HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

 

DAILY REPORT       #4936

 

PERIOD COVERED: 5am September 22 - 5am September 23, 2009 (DOY 265/09:00z-266/09:00z)

 

OBSERVATIONS SCHEDULED

 

ACS/WFC3/STIS/CCD 11889

 

Photometric Cross-Calibration using Stellar Flux Standards

 

The purpose of this proposal is to: A) Verify the ACS HRC and WFC

photometric calibrations with a repeat visit to one of the three primary

WDs. B) Measure the change in sensitivity with time for bright stars

(which would include any small CTE contributions). C) Continue to

investigate the ~2% discrepancy between ACS flux calibration and that of

STIS (ACS ISR 2007-06). The goal is to measure any filter bandpass

shifts in ACS or rule out the possibility of shifts as the primary

contributors to the ACS/STIS discrepancy for cool stars.

 

COS/FUV 11482

 

FUV Detector Dark

 

The purpose of this proposal is to measure the FUV 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 data in order to verify the nominal operation of the

detector, and for use in the CalCOS calibration pipeline. Variations of

count rate as a function of orbital position will be analyzed to find

dependence of dark rate on proximity to the SAA.

 

This is SMOV Activity COS-24.

 

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 11466

 

NUV Detector Dark

 

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 data in order to verify the nominal operation of the

detector, and for use in the CalCOS calibration pipeline. Variations of

count rate as a function of orbital position will be analyzed to find

dependence of dark rate on proximity to the SAA.

 

COS/NUV 11481

 

COS NUV High S/N Verification

 

The purpose of this proposal is to collect data at several central

wavelengths for each NUV grating in Time-Tag mode, using multiple FP-POS

positions, in order to verify that high signal-to-noise spectra can be

obtained. All spectra will have enough counts to permit standard

reduction techniques to be used to obtain spectra with a signal-to-noise

ratio of at least 30. Very high signal-to-noise spectra will also be

obtained in some medium resolution modes in order to demonstrate that a

signal-to-noise ratio of at least 100 is possible.

 

COS/NUV/FUV/WFC3/UVIS/IR 11520

 

COS-GTO: QSO Absorbers, Galaxies and Large-Scale Structures in the Local Universe

 

This is a program to probe the large scale structure of baryons in the

universe, including addressing questions of baryon fraction, physical

conditions and relationships between absorbers and large-scale

structures of galaxies. Besides these specific goals, this proposed GTO

program also probes a large enough total path length in Ly alpha and OVI

to add significantly to what STIS/FUSE has already observed. Several

Galactic High Velocity Cloud Complexes also are probed by these

sightlines, particularly the M Complex. The total path length of this

proposed program for Ly alpha large-scale structure surveys is

delta_z~5.5.

 

We have selected a variety of targets to address these questions, under

the following subcategories:

 

1. Target 8 bright BL Lac objects to search for low contrast Ly alpha

absorbers from the warm-hot interstellar medium (WHIM).

 

2. Ly alpha cloud sizes: The targets are a bright AGN pair which yield

tangential distance separations of 100--500 kpc at z=0.01--0.05, where

galaxy surveys are excellent. This pair has two filaments and two voids

in this distance range.

 

3. Probes of starburst outflows: The targets are bright AGN, <= 100 kpc

in projection out of the minor axis of nearby starburst galaxies.

 

4. A large galaxy's gaseous halo: Three probes of the kinematics and

metallicity of a single L* galaxy halo. These observations includes

G130M, G160M exposures at SNR~20 and G285M at 2850A and SNR~10 for MgII.

The 2L* galaxy, ESO 157-G049 (cz=1678 km/s), being probed by these

sightlines has an available H I 21cm map from ATCA, H alpha imaging from

CTIO and long-slit spectra from MSSSO.

 

5. Dwarf galaxy winds: These targets probe the kinematics and

metallicities of outflows from active and inactive (in terms of star

formation) dwarfs.

 

FGS 11704

 

The Ages of Globular Clusters and the Population II Distance Scale

 

Globular clusters are the oldest objects in the universe whose age can

be accurately determined. The dominant error in globular cluster age

determinations is the uncertain Population II distance scale. We propose

to use FGS 1R to obtain parallaxes with an accuracy of 0.2

milliarcsecond for 9 main sequence stars with [Fe/H] < -1.5. This will

determine the absolute magnitude of these stars with accuracies of 0.04

to 0.06mag. This data will be used to determine the distance to 24

metal-poor globular clusters using main sequence fitting. These

distances (with errors of 0.05 mag) will be used to determine the ages

of globular clusters using the luminosity of the subgiant branch as an

age indicator. This will yield absolute ages with an accuracy of 5%,

about a factor of two improvement over current estimates. Coupled with

existing parallaxes for more metal-rich stars, we will be able to

accurately determine the age for globular clusters over a wide range of

metallicities in order to study the early formation history of the Milky

Way and provide an independent estimate of the age of the universe.

 

The Hipparcos database contains only 1 star with [Fe/H] < -1.4 and an

absolute magnitude error less than 0.18 mag which is suitable for use in

main sequence fitting. Previous attempts at main sequence fitting to

metal-poor globular clusters have had to rely on theoretical

calibrations of the color of the main sequence. Our HST parallax program

will remove this source of possible systematic error and yield distances

to metal- poor globular clusters which are significantly more accurate

than possible with the current parallax data. The HST parallax data will

have errors which are 10 times smaller than the current parallax data.

Using the HST parallaxes, we will obtain main sequence fitting distances

to 11 globular clusters which contain over 500 RR Lyrae stars. This will

allow us to calibrate the absolute magnitude of RR Lyrae stars, a

commonly used Population II distance indicator.

 

NIC1/NIC2/NIC3 11947

 

Extended Dark Monitoring

 

This program takes a series of darks to obtain darks (including

amplifier glow, dark current, and shading profiles) for all three

cameras in the read-out sequences used in Cycle 17. A set of 12 orbits

will be observed every two months for a total of 72 orbits for a 12

month Cycle 17. This is a continuation of Cycle 16 program 11330 scaled

down by ~80%.

 

The first orbit (Visit A0) should be scheduled in the NICMOS SMOV after

the DC Transfer Test (11406) and at least 36h before the Filter Wheel

Test (11407). Data download using fast track.

 

The following 28 orbits (visit A1-N2) should be scheduled AFTER the SMOV

Proposal 11407 (Filter Wheel Test). This is done in order to monitor the

dark current following an adjustment of the NCS set-point. These visits

should be executed until the final temperature is reached during SMOV.

 

NIC1/NIC2/NIC3 8795

 

NICMOS Post-SAA Calibration - CR Persistence Part 6

 

This is 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 'Use After' 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 darks. 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 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/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/ACS/IR 11359

 

Panchromatic WFC3 Survey of Galaxies at Intermediate z: Early Release

Science Program for Wide Field Camera 3

 

The unique panchromatic capabilities of WFC3 will be used to survey the

structure and evolution of galaxies at the peak of the galaxy assembly

epoch. Deep ultraviolet and near-IR imaging and slitless spectroscopy of

existing deep multi-color ACS fields will be used to gauge

star-formation and the growth of stellar mass as a function of

morphology, structure and surrounding density in the critical epoch 1 <

z < 4. Images in the F225W, F275W, and F336W filters will identify

galaxies at z < 1.5 from their UV continuum breaks, and provide

star-formation indicators tied directly to both local and z > 3

populations. Deep near-IR (F125W and F160W) images will probe the

stellar mass function well below 10^9 Msun for mass-complete samples.

Lastly, the WFC3 slitless UV and near-IR grisms will be used to measure

redshifts and star-formation rates from H- alpha and rest-frame UV

continuum slope. This WFC3 ERS program will survey one 4 x 2 mosaic for

a total area of 50 square arcminutes to 5-sigma depths of m_AB = 27 in

most filters from the mid-UV through the near-IR.

 

This multicolor high spatial resolution data set will allow the user to

gauge the growth of galaxies through star-formation and merging. High

precision photometric and low- resolution spectroscopic redshifts will

allow accurate determinations of the faint-end of the luminosity and

mass functions, and will shed light on merging and tidal disruption of

stellar and gaseous disks. The WFC3 images will also allow detailed

studies of the internal structure of galaxies, and the distribution of

young and old stellar populations. This program will demonstrate the

unique power of WFC3 by applying its many diverse modes and full

panchromatic capability to a forefront problem in astrophysics.

 

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/IR/S/C 12006

 

CSM Test

 

The purpose of this proposal is to test of the repeatability of the CSM

mechanism as measured using bright IR blobs. This proposal will also

test the amount of motion of the CSM per commanded CSM step. This

proposal observe the same field, with a high background level, using

increasing number of CSM steps and then progressively moves the CSM

back, backtracking the first half of the observations.

 

WFC3/UVIS 11559

 

Jovian Upheaval and Its Impact on Vortices

 

We propose observations of Jupiter with global coverage at high

resolution to quantify changes in its atmosphere during and following

the global upheaval. Only HST has the capability to obtain images with

enough spatial resolution and contrast to extract velocity fields (we

will use our newly developed technique to accomplish this), and with

WFC3 we can image Jupiter in its entirety in a single exposure. We are

in particular interested in the Red Oval BA: Will the Oval be long

lived, remain red, or turn white again, disappear? Both the merger of

its precursors, and change in color has never before been witnessed. The

Great Red Spot: This storm system appears to decrease in size and has

become rounder, both as derived from its associated cloud deck, but also

from its potential vorticity, a more dynamically-relevant quantity. How

will the GRS evolve? Will it swallow the new vortices detected in

amateur images at this same latitude band? How will this effect the

potential vorticity? In addition, we hope to understand disturbances and

stagnation points, both of which were detected during the present global

upheaval: are these cyclonic regions, can they spawn anticyclones (as

suggested by amateur images)?

 

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.

 

FLIGHT OPERATIONS SUMMARY:

 

Significant Spacecraft Anomalies: (The following are preliminary reports

of potential non-nominal performance that will be investigated.)

 

HSTARS:

 

12018 - GSAcq (1,2,1), scheduled from 265/09:27:51z - 265/09:34:40z, resulted in

           Fine Lock Back-up (1,0,1).

 

           Observations possibly affected: COS 119 Proposal ID# 11895;  STIS 20 & 21,

           Proposal ID# 11889.

 

 

12021 - WFC3 Channel Select Mechanism (CSM) move scheduled at

           265/22:53:50z was unsuccessful because the final position achieved was

           not within tolerance of the desired position.

 

           Observations affected: WFC3 33 - 36 Proposal Id#12006.

 

 

COMPLETED OPS REQUEST: (None)

 

COMPLETED OPS NOTES:

1912-0 - Adjust WFC3 FSW Error Count @ 266/0043z

 

                       SCHEDULED      SUCCESSFUL

FGS GSAcq               13                  13              

FGS REAcq               02                  02 

OBAD with Maneuver 13                  13    

 

SIGNIFICANT EVENTS: (None)