Status Report

NASA Hubble Space Telescope Daily Report #3904

By SpaceRef Editor
July 21, 2005
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HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science


PERIOD COVERED: UT July 18, 2005 (DOY 199)


ACS/HRC 10377

ACS Earth Flats

High signal sky flats will be obtained by observing the bright Earth
with the HRC and WFC. These observations will be used to verify the
accuracy of the flats currently used by the pipeline and will provide
a comparison with flats derived via other techniques: L- flats from
stellar observations, sky flats from stacked GO observations, and
internal flats using the calibration lamps. Weekly coronagraphic
monitoring is required to assess the changing position of the spots.


ACS CCDs daily monitor – Cycle 13 – Part 2

This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in ACS CCD detectors. The files, biases and dark will be used to
create reference files for science calibration. This program will be
for the entire lifetime of ACS.

ACS/WFC 10235

Dark vs. luminous matter in the CenA/M83 galaxy complex

The distribution of dark vs. luminous matter on scales of 0.1-1.0 Mpc
remains poorly understood. For a nearby group, the total mass can be
determined from the radius of “the zero-velocity surface”, which
separates the group from the general Hubble flow. This new method
requires the measurement of accurate distances and radial velocities
of galaxies around the group, but gives total mass estimates
independent of assumptions about the state of relaxation or orbital
characteristics. The mass pertains to the group at the full scale to
which it is bound. Upon application in several nearest groups, the
method yields mass estimates in agreement with the sum of the virial
masses of subcomponents. However, the typical total M/L ratio for the
nearby groups of ~30 Mo/Lo implies a local mean density of matter
which is only 1/7 the canonical global density . The nearby complex of
galaxies around Cen A and M83 resembles our Local Group by the
dumb-bell concentration of objects around a pair of dominant galaxies.
Accurate distances have been acquired recently for ~20 group members
by the TRGB method using HST. We will measure TRGB distances to the 17
remaining galaxies in the region. These observations will constrain
the dynamical state of the halo surrounding the nearest giant E-galaxy
Cen A, providing a comparison with the halos of the nearest spirals.

ACS/WFC 10374

ACS photometric Stability

This program consists of three parts. In the first part we will
observe a subset of the ACS white dwarfs with HRC and ACS to verify
repeatability to ~0.2%, because the filter shifts are based on
photometric differences between stars of ~1%. These observations are
also required to establish relative magnitudes of the primary WD
standards at the 0.1% level. Targets should be GD153 and G191B2B,
which seems to have the largest V mag error of ~0.008 mag. One orbit
on the most important filters, including the grism and the prisms,
should be expended with each camera for both stars for a total of 4
orbits. In the second part will observe with HRC and WFC a solar
analog star, P330E, to estimate any shifts in the short and the long
wavelength cutoffs of selected filters. Complete filter bandpasses can
be derived directly from the ratio of grism observations with and
without the filter in place. The grism is on filter wheel 1, while
four filters of interest F330W, F344N, F660N, and F814W are on wheel
2. Each grism observation requires 3 settings: filter alone,
filter+grism, and grism alone. In the third part we obtain high S/N
photometric and spectroscopic observations of three red stars, VB-8
{M7}, 2M0038+18 {L3.5} and 2M0559-14 {T5} with HRC and WFC to verify
the photometry at the new standard position and to obtain accurate
calibration {1% or better} of the grism spectra.


An ACS H-alpha Survey of the Carina Nebula

We propose an H-alpha ACS imaging survey covering 540 square
arcminutes of the Carina Nebula, including an unbiased survey of the
bright core, and several prominent dust pillars in the rich southern
region of the nebula. Carina provides an important link between
well-studied nearby H II regions like Orion, and more distant
mini-starbusts like 30 Doradus. CVZ orbits will allow extremely
efficient use of HST to map a large area of this complex and important
region — more than 95 percent of the proposed survey will be observed
by HST for the first time. This survey will provide a complete census
of microjets, proplyds, and silhouette disks with diameters as small
as 200 AU, enough to spatially resolve disks like those in Orion, and
will provide the first catalog of outflows {jets} from embedded
low-mass stars, thin filamentary shocks, and wind-wind collisions in
Carina. An accurate census of these phenomena is needed to
characterize the star formation activity and gas dynamics as a
function of position in the nebula, and to determine if models for
protoplanetary disk evaporation from Orion are applicable in more
extreme regions. Our previous ground-based optical and IR surveys have
already revealed dozens of candidates for this type of activity — but
this is just the tip of the iceberg. Our proposed HST/ACS survey
promises to be a bonanza for understanding ongoing low-mass star
formation influenced by extremely high-mass stars.

NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration – CR Persistence Part 4

A new procedure proposed to alleviate the CR-persistence problem of
NICMOS. Dark frames will be obtained immediately upon exiting the SAA
contour 23, and every time a NICMOS exposure is scheduled within 50
minutes of coming out of the SAA. The darks will be obtained in
parallel in all three NICMOS Cameras. The POST-SAA darks will be
non-standard reference files available to users with a USEAFTER
date/time mark. The keyword ‘USEAFTER=date/time’ will also be added to
the header of each POST-SAA DARK frame. The keyword must be populated
with the time, in addition to the date, because HST crosses the SAA ~8
times per day so each POST-SAA DARK will need to have the appropriate
time specified, for users to identify the ones they need. Both the raw
and processed images will be archived as POST-SAA DARKSs. Generally we
expect that all NICMOS science/calibration observations started within
50 minutes of leaving an SAA will need such maps to remove the CR
persistence from the science images. Each observation will need its
own CRMAP, as different SAA passages leave different imprints on the
NICMOS detectors.

NIC2 10147

Detecting the elusive low mass companion around epsilon Indi

We propose coronagraphic NICMOS observations of the nearby {d = 3.6
pc} K5V star epsilon Indi {HD 209100} to search for the unknown
companion which causes a low amplitude radial velocity {RV} trend in
our 11 years of precise Doppler measurements. This RV data set places
a lower limit of 4.5 AU for the orbital semimajor axis of this
companion. Moreover, the fact that the RV trend is lacking any sign of
curvature over this long time period clearly points towards a much
larger orbital separation. Epsilon Indi also has a T dwarf {binary}
companion at a separation of 1400 AU. However, these brown dwarf
companions are too distant from the primary to induce the observed RV
variation. It is also unlikely that this nearby star has an unknown
stellar {M dwarf} companion. The RV signal is thus most probably
caused by a yet unknown giant planetary or brown dwarf companion at a
separation of more than 5 AU. Because epsilon Indi is so near to the
Sun, it constitutes an ideal target for high contrast imaging with
NICMOS in its coronagraphic mode. Indeed, NICMOS coronagraphy is
capable of detecting objects down to 15 Jupiter masses at separations
greater than 2.3 arcseconds {S/N=25} – precisely the separation and
mass range indicated by our Doppler spectroscopy. Only 2 orbits of
HST/NICMOS observations could directly image the coolest and lowest
mass companion ever found around a solar-type star.

WFPC2 10359

WFPC2 CYCLE 13 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.


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


#9893 – GSacq(1,2,1) Resulted in Fine Lock Backup (1,0,1) @199/0252z
GSacq(1,2,1) scheduled at 199/02:49:37 resulted in fine lock backup
(1,0,1) due to scan step limit exceeded on fgs 2.

#9894 – GSACQ(2,1,2) fine lock backup, scan step limit exceeded on FGS
@199/1513z GSACQ(2,1,2) at 199/15:08:28 ended in fine lock backup on
FGS 2 due to scan step limit exceeded on FGS 1 at 15:12:48.

#9895 – ReAcq(2,1,2) loss of lock during acquisition @199/0935z
ReAcq(2,1,2) at 199/09:32:17 lost fine lock at 09:35:48 and reacquired
at 09:36:15, second attempt was successful.

#17475-0 – GenSlew for Proposal 10147- Slot#14 @199/1625z
#17476-0 – GenSlew for Proposal 10147- Slot#13 @199/1627z

#1355-0 – Transfer FSW 2.8A Loads to CMD Queue on all strings @199/2025z

              SCHEDULED     SUCCESSFUL
FGS Gsacq      16              16
FGS Reacq      03              03
FHST Update    16              16


SpaceRef staff editor.