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      # 4437

PERIOD COVERED: UT August 29, 2007 (DOY 241)

OBSERVATIONS SCHEDULED

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.

NIC2 11219

Active Galactic Nuclei in nearby galaxies: a new view of the origin of

the radio-loud radio- quiet dichotomy?

Using archival HST and Chandra observations of 34 nearby early-type

galaxies {drawn from a complete radio selected sample} we have found

evidence that the radio-loud/radio-quiet dichotomy is directly connected

to the structure of the inner regions of their host galaxies in the

following sense: [1] Radio-loud AGN are associated with galaxies with

shallow cores in their light profiles [2] Radio-quiet AGN are only

hosted by galaxies with steep cusps. Since the brightness profile is

determined by the galaxy's evolution, through its merger history, our

results suggest that the same process sets the AGN flavour. This

provides us with a novel tool to explore the co-evolution of galaxies

and supermassive black holes, and it opens a new path to understand the

origin of the radio-loud/radio-quiet AGN dichotomy. Currently our

analysis is statistically incomplete as the brightness profile is not

available for 82 of the 116 targets. Most galaxies were not observed

with HST, while in some cases the study is obstructed by the presence of

dust features. We here propose to perform an infrared NICMOS snapshot

survey of these 82 galaxies. This will enable us to i} test the reality

of the dichotomic behaviour in a substantially larger sample; ii} extend

the comparison between radio-loud and radio-quiet AGN to a larger range

of luminosities.

WFPC2 10789

The Role of Environment in the Formation of Dwarf Galaxies

Clusters of galaxies contain an overdensity of dwarfs compared to the

field. Within galaxy clusters there is also a correlation between the

overdensity of dwarfs and local galaxy density, such that areas of lower

galaxy density contain more dwarfs per giant. The origin of these

'extra' dwarfs is unknown, but a large fraction of them did not form

through standard collapses early in the universe. Some dwarf ellipticals

in clusters have metal rich and young {< 6 Gyr} stellar populations

while others contain old metal poor populations, suggesting multiple

formation mechanisms and time scales. We propose to test the idea that

dwarfs descend from galaxies accreted into clusters during the past 8

Gyr by correlating ages and metallicities of dwarfs with their internal

structures - spiral arms, bars, and disks. If dwarfs originate from more

massive galaxies then these features should be common in metal rich and

young dwarfs. On the other hand, if no correlation is found it would

suggest that dwarfs form through in-situ collapses of gas in the

intragalactic medium after the universe was reionized.

WFPC2 10818

Very Young Globular Clusters in M31 ?

We propose to use HST's unique high spatial resolution imaging

capabilities to conclusively confirm or refute the presence of alleged

very young globular clusters in M31. Such young globular clusters with

ages < 3 Gyr are not present in our galaxy, and, if real, would lead to

a striking difference in the age distribution of the GCs between M31 and

the Milky Way. If the apparent presence of very young globular clusters

in M31 is confirmed through our proposed ACS imaging {now WFPC2 imaging}

with HST, this would suggest major differences in the history of

assembly of the two galaxies, with probable substantial late accretion

into M31 which did not occur in our own galaxy.

WFPC2 10915

ACS Nearby Galaxy Survey

Existing HST observations of nearby galaxies comprise a sparse and

highly non-uniform archive, making comprehensive comparative studies

among galaxies essentially impossible. We propose to secure HST's

lasting impact on the study of nearby galaxies by undertaking a

systematic, complete, and carefully crafted imaging survey of ALL

galaxies in the Local Universe outside the Local Group. The resulting

images will allow unprecedented measurements of: {1} the star formation

history {SFH} of a >100 Mpc^3 volume of the Universe with a time

resolution of Delta[log{t}]=0.25; {2} correlations between spatially

resolved SFHs and environment; {3} the structure and properties of thick

disks and stellar halos; and {4} the color distributions, sizes, and

specific frequencies of globular and disk clusters as a function of

galaxy mass and environment. To reach these goals, we will use a

combination of wide-field tiling and pointed deep imaging to obtain

uniform data on all 72 galaxies within a volume-limited sample extending

to ~3.5 Mpc, with an extension to the M81 group. For each galaxy, the

wide-field imaging will cover out to ~1.5 times the optical radius and

will reach photometric depths of at least 2 magnitudes below the tip of

the red giant branch throughout the limits of the survey volume. One

additional deep pointing per galaxy will reach SNR~10 for red clump

stars, sufficient to recover the ancient SFH from the color-magnitude

diagram. This proposal will produce photometric information for ~100

million stars {comparable to the number in the SDSS survey} and uniform

multi- color images of half a square degree of sky. The resulting

archive will establish the fundamental optical database for nearby

galaxies, in preparation for the shift of high- resolution imaging to

the near-infrared.

WFPC2 11033

Full Moon Earth Flats Closeout

Flat field exposures will be obtained by observing the moonlit Earth

with the broadband WFPC2 filters F606W and F814W, which saturate in the

minimum exposure time on the sunlit Earth. These observations will be

used to improve the flats currently in the pipeline and are part of the

WFPC2 closeout operations. Because CTE effects are large for star flats

and small for full field illumination, Earth flats are the superior

technique.

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               05                 05                       

FGS REacq               06                 06                         

OBAD with Maneuver 24                 24              

SIGNIFICANT EVENTS: (None)