HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT      #5022

PERIOD COVERED: 5am January 28 - 5am January 29, 2010 (DOY 028/10:00z-029/10:00z)

OBSERVATIONS SCHEDULED

COS/FUV 11897

FUV Spectroscopic Sensitivity Monitoring

The purpose of this proposal is to monitor sensitivity in each FUV

grating mode to detect any changes due to contamination or other causes.

STIS/CC/MA 11608

How Far Does H2 Go: Constraining FUV Variability in the Gaseous Inner

Holes of Protoplanetary Disks

By studying the innermost, planet-forming regions of circumstellar disks

around low-mass pre-main sequence stars we can refine theories of planet

formation and develop timescales for the evolution of disks and their

planets. Spitzer infrared observations of T Tauri stars have given us an

unprecedented look at dust evolution in young objects, particularly the

transitional disks. However, despite this ground breaking progress in

studying the dust in young disks, the relationship between the dust and

gas properties in the inner disk remains essentially unknown. Using STIS

on HST, we propose to quantify the variability of H2 emission

originating within the inner holes of transitional disks and explore its

implications on dust distribution and planet formation.

STIS/CCD 11844

CCD Dark Monitor Part 1

The purpose of this proposal is to monitor the darks for the STIS CCD.

STIS/CCD 11846

CCD Bias Monitor-Part 1

The purpose of this proposal is to monitor the bias in the 1x1, 1x2,

2x1, and 2x2 bin settings at gain=1, and 1x1 at gain = 4, to build up

high-S/N superbiases and track the evolution of hot columns.

STIS/CCD/MA2 11568

A SNAPSHOT Survey of the Local Interstellar Medium: New NUV Observations

of Stars with Archived FUV Observations

We propose to obtain high-resolution STIS E230H SNAP observations of

MgII and FeII interstellar absorption lines toward stars within 100

parsecs that already have moderate or high-resolution far-UV (FUV),

900-1700 A, observations available in the MAST Archive. Fundamental

properties, such as temperature, turbulence, ionization, abundances, and

depletions of gas in the local interstellar medium (LISM) can be

measured by coupling such observations. Due to the wide spectral range

of STIS, observations to study nearby stars also contain important data

about the LISM embedded within their spectra. However, unlocking this

information from the intrinsically broad and often saturated FUV

absorption lines of low-mass ions, (DI, CII, NI, OI), requires first

understanding the kinematic structure of the gas along the line of

sight. This can be achieved with high resolution spectra of high-mass

ions, (FeII, MgII), which have narrow absorption lines, and can resolve

each individual velocity component (interstellar cloud). By obtaining

short (~10 minute) E230H observations of FeII and MgII, for stars that

already have moderate or high- resolution FUV spectra, we can increase

the sample of LISM measurements, and thereby expand our knowledge of the

physical properties of the gas in our galactic neighborhood. STIS is the

only instrument capable of obtaining the required high resolution data

now or in the foreseeable future.

WFC3/ACS/IR 11677

Is 47 Tuc Young? Measuring its White Dwarf Cooling Age and Completing a

Hubble Legacy

With this proposal we will firmly establish the age of 47 Tuc from its

cooling white dwarfs. 47 Tuc is the nearest and least reddened of the

metal-rich disk globular clusters. It is also the template used for

studying the giant branches of nearby resolved galaxies. In addition,

the age sensitive magnitude spread between the main sequence turnoff and

horizontal branch is identical for 47 Tuc, two bulge globular clusters

and the bulge field population. A precise relative age constraint for 47

Tuc, compared to the halo clusters M4 and NGC 6397, both of which we

recently dated via white dwarf cooling, would therefore constrain when

the bulge formed relative to the old halo globular clusters. Of

particular interest is that with the higher quality ACS data on NGC

6397, we are now capable with the technique of white dwarf cooling of

determining ages to an accuracy of +/-0.4 Gyrs at the 95% confidence

level. Ages derived from the cluster turnoff are not currently capable

of reaching this precision. The important role that 47 Tuc plays in

galaxy formation studies, and as the metal-rich template for the

globular clusters, makes the case for a white dwarf cooling age for this

metal-rich cluster compelling.

Several recent analyses have suggested that 47 Tuc is more than 2 Gyrs

younger than the Galactic halo. Others have suggested an age similar to

that of the most metal poor globular clusters. The current situation is

clearly uncertain and obviously a new approach to age dating this

important cluster is required.

With the observations of 47 Tuc, this project will complete a legacy for

HST. It will be the third globular cluster observed for white dwarf

cooling; the three covering almost the full metallicity range of the

cluster system. Unless JWST has its proposed bluer filters (700 and 900

nm) this science will not be possible perhaps for decades until a large

optical telescope is again in space. Ages for globular clusters from the

main sequence turnoff are less precise than those from white dwarf

cooling making the science with the current proposal truly urgent.

WFC3/IR/S/C 11929

IR Dark Current Monitor

Analyses of ground test data showed that dark current signals are more

reliably removed from science data using darks taken with the same

exposure sequences as the science data, than with a single dark current

image scaled by desired exposure time. Therefore, dark current images

must be collected using all sample sequences that will be used in

science observations. These observations will be used to monitor changes

in the dark current of the WFC3-IR channel on a day-to-day basis, and to

build calibration dark current ramps for each of the sample sequences to

be used by Gos in Cycle 17. For each sample sequence/array size

combination, a median ramp will be created and delivered to the

calibration database system (CDBS).

WFC3/UV 11640

Lyman Alpha Imaging of Two Quasar Host Galaxies at z>6

We propose to image the Lyman Alpha emission line in two of the highest

redshift quasar host galaxies (redshifts z=6.31 and 6.42) to map the

amount and extent of star formation in the hosts and in their immediate

environment. These observations are now possible for the first time, as

UVIS on WFC3 (coincidentally) provides narrow-band filters at the right

wavelengths. Circumstantial evidence (based on NIR, radio/millimeter and

molecular gas measurements) suggests that these quasar hosts are

undergoing intense ~1000 Msun/yr bursts of star formation over scales of

~5kpc (0.6"). Our program will provide (continuum-subtracted) images of

the Lyman Alpha emission in the host which will in turn directly

constrain the extent and magnitude of star formation in the host. In the

case of the host galaxy of J1148+5251 (z=6.42) the Lyman Alpha emission

will be compared to resolved imaging of the molecular gas phase (CO and

[CII]) which in turn will yield critical constraints on the structure of

the host galaxy and the conditions of the interstellar medium. The

observations should also be sensitive enough to reveal potential

companion galaxies (if the quasars are residing in major overdensities

at these redshifts) and infall signatures in the immediate vicinity of

the quasar. The narrow-band filters of UVIS/WFC3 provide the unique

opportunity to study host/bulge formation at the end of cosmic

reionization (less than 1Gyr after the Big Bang).

WFC3/UVIS 11565

A Search for Astrometric Companions to Very Low-Mass, Population II

Stars

We propose to carry out a Snapshot search for astrometric companions in

a subsample of very low-mass, halo subdwarfs identified within 120

parsecs of the Sun. These ultra-cool M subdwarfs are local

representatives of the lowest-mass H burning objects from the Galactic

Population II. The expected 3-4 astrometric doubles that will be

discovered will be invaluable in that they will be the first systems

from which gravitational masses of metal-poor stars at the bottom of the

main sequence can be directly measured.

WFC3/UVIS 11577

Opening New Windows on the Antennae with WFC3

We propose to use WFC3 to provide key observations of young star

clusters in "The Antennae" (NGC4038/39). Of prime importance is the

WFC3's ability to push the limiting UV magnitude FIVE mag deeper than

our previous WFPC2 observations. This corresponds to pushing the

limiting cluster mass from ~10**5 to ~10**3 solar masses for cluster

ages ~10**8 yrs. In addition, the much wider field of view of the WFC3

IR channel will allow us to map out both colliding disks rather than

just the Overlap Region between them. This will be especially important

for finding the youngest clusters that are still embedded in their

placental cocoons. The extensive set of narrow-band filters will provide

an effective means for determining the properties of shocks, which are

believed to be a primary triggering mechanism for star formation. We

will also use ACS in parallel with WFC3 to observe portions of both the

northern and southern tails at no additional orbital cost. Finally, one

additional primary WFC3 orbit will be used to supplement existing HST

observations of the star-forming "dwarf" galaxy at the end of the

southern tail. Hence, when completed we will have full UBVI + H_alpha

coverage (or more for the main galaxy) of four different environments in

the Antennae. In conjunction with the extensive multi- wavelength

database we have collected (both HST and ground based) these

observations will provide answers to fundamental questions such as: How

do these clusters form and evolve? How is star formation triggered? How

do star clusters affect the local and global ISM, and the evolution of

the galaxy as a whole? The Antennae galaxies are the nearest example of

a major disk--disk merger, and hence may represent our best chance for

understanding how mergers form tremendous numbers of clusters and stars,

both in the local universe and during galaxy assembly at high redshift.

WFC3/UVIS 11905

WFC3 UVIS CCD Daily Monitor

The behavior of the WFC3 UVIS CCD will be monitored daily with a set of

full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K

subarray biases are acquired at less frequent intervals throughout the

cycle to support subarray science observations. The internals from this

proposal, along with those from the anneal procedure (Proposal 11909),

will be used to generate the necessary superbias and superdark reference

files for the calibration pipeline (CDBS).

WFC3/UVIS 11908

Cycle 17: UVIS Bowtie Monitor

Ground testing revealed an intermittent hysteresis type effect in the

UVIS detector (both CCDs) at the level of ~1%, lasting hours to days.

Initially found via an unexpected bowtie-shaped feature in flatfield

ratios, subsequent lab tests on similar e2v devices have since shown

that it is also present as simply an overall offset across the entire

CCD, i.e., a QE offset without any discernable pattern. These lab tests

have further revealed that overexposing the detector to count levels

several times full well fills the traps and effectively neutralizes the

bowtie. Each visit in this proposal acquires a set of three 3x3 binned

internal flatfields: the first unsaturated image will be used to detect

any bowtie, the second, highly exposed image will neutralize the bowtie

if it is present, and the final image will allow for verification that

the bowtie is gone.

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:

18808-0 - Null genslews for proposal 12053 - Slots 2 and 3 @ 028/1836z

COMPLETED OPS NOTES: (None)

                      SCHEDULED  SUCCESSFUL             

FGS GSAcq               9                9              

FGS REAcq               7                7              

OBAD with Maneuver 6                6              

SIGNIFICANT EVENTS: (None)