HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT       #4634

PERIOD COVERED: 5am June 17 - 5am June 18, 2008 (DOY 169/0900z-170/0900z)

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 8795

NICMOS Post-SAA Calibration - CR Persistence Part 6

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 DARKSs. 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 i

mages. Each observation will need its own CRMAP, as different SAA

passages leave different imprints on the NICMOS detectors.

NIC2 11143

NICMOS Imaging of Submillimeter Galaxies with CO and PAH Redshifts

We propose to obtain F110W and F160W imaging of 10 z~2.4 submillimeter

galaxies {SMGs} whose optical redshifts have been confirmed by the

detection of millimeter CO and/or mid- infrared PAH emission. With the

4000A break falling within/between the two imaging filters, we will be

able to study these sources' spatially resolved stellar populations

{modulo extinction} in the rest-frame optical. SMGs' large luminosities

appear to be due largely to merger-triggered starbursts; high-resolution

NICMOS imaging will help us understand the stellar masses, mass ratios,

and other properties of the merger progenitors, valuable information in

the effort to model the mass assembly history of the universe.

NIC3/WFPC2 11192

NICMOS Confirmation of Candidates of the Most Luminous Galaxies at z > 7

While the deepest pencil-beam near-IR survey suggested that the Universe

was too young to build up many luminous galaxies by z ~ 7--8 (Bouwens &

Illingworth 2006), there is also evidenc indicating the contrary. It is

now known that some galaxies with stellar masses of M>1e10 Msun were

already in place by z ~ 6--7, which strongly suggests that their

progenitors should be significantly more luminous, and hence detectable

in deep, wide-field near-IR surveys (Yan et al. 2006). As galaxies at

such a high redshift should manifest themselves as "dropouts" from the

optical, we have carried out a very wide-field, deep near-IR survey in

the GOODS fields to search for z-band dropouts as candidates of galaxies

at z > 7. In total, six promising candidates have been found in ~ 300

sq. arcmin to J_AB ~ 24.5 mag (corresponding to restframe M(UV) < -22.5

mag at z ~ 7). By contrast, the galaxy luminosity function (LF)

suggested in BI06 would predict at most 3--5 galaxies over the entire

2-pi sky at this brightness level. Here we propose to observe these

candidates with NIC3 in F110W and F160W to further investigate their

nature. If any of these candidates are indeed at z > 7, the result will

lead to a completely new picture of star formation in the early

universe. If none of our candidates are consistent with being at z > 7,

then the depth and area of our near-IR survey (from which the candidates

are drawn) will let us set a very stringent upper limit on the bright

end of the galaxy LF at those redshift. As a result, our program will

still be able to provide new clues about the processes of early galaxy

formation, such as their dust contents and their merging time scale (Yan

et al. 2006).

WFPC2 11022

WFPC2 Cycle 15 Decontaminations and Associated Observations

This proposal is for the WFPC2 decons. Also included are instrument

monitors tied to decons: photometric stability check, focus monitor,

pre- and post-decon internals {bias, intflats, kspots, & darks}, UV

throughput check, VISFLAT sweep, and internal UV flat check.

WFPC2 11235

HST NICMOS Survey of the Nuclear Regions of Luminous Infrared Galaxies

in the Local Universe

At luminosities above 10^11.4 L_sun, the space density of far-infrared

selected galaxies exceeds that of optically selected galaxies. These

`luminous infrared galaxies' {LIRGs} are primarily interacting or

merging disk galaxies undergoing enhanced star formation and Active

Galactic Nuclei {AGN} activity, possibly triggered as the objects

transform into massive S0 and elliptical merger remnants. We propose

NICMOS NIC2 imaging of the nuclear regions of a complete sample of 88

L_IR > 10^11.4 L_sun luminous infrared galaxies in the IRAS Revised

Bright Galaxy Sample {RBGS: i.e., 60 micron flux density > 5.24 Jy}.

This sample is ideal not only in its completeness and sample size, but

also in the proximity and brightness of the galaxies. The superb

sensitivity and resolution of NICMOS NIC2 on HST enables a unique

opportunity to study the detailed structure of the nuclear regions,

where dust obscuration may mask star clusters, AGN and additional nuclei

from optical view, with a resolution significantly higher than possible

with Spitzer IRAC. This survey thus provides a crucial component to our

study of the dynamics and evolution of IR galaxies presently underway

with Wide-Field, HST ACS/WFC and Spitzer IRAC observations of these 88

galaxies. Imaging will be done with the F160W filter {H-band} to examine

as a function of both luminosity and merger stage {i} the luminosity and

distribution of embedded star clusters, {ii} the presence of optically

obscured AGN and nuclei, {iii} the correlation between the distribution

of 1.6 micron emission and the mid- IR emission as detected by Spitzer

IRAC, {iv} the evidence of bars or bridges that may funnel fuel into the

nuclear region, and {v} the ages of star clusters for which photometry

is available via ACS/WFC observations. The NICMOS data, combined with

the HST ACS, Spitzer, and GALEX observations of this sample, will result

in the most comprehensive study of merging and interacting galaxies to

date.

WFPC2/NIC3/ACS/SBC 11144

Building on the Significant NICMOS Investment in GOODS: A Bright,

Wide-Area Search for z>=7 Galaxies

One of the most exciting frontiers in observational cosmology has been

to trace the buildup and evolution of galaxies from very early times.

While hierarchical theory teaches us that the star formation rate in

galaxies likely starts out small and builds up gradually, only recently

has it been possible to see evidence for this observationally through

the evolution of the LF from z~6 to z~3. Establishing that this build up

occurs from even earlier times {z~7-8} has been difficult, however, due

to the small size of current high-redshift z~7-8 samples -- now

numbering in the range of ~4-10 sources. Expanding the size of these

samples is absolutely essential, if we are to push current studies of

galaxy buildup back to even earlier times. Fortunately, we should soon

be able to do so, thanks to ~50 arcmin**2 of deep {26.9 AB mag at 5

sigma} NICMOS 1.6 micron data that will be available over the two ACS

GOODS fields as a result of one recent 180- orbit ACS backup program and

a smaller program. These data will nearly triple the deep near-IR

imaging currently available and represent a significant resource for

finding and characterizing the brightest high-redshift sources -- since

high-redshift candidates can be easily identified in these data from

their red z-H colours. Unfortunately, the red z-H colours of these

candidates are not sufficient to determine that these sources are at

z>=7, and it is important also to have deep photometry at 1.1 microns.

To obtain this crucial information, we propose to follow up each of

these z-H dropouts with NICMOS at 1.1 microns to determine which are at

high redshift and thus significantly expand our sample of luminous, z>=7

galaxies. Since preliminary studies indicate that these candidates occur

in only 30% of the NIC3 fields, our follow-up strategy is ~3 times as

efficient as without this preselection and 9 times as efficient as a

search in a field with no pre-existing data. In total, we expect to

identify ~8 luminous z-dropouts and possibly ~2 z~10 J-dropouts as a

result of this program, more than tripling the number currently known.

The increased sample sizes are important if we are to solidify current

conclusions about galaxy buildup and the evolution of the LF from z~8.

In addition to the high redshift science, these deep 1.1 micron data

would have significant value for many diverse endeavors, including {1}

improving our constraints on the stellar mass density at z~7-10 and {2}

doubling the number of galaxies at z~6 for which we can estimate dust

obscuration.

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                 09                 09                   

OBAD with Maneuver  30                  30              

SIGNIFICANT EVENTS: (None)