Daily Report #4640

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 images. 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
M1e10 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 z6. 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)