Daily Request #4387

Notice: For the foreseeable future, the daily reports may contain apparent
discrepancies between some proposal descriptions and the listed instrument
usage. This is due to the conversion of previously approved ACS WFC or HRC
observations into WFPC2, or NICMOS observations subsequent to the loss of
ACS CCD science capability in late January.


HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4387

PERIOD COVERED: UT June 19, 2007 (DOY 170)

OBSERVATIONS SCHEDULED

FGS 10612

Binary Stars in Cyg OB2: Relics of Massive Star Formation in a Super-Star
Cluster

We propose to make a high angular resolution SNAP survey of the massive
stars in the nearby, super-star cluster Cyg OB2. We will use FGS1r TRANS
mode observations to search for astrometric companions in the separation
range of 0.01 to 1.00 arcsec and in the magnitude difference range smaller
than 4 magnitudes. The observations will test the idea that the formation of
very massive stars involves mergers and the presence of nearby companions.
Discovery of companions to massive stars in this relatively nearby complex
will provide guidance in the interpretation of apparently supermassive stars
in distant locations. The search for companions will also be important for
verification of fundamental parameters derived from spectroscopy,
adjustments to main sequence fitting and distance estimations, determining
third light contributions of eclipsing binaries, identifying wide colliding
wind binaries, studying the relationship between orbital and spin angular
momentum, and discovering binaries amenable to future mass determinations.
The massive star environment in Cyg OB2 may be similar to the kinds found in
the earliest epoch of star formation, so that a study of the role of
binaries in Cyg OB2 will help us understand the formation processes of the
first stars in the Universe.

FGS 10927

The Weight-Watcher Program for Subdwarfs

We propose to use HST/FGS1r to measure five subdwarf spectroscopic binaries
to determine masses for the components. Their metallicities, [Fe/H], range
from -0.5 to -2.5, and their projected minimum separations range from 9 to
24 mas. These binaries are resolvable with HST/FGS1r but not any
ground-based technique. Currently, there are only two subdwarf systems
having any mass measurements. The proposed work will boost the total number
of subdwarf systems with masses from two to seven, and allow us to construct
the first mass-luminosity relation for low-metallicity stars.

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 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.

NIC3 10792

Quasars at Redshift z=6 and Early Star Formation History

We propose to observe four high-redshift quasars {z=6} in the NIR in order
to estimate relative Fe/Mg abundances and the central black hole mass. The
results of this study will critically constrain models of joint quasar and
galaxy formation, early star formation, and the growth of supermassive black
holes. Different time scales and yields for alpha-elements {like O or Mg}
and for iron result into an iron enrichment delay of ~0.3 to 0.6 Gyr. Hence,
despite the well-known complexity of the FeII emission line spectrum, the
ratio iron/alpha - element is a potentially useful cosmological clock. The
central black hole mass will be estimated based on a recently revised back
hole mass - luminosity relationship. The time delay of the iron enrichment
and the time required to form a supermassive black hole {logM8 Msol, tau
~0.5Gyr} as evidenced by quasar activity will be used to date the beginning
of the first intense star formation, marking the formation of the first
massive galaxies that host luminous quasars, and to constrain the epoch when
supermassive black holes start to grow by accretion.

NIC3 11072

Measuring the Physical Properties of the first two WASP transiting
extrasolar planets

We have recently discovered the first two transiting extrasolar planets from
the Wide Angle Search for Planets {WASP} project and confirmed both as
planets using SOPHIE radial velocity measurements. Both WASP-1b and WASP-2b
orbit about stars brighter than V=12, and are thus ideal targets for HST
followup. WASP-1b is probably inflated in a manner similar to HD209458b but
is in a closer orbit about the parent, which itself is the earliest-type
parent star yet announced for a transiting extrasolar planet. At 0.03 AU
from the parent star, WASP-2b is close to the minimum separation at which
planets of this mass range are thought to survive. We request DD
observations of WASP-1b and WASP- 2b, to constrain the masses and radii of
both objects to a precision of a few tenths of a percent. Both parent stars
have very similar brightnesses to the TrES-1 parent star, thus we will
achieve equivalent photometric precision to previous successful observations
of TrES-1b. As all further physical investigations {such as interior
heating} depend on precise mass- and radius-determinations, this
investigation is the essential next step in uncovering the physical
characteristics of these planets and their parent stars. We have requested
12 orbits, though 9 orbits would provide the minimum acceptable coverage for
our program. The consortium will formally announce the discoveries of
WASP-1b and WASP-2b on Tuesday 26th September 2006. We ask that all material
in this proposal be kept confidential until that date. We can supply the
discovery paper on request after this date.

WFPC2 10890

Morphologies of the Most Extreme High-Redshift Mid-IR-Luminous Galaxies

The formative phase of the most massive galaxies may be extremely luminous,
characterized by intense star- and AGN-formation. Till now, few such
galaxies have been unambiguously identified at high redshift, restricting us
to the study of low-redshift ultraluminous infrared galaxies as possible
analogs. We have recently discovered a sample of objects which may indeed
represent this early phase in galaxy formation, and are undertaking an
extensive multiwavelength study of this population. These objects are bright
at mid-IR wavelengths {F[24um]0.8mJy}, but deep ground based imaging
suggests extremely faint {and in some cases extended} optical counterparts
{R~24-27}. Deep K-band images show barely resolved galaxies. Mid-infrared
spectroscopy with Spitzer/IRS reveals that they have redshifts z ~ 2-2.5,
suggesting bolometric luminosities ~10^{13-14}Lsun! We propose to obtain
deep ACS F814W and NIC2 F160W images of these sources and their environs in
order to determine kpc-scale morphologies and surface photometry for these
galaxies. The proposed observations will help us determine whether these
extreme objects are merging systems, massive obscured starbursts {with
obscuration on kpc scales!} or very reddened {locally obscured} AGN hosted
by intrinsically low-luminosity galaxies.

WFPC2 10915

ACS Nearby Galaxy Survey

Existing HST observations of nearby galaxies comprise a sparse and highly
non-uniform archive, making comprehensive comparative studies among galaxies
essentially impossible. We propose to secure HST's lasting impact on the
study of nearby galaxies by undertaking a systematic, complete, and
carefully crafted imaging survey of ALL galaxies in the Local Universe
outside the Local Group. The resulting images will allow unprecedented
measurements of: {1} the star formation history {SFH} of a 100 Mpc^3 volume
of the Universe with a time resolution of Delta[log{t}]=0.25; {2}
correlations between spatially resolved SFHs and environment; {3} the
structure and properties of thick disks and stellar halos; and {4} the color
distributions, sizes, and specific frequencies of globular and disk clusters
as a function of galaxy mass and environment. To reach these goals, we will
use a combination of wide-field tiling and pointed deep imaging to obtain
uniform data on all 72 galaxies within a volume-limited sample extending to
~3.5 Mpc, with an extension to the M81 group. For each galaxy, the
wide-field imaging will cover out to ~1.5 times the optical radius and will
reach photometric depths of at least 2 magnitudes below the tip of the red
giant branch throughout the limits of the survey volume. One additional deep
pointing per galaxy will reach SNR~10 for red clump stars, sufficient to
recover the ancient SFH from the color-magnitude diagram. This proposal will
produce photometric information for ~100 million stars {comparable to the
number in the SDSS survey} and uniform multi- color images of half a square
degree of sky. The resulting archive will establish the fundamental optical
database for nearby galaxies, in preparation for the shift of high-
resolution imaging to the near-infrared.

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:

18103-1 - MSS/CSS Gyro2 Converged & Remove Gyro2 Test#39 for day 170
18054-0 - Preview KF Sun Vector Data via Telemetry Diags

SCHEDULED SUCCESSFUL

FGS GSacq 06 06
FGS REacq 08 08
OBAD with Maneuver 28 28

COMPLETED OPS NOTES: (None)

SIGNIFICANT EVENTS: (None)