst activity 10-20 years ago. We suggest that the white
dwarf,
heated to several 100.000K during the thermonuclear surface burning event,
suppressed through irradiation of the accretion disc the thermal instability
underlying dwarf nova outbursts for the first 20-30 years following the nova
eruption. The gradual cooling of the white dwarf results in a continuos
decrease
of the irradiating flux and, as a result, at present the outer parts of the
accretion disc are thermally unstable and produce the observed dwarf nova
outbursts. V446 Her provides, hence, the exceptional opportunity to study
the
structure of a strongly irradiated and thermally unstable accretion disc. To
make rigorous use of V446 Her as a laboratory for irradiated accretion
discs, it
is mandatory to know the temperature of the still extremely hot white dwarf
illuminating the disc. We propose to obtain STIS UV spectroscopy of V446 Her
in
order to detect the photospheric emission of the white dwarf, and to derive
accurately its temperature. With this parameter at hand, we will be able to
determine the dynamical importance of disc irradiation. Using our HST/STIS
data
of V446 Her, we will derive an observational calibration of the essential
parameter in the framework of irradiated accretion discs i.e. the
reprocessing
efficiency beta, with considerable importance not only for our understanding
of
CV’s but also of Super Soft Sources, X-Ray binaries, and AGN.

ACS 9760

ACS Imaging of the Gemini Deep Deep Survey Fields: Galaxy Assembly at z =
1.5

We are presently carrying out the deepest redshift survey ever undertaken
{the
Gemini Deep Deep Survey}. Spectra of extraordinary quality have been taken
in
order to obtain redshifts in the so-called "redshift desert" at 1<z<2. This
redshift range corresponds to the epoch of peak galaxy formation. In this
proposal we request 40 orbits of ACS imaging to determine the morphologies
of
100-120 candidate early-type galaxies with known redshifts in our survey
fields.
We seek to determine if these systems are indeed elliptical galaxies and to
link
their morphological states to their spectroscopically determined ages,
recent
star-formation histories, and to the evolving global stellar mass function
at
the peak epoch of galaxy assembly.

ACS/WFC 9830

A New Member of the Local Group?

An August 2002 detection at 21-cm of a previously undetected low surface
brightness galaxy yielded a radial velocity of -360 km/s. As the galaxy is
located in the opposite part of the sky as the Virgo cluster, its seems
quite
likely that this velocity places it squarely in the Local Group {LG}. The
characteristics of this galaxy, if its at a distance of 1-2 Mpc, are such
that
it easily could have escaped detection from previous searches. Its optical
surface brightness is low and its integrated blue magnitude would lie in the
range -6.5 to -8.0. The total H I mass is less than 3 x 10^5 solar masses.
The H
I profile is relatively low S/N and distorted, with a signal that is spread
out
over about 80 km/s. much larger than the internal velocity dispersion of the
galaxy. This is likely the result of an interaction {most probably with
M31}.
With the efficiency of the ACS, we can easily detect the TRGB population in
this
object using V and I observations in 2 orbits. The goal here is to provide
confirming evidence that this object is indeed a member of the LG by
obtaining
its distance via the now well calibrated TRGB method using V-I as the filter
system. If indeed in the LG {which seems likely} it would also represent a
new
kind of dwarf galaxy as its considerably more compact than other LG dwarfs
of
similar absolute magnitude.

ACS/HRC 9853

A Search for Young Binary Brown Dwarfs: Constraining Formation Scenarios and
Masses Through Multiplicity

We propose to use the Advanced Camera for Surveys / High Resolution Camera
to
conduct a direct imaging multiplicity survey of 34 young brown dwarfs in the
nearest regions of recent star formation, the T association Taurus-Auriga
and
the OB association Upper Scorpius. The determined multiplicity fraction, the
separation distribution, and the mass ratio distribution will offer
stringent
observational constraints on proposed brown dwarf formation scenarios.
Moreover,
the small semi-major axes of known field and open cluster brown dwarf
binaries
suggest the exciting possibility of our identifying several very close
binaries
{< 15 AU}. Continued monitoring of these systems would yield, on a decade
timescale, the first dynamical mass estimates of T Tauri brown dwarfs. With
masses intermediate between those of stars and planets, brown dwarfs offer
our
best hope of relating the reasonably well understood processes of star
formation
to the less well understood processes of planet formation.

STIS/CCD/MA1 9876

Where is the Local Hot Gas?

We wish to sample the absorption characteristics of 3 lines-of-sight in the
local interstellar medium to establish the physical location of the
production
sites of the highly ionized absorption lines of CIV, SiIV and NV. Such
lines are
formed at gas temperatures of ~ 100, 000K and all have been widely observed
throughout the Galaxy. However, evidence for the formation of any of these
high
ions within the hot gas of the Local Bubble {LB} remains inconclusive,
supporting the similar lack of detections of the OVI ion {T ~ 300, 000K}
within
100pc recently reported by the FUSE satellite. Using our recently gained
information on the contours of the neutral boundary to the LB, we have
selected
3 pairs of stars located just within, and just beyond the LB boundary. We
shall
test whether high ionization ions are formed either {a} beyond the LB
boundary
in more distant interstellar bubbles of hot gas, {b} at the conductive
interface
of the LB neutral boundary, or {c} at possible conductive interfaces
between hot
gas within the LB and the diffuse clouds embedded within it. Hopefully,
these
observations will enable theorists to better model the {anomalous}
ionization
state, pressure and chemical abundance of the local interstellar gas and
will
assist in the interpretation of data soon to be gained from the NASA CHIPS
mission.

FGS 9969

FGS Astrometry of the Extrasolar Planet of Epsilon Eridani

We propose observations with HST/FGS in Position Mode to determine the
astrometric elements {perturbation orbit semimajor axis and inclination} of
the
candidate extra-solar planet around the K2 V star Epsilon Eridani that has
been
detected by Doppler spectroscopy. These observations will also permit us to
determine the actual mass of the planet by providing the sin{i} factor
which can
not be determined with the radial velocity method. High precision radial
velocity {RV} measurements spanning the years 1980.8–2000.0 for the nearby
{3.22 pc} star Epsilon Eri show convincing variations with a period of ~ 7
yrs.
These data represent a combination of six independent data sets taken with
four
different telescopes. A least squares orbital solution using robust
estimation
yields orbital parameters of period, P = 6.9 yrs, velocity K- amplitude = 19
m/s, eccentricity e = 0.6, projected companion mass M_B sin{i} = 0.83
M_Jupiter.
An estimate of the inclination yields a perturbation semi-major axis, Alpha
=
0arcs0022, easily within the reach of HST/FGS astrometry.

ACS 9984

Cosmic Shear With ACS Pure Parallels

Small distortions in the shapes of background galaxies by foreground mass
provide a powerful method of directly measuring the amount and distribution
of
dark matter. Several groups have recently detected this weak lensing by
large-scale structure, also called cosmic shear. The high resolution and
sensitivity of HST/ACS provide a unique opportunity to measure cosmic shear
accurately on small scales. Using 260 parallel orbits in Sloan textiti
{F775W}
we will measure for the first time: beginlistosetlength sep0cm
setlengthemsep0cm
setlength opsep0cm em the cosmic shear variance on scales <0.7 arcmin, em
the
skewness of the shear distribution, and em the magnification effect.
endlist Our
measurements will determine the amplitude of the mass power spectrum
sigma_8Omega_m^0.5, with signal-to-noise {s/n} ~ 20, and the mass density
Omega_m with s/n=4. They will be done at small angular scales where
non-linear
effects dominate the power spectrum, providing a test of the gravitational
instability paradigm for structure formation. Measurements on these scales
are
not possible from the ground, because of the systematic effects induced by
PSF
smearing from seeing. Having many independent lines of sight reduces the
uncertainty due to cosmic variance, making parallel observations ideal.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports of
potential non-nominal performance that will be investigated.) None

COMPLETED OPS REQs: None

OPS NOTES EXECUTED: None

                          SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq               8                         8
FGS REacq               6                         6
FHST Update             20                       20
LOSS of LOCK

SIGNIFICANT EVENTS:

Completed CCS 5.0.3 Load, Dump and Compare test 223/13:37Z-19:05Z. Test
verified uplink,
dump and compare of HST486 loads, including FSW, hardware, table and SPC
loads. The test
also successfully exercised a 32 kbps memory dump and a partial parameters
table uplink.
However, during the NSSC-1 FSW dump, CCS reported an error "could not
establish socket to
SDH". This is a known problem, fix is scheduled for next CCS Release 5.0.3
installment on
8/13. HITT will verify the function following the upgrade. All activities
were commanded
from the "D" String. Data collection activities were executed on the "D"
String and run in
parallel on the "B" String for comparison purposes.

SpaceRef staff editor.