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Daily #4077



 
 
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Old March 28th 06, 07:16 PM posted to sci.astro.hubble
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Default Daily #4077

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4077

PERIOD COVERED: UT March 23, 2006 (DOY 082)

OBSERVATIONS SCHEDULED

ACS/WFC 10475

An ACS H-alpha Survey of the Carina Nebula

We propose an H-alpha ACS imaging survey covering 540 square
arcminutes of the Carina Nebula, including an unbiased survey of the
bright core, and several prominent dust pillars in the rich southern
region of the nebula. Carina provides an important link between
well-studied nearby H II regions like Orion, and more distant
mini-starbusts like 30 Doradus. CVZ orbits will allow extremely
efficient use of HST to map a large area of this complex and important
region -- more than 95 percent of the proposed survey will be observed
by HST for the first time. This survey will provide a complete census
of microjets, proplyds, and silhouette disks with diameters as small
as 200 AU, enough to spatially resolve disks like those in Orion, and
will provide the first catalog of outflows {jets} from embedded
low-mass stars, thin filamentary shocks, and wind-wind collisions in
Carina. An accurate census of these phenomena is needed to
characterize the star formation activity and gas dynamics as a
function of position in the nebula, and to determine if models for
protoplanetary disk evaporation from Orion are applicable in more
extreme regions. Our previous ground-based optical and IR surveys have
already revealed dozens of candidates for this type of activity -- but
this is just the tip of the iceberg. Our proposed HST/ACS survey
promises to be a bonanza for understanding ongoing low-mass star
formation influenced by extremely high-mass stars.

ACS/WFC 10496

Decelerating and Dustfree: Efficient Dark Energy Studies with
Supernovae and Clusters

We propose a novel HST approach to obtain a dramatically more useful
"dust free" Type Ia supernovae {SNe Ia} dataset than available with
the previous GOODS searches. Moreover, this approach provides a
strikingly more efficient search-and-follow-up that is primarily pre-
scheduled. The resulting dark energy measurements do not share the
major systematic uncertainty at these redshifts, that of the
extinction correction with a prior. By targeting massive galaxy
clusters at z 1 we obtain a five-times higher efficiency in
detection of Type Ia supernovae in ellipticals, providing a
well-understood host galaxy environment. These same deep cluster
images then also yield fundamental calibrations required for future
weak lensing and Sunyaev-Zel'dovich measurements of dark energy, as
well as an entire program of cluster studies. The data will make
possible a factor of two improvement on supernova constraints on dark
energy time variation, and much larger improvement in systematic
uncertainty. They will provide both a cluster dataset and a SN Ia
dataset that will be a longstanding scientific resource.

ACS/WFC 10576

An ACS Imaging Survey of the Galaxies Hosting Strong Mg II Absorption

Strong MgII absorbers {with rest-frame absorption equivalent width
W_MgII 0.3 A} at redshift z 1 are known to arise in extended
gaseous halos around luminous galaxies. Detailed absorption line
studies based on high-solution spectra of background quasars yield
tight constraints on the metallicity, ionization state, and kinematics
of the gaseous clouds. But whether they originate in gas accreted from
surrounding satellite galaxies or outflows associated with active
starburst in the host galaxies remains unclear. We have recently
completed a search of the Sloan Digital Sky Survey data archive for
strong MgII absorbers and identified over 1000 new systems that are
previously unknown. A subset of these MgII absorbers with W_MgII 1.8
A exhibit extreme kinematics with velocity widths {exceeding 200 km/s}
in our follow-up echelle spectra. Their dynamics are consistent with
various scenarios that include gas accretion {with speeds exceeding
the virial velocity} and starburst outflows {possibly driven by recent
merger events}. Independent of their exact nature, it is clear that
strong MgII systems serve as signposts to galactic halos with extreme
gas dynamics. Here we propose to conduct a snapshot survey of galaxies
in the fields toward high-redshift quasars with known, strong MgII
absorbers at 0.5 z 2. We plan to obtain high spatial-resolution
ACS/WFC images of 60 fields to uncover galaxies fainter than L* at the
redshifts of these absorbers and study their morphology. We will
complement the HST observations with follow-up spectroscopic
observations and IR images acquired at the Keck and Magellan
Observatories to for redshift identifications and for measuring
broad-band colors. We will investigate the correlation between
absorption line kinematics and galaxy morphology. In particular, we
will address whether on-going mergers is responsible for the extreme
dynamics observed in MgII absorption based on their rest-frame
ultraviolet morphology.

ACS/WFC 10605

Quantifying Star Formation and Feedback: The M81 Group Dwarf Galaxies

Studies of the impact of star formation via stellar winds and
supernovae {'feedback'} on the properties of a galaxy are of
fundamental importance to understanding galaxy evolution. One crucial
aspect in these studies is a precise census of the recent star
formation in a galaxy. The aim of this proposal is to obtain spatially
resolved star formation histories with a time resolution of roughly 30
Myr over the last 500 Myr in a carefully designed sample using the
absolutely unique capabilities of the ACS. Our sample comprises 10
galaxies in the M81 group which is host to a wide diversity of dwarf
star forming galaxies. They span ranges of 6 magnitudes in luminosity,
1000 in current star formation rate, and 0.5 dex in metallicity. The
ACS observations will allow us to directly observe the strength and
spatial relationships of all of the star formation in these galaxies
in the last 500 Myr. We can then quantify the star formation and
measure {1} the fraction of star formation that is triggered by
feedback, {2} the fraction of star formation that occurs in clusters
and associations, and {3} to what degree future star formation is
governed by the feedback from previous star formation. The ACS
observations will be complemented with high-quality ancillary data
collected by our team for all galaxies {e.g., Spitzer, UV/optical/NIR,
VLA HI}. We will calculate the energy created by star formation events
and compare it to the estimated energy deposited into the local ISM.
This will enable us to construct prescriptions of how star formation
and feedback depend on metallicity, size, gas content, and current
star formation rates in galaxies. Our resolved star formation maps
will be compared with star formation rates inferred from H-alpha, UV,
and IR observations - allowing an independent calibration of these
techniques. Recent ACS imaging by us of one galaxy in the same group
clearly demonstrates the feasibility of the proposed program. Most of
the sample galaxies are located in the CVZ, making this an extremely
efficient program.

ACS/WFC 10762

The Long X-ray Jet of Quasar 4C19.44

We propose to obtain a high signal/noise image of the very long jet of
4C 19.44. The observation should provide sufficient counts per jet
feature to obtain X-ray spectral indices capable of discriminating
between spectral models of the jet. We will examine the data for
offsets between X-ray and radio features and compare the beaming of
the kpc jet with the information obtained from the pc scale using
VLBI.

ACS/WFC/WFPC2 10584

The link between X-ray source and stellar populations in M81

We propose to perform a deep v~26-27.0 HST-ACS survey of the nearby
{3.6 Mpc} spiral galaxy M~81 in order to study the nature of its X-ray
source populations detected with Chandra. For the first time in a
galaxy other than the Milky-Way or the Magelanic Clouds, we will
classify X-ray sources as High-Mass and Low-Mass X-ray binaries
{HMXBs, LMXBs} and investigate how these populations depend on their
galactic environment. The classification will be performed {a} by
finding and classifying unique optical counterparts for the X-ray
sources and {b} studying the stellar populations in their vicinity.
Both tasks require the 0.1'' resolution of HST-ACS which matches well
the positional accuracy of Chandra. Finally we will use these results
together with X-ray binary evolution synthesis models in order to
constrain X-ray binary {XRB} evolution channels. These data will also
be a great resource for studies of the star-formation and star-
cluster populations in one of the prototypical spiral galaxies.

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 09 09
FGS REacq 04 04
OBAD with Maneuver 24 24

SIGNIFICANT EVENTS: (None)

 




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