Status Report

NASA Hubble Space Telescope Daily Report # 3667

By SpaceRef Editor
August 5, 2004
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science




ACS/HRC 10050

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.


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.

ACS/WFC 10120

The Formation Histories and Dynamical Roles of X-ray Binaries in
Globular Clusters

Close binaries are fundamental to the dynamical stability and
evolution of globular clusters, but large populations have been
extremely difficult to identify. Chandra X-ray images provide a
revolutionary resource, revealing a few to dozens of low-luminosity
X-ray sources in every cluster deeply examined; our own Chandra
programs uniformly study these ubiquitous X-ray sources {close
binaries and their progeny} in 11 clusters. However, definitive
understanding of the nature of the various X-ray subpopulations
requires the identification of optical counterparts, and HST is the
demonstrated key in these crowded environments. We thus propose a
proven, efficient, and uniform, HST multicolor imaging program for
optical identifications in 6 of our clusters with Chandra data
on-hand, but which lack adequate optical images in the HST archive.
The proposed ACS images will permit statistical classifications into
the various subtypes: CVs, qLMXBs, BY Dra’s/RS CVn’s {and MSPs}. A
unique aspect of our program is that our clusters span a range of
physical properties such as central concentration, cluster size, and
mass–essential ingredients in the formation, evolution, and dynamical
roles of cluster binaries. Exploiting this range of properties, we
have identified a relation that provides the first compelling link
between the number of X-ray sources and the predicted stellar
encounter frequency in globular cluster cores. But further progress in
understanding the details implicit in this relationship {e.g., whether
CVs and qLMXBs formed primarily via stellar encounters, while BY
Dra’s/RS CVn’s are mainly primordial binaries} demands uniform optical
identifications for multiple clusters, spanning the full range
physical properties.

ACS/WFC 10210

Groups of Dwarf Galaxies: Pools of Mostly Dark Matter?

Within 5 Mpc, there are 6 groups with well-known luminous galaxies but
there also appears to be a comparable number of groups containing only
dwarfs. If these dwarf entities are truly bound then M/L values are an
order of magnitude higher than values found for groups with luminous
spiral galaxies. There are theoretical reasons to anticipate that low
mass halos may frequently be mostly dark. The dynamical influence of
low mass halos is negligible in familiar groups with luminous members.
By contrast, a study of the dynamics of `groups of dwarfs’ may provide
direct evidence of the existence of dark matter potential wells with
few baryons. The goal of the present study is to gather detailed
information on the 3-D distribution of dwarf galaxies suspected to lie
within 7 groups of dwarfs within 5 Mpc. Distances with 7% relative
accuracy can be measured with the Tip of the Giant Branch method with
ACS and integrations within 1 orbit per target.

ACS/WFC 9727

Exploration of the SN Ia Hubble Diagram at z > 1.2

In the spirit of a Treasury proposal, we propose to organize, and
deliver to the astronomical community, non-proprietary follow-up
observations of ~10 Type Ia supernovae at 1<z<1.7 that are expected to
be discovered in a Cycle 12 Treasury proposal. Together with the
currently available sample, this would provide a Hubble diagram with
over 20 SNe Ia in this redshift range, where it is possible to test
the current cosmological model in the epoch of deceleration: If z ~
0.5 SNe Ia are fainter due to evolution rather than an accelerating
expansion, they should continue to get fainter at even higher
redshifts. This size sample will show trends and outliers, and permit
a more rigorous treatment of the asymmetric amplification distribution
from gravitational lensing. This is a key redshift range for the
studies of dark energy that will be done with future surveys {and
future instruments now being designed}; this dataset will lay the
ground-work for these studies by establishing the simple properties of
the supernovae in this redshift range, including magnitudes, colors,
and timescales. If considered more appropriate, this proposal could be
treated as a part of a Treasury or Director’s Discretionary program,
since the data would be available to everybody immediately, and we
would welcome others who would want to work with us on it.

FGS 10113

Trigonometric Calibration of the Period- Luminosity Relations for
Fundamental and First-Overtone Galactic Cepheids

Cepheids are the primary distance indicators for the extragalactic
distance scale and the Hubble constant. The Hubble Constant Key
Project set the zero-point for their Cepheid distance scale by
adopting a distance to the LMC, averaged over a variety of techniques.
However, different methods give an LMC distance modulus ranging from
18.1 to 18.8, and the uncertainty in the Cepheid zero-point is now the
largest contributor to the error budget for H_0. Moreover, the low
metallicity of the LMC raises additional concerns, since the PL
relation probably depends on metallicity. The zero-point can be
determined from Hipparcos parallaxes of Galactic Cepheids out to
several hundred parsecs, but with a typical parallax error of 0.5-1
mas, the Hipparcos error bars are uncomfortably large for this
demanding application. By contrast, HST’s FGS1R interferometer can
achieve astrometric accuracy of 0.2 mas. We propose to use FGS1R to
determine trigonometric parallaxes for a sample of 9 nearby Cepheids,
including both fundamental {F} and first-overtone {FO} pulsators. We
show that the improvement in the PL relations for F and FO Cepheids
will be dramatic. We will determine the PL slopes from our nearby
solar- metallicity sample alone, without recourse to nearby galaxies
and the issue of [Fe/H] dependence. The zero-point will be determined
robustly to about 0.05 mag, based on accurate, purely geometrical
measurements. All of this can be achieved in the next few years with
HST, without having to wait for the technically demanding and risky
SIM and GAIA missions well into the next decade.

NIC/NIC3 10226

The NICMOS Grism Parallel Survey

We propose to continue managing the NICMOS pure parallel program.
Based on our experience, we are well prepared to make optimal use of
the parallel opportunities. The improved sensitivity and efficiency of
our observations will substantially increase the number of
line-emitting galaxies detected. As our previous work has
demonstrated, the most frequently detected line is Halpha at
0.7<z<1.9, which provides an excellent measure of current star
formation rate. We will also detect star-forming and active galaxies
in other redshift ranges using other emission lines. The grism
observations will produce by far the best available Halpha luminosity
functions over the crucial–but poorly observed–redshift range where
galaxies appear to have assembled most of their stellar mass. This key
process of galaxy evolution needs to be studied with IR data; we found
that observations at shorter wavelengths appear to have missed a large
fraction of the star-formation in galaxies, due to dust reddening. We
will also obtain deep F110W and F160W images, to examine the space
densities and morphologies of faint red galaxies. In addition to
carrying out the public parallels, we will make the fully reduced and
calibrated images and spectra available on-line, with some
ground-based data for the deepest parallel fields included.

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.

STIS/CCD 10018

CCD Dark Monitor-Part 2

Monitor the darks for the STIS CCD.

STIS/CCD 10020

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/CCD 10030

STIS/CCD Spectroscopic Sensitivity Monitor for Cycle 12

Monitor sensitivity of each CCD grating mode to detect any change due
to contamination or other causes.

STIS/MA1 10034

Cycle 12 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.

WFPC2 10071

WFPC2 CYCLE 12 Supplemental Darks Part 3/3

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


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

HSTAR 9500: STIS Mechanism Power (OMBMC5V) flagged OOL red low
(6.2943-5 Volts) @ 216/15:57:22Z. In FN format, STIS was not in use.
Under investigation.

HSTAR 9501: STIS Suspend @ 216/16:38:21. Received Status Buffer
message STIS 738 and STIS 734. Under investigation.

HSTAR 9503: STIS Zone 3B Temperature (OTCZ3BT) began flagging OOL
intermittently @ 217/06:54:32Z, reaching a low value of 16.6429 ¬?C.
Lower limit is 17.0 ¬?C. Under investigation.


  • 17238-0 Real Time Map @ 216/0929z
  • 17239-0 Dump STIS Memory after Suspend @ 216/1818z


  • 0900-1 COMMAND PROBLEM @ 216/20:32:19z
  • 0924-0 HSTAR Documentation for Guide Star Acq Failure/Loss of Lock @ 216/08:57:58z (Ref HSTAR # 9499)

                       SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq            08                       08
FGS REacq            05                       04             216/08:57:58z 
(Ref HSTAR # 9499)
FHST Update          10                       10


STIS suspended @ 216/16:38:21Z following receipt of two Status Buffer
messages (STIS 738 and STIS 734). See HSTARs 9501. Prior to the
suspend, STIS was in Operate with Low Voltage on. MEB/SES + 5 Volt
Power Supply (OMBMC5V) was flagging OOL low (6.29425-5 Volts) coming
out of ZOE @ 216/15:57Z. See HSTAR 9500. Subsequent extraction of SSR
engineering data indicated there was a sudden drop from the nominal
operating Voltage @ 216/15:55:21Z. No STIS SPC was taking place around
the initial OOL or the suspend. Successfully executed STIS memory dump
after Suspend @ 216/18:18Z (OR 17239 with ROP NS-10).

SpaceRef staff editor.