HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

 

DAILY REPORT       #4943

 

PERIOD COVERED: 5am October 1 - 5am October 2, 2009 (DOY 274/09:00z-275/09:00z)

 

OBSERVATIONS SCHEDULED

 

ACS/WFC3 11882

 

CCD Hot Pixel Annealing

 

All the data for this program is acquired using internal targets (lamps)

only, so all of the exposures should be taken during Earth occultation

time (but not during SAA passages). This program emulates the ACS

pre-flight ground calibration and post launch SMOV testing (program

8948), so that results from each epoch can be directly compared.

Extended Pixel Edge Response (EPER) and First Pixel Response (FPR) data

will be obtained over a range of signal levels for the Wide Field

Channel (WFC). The High Resolution Channel (HRC) visits have been

removed since it could not be repaired during SM4.

 

COS/NUV 11899

 

NUV Imaging Sensitivity, Cycle 17

 

The purpose of this proposal is to test NUV imaging sensitivity for a

range of target spectral energy distributions. All targets have

wide-slit STIS spectra in the HST Archive. We use eleven horizontal

branch stars in the globular cluster NGC 6681 covering a range of

effective temperatures, plus a solar-analog standard star.

 

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/CCD/MA1 11525

 

COS-GTO: STIS High Resolution Observations of the Local ISM

 

We shall use bright early-type B stars located within 150pc of the Sun

to probe the absorption properties of the interstellar gas associated

with the local cavity. By utilizing the high sensitivity and high

spectral resolution of the HST-STIS spectrograph we shall be able to

place new detection limits on absorption occurring in any highly ionized

gas associated with the lines of NV, SiIV and CIV that may be present

along these sight-lines within the local cavity. These data will be used

to test current theoretical models that generally predict far higher

absorption column densities than have been previously found. Also, the

high spectral resolution will enable far stricter limits to be placed on

the thermal widths of such highly ionized absorption lines, which

previous observations towards the Loop I region have suggested

anomalously narrow profiles consistent with their formation by either

photo ionization or highly non-equilibrium processes.

 

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/ACS/IR 11584

 

Resolving the Smallest Galaxies with ACS

 

An order of magnitude more dwarf galaxies are expected to inhabit the

Local Group, based on currently accepted galaxy formation models, than

have been observed. This discrepancy has been noted in environments

ranging from the field to rich clusters, with evidence emerging that

lower density regions contain fewer dwarfs per giant than higher density

regions, in further contrast to model predictions. However, there is no

complete census of the faintest dwarf galaxies in any environment. The

discovery of the smallest and faintest dwarfs is hampered by the

limitations in detecting such compact or low surface brightness

galaxies, and this is compounded by the great difficulty in determining

accurate distances to, or ascertaining group membership for, such faint

objects. The M81 group provides a powerful means for establishing

membership for faint galaxies in a low density region. With a distance

modulus of 27.8, the tip of the red giant branch (TRGB) appears at I ~

24, just within the reach of ground based surveys. We have completed a

65 square degree survey in the region around M81 with the CFHT/MegaCam.

Half of our survey was completed before Cycle 16 and we were awarded

time with WFPC2 to observe 15 new candidate dwarf galaxy group members

in F606W and F814W bands in order to construct color-magnitude diagrams

from which to measure accurate TRGB distances and determine star

formation and metallicity histories. The data obtained show that 8 - 9

of these objects are galaxies at the same distance as M81. In completing

our survey, we have discovered an additional 8 candidate galaxies we

propose to image with ACS in order to measure TRGB distances and

establish membership. We also wish to re-observe our smallest candidate

group member and a tidal dwarf candidate with deeper observations made

possible with ACS. Once membership has been established for this second

set of candidates, we will have a complete census of the dwarf galaxy

population in the M8 group to M_r ~ -10, allowing us to obtain a firm

measurement of the luminosity function faint-end slope, and, combined

with previous HST data, to provide a complete inventory of the age and

abundance properties for the collapsed core of the M81 group.

 

WFC3/IR 11838

 

Completing a Flux-limited Survey for X-ray Emission from Radio Jets

 

We will measure the changing flow speeds, magnetic fields, and energy

fluxes in well- resolved quasar jets found in our short-exposure Chandra

survey by combining new, deep Chandra data with radio and optical

imaging. We will image each jet with sufficient sensitivity to estimate

beaming factors and magnetic fields in several distinct regions, and so

map the variations in these parameters down the jets. HST observations

will help diagnose the role of synchrotron emission in the overall SED,

and may reveal condensations on scales less than 0.1 arcsec.

 

WFC3/IR 11915

 

IR Internal Flat Fields

 

This program is the same as 11433 (SMOV) and depends on the completion

of the IR initial alignment (Program 11425). This version contains three

instances of 37 internal orbits: to be scheduled early, middle, and near

the end of Cycle 17, in order to use the entire 110-orbit allocation.

 

In this test, we will study the stability and structure of the IR

channel flat field images through all filter elements in the WFC3-IR

channel. Flats will be monitored, i.e. to capture any temporal trends in

the flat fields and delta flats produced. High signal observations will

provide a map of the pixel-to-pixel flat field structure, as well as

identify the positions of any dust particles.

 

WFC3/IR 11926

 

IR Zero Points

 

We will measure and monitor the zeropoints through the IR filters using

observations of the white dwarf standard stars, GD153, GD71 and GD191B2B

and the solar analog standard star, P330E. Data will be taken monthly

during Cycle 17. Observations of the star cluster, NGC 104, are made

twice to check color transformations. We expect an accuracy of 2% in the

wide filter zeropoints relative to the HST photometric system, and 5% in

the medium- and narrow-band filters.

 

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 11707

 

Detecting Isolated Black Holes through Astrometric Microlensing

 

This proposal aims to make the first detection of isolated stellar-mass

black holes (BHs) in the Milky Way, and to determine their masses. Until

now, the only directly measured BH masses have come from radial-velocity

measurements of X-ray binaries. Our proposed method uses the astrometric

shifts that occur when a galactic-bulge microlensing event is caused by

a BH lens. Out of the hundreds of bulge microlensing events found

annually by the OGLE and MOA surveys, a few are found to have very long

durations (>200 days). It is generally believed that the majority of

these long- duration events are caused by lenses that are isolated BHs.

 

To test this hypothesis, we will carry out high-precision astrometry of

5 long-duration events, using the ACS/HRC camera. The expected

astrometric signal from a BH lens is >1.4 mas, at least 7 times the

demonstrated astrometric precision attainable with the HRC.

 

This proposal will thus potentially lead to the first unambiguous

detection of isolated stellar-mass BHs, and the first direct mass

measurement for isolated stellar-mass BHs through any technique.

Detection of several BHs will provide information on the frequency of

BHs in the galaxy, with implications for the slope of the IMF at high

masses, the minimum mass of progenitors that produce BHs, and

constraints on theoretical models of BH formation.

 

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).

 

FLIGHT OPERATIONS SUMMARY:

 

Significant Spacecraft Anomalies: (The following are preliminary reports

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

 

HSTARS:

12028 - GSAcq(2,1,1) at 274/17:57z failed due search radius exceeded

           flag on FGS2.

 

           Observation affected: ACS 78-82 Proposal ID# 11882 and WFC3 95-96

           Proposal ID# 11657 and 11915.

 

 

12030 - REAcq(1, 2, 1) scheduled for 274/20:30:09z failed to RGA HOLD.

 

           Observation affected: STIS 55-59 Proposals ID# 11525, 11857.

 

COMPLETED OPS REQUEST: (None)

 

COMPLETED OPS NOTES: (None)

 

                       SCHEDULED      SUCCESSFUL

FGS GSAcq               07                  06 

FGS REAcq               10                   09   

OBAD with Maneuver 06                   06                

 

SIGNIFICANT EVENTS: (None)