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Daily Report #4634



 
 
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Old June 18th 08, 12:27 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #4634

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 images. 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
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 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)


 




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