Daily Report #4630

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT***** # 4630

PERIOD COVERED: 5am June 11 - 5am June 12, 2008 (DOY
163/0900z-164/0900z)

OBSERVATIONS SCHEDULED

ACS/SBC 11110

Searching for Lyman Alpha Emission from FUSE Lyman Continuum
Candidates

We have recently been granted time on FUSE to characterize the escape
fraction of hydrogen Lyman continuum (Lyc) photons from a
morphologically diverse set of star forming galaxies. The FUSE program
is designed to provide ~ 5 sigma detections of Lyc photons emitted
from star forming galaxies with escape fractions ~5%. With this
proposal we seek hydrogen Lyman alpha (Lya) observations of a
representative subset of the FUSE program targets to constrain the
observational relationship between Lyc, Lya, and hydrogen Balmer line
emission in these systems. Such observations explore the detailed
balance between the simple optically thin (Case A) and optically thick
(Case B) limits in recombination theory. The ultimate goal of this
program is to quantify the relationship between escaping Lya and Lyc
emission and the first structures that form in the early universe.

WFPC2 10583

Resolving the LMC Microlensing Puzzle: Where Are the Lensing Objects?

We are requesting 32 HST orbits to help ascertain the nature of the
population that gives rise to the observed set of microlensing events
towards the LMC. The SuperMACHO project is an ongoing ground-based
survey on the CTIO 4m that has demonstrated the ability to detect LMC
microlensing events in real-time via frame subtraction. The
improvement in angular resolution and photometric accuracy available
from HST will allow us to 1} confirm that the detected flux excursions
arise from LMC source stars rather than extended objects {such as for
background supernovae or AGN}, and 2} obtain reliable baseline flux
measurements for the objects in their unlensed state. The latter
measurement is important to resolve degeneracies between the event
timescale and baseline flux, which will yield a tighter constraint on
the microlensing optical depth.

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/WFPC2 11142

Revealing the Physical Nature of Infrared Luminous Galaxies at
0.3z2.7 Using HST and Spitzer

We aim to determine physical properties of IR luminous galaxies at
0.3z2.7 by requesting coordinated HST/NIC2 and MIPS 70um observations
of a unique, 24um flux-limited sample with complete Spitzer mid-IR
spectroscopy. The 150 sources investigated in this program have S{24um}
0.8mJy and their mid-IR spectra have already provided the majority
targets with spectroscopic redshifts {0.3z2.7}. The proposed
150~orbits of NIC2 and 66~hours of MIPS 70um will provide the physical
measurements of the light distribution at the rest-frame ~8000A and
better estimates of the bolometric luminosity. Combining these
parameters together with the rich suite of spectral diagnostics from
the mid-IR spectra, we will {1} measure how common mergers are among
LIRGs and ULIRGs at 0.3z2.7, and establish if major mergers are the
drivers of z1 ULIRGs, as in the local Universe. {2} study the
co-evolution of star formation and blackhole accretion by
investigating the relations between the fraction of starburst/AGN
measured from mid-IR spectra vs. HST morphologies, L{bol} and z. {3}
obtain the current best estimates of the far-IR emission, thus L{bol}
for this sample, and establish if the relative contribution of
mid-to-far IR dust emission is correlated with morphology {resolved
vs. unresolved}.

WFPC2 11206

At the Cradle of the Milky Way: Formation of the Most Massive Field
Disk Galaxies at z1

We propose to obtain 2 orbit WFPC2 F814W images of a sample of the 15
most massive galaxies found at $1 z 1.3$. These were culled from
over 20,000 Keck spectra collected as part of DEEP and are unique
among high redshift massive galaxy samples in being kinematically
selected. Through a recent HST NICMOS-2 imaging program {GO-10532}, we
have confirmed that these galaxies have regular stellar disks, and
their emission line kinematics are not due to gradients from merging
components. These potentially very young galaxies are likely
precursors to massive local disks, assuming no further merging. The
proposed WFPC2 and existing NIC-2 data provide colors, stellar masses,
and ages of bulge and disk subcomponents, to assess whether old
stellar bulges and disks are in place at that time or still being
built, and constrain their formation epochs. Finally, this sample will
yield the first statistically significant results on the $z 1$
evolution of the size-velocity-luminosity scaling relations, for
massive galaxies at different wavelengths, and constrain whether this
evolution reflects stellar mass growth, or passive evolution, of
either bulge or disk components.

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.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

11340 - GSAcq(1,2,1) failed to RGA Hold

At acquisition of signal 164/02:16:00, GSAcq (1,2,1) scheduled from
164/02:08:02 - 02:15:38 had failed to RGA Hold. Received a QSTOPF flag
on FGS 1. No 486 ESB messages received. OBAD #1 values: V1 705.62, V2
-373.10, V3 -342.08, RSS 868.40 arc seconds. OBAD #2 values: V1 0.10,
V2 -2.40, V3 17.55, RSS 17.71. OBAD MAP not visible due to loss of
signal.

Possible observations affected: WFPC Proposal # 11142, Observation
#140 #143. NICMOS Proposal #11142, Observation #40-41.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

*********************** SCHEDULED***** SUCCESSFUL

FGS GSacq************** 09***************** 08
FGS REacq************** 02***************** 02
OBAD with Maneuver **** 22***************** 22

SIGNIFICANT EVENTS: (None)