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Daily Report # 4356



 
 
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Old May 7th 07, 02:25 PM posted to sci.astro.hubble
Cooper, Joe
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Posts: 568
Default Daily Report # 4356

Notice: For the foreseeable future, the daily reports may contain apparent
discrepancies between some proposal descriptions and the listed instrument
usage. This is due to the conversion of previously approved ACS WFC or HRC
observations into WFPC2, or NICMOS observations subsequent to the loss of
ACS CCD science capability in late January.


HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4356

PERIOD COVERED: UT May 04,05,06, 2007 (DOY 124,125,126)

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 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.

NIC3 11080

Exploring the Scaling Laws of Star Formation

As a variety of surveys of the local and distant Universe are approaching a
full census of galaxy populations, our attention needs to turn towards
understanding and quantifying the physical mechanisms that trigger and
regulate the large-scale star formation rates {SFRs} in galaxies.

ACS/SBC 11056

Improved Sensitivity SBC Prisms

The flux calibration of the SBC {PR110L and PR130L} will be improved by
observing for each prism white dwarf standards {WD1657+343 and LTT9491}. The
blue standard star WD1657+343 has previously been observed with ACS/SBC and
will serve as a reference point to track time dependent variations. LTT9491
is much redder and thus will be used to investigate the sensitivity curve of
?red? targets to check for a potential red leak of the SBC. Additionally,
LTT9491 shows various strong absorption lines which can be used to confirm
the wavelength calibration of the PR110L and PR130L prisms. The standard
stars are observed at a variety of pointings across the SBC detector in
order to map spatial variations. LTT9491 will also be observed with ACS/HRC
PR200L to obtain an improved flux calibration from about 1800 A to 4000 A.

WFPC2 11029

WFPC2 CYCLE 15 Intflat Linearity Check and Filter Rotation Anomaly Monitor

Intflat observations will be taken to provide a linearity check: the
linearity test consists of a series of intflats in F555W, in each gain and
each shutter. A combination of intflats, visflats, and earthflats will be
used to check the repeatability of filter wheel motions. {Intflat sequences
tied to decons, visits 1-18 in prop 10363, have been moved to the cycle 15
decon proposal xxxx for easier scheduling.} Note: long-exposure WFPC2
intflats must be scheduled during ACS anneals to prevent stray light from
the WFPC2 lamps from contaminating long ACS external exposures.

ACS/SBC/WFPC2 10904

Star formation in extended UV disk {XUV-disk} galaxies

The Galaxy Evolution Explorer {GALEX} has discovered the existence of
extended UV-disk {XUV-disk} galaxies. This class of intriguing spiral
galaxies is distinguished by UV-bright regions of star formation located at
extreme galactocentric radii, commonly reaching many times the optical
extent of each target. XUV-disks represent a population of late-type
galaxies still actively building, or significantly augmenting, their stellar
disk in the outer, low-density environment. Prior to GALEX, such regions
were considered to be far more stable against star formation than now
realized. Our work on these targets has led to the recognition of the XUV
phenomenon as probing a diverse population of galaxies which, although
having certain commonality in terms of their present XUV star formation,
have apparently experienced different star formation histories {as judged by
their outer disk UV- optical colors and morphology}. In ordinary spirals,
disk formation occurred at a much earlier epoch, making today's XUV-disks
useful templates for commonplace, high z galaxies. The diverse XUV-disks in
our sample may represent snapshots of different phases in the disk building
process. We seek to characterize the demographics of star forming regions
occupying this environmental range, especially in contrast to their inner
disk counterparts. HST imaging is needed to accurately characterize the
massive stars and clusters which have, in fact, managed to form. The GALEX
observations are limited by 5" resolution. Deep ACS FUV, B, V, I, and
H-alpha imaging {along with parallel WFPC2 data} will allow: {1} photometric
classification of the OB star population, {2} constraint on the cluster mass
function and age distribution, {3} critical accounting for possible leakage
of Lyman continuum photons in a porous ISM or an IMF change, and {4}
population synthesis modeling of the field SFH on Gyr timescales. We benefit
from extensive archival HST observations of our target galaxies, although
the outer disk has yet to be probed.

WFPC2 10890

Morphologies of the Most Extreme High-Redshift Mid-IR-Luminous Galaxies

The formative phase of the most massive galaxies may be extremely luminous,
characterized by intense star- and AGN-formation. Till now, few such
galaxies have been unambiguously identified at high redshift, restricting us
to the study of low-redshift ultraluminous infrared galaxies as possible
analogs. We have recently discovered a sample of objects which may indeed
represent this early phase in galaxy formation, and are undertaking an
extensive multiwavelength study of this population. These objects are bright
at mid-IR wavelengths {F[24um]0.8mJy}, but deep ground based imaging
suggests extremely faint {and in some cases extended} optical counterparts
{R~24-27}. Deep K-band images show barely resolved galaxies. Mid-infrared
spectroscopy with Spitzer/IRS reveals that they have redshifts z ~ 2-2.5,
suggesting bolometric luminosities ~10^{13-14}Lsun! We propose to obtain
deep ACS F814W and NIC2 F160W images of these sources and their environs in
order to determine kpc-scale morphologies and surface photometry for these
galaxies. The proposed observations will help us determine whether these
extreme objects are merging systems, massive obscured starbursts {with
obscuration on kpc scales!} or very reddened {locally obscured} AGN hosted
by intrinsically low-luminosity galaxies.

WFPC2 10880

The host galaxies of QSO2s: AGN feeding and evolution at high luminosities

Now that the presence of supermassive black holes in the nuclei of galaxies
is a well established fact, other questions related to the AGN phenomena
still have to be answered. Problems of particular interest are how the AGN
gets fed, how the black hole evolves and how the evolution of the black hole
is related to the evolution of the galaxy bulge. Here we propose to address
some of these issues using ACS/WFC + F775W snapshot images of 73 QSO2s with
redshifts in the range 0.3z0.4. These observations will be combined with
similar archival data of QSO1s and ground based data of Seyfert and normal
galaxies. First, we will intestigate whether interactions are the most
important feeding mechanism in high luminosity AGNs. This will be done in a
quantitative way, comparing the asymmetry indices of QSO2 hosts with those
of lower luminosity AGNs and normal galaxies. Second, we will do a detailed
study of the morphology of the host galaxies of both QSO types, to determine
if they are similar, or if there is an evolutionary trend from QSO2s to
QSO1s. The results from this project will represent an important step in the
understanding of AGN evolution, and may also introduce a substantial
modification to the Unified Model.

WFPC2 10877

A Snapshot Survey of the Sites of Recent, Nearby Supernovae

During the past few years, robotic {or nearly robotic} searches for
supernovae {SNe}, most notably our Lick Observatory Supernova Search {LOSS},
have found hundreds of SNe, many of them in quite nearby galaxies {cz 4000
km/s}. Most of the objects were discovered before maximum brightness, and
have follow-up photometry and spectroscopy; they include some of the
best-studied SNe to date. We propose to conduct a snapshot imaging survey of
the sites of some of these nearby objects, to obtain late-time photometry
that {through the shape of the light and color curves} will help reveal the
origin of their lingering energy. The images will also provide
high-resolution information on the local environments of SNe that are far
superior to what we can procure from the ground. For example, we will obtain
color-color and color-magnitude diagrams of stars in these SN sites, to
determine the SN progenitor masses and constraints on the reddening.
Recovery of the SNe in the new HST images will also allow us to actually
pinpoint their progenitor stars in cases where pre- explosion images exist
in the HST archive. This proposal is an extension of our successful Cycle 13
snapshot survey with ACS. It is complementary to our Cycle 15 archival
proposal, which is a continuation of our long-standing program to use
existing HST images to glean information about SN environments.

NIC2 10858

NICMOS Imaging of the z ~ 2 Spitzer Spectroscopic Sample of Ultraluminous
Infrared

We propose to obtain NICMOS images of the first large sample of high-z
ultra-luminous infrared galaxies {ULIRGs} whose redshifts and physical
states have been determined with Spitzer mid-IR spectra. The detection of
strong silicate absorption and/or PAH emission lines suggest that the these
sources are a mixture of highly obscured starbursts, AGNs and composite
systems at z=2. Although some of the spectra show PAH emission similar to
local starburst ULIRGs, their bolometric luminosities are roughly an order
of magnitude higher. One important question is if major mergers, which are
the trigger for 95% of local ULIRGs, also drive this enormous energy output
observed in our z=2 sample. The NICMOS images will allow us to {1} measure
surface brightness profiles of z~2 ULIRGs and establish if major mergers
could be common among our luminous sources at these early epochs, {2}
determine if starbursts and AGNs classified based on their mid-IR spetra
would have different morphological signatures, thus different dynamic state;
{3} make comparisons with the similar studies of ULIRGs at z ~ 0 - 1, thus
infer any evolutionary connections between high-z ULIRGs and the formation
of normal, massive galaxies and quasars observed today.

WFPC2 10845

HUNTING FOR OPTICAL COMPANIONS TO BINARY MILLISECOND PULSARS IN TERZAN 5 AND
NGC6266

We propose deep WFPC2 and NICMOS observations to search for optical
companions to binary millisecond pulsar {MSPs} in two Globular Clusters
{GCs}: Terzan 5 and NGC6266. Terzan 5 has the largest MSP population of any
GC: 33 MSP {17 in binary systems} have been discovered up to now in this
stellar system. NGC6266 ranks fifth among the GC for wealth of MSPs but it
is the only one in which all the {six} detected MSPs are in binary systems.
Only 5 optical counterparts to binary MSP companions are known in GCs {two
of them have been discovered by our group}: hence even the addition of a few
new identifications are crucial to investigate the variety of processes
occurring in binary MSPs in dense environment. The observations proposed
here would easily double/triple the existing sample of known MSP companions,
allowing the first meaningful study of the phenomena which drive the
formation and evolution of these exotic systems. Moreover, since most of
binary MSP in GC are formed via stellar interactions in the high density
regions of the cluster, the determination of the nature of the companion and
the incidence of this collisionally induced population have a significant
impact on our knowledge of the cluster dynamics. Even more interesting, the
study of the optical companions to NSs in a GC allows to derive tighter
constraints {than those obtainable for NS binaries in the galactic field} on
the properties {mass, orbital inclination and so on} of the compation star.
This has, in turn, an intrisic importance for fundamental physics since it
offers the opportunity of measuring the mass of the NS and hence to put
constraints to the equation of state of matter at nuclear equilibrium
density.

NIC3 10836

The Red Sequence at 1.3 z 1.4 in Galaxy Clusters

We propose to obtain NIC3/F160W imaging of three new IRAC-selected galaxy
clusters at 1.3 z 1.5. In combination with deep ACS/F850LP images being
obtained in Cycle 14, the resulting precision photometry in a rest ~U - R
color will allow us to construct color- magnitude diagrams which can be used
to measure the slope and scatter in the red sequence galaxies, thereby
constraining the history of star formation in the early-type galaxies. The
number of morphologically-selected early-type galaxies more luminous than L*
will allow us to test the predictions of the hierarchical merging scenario
for galaxy formation in clusters at the highest available redshifts in
galaxy clusters.

WFPC2 10815

The Blue Hook Populations of Massive Globular Clusters

Blue hook stars are a class of hot {~35,000 K} subluminous horizontal branch
stars that have been recently discovered using HST ultraviolet images of the
globular clusters omega Cen and NGC 2808. These stars occupy a region of the
HR diagram that is unexplained by canonical stellar evolution theory. Using
new theoretical evolutionary and atmospheric models, we have shown that the
blue hook stars are very likely the progeny of stars that undergo extensive
internal mixing during a late helium core flash on the white dwarf cooling
curve. This "flash mixing" produces an enormous enhancement of the surface
helium and carbon abundances, which suppresses the flux in the far
ultraviolet. Although flash mixing is more likely to occur in stars that are
born with high helium abundances, a high helium abundance, by itself, does
not explain the presence of a blue hook population - flash mixing of the
envelope is required. We propose ACS ultraviolet {SBC/F150LP} observations
of the five additional globular clusters for which the presence of blue hook
stars is suspected from longer wavelength observations. Like omega Cen and
NGC 2808, these five targets are also among the most massive globular
clusters, because less massive clusters show no evidence for blue hook
stars. Because our targets span 1.5 dex in metallicity, we will be able to
test our prediction that flash-mixing should be less drastic in metal-rich
blue hook stars. In addition, our observations will test the hypothesis that
blue hook stars only form in globular clusters massive enough to retain the
helium-enriched ejecta from the first stellar generation. If this hypothesis
is correct, then our observations will yield important constraints on the
chemical evolution and early formation history in globular clusters, as well
as the role of helium self-enrichment in producing blue horizontal branch
morphologies and multiple main sequence turnoffs. Finally, our observations
will provide new insight into the formation of the hottest horizontal branch
stars, with implications for the origin of the hot helium-rich subdwarfs in
the Galactic field.

NIC2 10798

Dark Halos and Substructure from Arcs & Einstein Rings

The surface brightness distribution of extended gravitationally lensed arcs
and Einstein rings contains super-resolved information about the lensed
object, and, more excitingly, about the smooth and clumpy mass distribution
of the lens galaxies. The source and lens information can non-parametrically
be separated, resulting in a direct "gravitational image" of the inner
mass-distribution of cosmologically-distant galaxies {Koopmans 2005;
Koopmans et al. 2006 [astro-ph/0601628]}. With this goal in mind, we propose
deep HST ACS-F555W/F814W and NICMOS-F160W WFC imaging of 20 new
gravitational-lens systems with spatially resolved lensed sources, of the 35
new lens systems discovered by the Sloan Lens ACS Survey {Bolton et al.
2005} so far, 15 of which are being imaged in Cycle-14. Each system has been
selected from the SDSS and confirmed in two time- efficient HST-ACS snapshot
programs {cycle 13&14}. High-fidelity multi-color HST images are required
{not delivered by the 420s snapshots} to isolate these lensed images
{properly cleaned, dithered and extinction-corrected} from the lens galaxy
surface brightness distribution, and apply our "gravitational maging"
technique. Our sample of 35 early-type lens galaxies to date is by far the
largest, still growing, and most uniformly selected. This minimizes
selection biases and small-number statistics, compared to smaller, often
serendipitously discovered, samples. Moreover, using the WFC provides
information on the field around the lens, higher S/N and a better understood
PSF, compared with the HRC, and one retains high spatial resolution through
drizzling. The sample of galaxy mass distributions - determined through this
method from the arcs and Einstein ring HST images - will be studied to: {i}
measure the smooth mass distribution of the lens galaxies {dark and luminous
mass are separated using the HST images and the stellar M/L values derived
from a joint stellar-dynamical analysis of each system}; {ii} quantify
statistically and individually the incidence of mass-substructure {with or
without obvious luminous counter- parts such as dwarf galaxies}. Since
dark-matter substructure could be more prevalent at higher redshift, both
results provide a direct test of this prediction of the CDM hierarchical
structure-formation model.

WFPC2 10786

Rotational state and composition of Pluto's outer satellites

We propose an intricate set of observations aimed at discovering the
rotational state of the newly discovered satellites of Pluto, S/2005 P1 and
S/2005 P2. These observations will indicate if the satellites are in
synchronous rotation or not. If they are not, then the observations will
determine the rotational period or provide tight constraints on the
amplitude. The other primary goal is to extend the wavelength coverage of
the colors of the surface and allow us to constrain the surface compositions
of both objects. From these data we will also be able to significantly
improve the orbits of P1 and P2, improve the measurement of the bulk density
of Charon, and search for albedo changes on the surface of Pluto.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports of
potential non-nominal performance that will be investigated.)

HSTARS:

10800 - GSAcq(1,2,1) failed to RGA Hold (Gyro Control)

GSACQ(1,2,2) at 126/05:37:26 failed to RGA control with QF1STOPF and QSTOP
flags set.

Subsequent REacq(1,2,1) scheduled at 125/17:22:30 using same star id failed
to RGA Hold due to search radius limit exceeded on FGS1.

10801 - GSACQ(1,2,2) failed

GSACQ(1,2,2) at 126/05:37:26 failed to RGA control with QF1STOPF and QSTOP
flags set.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL

FGS GSacq 20 18
FGS REacq 22 21
OBAD with Maneuver 84 84

SIGNIFICANT EVENTS: (None)
 




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