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 i

mages. 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 0.3<z<2.7

Using HST and Spitzer

We aim to determine physical properties of IR luminous galaxies at

0.3<z<2.7 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 {0.3<z<2.7}. 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 0.3<z<2.7, and establish if major mergers are the drivers

of z>1 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 z>1

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)