HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT      #4640

PERIOD COVERED: 5am June 25 - 5am June 26, 2008 (DOY 177/0900z-178/0900z)

OBSERVATIONS SCHEDULED

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 11237

The Origin of the Break in the AGN Luminosity Function

We propose to use NICMOS imaging to measure rest-frame optical

luminosities and morphological properties of a complete sample of faint

AGN host galaxies at redshifts z ~ 1.4. The targets are drawn from the

VLT-VIMOS Deep Survey, and they constitute a sample of the lowest

luminosity type 1 AGN known at z > 1. The spectroscopically estimated

black hole masses are up to an order of magnitude higher than expected

given their nuclear luminosities, implying highly sub-Eddington

accretion rates. This exactly matches the prediction made by recent

theoretical models of AGN evolution, according to which the faint end of

the AGN luminosity function is populated mainly by big black holes that

have already exhausted a good part of their fuel. In this proposal we

want to test further predictions of that hypothesis, by focussing on the

host galaxy properties of our low-luminosity, low- accretion AGN. If the

local ratio between black hole and bulge masses holds at least

approximately at these redshifts, one expects most of these

low-luminosity AGN to reside in fairly big ellipticals with stellar

masses around and above 10^11 solar masses (in contrast to the Seyfert

phenomenon in the local universe). With NICMOS imaging we will find out

whether that is true, implying also a sensitive test for the validity of

the M_BH/M_bulge relation at z ~ 1.4.

NIC2 11341

Lower Luminosity AGNs at Cosmologically Interesting Redshifts: SEDs and

Accretion Rates of z~0.36 Seyferts

We propose a multiwavelength campaign to constrain the SEDs of Seyferts

at z~0.36. This epoch, corresponding to a look back time of 4 Gyrs, is

cosmologically interesting for studies of the coeval development of

black holes and their host galaxy bulges. Our sample, comprising 24

Seyferts, has unprecedented high quality Keck spectroscopy and HST

imaging already invested to extract host galaxy bulge properties,

estimate black hole masses, and separate nuclear and host optical

luminosities. To supplement and extend this successful program, we

request 93 ks of Chandra time (to measure the shape and power of the

AGN-only X-ray continuum), 11 hrs each of Spitzer and Gemini (to

constrain the dust temperature), and 7 orbits of HST (to determine the

nuclear luminosity for the final 7 objects).

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 evidence 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/NIC3 11188

First Resolved Imaging of Escaping Lyman Continuum

The emission from star-forming galaxies appears to be responsible for

reionization of the universe at z>6. However, the models that attempt to

describe the detailed impact of high- redshift galaxies on the

surrounding inter-galactic medium {IGM} are strongly dependent upon

several uncertain parameters. Perhaps the most uncertain is the fraction

of HI-ionizing photons produced by young stars which escape into the

IGM. Most attempts to measure this "escape fraction" {f_esc} have

produced null results. Recently, a small subset of z~3 Lyman Break

Galaxies {LBGs} has been found exhibiting large escape fractions. It

remains unclear however, what differentiates them from other LBGs.

Several models attempt to explain how such a large fraction of ionizing

continuum can escape through the HI and dust in the ISM {eg. "chimneys"

created by SNe winds, globular cluster formation, etc.}, each producing

unique signatures which can be observed with resolved imaging of the

escaping Lyman continuum. We propose a deep, high resolution WFPC2 image

of the ionizing continuum {F336W} and the rest-frame 1500 Angstrom

continuum {F606W} of five of the six known LBGs with large escape

fractions. These LBGs all fit within a single WFPC2 pointing, yielding

high observing efficiency. Additionally, they all have z~3.1 or higher,

the optimal redshift range for probing the Lyman Continuum region with

available WFPC2 filters. These factors make our proposed sample

especially suitable for follow- up. With these data we will discern the

mechanisms responsible for producing large escape fractions, and

therefore gain insight into the process of reionization.

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:

11353 - GSacq(2,1,1) failed to RGA control @ 177/11:05:04:13z

           GSacq(2,1,1) at 177/11:05:04 failed to RGA control with QF2STOPF and

           QSTOP flags set. #44 commands did not change since previous acquisition.

           OBAD prior to acquisition had RSS error of 8.07 arcseconds.

           Observation affected: NICMOS 154 proposal #11237.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                       SCHEDULED      SUCCESSFUL  

FGS GSacq               05                  04                             

FGS REacq               10                  10        

OBAD with Maneuver 30                  30                                                 

SIGNIFICANT EVENTS: (None)