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Daily #4067



 
 
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Old March 10th 06, 02:39 PM posted to sci.astro.hubble
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Default Daily #4067

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT #4067

PERIOD COVERED: UT March 09, 2006 (DOY 068)

OBSERVATIONS SCHEDULED

ACS/HRC 10525

Characterizing the Near-UV Environment of M Dwarfs: Implications for
Extrasolar Planetary Searches and Astrobiology

We propose SNAP observations with the ACS HRC PR200L prism, designed
to measure the near ultraviolet emission in a sample of 107 nearby M
dwarfs. The sample spans the mass range from 0.1 - 0.6 solar masses
{temperature range 2200K - 4000K} where the UV energy distributions
vary widely between active and inactive stars. The strength and
distribution of this UV emission can have critical consequences for
the atmospheres of attendant planets. Our proposed observations will
provide desperately needed constraints on models of the habitability
zone and the atmospheres of possible terrestrial planets orbiting M
dwarf hosts, and will be used to sharpen TPF target selection. In
addition, the NUV data will be used in conjunction with existing
optical, FUV and X-ray data to constrain a new generation of M dwarf
atmospheric models, and to explore unanswered questions regarding the
dynamo generation and magnetic heating in these low-mass stars.

ACS/WFC 10181

ACS/NICMOS Imaging of Bright Lyman Break Galaxy Candidates from SDSS

The recent surprising discovery of six unusually bright {r~20 mag}
Lyman break galaxy {LBG} candidates with z=2.45-2.80 in the Sloan
Digital Sky Survey {SDSS} raises a number of questions that only HST
can address. Specifically, what is the true nature of these objects,
and what role if any is played by gravitational lensing? We propose to
use the superior resolution and sensitivity of ACS and NICMOS to
obtain deep images of these objects and their environments. Compared
to SDSS images, HST will allow us to determine their morphologies
{extended, point-source, or lensed}, the appearance of their
environments {rich or poor}, and to detect any faint foreground groups
or clusters that might be responsible for lensing these objects. All
outcomes would be intriguing. If the objects are lensed, it increases
from 1 {MS1512- cB58} to 7 the number of normal LBGs bright enough to
study individually. If they are instead unlensed point sources, they
will represent a new class of previously unidentified absorption- line
quasars. Finally, if they are unlensed and extended star-forming
galaxies, they are at least 4mag brighter than L_* LBGs, thus making
them the most luminous star-forming objects yet seen, representing a
heretofore unknown extreme population of objects.

ACS/WFC 10626

A Snapshot Survey of Brightest Cluster Galaxies and Strong Lensing to
z = 0.9

We propose an ACS/WFC snapshot survey of the cores of 150 rich galaxy
clusters at 0.3 z 0.9 from the Red Sequence Cluster Survey {RCS}.
An examination of the galaxian light in the brightest cluster
galaxies, coupled with a statistical analysis of the strong-lensing
properties of the sample, will allow us to contrain the evolution of
both the baryonic and dark mass in cluster cores, over an
unprecedented redshift range and sample size. In detail, we will use
the high- resolution ACS images to measure the metric {10 kpc/h}
luminosity and morphological disturbances around the brightest
clusters galaxies, in order to calibrate their accretion history in
comparison to recent detailed simulations of structure formation in
cluster cores. These images will also yield a well-defined sample of
arcs formed by strong lensing by these clusters; the frequency and
detailed distribution {size, multiplicity, redshifts} of these strong
lens systems sets strong constraints on the total mass content {and
its structure} in the centers of the clusters. These data will also be
invaluable in the study of the morphological evolution and properties
of cluster galaxies over a significant redshift range. These analyses
will be supported by extensive ongoing optical and near-infrared
imaging, and optical spectroscopy at Magellan, VLT and Gemini
telescopes, as well as host of smaller facilities.

FGS 10610

Astrometric Masses of Extrasolar Planets and Brown Dwarfs

We propose observations with HST/FGS to estimate the astrometric
elements {perturbation orbit semi-major axis and inclination} of
extra-solar planets orbiting six stars. These companions were
originally detected by radial velocity techniques. We have
demonstrated that FGS astrometry of even a short segment of reflex
motion, when combined with extensive radial velocity information, can
yield useful inclination information {McArthur et al. 2004}, allowing
us to determine companion masses. Extrasolar planet masses assist in
two ongoing research frontiers. First, they provide useful boundary
conditions for models of planetary formation and evolution of
planetary systems. Second, knowing that a star in fact has a plantary
mass companion, increases the value of that system to future
extrasolar planet observation missions such as SIM PlanetQuest, TPF,
and GAIA.

NIC1/NIC2/NIC3/NIC 10466

The Galactic Bulge Deep Field: A Planetary Transit Survey and Very
Deep Stellar Mass Function

We propose to observe a Galactic bulge field continuously with ACS/WFC
over a 7-day period. We will monitor ~167, 000 F, G, and K dwarfs down
to V=23, in order to detect transits by orbiting Jovian planets. If
the frequency of "hot Jupiters" is similar to that in the solar
neighborhood, we will detect over 100 planets, more than doubling the
number of extrasolar planets known. For the brighter stars with
transits, we will confirm the planetary nature of the companions
through radial- velocity measurements using the 8-m VLT. We will
determine the metallicities of most of the planet-bearing stars as
well as a control sample, through follow-up VLT spectroscopy. The
metallicities of the target stars range over more than 1.5 dex,
allowing for a determination of the dependence of planet frequency
upon metallicity--a crucial element in understanding planet formation.
We will be able to discriminate between the equally numerous disk and
bulge stars via proper motions. Hence we will determine, for the first
time, the frequencies of planets in two entirely different stellar
populations. We will also determine for the first time the
distribution of planetary radii for extrasolar planets for both these
populations. Parallel observations with NICMOS will provide ultra-deep
near-infrared images of a nearby bulge field, which will be used to
determine the stellar luminosity and mass functions down to the
brown-dwarf regime. The data will also be useful for a variety of
spinoff projects, including a census of variable stars and of hot
white dwarfs in the bulge, and the metallicity distribution of bulge
dwarfs.

NIC2/ACS/WFC/WFPC2 10532

Kinematics and morphology of the most massive field disk galaxies at
z1

We propose to obtain 1 orbit NIC-2 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.
We intend to test whether these potentially very young galaxies are
likely precursors to massive local disks, assuming no further merging.
NIC-2 images provide rest-frame optical morphologies that will show
whether they are normal disky systems or instead more disturbed
looking objects with multiple subcomponents, mergers, peculiar
structure, etc. NIC-2 provides near-IR resolutions sufficient to
enable measurements of bulges and disks subcomponents. The near-IR
will fill a critical gap in the broad-band SED photometry of the
galaxy and its subcomponents to estimate mean stellar ages and stellar
masses and to assess whether old stellar bulges and disks are in place
at that time. Finally, this sample will yield the first statistically
significant results on the $z 1$ evolution of the Tully-Fisher
relation for massive galaxies. In addition, we propose parallel
observations with ACS WFC {V and I bands} and WFPC2 {I-band}. These
will target up to 700 galaxies at redshifts 0.7 ... 1.2 for which the
DEEP2 survey has obtained precision redshifts and high-resolution
kinematic data. The added HST morphology and color information will
allow a variety of detailed studies on dynamical, structural, and
photometric evolution of galaxies.

WFPC2 10492

A detailed study of the mass properties for the galaxy cluster RX
J1347-1145

We propose to obtain deep, multi-colour imaging for the galaxy cluster
RX J1347-1145 at z=0.45. Together with our high-quality ground-based
optical and X-ray data sets already at hand this observation will
produce a precise mass determination of this most X-ray luminous
cluster. The analysis will mainly be carried out by a newly developed
and novel technique that combines weak and strong lensing information
and which is able to break the mass-sheet degeneracy that hampered
most previous lensing mass determinations. Within our extensive
campaign to understand the mass properties of RX J1347-1145, the main
goal of the ACS images will be a refined, high-resolution lensing mass
reconstruction of the cluster core. This will be achieved by a
substantially increased number density of background sources for a
weak lensing analysis in combination with constraints from multiply
lensed images that are identified with morphology and colour
information. Both of these require the unique resolving power of ACS.
RX J1347-1145 is an ideal candidate for elucidating the discrepant
mass estimates obtained from traditional methods. It plays the same
role at high redshift as A1689 at intermediate redshifts for which a
similar analysis has been performed with ACS. Our results will
therefore be an important ingredient in the use of galaxy clusters as
cosmological probes.

WFPC2 10779

WFPC2 WF4 Temperature Reduction Test #2

The WF4 CCD bias level appears to have become unstable, resulting in
sporadic images with either low or zero bias level. The other three
CCDs {PC1, WF2, and WF3} appear to be unaffected and continue to
operate properly. This is a second test to further reduce
temperatures. Orbits: internal 26, external 1

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 07 07
FGS REacq 08 08
OBAD with Maneuver 28 28

SIGNIFICANT EVENTS: (None)

 




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