Notice: Due to the conversion of some ACS WFC or HRC observations into

WFPC2, or NICMOS observations after the loss of ACS CCD science

capability in January, there may be an occasional discrepancy between a

proposal's listed (and correct) instrument usage and the abstract that

follows it.

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4478

PERIOD COVERED: UT October 29, 2007 (DOY 302)

OBSERVATIONS SCHEDULED

ACS/SBC 10907

New Sightlines for the Study of Intergalactic Helium: A Dozen

High-Confidence, UV-Bright Quasars from SDSS/GALEX

The reionization of intergalactic helium is thought to have occurred

between redshifts of about 3 and 4. Detailed study of HeII Lyman-alpha

absorption toward a handful quasars at 2.7<z<3.3 demonstrates the great

potential of such probes of the IGM, but the current critically-small

sample limits confidence in resulting cosmological inferences. The

requisite unobscured quasar sightlines to high-redshift are extremely

rare, especially due to severe absorption in random intervening

Lyman-limit systems, but SDSS provides thousands of z>3.1 quasars

potentially suitable for HeII studies. We have cross-correlated SDSS

quasars with GALEX UV sources to obtain a dozen new, very

high-confidence, candidate quasars/sightlines {z=3.1 to 4.1} potentially

useful for detailed HeII studies even with current HST instruments. We

propose brief, 2-orbit per target, reconnaissance spectral exposures

with the ACS SBC prism to definitively verify UV flux down to the HeII

break. Our combined SDSS/GALEX selection insures a very high-yield of

confirmations, as the quasars are already known to be UV-bright from

broadband GALEX images. The additional sightlines, extending to very

high-redshift, will directly enable ensemble spectral stacks, as well as

long exposure follow-up spectra, at high S/N with the ACS/SBC

ultraviolet prisms {or perhaps STIS or COS later}, to confidently

measure the spectrum and evolution of the ionizing background radiation,

the evolution of HeII opacity, and the density of intergalactic baryons.

FGS 11213

Distances to Eclipsing M Dwarf Binaries

We propose HST FGS observations to measure accurate distances of 5

nearby M dwarf eclipsing binary systems, from which model-independent

luminosities can be calculated. These objects have either poor or no

existing parallax measurements. FGS parallax determinations for these

systems, with their existing dynamic masses determined to better than

0.5%, would serve as model-independent anchor points for the low-mass

end of the mass-luminosity diagram.

NIC1/NIC2/NIC3 11330

NICMOS Cycle 16 Extended Dark

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

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 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 11084

Probing the Least Luminous Galaxies in the Local Universe

We propose to obtain deep color-magnitude data of eight new Local Group

galaxies which we recently discovered: Andromeda XI, Andromeda XII, and

Andromeda XIII {satellites of M31}; Canes Venatici I, Canes Venatici II,

Hercules, and Leo IV {satellites of the Milky Way}; and Leo T, a new

"free-floating" Local Group dwarf spheroidal with evidence for recent

star formation and associated H I gas. These represent the least

luminous galaxies known at *any* redshift, and are the only accessible

laboratories for studying this extreme regime of galaxy formation. With

deep WFPC-2 F606W and F814W pointings at their centers, we will

determine whether these objects contain single or multiple age stellar

populations, as well as whether these objects display a range of

metallicities.

WFPC2 11119

The Stellar Origins of Supernovae

Supernovae {SNe} have a profound effect on galaxies, and have been used

recently as precise cosmological probes, resulting in the discovery of

the accelerating Universe. They are clearly very important events

deserving of intense study. Yet, even with nearly 4000 known SNe, we

know relatively little about the stars which give rise to these powerful

explosions. The main limitation has been the lack of spatial resolution

in pre-SN imaging data. However, since 1999 our team has been at the

vanguard of directly identifying SN progenitor stars in HST images. From

this exciting new line of study, the emerging trend from 5 detections

for Type II-Plateau SNe is that their progenitors appear to be

relatively low mass {8 to 20 Msun} red supergiants, although more cases

are needed. Nonetheless, the nature of the progenitors of Type Ib/c SNe,

a subset of which are associated with the amazing gamma-ray bursts,

remains ambiguous. Furthermore, we remain in the continually

embarrassing situation that we still do not yet know which progenitor

systems explode as Type Ia SNe, which are currently being used for

precision cosmology. We propose to confirm the identities of the

progenitors of 4 SNe within 17 Mpc, which we expect to occur during

Cycle 16, through ToO observations using WFPC2/PC.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports

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

HSTARS: (None)

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL

FGS GSacq 8 8

FGS REacq 5 5

OBAD with Maneuver 24 24

SIGNIFICANT EVENTS: (None)

-Lynn
____________________________________________________________
Lynn F. Bassford
Hubble Space Telescope
CHAMP Mission Operations Manager

CHAMP Flight Operations Team Manager
Lockheed Martin Mission Services (LMMS)

NASA GSFC PH#: 301-286-2876

"The Hubble Space Telescope is the astronomical observatory and key to unlocking the most cosmic mysteries of the past, present and future."    - 7/26/6