Daily Rpt #4627

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4627

PERIOD COVERED: 5am June 06 - 5am June 09, 2008 (DOY 158/0900z-161/0900z)

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.

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 DARKs. 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.

WFPC2 11340

X-ray Observations of 11 Millisecond Pulsars in M28

We propose a deep X-ray survey of the globular cluster M28 which will yield
a wealth of important and unique science, ranging from the first direct
measurement of the magnetic field of a millisecond pulsar and constraints on
the neutron star equation of state to likely X-ray/optical (HST) detection
of a re-exchanged binary MSP. The proposed joint HST WFPC2 observation will
tie the X-ray, optical, and radio data to a common astrometric frame
allowing an unambiguous identification of numerous cataclysmic variables and
active binaries in M28 as well as making possible the first direct optical
detection of a millisecond pulsar.

NIC1/NIC2/NIC3 11330

NICMOS Cycle 16 Extended Dark

This takes a series of Darks in parallel to other instruments.

WFPC2 11311

The High-Amplification Microlensing Event OGLE-2007-BLG-224: A Substellar
Lens in the Galactic Disk Or A Low-Mass Stellar Lens in the Halo?

OGLE-2007-BLG-224/MOA-2007-BLG-163 is a remarkable microlensing event
towards the Galactic bulge, which peaked on May 12, 2007. The light curve
reached a peak magnification of ~3700, which is the highest magnification
ever observed. The color and magnitude of the source indicate that it is a
G-dwarf in the Galactic bulge, and source radius crossing time of t* = 8.2
minutes implies that the lens-source relative proper motion is 45 mas/yr.
This indicates that the lens must either be a very nearby brown dwarf, or a
halo star. The HST observations proposed here provide a very good chance to
distinguish between these two possibilities and to determine the distance
and mass of the lens. If it is a nearby brown dwarf, it is likely to be
associated with a high-proper-motion star that is found close to the source.
HST observations taken at two epochs will resolve out the geocentric and the
heliocentric the proper-motions, thus providing unambiguous proof that it is
a substellar lens. If the lens is a halo star, then it should be detectable
as it separates from the source star over the next year. This would be the
first definitive detection of a lens star in the Galactic halo and it would
help to resolve the long running controversy over whether a significant
fraction of the microlensing events seen towards the Magellanic Clouds are
due to lens objects in the halo. Thus, it will either be the first clear
proof of a substellar lens in the Galactic disk, or the first clear
detection of a halo lens.

WFPC2 11289

SL2S: The Strong Lensing Legacy Survey

Recent systematic surveys of strong galaxy-galaxy lenses {CLASS, SLACS,
GOODS, etc.} are producing spectacular results for galaxy masses roughly
below a transition mass M~10^13 Mo. The observed lens properties and their
evolution up to z~0.2, consistent with numerical simulations, can be
described by isothermal elliptical potentials. In contrast, modeling of
giant arcs in X-ray luminous clusters {halo masses M ~10^13 Mo} favors NFW
mass profiles, suggesting that dark matter halos are not significantly
affected by baryon cooling. Until recently, lensing surveys were neither
deep nor extended enough to probe the intermediate mass density regime,
which is fundamental for understanding the assembly of structures. The CFHT
Legacy Survey now covers 125 square degrees, and thus offers a large
reservoir of strong lenses probing a large range of mass densities up to
z~1. We have extracted a list of 150 strong lenses using the most recent
CFHTLS data release via automated procedures. Following our first SNAPSHOT
proposal in cycle 15, we propose to continue the Hubble follow-up targeting
a larger list of 130 lensing candidates. These are intermediate mass range
candidates {between galaxies and clusters} that are selected in the redshift
range of 0.2-1 with no a priori X-ray selection. The HST resolution is
necessary for confirming the lensing candidates, accurate modeling of the
lenses, and probing the total mass concentration in galaxy groups up to z~1
with the largest unbiased sample available to date.

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 focusing
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.

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.

ACS/SBC 11230

HST FUV Observations of Brightest Cluster Galaxies: The Role of Star
Formation in Cooling Flows and BCG Evolution

The intracluster medium (ICM) now appears to be a very dynamic place where
heating and cooling processes vie for dominance and an uneasy equilibrium is
maintained. Since these same processes may operate during the process of
galaxy formation, the centers of clusters of galaxies provide low redshift
laboratories for studying the critical processes involved in galaxy
formation and black hole growth. At the present time, the main questions are
(1) How much gas is cooling out of the ICM? (2) How much star formation is
ongoing? (3) What is the impact of the gas and star formation on the central
BCG? In order to measure the current star formation in BCGs we have
undertaken a program of Spitzer IRAC and MIPS observations. We are in
process of obtaining observations of a sample of Brightest Cluster Galaxies
in 70 clusters selected from the ROSAT all sky survey. In about 25% of the
sources observed so far, we detect a mid-IR excess which we attribute to
dust heated by star formation. We propose to obtain ACS/SBC observations of
the Lyman Alpha emission line and the adjacent FUV continuum in 7 BCGs which
are in cooling core clusters of galaxies and have a large mid-IR excess. We
also propose WFPC2 F606W observations of the two clusters without high
resolution imaging to allow us to image the dust on the same scale as the
Far UV continuum. The FUV will allow us to confirm the presence of ongoing
star formation in these BCGs and will allow us to rule out an AGN as the
dominant contributor to the mid-IR. The morphology and spatial extent of the
young stars and the heated dust and CO will constrain the spatial scale over
which star formation occurs and thus where the cooling gas is deposited. The
combination of our FUV and IR observations will allow us to estimate the
star formation rates which must balance the rate at which cold gas is
deposited in the BCG. Our proposed FUV observations will produce unique
information about the cooling gas, the true mass accretion rates, and the
star formation rates in BCGs and its effect on the galaxy.

WFPC2 11227

The Orbital Period for an Ultraluminous X-ray Source in NGC1313

The ultraluminous X-ray sources {ULXs} are extragalactic point sources with
luminosities that exceed the Eddington luminosity for conventional
stellar-mass black holes by factors of 10 - 100. It has been hotly debated
whether the ULXs are just common stellar-mass black hole sources with beamed
emission or whether they are sub-Eddington sources that are powered by the
long-sought intermediate mass black holes {IMBH}. To firmly decide this
question, one must obtain dynamical mass measurements through photometric
and spectroscopic monitoring of the secondaries of these system. The crucial
first step is to establish the orbital period of a ULX, and arguably the
best way to achieve this goal is by monitoring its ellipsoidal light curve.
The extreme ULX NGC1313 X-2 provides an outstanding target for an orbital
period determination because its relatively bright optical counterpart {V =
23.5} showed a 15% variation between two HST observations separated by three
months. This level of variability is consistent with that expected for a
tidally distorted secondary star. Here we propose a set of 20 imaging
observations with HST/WFPC2 to define the orbital period. This would be the
first photometric measurement of the orbital period of a ULX binary.
Subsequently, we will propose to obtain spectroscopic observations to obtain
its radial velocity amplitude and thereby a dynamical estimate of its mass.

FGS 11212

Filling the Period Gap for Massive Binaries

The current census of binaries among the massive O-type stars is seriously
incomplete for systems in the period range from years to millennia because
the radial velocity variations are too small and the angular separations too
close for easy detection. Here we propose to discover binaries in this
observational gap through a Faint Guidance Sensor SNAP survey of relatively
bright targets listed in the Galactic O Star Catalog. Our primary goal is to
determine the binary frequency among those in the cluster/association,
field, and runaway groups. The results will help us assess the role of
binaries in massive star formation and in the processes that lead to the
ejection of massive stars from their natal clusters. The program will also
lead to the identification of new, close binaries that will be targets of
long term spectroscopic and high angular resolution observations to
determine their masses and distances. The results will also be important for
the interpretation of the spectra of suspected and newly identified binary
and multiple systems.

FGS 11211

An Astrometric Calibration of Population II Distance Indicators

In 2002 HST produced a highly precise parallax for RR Lyrae. That
measurement resulted in an absolute magnitude, M{V}= 0.61+/-0.11, a useful
result, judged by the over ten refereed citations each year since. It is,
however, unsatisfactory to have the direct, parallax-based, distance scale
of Population II variables based on a single star. We propose, therefore, to
obtain the parallaxes of four additional RR Lyrae stars and two Population
II Cepheids, or W Vir stars. The Population II Cepheids lie with the RR
Lyrae stars on a common K-band Period-Luminosity relation. Using these
parallaxes to inform that relationship, we anticipate a zero-point error of
0.04 magnitude. This result should greatly strengthen confidence in the
Population II distance scale and increase our understanding of RR Lyrae star
and Pop II Cepheid astrophysics.

FGS 11210

The Architecture of Exoplanetary Systems

Are all planetary systems coplanar? Concordance cosmogony makes that
prediction. It is, however, a prediction of extrasolar planetary system
architecture as yet untested by direct observation for main sequence stars
other than the Sun. To provide such a test, we propose to carry out FGS
astrometric studies on four stars hosting seven companions. Our
understanding of the planet formation process will grow as we match not only
system architecture, but formed planet mass and true distance from the
primary with host star characteristics for a wide variety of host stars and
exoplanet masses. We propose that a series of FGS astrometric observations
with demonstrated 1 millisecond of arc per-observation precision can
establish the degree of coplanarity and component true masses for four
extrasolar systems: HD 202206 {brown dwarf+planet}; HD 128311
{planet+planet}, HD 160691 = mu Arae {planet+planet}, and HD 222404AB =
gamma Cephei {planet+star}. In each case the companion is identified as such
by assuming that the minimum mass is the actual mass. For the last target, a
known stellar binary system, the companion orbit is stable only if coplanar
with the AB binary orbit.

WFPC2 11185

Search for H-poor/He-rich Inclusions and a Solution to the Abundance,
Temperature Problems

Our recent abundance survey of a large sample of Galactic planetary nebulae
(PNe) has led to the discovery of a group of super-metal-rich nebulae whose
spectra are characterized by prominent optical recombination lines (ORLs)
from C, N, O, & Ne ions and a large Balmer discontinuity jump. The heavy
element abundances derived from ORLs for several PNe are more than an order
of magnitude higher than those derived from the traditional method based on
collisionally excited lines (CELs), while the Balmer jump yields electron
temperatures (Te) significantly lower than values derived from the [O III]
5007/4363 CEL line ratio. A proposition that aspires to explain both the
nebular abundance and Te problems is one according to which these nebulae
contain (at least) two distinct emission regions - one of "normal" Te (~
10000 K) and chemical composition (~solar) and another of very low Te that
is H- deficient, thus having high helium and metal abundances relative to
hydrogen. The latter component emits strong He and heavy element ORLs but
essentially no CELs. The consistent picture that emerges from fitting a
2-component photoionization model to the spectroscopic data is that the
H-poor component is in high-density inclusions, which provide only a minor
fraction of the total nebular mass. We propose to directly detect these
inclusions in the planetary nebula M 1-42 using WFPC2 (PC) to make a high
spatial resolution image in the He I 5876 A ORL and ratio it to Halpha. With
NICMOS (NIC1), we plan to observe the He I 10830 A line, which is
substantially collisionally excited, along with Palpha 18760 A. The ratio
image of He I 10830 to Palpha is expected to be less likely to show the
inclusions, thus serving as an important control to the optical imaging. M
1-42 is one of the most extreme cases of the abundance and Te problem; it is
reasonably bright and compact. This program has the potential to resolve a
serious challenge to our current understanding of nebular astrophysics.

NIC2 11150

Beta Pic Polarimetry with NICMOS

Debris disk stars host transient dust grains that comprise a collisional
cascade with sizes ranging from planetesimals to the sub-micron. In addition
to the gravity of the host star and any planets present, these grains are
subject to size-dependent non-gravitational forces, e.g., corpuscular drag
and radiation pressure. When a steep spectrum of grain sizes prevails, such
as the Dohnanyi distribution, scattered light images preferentially trace
grains with dimensionless size parameter of order unity. Thus images in
scattered starlight provide unique windows on the balance of forces acting
on grains at a specific size. Therefore, in an A star system such as beta
Pic, the near-IR is dominated by grains close to the blow out size and
therefore NICMOS traces dust on hyperbolic orbits.

Scattering is fundamentally polarization sensitive, and measurements that
record intensity literally see only half the picture. If linear polarization
is measured then the elements of the complex scattering matrix can be
reconstructed. These matrix elements provide fundamental constraints on the
size, composition and structure of the scatterers. Notably, polarimetry can
be used to break the degeneracy between scattering asymmetry, g, and the
radial dust gradient, which are otherwise covariant in an edge-on disk.
Thus, we can use polarimetry to localize the parent bodies in the beta Pic
disk.

In beta Pic, dust is thought to originate mainly from the sublimation of
cometary bodies near periastron. The irradiation of cometary material leads
to sublimation and photodissociation of ices forming porous grains
consisting of a matrix of refractory material. Such grains have a
characteristic scattering signature in polarized light that can be
distinguished from compact grains that arise from collisional erosion of
asteroidal material.

NIC2 10852

Coronagraphic Polarimetry with NICMOS: Dust Grain Evolution in T Tauri Stars

The formation of planetary systems is intimately linked to the dust
population in circumstellar disks, thus understanding dust grain evolution
is essential to advancing our understanding of how planets form. By
combining {1} the coronagraphic polarimetry capabilities of NICMOS, {2}
powerful 3-D radiative transfer codes, and {3} observations of objects known
to span the Class II- III stellar evolutionary phases, we will gain crucial
insight into dust grain growth. By observing objects representative of a
known evolutionary sequence of YSOs, we will be able to investigate how the
dust population evolves in size and distribution during the crucial
transition from a star+disk system to a system containing planetesimals.
When combine with our previous study on dust grain evolution in the Class
I-II phase, the proposed study will help to establish the fundamental time
scales for the depletion of ISM-like grains: the first step in understanding
the transformation from small submicron sized dust grains, to large
millimeter sized grains, and untimely to planetary bodies.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

#11328 GSACQ(1,2,1) failed while LOS @ 159/0346z to RGA control.

#44 commands did not change since previous acquisition. Two 486 ESB "1805"
messages (T2G_MOVING_TARGET_DETECTED) were observed. OBAD prior to
acquisition had RSS error of 12.14 arcseconds. Further information after
engineering recorder dump. REACQ(1,2,1) at 05:21:55 could not be observed
due to lack of telemetry but #44 commands did change while vehicle was LOS.
Observation affected: NICMOS 141, proposal 11235.

#11329 REAcq (2,1,2) Loss of Lock while guiding @ 160/1754z

REAcq (2,1,2), scheduled at 160/17:22:01-17:29:38 was successful. At
Acquisition of Signal (AOS), 160/17:54:00, stop flag indications (QF2STOPF,
QF1STOPF, QSTOP) were set on FGS 2 & FGS 1. A Loss of Lock occurred while
guiding under FGS 2 and 1 during the Loss of Signal scheduled from
160/17:33:04-17:54:00. No additional 486 ESB messages or NSSC-1 STB messages
were received. P4TAKDAT (Take Data Flag) was down at AOS. At AOS the
spacecraft was in M2G mode. TERM EXP was not scheduled until 160/18:18:19.
The next engineering data dump is scheduled for 160/21:12:00. Possible
Observations affected: WFPC Proposal #11340, Observation # 106-110. At AOS,
160/19:27:45, REAcq (2,1,2), scheduled from 18:57:55-19:05:32 was
successful. TERM EXP occurred on schedule at 19:54:12.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSacq 26 25
FGS REacq 16 16
OBAD with Maneuver B84 84

SIGNIFICANT EVENTS: (None)