HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

 

DAILY REPORT      #4946

 

PERIOD COVERED: 5am October 6 - 5am October 7, 2009 (DOY 279/09:00z-280/09:00z)

 

OBSERVATIONS SCHEDULED

 

COS/FUV 11592

 

Testing the Origin(s) of the Highly Ionized High-Velocity Clouds: A

Survey of Galactic Halo Stars at z>3 kpc

 

Cosmological simulation predicts that highly ionized gas plays an

important role in the formation and evolution of galaxies and their

interplay with the intergalactic medium. The NASA HST and FUSE missions

have revealed high-velocity CIV and OVI absorption along extragalactic

sightlines through the Galactic halo. These highly ionized high-velocity

clouds (HVCs) could cover 85% of the sky and have a detection rate

higher than the HI HVCs. Two competing, equally exciting, theories may

explain the origin of these highly ionized HVCs: 1) the "Galactic"

theory, where the HVCs are the result of feedback processes and trace

the disk-halo mass exchange, perhaps including the accretion of matter

condensing from an extended corona; 2) the "Local Group" theory, where

they are part of the local warm-hot intergalactic medium, representing

some of the missing baryonic matter of the Universe. Only direct

distance determinations can discriminate between these models. Our group

has found that some of these highly ionized HVCs have a Galactic origin,

based on STIS observations of one star at z<5.3 kpc. We propose an HST

FUV spectral survey to search for and characterize the high velocity NV,

CIV, and SiIV interstellar absorption toward 24 stars at much larger

distances than any previous searches (4<d<21 kpc, 3<|z|<13 kpc). COS

will provide atomic to highly ionized species (e.g., OI, CII, CIV, SiIV)

that can be observed at sufficient resolution (R~22, 000) to not only

detect these highly ionized HVCs but also to model their properties and

understand their physics and origins. This survey is only possible

because of the high sensitivity of COS in the FUV spectral range.

 

COS/FUV/ACS/WFC/WFC3/UV/ 11632 NUV The Gaseous Corona of M31

 

We propose to obtain ultraviolet spectroscopy of the halo of M31, to

probe for a hot corona on scales of 30-40 pc from the galaxy. We seek to

obtain absorption line spectra of O I, Mg II, Si II, C IV, and Si IV

toward bright QSOs located behind the galaxy. One of the sightlines

falls on the projection of Ibata's giant stream. All background sources

have been vetted with GALEX photometry and are therefore bright enough

for observation. If hot gas is detected with this initial study, we will

endeavor to use a grid of background sources to map the structure and

kinematics of this gas in detail. M31 is the nearest major spiral galaxy

for which such a study can be undertaken, other than our own Milky Way.

Recent studies find a substantial population of HI high velocity clouds

at distances form M31 of up to 50 kpc, and there is well documented

evidence of disrupted satellites and tidal streams. These observations

will shed light on the hot gaseous halo of M31, but also will help in

interpreting QSO sightlines at high redshift.

 

NIC 11413

 

NICMOS Mode-2 Coronagraphic Target Acquisition Test

 

NICMOS coronagraphy is extremely sensitive to small centering errors

which can result from imperfections in the target acquisition (TA)

process. During HST Cycle 7 the on-board (TA) process was augmented

which resulted in post-acquisition dispersions of target placements

w.r.t. the fiducial position in the occulting system with 1-sigma RSX

(a) dispersions of 0.08 mas (or ~ 1/10 pixel) between targets and (b)

repeatability of 0.04 mas for identically executed target acquisitions

of the same target. This levels of acquisition precision and accuracy

are required to enable high-contrast imaging near occulted targets of

which the system is capable. This proposal corresponds to SMOV activity

NIC-10.

 

NIC1 11205

 

The Effects of Multiplicity on the Evolution of Young Stellar Objects: A

NICMOS Imaging Study

 

We propose to use NICMOS to investigate the multiplicity of young

stellar objects (YSOs) in the Orion B molecular cloud. Previous

observations with the Spitzer Space Telescope have revealed a remarkable

star forming filament near the NGC 2068 reflection nebula. The

population of YSOs associated with the filament exhibit a surprisingly

wide range of circumstellar evolutionary states, from deeply embedded

protostars to T Tauri accretion disks. Many of the circumstellar disks

themselves show evidence for significant dust evolution, including grain

growth and settling and cleared inner holes, apparently in spite of the

very young age of these stars. We will estimate the binary fraction of a

representative sample of objects in these various stages of evolution in

order to test whether companions may play a significant role in that

evolution.

 

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.

 

NIC2/WFC3/IR 11548

 

Infrared Imaging of Protostars in the Orion A Cloud: The Role of

Environment in Star Formation

 

We propose NICMOS and WFC3/IR observations of a sample of 252 protostars

identified in the Orion A cloud with the Spitzer Space Telescope. These

observations will image the scattered light escaping the protostellar

envelopes, providing information on the shapes of outflow cavities, the

inclinations of the protostars, and the overall morphologies of the

envelopes. In addition, we ask for Spitzer time to obtain 55-95 micron

spectra of 75 of the protostars. Combining these new data with existing

3.6 to 70 micron photometry and forthcoming 5-40 micron spectra measured

with the Spitzer Space Telescope, we will determine the physical

properties of the protostars such as envelope density, luminosity,

infall rate, and outflow cavity opening angle. By examining how these

properties vary with stellar density (i.e. clusters vs. groups vs.

isolation) and the properties of the surrounding molecular cloud; we can

directly measure how the surrounding environment influences protostellar

evolution, and consequently, the formation of stars and planetary

systems. Ultimately, this data will guide the development of a theory of

protostellar evolution.

 

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 11849

 

STIS CCD Hot Pixel Annealing

 

This purpose of this activity is to repair radiation induced hot pixel

damage to the STIS CCD by warming the CCD to the ambient instrument

temperature and annealing radiation-damaged pixels.

 

Radiation damage creates hot pixels in the STIS CCD Detector. Many of

these hot pixels can be repaired by warming the CCD from its normal

operating temperature near -83 deg. C to the ambient instrument

temperature (~ +5 deg. C) for several hours. The number of hot pixels

repaired is a function of annealing temperature. The effectiveness of

the CCD hot pixel annealing process is assessed by measuring the dark

current behavior before and after annealing and by searching for any

window contamination effects.

 

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/UVI/IR 11557

 

The Nature of Low-Ionization BAL QSOs

 

The rare subclass of optically-selected QSOs known as low-ionization

broad absorption line (LoBAL) QSOs show signs of high-velocity gas

outflows and reddened continua indicative of dust obscuration. Recent

studies show that galaxies hosting LoBAL QSOs tend to be ultraluminous

infrared systems that are undergoing mergers, and that have dominant

young (< 100 Myr) stellar populations. Such studies support the idea

that LoBAL QSOs represent a short- lived phase early in the life of

QSOs, when powerful AGN-driven winds are blowing away the dust and gas

surrounding the QSO. If so, understanding LoBALs would be critical in

the study of phenomena regulating black hole and galaxy evolution, such

as AGN feedback and the early stages of nuclear accretion. These

results, however, come from very small samples that may have serious

selection biases. We are therefore taking a more aggressive approach by

conducting a systematic multiwavelength study of a volume limited sample

of LoBAL QSOs at 0.5 < z < 0.6 drawn from SDSS. We propose to image

their host galaxies in two bands using WFC3/UVIS and WFC3/IR to study

the morphologies for signs of recent tidal interactions and to map their

interaction and star forming histories. We will thus determine whether

LoBAL QSOs are truly exclusively found in young merging systems that are

likely to be in the early stages of nuclear accretion.

 

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: (None)

 

COMPLETED OPS REQUEST: (None)

 

COMPLETED OPS NOTES: (None)

 

                      SCHEDULED      SUCCESSFUL 

FGS GSAcq               7                    7                    

FGS REAcq               7                    7                 

OBAD with Maneuver 5                    5                

 

SIGNIFICANT EVENTS: (None)