HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT       #4638

PERIOD COVERED: 5am June 23 - 5am June 24, 2008 (DOY 175/0900z-176/0900z)

OBSERVATIONS SCHEDULED

ACS/SBC 11110

Searching for Lyman Apha 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.

ACS/SBC 11131

Star Formation at Large Radii in Cooling Flow Brightest Cluster Galaxies

We propose to take deep ACS FUV images of the bright central galaxies in

two powerful cooling flow clusters for which we have VLT UBR images,

with the object of determining whether the UV excesses we observe at

large radii (>15kpc) are caused by young stars, ultrahot (WR) stars, or

an as yet unknown source. Current models of excess UV light at the

AGN-dominated centers of these galaxies cannot easily be extended to

large radii. New understanding of star formation in these clusters will

be directly applicable to scenarios of galaxy formation in the early

universe.

WFPC2 11024

WFPC2 CYCLE 15 INTERNAL MONITOR

This calibration proposal is the Cycle 15 routine internal monitor for

WFPC2, to be run weekly to monitor the health of the cameras. A variety

of internal exposures are obtained in order to provide a monitor of the

integrity of the CCD camera electronics in both bays {both gain 7 and

gain 15 -- to test stability of gains and bias levels}, a test for

quantum efficiency in the CCDs, and a monitor for possible buildup of

contaminants on the CCD windows. These also provide raw data for

generating annual super-bias reference files for the calibration

pipeline.

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.

NIC1/NIC2/NIC3 11330

NICMOS Cycle 16 Extended Dark

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

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.

WFPC2 11070

WFPC2 CYCLE 15 Standard Darks - part II

This dark calibration program obtains dark frames every week in order to

provide data for the ongoing calibration of the CCD dark current rate,

and to monitor and characterize the evolution of hot pixels. Over an

extended period these data will also provide a monitor of radiation

damage to the CCDs.

WFPC2 11079

Treasury Imaging of Star Forming Regions in the Local Group:

Complementing the GALEX and NOAO Surveys

We propose to use WFPC2 to image the most interesting star-forming

regions in the Local Group galaxies, to resolve their young stellar

populations. We will use a set of filters including F170W, which is

critical to detect and characterize the most massive stars, to whose hot

temperatures colors at longer wavelengths are not sensitive. WFPC2's

field of view ideally matches the typical size of the star-forming

regions, and its spatial resolution allows us to measure individual

stars, given the proximity of these galaxies. The resulting H-R diagrams

will enable studies of star-formation properties in these regions, which

cover largely differing metallicities {a factor of 17, compared to the

factor of 4 explored so far} and characteristics. The results will

further our understanding of the star-formation process, of the

interplay between massive stars and environment, the properties of dust,

and will provide the key to interpret integrated measurements of

star-formation indicators {UV, IR, Halpha} available for several

hundreds more distant galaxies. Our recent deep surveys of these

galaxies with GALEX {FUV, NUV} and ground-based imaging {UBVRI, Halpha,

[OIII] and [SII]} provided the identification of the most relevant SF

sites. In addition to our scientific analysis, we will provide catalogs

of HST photometry in 6 bands, matched corollary ground-based data, and

UV, Halpha and IR integrated measurements of the associations, for

comparison of integrated star-formation indices to the resolved

populations. We envisage an EPO component.

WFPC2 11316

HST Cycle 16 & Pre-SM4 Optical Monitor

This is a continuation of the Cycle 15 & pre-SM4 Optical Monitor, 11020.

Please see that proposal for a more complete description of the

observing strategy. The 6 visits comprising this proposal observe two

single standard stars with WFPC2/PC in order to establish overall OTA

focal length for the purposes of focus maintenance. The goal of this

monitoring before SM4 is to establish a best estimate of the OTA focus

entering SMOV.

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 M>1e10 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/NIC3 11188

First Resolved Imaging of Escaping Lyman Continuum

The emission from star-forming galaxies appears to be responsible for

reionization of the universe at z>6. However, the models that attempt to

describe the detailed impact of high- redshift galaxies on the

surrounding inter-galactic medium {IGM} are strongly dependent upon

several uncertain parameters. Perhaps the most uncertain is the fraction

of HI-ionizing photons produced by young stars which escape into the

IGM. Most attempts to measure this "escape fraction" {f_esc} have

produced null results. Recently, a small subset of z~3 Lyman Break

Galaxies {LBGs} has been found exhibiting large escape fractions. It

remains unclear however, what differentiates them from other LBGs.

Several models attempt to explain how such a large fraction of ionizing

continuum can escape through the HI and dust in the ISM {eg. "chimneys"

created by SNe winds, globular cluster formation, etc.}, each producing

unique signatures which can be observed with resolved imaging of the

escaping Lyman continuum. We propose a deep, high resolution WFPC2 image

of the ionizing continuum {F336W} and the rest-frame 1500 Angstrom

continuum {F606W} of five of the six known LBGs with large escape

fractions. These LBGs all fit within a single WFPC2 pointing, yielding

high observing efficiency. Additionally, they all have z~3.1 or higher,

the optimal redshift range for probing the Lyman Continuum region with

available WFPC2 filters. These factors make our proposed sample

especially suitable for follow- up. With these data we will discern the

mechanisms responsible for producing large escape fractions, and

therefore gain insight into the process of reionization.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports

of potential non-nominal performance that will be investigated.)

HSTARS: 

11351 - REacq(2,1,1) failed to RGA Hold (Gyro Control)

           REacq(2,1,1) scheduled at 176/03:16:08 - 03:24:13 failed to RGA Hold due

           to stop flag (QF2STOPF) indication on FGS-2. Pre-acquisition OBADs had

           attitude corrections (RSS) values of 19.65 and 1.46 arcseconds. Post-acq

           OBAD/MAP had 3-axis (RSS) error of 2671.54 arcseconds. Prior guide star

           acquisition at 176/01:44:02 was successful.

           Possible Observations affected: WFPC 79 thru 81 Proposal ID#11192,

           NICMOS 93 same Proposal ID#11192.

           Upon acquisition of signal at 176/05:25:15, the REacq(2,1,1) scheduled

           at 176/04:52:53 had failed to RGA Hold with stop flag (QF2STOPF)

           indication on FGS-2. Pre-acq OBADs attitude correction values are not

           available due to LOS.

           Possible Observations affected: WFPC 82 thru 84 Proposal ID#11192

           Upon acquisition of signal at 176/08:04:46, the REacq(2,1,1) scheduled

           at 176/06:28:47 had failed to RGA Hold due to stop flag (QF2STOPF)

           indication on FGS-2. Pre-acq OBAD1 (RSS) value is not available due to

           LOS. Pre-acq OBAD2 had (RSS) value of 14.20 arcseconds.

           Possible Observations affected: WFPC 85 thru 87 Proposal ID#11192,

           NICMOS same Proposal ID#11192.

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                       SCHEDULED      SUCCESSFUL  

FGS GSacq               07                   07                           

FGS REacq               07                   04     

OBAD with Maneuver 28                   28  

SIGNIFICANT EVENTS: (None)