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       # 4475

PERIOD COVERED: UT October 24, 2007 (DOY 297)

OBSERVATIONS SCHEDULED

WFPC2 10795

The Largest Galaxies in the Local Universe: New Light on Disk Galaxy

Formation?

In the standard scenario of disk galaxy formation in a hierarchical

Universe, large disks form late via the accretion of either hot or cold

gas. Direct observational evidence for such late accretion-driven disk

formation has not been forthcoming. In this proposal, we describe the

discovery of a rare new type of galaxy that may be examples of massive

disks in the process of assembly. We have identified a sample of three

such galaxies selected from the SDSS DR4. They are extremely large

{diameters over 100 kpc} and highly luminous systems with amorphous

structures {no obvious spiral arms or bulges}. They are larger than the

largest normal spirals in the survey, and have significantly bluer

colors, lower metallicities, lower dust extinctions, higher UV

luminosities and higher total star formation rates than the most massive

ordinary spirals. We request HST images in the rest-frame near-UV and

red to provide detailed maps of the underlying structure of these

galaxies as well as the distribution of the young stars. The

interstellar medium of these galaxies is evidently quite different from

that of normal large spirals and starburst galaxies and they may be

experiencing a different mode of star formation. We believe they are

worthy of further investigation with the high-resolution imaging

capabilities of HST.

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.

NIC3 11082

NICMOS Imaging of GOODS: Probing the Evolution of the Earliest Massive

Galaxies, Galaxies Beyond Reionization, and the High Redshift Obscured

Universe

(uses ACS/SBC and WFPC2)

Deep near-infrared imaging provides the only avenue towards

understanding a host of astrophysical problems, including: finding

galaxies and AGN at z > 7, the evolution of the most massive galaxies,

the triggering of star formation in dusty galaxies, and revealing

properties of obscured AGN. As such, we propose to observe 60 selected

areas of the GOODS North and South fields with NICMOS Camera 3 in the

F160W band pointed at known massive M > 10^11 M_0 galaxies at z > 2

discovered through deep Spitzer imaging. The depth we will reach {26.5

AB at 5 sigma} in H_160 allows us to study the internal properties of

these galaxies, including their sizes and morphologies, and to

understand how scaling relations such as the Kormendy relationship

evolved. Although NIC3 is out of focus and undersampled, it is currently

our best opportunity to study these galaxies, while also sampling enough

area to perform a general NIR survey 1/3 the size of an ACS GOODS field.

These data will be a significant resource, invaluable for many other

science goals, including discovering high redshift galaxies at z > 7,

the evolution of galaxies onto the Hubble sequence, as well as examining

obscured AGN and dusty star formation at z > 1.5. The GOODS fields are

the natural location for HST to perform a deep NICMOS imaging program,

as extensive data from space and ground based observatories such as

Chandra, GALEX, Spitzer, NOAO, Keck, Subaru, VLT, JCMT, and the VLA are

currently available for these regions. Deep high-resolution

near-infrared observations are the one missing ingredient to this

survey, filling in an important gap to create the deepest, largest, and

most uniform data set for studying the faint and distant universe. The

importance of these images will increase with time as new facilities

come on line, most notably WFC3 and ALMA, and for the planning of future

JWST observations.

WFPC2 11194

Beyond the Bullet: Direct Detection of Dark Matter in Merging Galaxy

Clusters

Our comparison of the distribution of baryons {stars and gas} and mass

{from weak lensing} in the "Bullet" Cluster has recently yielded

concrete evidence for dark matter independent of basic assumptions

regarding the nature of the gravitational force. The one incomplete

aspect of the argument relates to potential, although highly unlikely,

coincidences {special alignments along the line of sight, and/or

fortuitous canceling in non-standard gravitational models} that can

always be invoked against results derived from the study of one object.

Therefore, we propose to complete this line of investigations by

increasing the size of our sample with observations of an additional

cluster. Here we propose to obtain HST WFPC2 imaging mosaics around the

cores of the cluster to detect at high significance if the weak

gravitational lensing mass peaks are routinely displaced from the X-ray

plasma clouds and aligned with the galaxy concentrations in interacting

clusters. With a relatively modest allocation of time, we seek to

complete a significant step toward the eventual resolution of the dark

matter question.

WFPC2 11203

A Search for Circumstellar Disks and Planetary-Mass Companions around

Brown Dwarfs in Taurus

During a 1-orbit program in Cycle 14, we used WFPC2 to obtain the first

direct image of a circumstellar disk around a brown dwarf. These data

have provided fundamental new constraints on the formation process of

brown dwarfs and the properties of their disks. To search for additional

direct detections of disks around brown dwarfs and to search for

planetary-mass companions to these objects, we propose a WFPC2 survey of

32 brown dwarfs in the Taurus star-forming region.

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                07                 07                   

FGS REacq                07                 07                     

OBAD with Maneuver  28                 28        

SIGNIFICANT EVENTS: (None)