HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT      #4958

PERIOD COVERED: 5am October 23 - 5am October 26, 2009 (DOY 296/09:00z-299/09:00z)

OBSERVATIONS SCHEDULED

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/UVIS 11924

WFC3/UVIS External and Internal CTE Monitor

CCD detector Charge Transfer Inefficiency (CTI)-induced losses in

photometry and astrometry will be measured using observations of the

rich open cluster NGC6791 and with the EPER (Extended Pixel Edge

Response) method using tungsten lamp flat field exposures. Although we

do not expect to see CTE effects at the outset of Cycle 17, this CTE

monitoring program is the first of a multi-cycle program to monitor and

establish CTE-induced losses with time. We expect to measure CTE effects

with a precision comparable to the ACS measurements.

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.

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).

ACS/WFC3 11879

CCD Daily Monitor (Part 1)

This program comprises basic tests for measuring the read noise and dark

current of the ACS WFC and for tracking the growth of hot pixels. The

recorded frames are used to create bias and dark reference images for

science data reduction and calibration. This program will be executed

four days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To

facilitate scheduling, this program is split into three proposals. This

proposal covers 352 orbits (22 weeks) from 31 August 2009 to 31 January

2010.

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 11844

CCD Dark Monitor Part 1

The purpose of this proposal is to monitor the darks for the STIS CCD.

ACS/SBC 11791

The Wavelength Dependence of Accretion Disk Structure

We can now routinely measure the size of quasar accretion disks using

gravitational microlensing of lensed quasars. The next step to testing

accretion disk models is to measure the size of accretion disks as a

function of wavelength, particularly at the UV and X-ray wavelengths

that should probe the inner, strong gravity regime. Here we focus on two

four-image quasar lenses that already have optical (R band) and X-ray

size measurements using microlensing. We will combine the HST

observations with ground-based monitoring to measure the disk size as a

function of wavelength from the near-IR to the UV. We require HST to

measure the image flux ratios in the ultraviolet continuum near the

Lyman limit of the quasars. The selected targets have estimated black

hole masses that differ by an order of magnitude, and we should find

wavelength scalings for the two systems that are very different because

the Blue/UV wavelengths should correspond to parts of the disk near the

inner edge for the high mass system but not in the low mass system. The

results will be modeled using a combination of simple thin disk models

and complete relativistic disk models. While requiring only 18 orbits,

success for one system requires observations in both Cycles 16 and 17.

WFC3/UV 11730

Continued Proper Motions of the Magellanic Clouds: Orbits, Internal

Kinematics, and Distance

In Cycles 11 and 13 we obtained two epochs of ACS/HRC data for fields in

the Magellanic Clouds centered on background quasars. We used these data

to determine the proper motions of the LMC and SMC to better than 5% and

15% respectively. The results had a number of unexpected implications

for the Milky Way-LMC-SMC system and received considerable attention in

the literature and in the press. The implied three-dimensional

velocities are larger than previously believed and close to the escape

velocity in a standard 10^12 solar mass Milky Way dark halo. Our orbit

calculations suggest the Clouds may not be bound to the Milky Way or may

just be on their first passage, both of which are unexpected in view of

traditional interpretations of the Magellanic Stream. Alternatively, the

Milky Way dark halo may be a factor two more massive than previously

believed, which would be surprising in view of other observational

constraints. Also, the relative velocity between the LMC and SMC was

larger than expected, leaving open the possibility that the Clouds may

not be bound to each other. To further verify and refine our results we

requested an additional epoch data in Cycle 16 which is being executed

with WFPC2/PC due to the failure of ACS. A detailed analysis of one LMC

field shows that the field proper motion using all three epochs of data

is consistent within 1-sigma with the two-epoch data, thus verifying

that there are no major systematic effects in our previous measurements.

The random errors, however, are only smaller by a factor of 1.4 because

of the relatively large errors in the WFPC2 data. A prediction for a

fourth epoch with measurement errors similar to epochs 1 and 2 shows

that the uncertainties will improve by a factor of 3. This will allow us

to better address whether the Clouds are indeed bound to each other and

to the Milky Way. It will also allow us to constrain the internal

motions of various populations within the Clouds, and to determine a

distance to the LMC using rotational parallax. Continuation of this

highly successful program is therefore likely to provide important

additional insights. Execution in SNAPshot mode guarantees maximally

efficient use of HST resources.

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.

COS/NUV 11601

UV Spectroscopy of the Hot Bare Stellar Core H1504+65

H1504+65 is the hottest known white dwarf (Teff=200, 000 K). It has an

extraordinary surface composition. The surface is devoid of hydrogen and

helium. It is mainly composed of carbon and oxygen (by equal amounts)

and neon (2%). We obviously see the exposed core of a former red giant.

The evolutionary history of this unique object is unknown. We have

identified magnesium absorption lines in the soft X-ray photospheric

Chandra spectrum, which suggests that H1504+65 may be an O-Ne-Mg white

dwarf. We will test this hypothesis by abundance determinations of Mg

and Na. If confirmed, then H1504+65 would be the most compelling case

for the existence of single O-Ne-Mg white dwarfs.

ACS/WFC3 11564

Optical and Ultraviolet Photometry of Isolated Neutron Stars

We propose ultraviolet and B-band observations of 5 nearby, thermally

emitting neutron stars. These data will measure the Rayleigh-Jeans tails

of their spectra, providing a vital complement to X-ray spectroscopy and

helping to constrain atmospheric models, working toward the ultimate

goal of unraveling the physics of neutron stars. With these data we will

have good-quality optical and UV data for the full sample of these

objects, allowing detailed comparisons between them. Finally, the data

should allow us to measure proper motions for one or two objects, and

will serve as the reference data for the remaining objects; such proper

motions allow ages to be determined for these objects by tracing them

back to likely birth locations.

COS/NUV/FUV 11531

COS-GTO: Brown Dwarf Activity

COS will obtain ultraviolet spectra of a representative sample of brown

dwarfs to study such questions as: (1) Is the hot gas in the outer

atmospheres of young brown dwarfs heated by accretion? (2) Is the

molecular hydrogen emission due to Lyman-alpha fluorescence or

collisional excitation? (3) Are the older brown dwarfs without disks low

mass analogs of active M dwarfs with flares and transient heating? (4)

Are young brown dwarfs with disks low mass analogs of classical T Tauri

stars?

COS/NUV/FUV 11522

COS-GTO: STAR FORMATION/LYMAN-ALPHA

A sample of 20 star-forming galaxies will be observed with COS G130M.

The galaxies were selected from the Kitt Peak International

Spectroscopic Survey (KISSR) data release and cover a broad range of

luminosity, oxygen abundance, and reddening. The goal of the program is

to characterize the Lyman-alpha properties and establish correlations

with fundamental galaxy properties. Each galaxy will be observed for one

orbit.

NIC 11417

NICMOS Detector Read noise and Dark Current

The NICMOS detector characteristics will be monitored during the entire

extent of the SMOV4 through a set of dark exposures. This will also

allow a determination of the detector temperature from bias

measurements. The data should be obtained in SAA-free orbits,

approximately every 24 hours. In addition, the detector read noise and

the detector shading profiles will be measured once a week.

WFC3/ACS/UVIS 11360

Star Formation in Nearby Galaxies

Star formation is a fundamental astrophysical process; it controls

phenomena ranging from the evolution of galaxies and nucleosynthesis to

the origins of planetary systems and abodes for life. The WFC3,

optimized at both UV and IR wavelengths and equipped with an extensive

array of narrow-band filters, brings unique capabilities to this area of

study. The WFC3 Scientific Oversight Committee (SOC) proposes an

integrated program on star formation in the nearby universe which will

fully exploit these new abilities. Our targets range from the

well-resolved R136 in 30 Dor in the LMC (the nearest super star cluster)

and M82 (the nearest starbursting galaxy) to about half a dozen other

nearby galaxies that sample a wide range of star-formation rates and

environments. Our program consists of broad band multiwavelength imaging

over the entire range from the UV to the near-IR, aimed at studying the

ages and metallicities of stellar populations, revealing young stars

that are still hidden by dust at optical wavelengths, and showing the

integrated properties of star clusters. Narrow-band imaging of the same

environments will allow us to measure star-formation rates, gas

pressure, chemical abundances, extinction, and shock morphologies. The

primary scientific issues to be addressed are: (1) What triggers star

formation? (2) How do the properties of star-forming regions vary among

different types of galaxies and environments of different gas densities

and compositions? (3) How do these different environments affect the

history of star formation? (4) Is the stellar initial mass function

universal or determined by local conditions?

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:

18734-1 - NCS CPL Restart (23 October 09) @ 296/2124z

COMPLETED OPS NOTES: (None)

                       SCHEDULED      SUCCESSFUL   

FGS GSAcq               22                  21    

FGS REAcq               20                  20                

OBAD with Maneuver 17                  17              

SIGNIFICANT EVENTS:

Flash Report: NCS CPL Restart

Ops Request 18734-1 to restart the NCS CPL has been successfully

completed.

The PCE was nominally commanded off at 296/14:29z UTC. The CPL was

transitioned from Standby to Pressure Prime at a reservoir setpoint of

+5 degC at 296/14:30z UTC. After achieving stability at the pressure

prime setpoint, the CPL was transitioned from Pressure Prime to Startup

at 296/16:41z UTC, enabling the 50 W Startup heater.

At this time, the +5 degC setpoint will be maintained until stable

operation at that temperature is confirmed.

Flash Report: SIs Recovered

ACS, STIS, COS, and WFC3 have all been recovered to their Operate states

via the intercept SMS, with WFC3 being the last to complete at 297/1329z.

ACS and COS have resumed observations. WFC3 will spend until ~297/2033z

UTC going through its detector cooldowns with its first observation

beginning at 297/2203z.