Notice: Due to the conversion of some ACS WFC or HRC observations into

WFPC2, or NICMOS observations after the loss of ACS CCD science

capability in January, there may be an occasional discrepancy between a

proposal's listed (and correct) instrument usage and the abstract that

follows it.

 

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

 

DAILY REPORT      # 4421

 

PERIOD COVERED: UT August 07, 2007 (DOY 219)

 

OBSERVATIONS SCHEDULED

 

ACS/SBC 11225

 

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.

 

NIC1/NIC2/NIC3 8794

 

NICMOS Post-SAA calibration - CR Persistence Part 5

 

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 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.

 

WFPC2 11124

 

The Origin of QSO Absorption Lines from QSOs

 

We propose using WFPC2 to image the fields of 10 redshift z ~ 0.7

foreground {FG} QSOs which lie within ~29-151 kpc of the sightlines to

high-z background {BG} QSOs. A surprisingly high fraction of the BG QSO

spectra show strong MgII {2796,2803} absorption lines at precisely the

same redshifts as the FG QSOs. The high resolution capabilities of WFPC2

are needed to understand the origin of these absorption systems, in two

ways. First, we wish to explore the FG QSO environment as close as

possible to the position of the BG QSO, to search for interloping group

or cluster galaxies which might be responsible for the absorption, or

irregularly shaped post-merger debris between the FG and BG QSO which

may indicate the presence of large amount of disrupted gas along a

sightline. Similarly, high resolution images are needed to search for

signs of tidal interactions between any galaxies which might be found

close to the FG QSO. Such features might provide evidence of young

merging events causing the start of QSO duty cycles and producing

outflows from the central AGN. Such winds may be responsible for the

observed absorption lines. Second, we seek to measure the intrinsic

parameters of the FG QSO host galaxy, such as luminosity and morphology,

to correlate with the properties of the MgII absorption lines. We wish

to observe each field through the F814W filter, close to the rest-frame

B-band of the FG QSO. These blue data can reveal enhanced star formation

regions close to the nucleus of the host galaxy, which may be indicative

of galaxy mergers with the FG QSO host. The FG QSO environment offers

quite a different set of phenomena which might be responsible for MgII

absorption, providing an important comparison to studies of MgII

absorption from regular field galaxies.

 

WFPC2 11178

 

Probing Solar System History with Orbits, Masses, and Colors of

Transneptunian Binaries

 

The recent discovery of numerous transneptunian binaries {TNBs} opens a

window into dynamical conditions in the protoplanetary disk where they

formed as well as the history of subsequent events which sculpted the

outer Solar System and emplaced them onto their present day heliocentric

orbits. To date, at least 47 TNBs have been discovered, but only about a

dozen have had their mutual orbits and separate colors determined,

frustrating their use to investigate numerous important scientific

questions. The current shortage of data especially cripples scientific

investigations requiring statistical comparisons among the ensemble

characteristics. We propose to obtain sufficient astrometry and

photometry of 23 TNBs to compute their mutual orbits and system masses

and to determine separate primary and secondary colors, roughly tripling

the sample for which this information is known, as well as extending it

to include systems of two near-equal size bodies. To make the most

efficient possible use of HST, we will use a Monte Carlo technique to

optimally schedule our observations.

 

WFPC2 11307

 

Completing the ACS Nearby Galaxy Survey with WFPC2

 

We are requesting 25 orbits of Director's Discretionary Time to complete

the primary science goals of our highly-ranked ACS Nearby Galaxy Survey

Treasury program {ANGST}. Our program lost ~2/3 of its orbits due to the

ACS failure. Roughly half of these were restored as a result of an

appeal to the Telescope Time Review Board which re-scoped the program.

The Board's response to our appeal was explicit in terms of which

targets were to be observed and how. We were directed to request

Director's discretionary time for the components of the appeal which

were not granted by the Review Board, but which were vital to the

success of the program. The observing strategy for ANGST is two-fold: to

obtain one deep field per galaxy which enables derivation of an accurate

ancient star formation history, and to obtain radial tilings sufficient

for recovering the full star formation history. The Review Board granted

WFPC2 observations for deep fields in 7 galaxies, but no time for radial

tilings. However, recovering the full star formation history of a galaxy

is not possible without additional radial coverage. We have searched the

archives for observations which may be used in place of the tilings

{conceding some of the Treasury goals, but providing significant

constraints on the full star formation history}, and have identified

suitable observations for all but two of the galaxies. Here we request

DD time for radial tilings for those last two galaxies.

 

WFPC2/ACS/SBC 11020

 

Cycle 15 Focus Monitor

 

The focus of HST is measured primarily with ACS/HRC over full CVZ orbits

to obtain accurate mean focus values via a well sampled breathing curve.

Coma and astigmatism are also determined from the same data in order to

further understand orbital effects on image quality and optical

alignments. To monitor the stability of ACS to WFPC2 relative focii,

we've carried over from previous focus monitor programs parallel

observations taken with the two cameras at suitable orientations of

previously observed targets, and interspersed them with the HRC CVZ

visits.

 

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               06                 06             

FGS REacq               08                 08              

OBAD with Maneuver 30                 30              

 

SIGNIFICANT EVENTS: (None)