HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5104

PERIOD COVERED: 5am May 25 - 5am May 26, 2010 (DOY 145/09:00z-146/09:00z)

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 06 06

FGS REAcq 09 09

OBAD with Maneuver 05 05

SIGNIFICANT EVENTS: (None)

OBSERVATIONS SCHEDULED:

ACS/WFC 11995

CCD Daily Monitor (Part 2)

This program comprises basic tests for measuring the read noise and dark

current of the ACS WFC and for tracking the growth of hot pixels. The

recorded frames are used to create bias and dark reference images for

science data reduction and calibration. This program will be executed

four days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To

facilitate scheduling, this program is split into three proposals. This

proposal covers 320 orbits (20 weeks) from 1 February 2010 to 20 June

2010.

COS/FUV 11895

FUV Detector Dark Monitor

Monitor the FUV detector dark rate by taking long science exposures

without illuminating the detector. The detector dark rate and spatial

distribution of counts will be compared to pre-launch and SMOV data in

order to verify the nominal operation of the detector. Variations of

count rate as a function of orbital position will be analyzed to find

dependence of dark rate on proximity to the SAA. Dependence of dark rate

as function of time will also be tracked.

COS/FUV/COS/NUV 11579

The Difference Between Neutral- and Ionized-Gas Metal Abundances in

Local Star-Forming Galaxies with COS

The metallicity of galaxies and its evolution with redshift is of

paramount importance for understanding galaxy formation. Abundances in

the interstellar medium (ISM) are typically determined using

emission-line spectroscopy of HII regions. However, since HII regions

are associated with recent SF they may not have abundances typical for

the galaxy as a whole. This is true in particular for star-forming

galaxies (SFGs), in which the bulk of the metals may be contained in the

neutral gas. It is therefore important to directly probe the metal

abundances in the neutral gas. This can be done using absorption lines

in the Far UV. We have developed techniques to do this in SFGs, where

the absorption is measured for sightlines toward bright SF regions

within the galaxy itself. We have successfully applied this technique to

a sample of galaxies observed with FUSE. The results have been very

promising, suggesting in I Zw 18 that abundances in the neutral gas may

be up to 0.5 dex lower than in the ionized gas. However, the

interpretation of the FUSE data is complicated by the very large FUSE

aperture (30 arcsec), the modest S/N, and the limited selection of

species available in the FUSE bandpass. The advent of COS on HST now

allows a significant advance in all of these areas. We will therefore

obtain absorption line spectroscopy with G130M in the same sample for

which we already have crude constraints from FUSE. We will obtain

ACS/SBC images to select the few optimal sightlines to target in each

galaxy. The results will be interpreted through line-profile fitting to

determine the metal abundances constrained by the available lines. The

results will provide important new insights into the metallicities of

galaxies, and into outstanding problems at high redshift such as the

observed offset between the metallicities of Lyman Break Galaxies and

Damped Lyman Alpha systems.

COS/FUV/COS/NUV 11601

UV spectroscopy of the hot bare stellar core H1504+65

H1504+65 is the hottest known white dwarf (Teff=200, 000 K). It has an

extraordinary surface composition. The surface is devoid of hydrogen and

helium. It is mainly composed of carbon and oxygen (by equal amounts)

and neon (2%). We obviously see the exposed core of a former red giant.

The evolutionary history of this unique object is unknown. We have

identified magnesium absorption lines in the soft X-ray photospheric

Chandra spectrum, which suggests that H1504+65 may be an O-Ne-Mg white

dwarf. We will test this hypothesis by abundance determinations of Mg

and Na. If confirmed, then H1504+65 would be the most compelling case

for the existence of single O-Ne-Mg white dwarfs.

COS/FUV/COS/NUV 11741

Probing Warm-Hot Intergalactic Gas at 0.5 < z < 1.3 with a Blind Survey

for O VI, Ne VIII, Mg X, and Si XII Absorption Systems

Currently we can only account for half of the baryons (or less) expected

to be found in the nearby universe based on D/H and CMB observations.

This "missing baryons problem" is one of the highest-priority challenges

in observational extragalatic astronomy. Cosmological simulations

suggest that the baryons are hidden in low-density, shock-heated

intergalactic gas in the log T = 5 - 7 range, but intensive UV and X-ray

surveys using O VI, O VII, and O VIII absorption lines have not yet

confirmed this prediction. We propose to use COS to carry out a

sensitive survey for Ne VIII and Mg X absorption in the spectra of nine

QSOs at z(QSO) > 0.89. For the three highest-redshift QSOs, we will also

search for Si XII. This survey will provide more robust constraints on

the quantity of baryons in warm-hot intergalactic gas at 0.5 < z < 1.3,

and the data will provide rich constraints on the metal enrichment,

physical conditions, and nature of a wide variety of QSO absorbers in

addition to the warm-hot systems. By comparing the results to other

surveys at lower redshifts (with STIS, FUSE, and from the COS GTO

programs), the project will also enable the first study of how these

absorbers evolve with redshift at z < 1. By combining the program with

follow-up galaxy redshift surveys, we will also push the study of

galaxy-absorber relationships to higher redshifts, with an emphasis on

the distribution of the WHIM with respect to the large-scale matter

distribution of the universe..

COS/NUV 11520

COS-GTO: QSO Absorbers, Galaxies and Large-scale Structures in the Local

Universe.

This is a program to probe the large scale structure of baryons in the

universe, including addressing questions of baryon fraction, physical

conditions and relationships between absorbers and large-scale

structures of galaxies. Besides these specific goals, this proposed GTO

program also probes a large enough total path length in Ly alpha and OVI

to add significantly to what STIS/FUSE has already observed. Several

Galactic High Velocity Cloud Complexes also are probed by these

sightlines, particularly the M Complex. The total path length of this

proposed program for Ly alpha large-scale structure surveys is

delta_z~5.5.

We have selected a variety of targets to address these questions, under

the following subcategories:

1. Target 8 bright BL Lac objects to search for low contrast Ly alpha

absorbers from the warm-hot interstellar medium (WHIM). Science drivers:

What are physical conditions and extent of warm-hot IGM in the current

epoch? Can we discover metal-poor WHIM using very broad Ly alpha lines?

What is the number density of such lines (dN/dz) and what is their

relationship if any with tentative Chandra detections of even hotter

gas?

2. Ly alpha cloud sizes: The targets are a bright AGN pair which yield

tangential distance separations of 100--500 kpc at z=0.01--0.05, where

galaxy surveys are excellent. This pair has two filaments and two voids

in this distance range. Science drivers: What are the characteristic

sizes of Ly alpha absorbers, weak metal-line absorbers and absorbers in

voids? Better size determinations will tighten current estimates of the

baryon content of the photoionzed IGM .

3. Probes of starburst outflows: The targets are bright AGN, <= 100 kpc

in projection out of the minor axis of nearby starburst galaxies.

Science drivers: Outflowing, unbound winds have been implicated as a

primary mechanism to enrich the IGM in mass, metals and energy. But do

starburst winds from massive galaxies escape the galaxy's gravitational

potential? If so, what is the metallicity and what are mass outflow

rates of these winds?

4. A large galaxy's gaseous halo: Three probes of the kinematics and

metallicity of a single L* galaxy halo. These observations includes

G130M, G160M exposures at SNR~20 and G285M at 2850A and SNR~10 for MgII.

The 2L* galaxy, ESO 157-G049 (cz=1678 km/s), being probed by these

sightlines has an available H I 21cm map from ATCA, H alpha imaging from

CTIO and long-slit spectra from MSSSO. Science drivers: What are the

extent, metallicity, ionization conditions and kinematics of gaseous

halos of normal luminous (L*) galaxies? Is there evidence for outflow,

inflow or galactic fountain circulation of gas in massive galaxy halos?

What is the source of halo gas (outflowing winds, infalling metal-poor

gas from stripping of nearby dwarf galaxies, nuclear outflows, large

numbers of bound dark matter halos??) and what is the relationship

between this gas and Galactic high-velocity clouds (HVCs)?

5. Dwarf galaxy

COS/NUV 11894

NUV Detector Dark Monitor

Measure the NUV detector dark rate by taking long science exposures with

no light on the detector. The detector dark rate and spatial

distribution of counts will be compared to pre-launch and SMOV data in

order to verify the nominal operation of the detector. Variations of

count rate as a function of orbital position will be analyzed to find

dependence of dark rate on proximity to the SAA. Dependence of dark rate

as function of time will also be tracked.

S/C/WFC3/IR 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).

STIS/CCD 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD.

STIS/CCD 11847

CCD Bias Monitor-Part 2

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 11855

STIS/CCD Spectroscopic Sensitivity Monitor for Cycle 17

Monitor sensitivity of each CCD grating mode to detect any change due to

contamination or other causes.

WFC3/IR 11702

Search for Very High-z Galaxies with WFC3 Pure Parallel

WFC3 will provide an unprecedented probe to the early universe beyond

the current redshift frontier. Here we propose a pure parallel program

using this new instrument to search for Lyman-break galaxies at

6.5<z<8.8 and to probe the epoch of reionization, a hallmark event in

the history of the early universe. We request 200 orbits, spreading over

30 ~ 50 high Galactic latitude visits (|b|>20deg) that last for 4 orbits

and longer, resulting a total survey area of about 140~230 square

arcminute. Based on our understanding of the new HST parallel

observation scheduling process, we believe that the total number of

long-duration pure parallel visits in Cycle 17 should be sufficient to

accommodate our program. We waive all proprietary rights to our data,

and will also make the enhanced data products public in a timely manner.

(1) We will use both the UVIS and the IR channels, and do not need to

seek optical data from elsewhere. (2) Our program will likely triple the

size of the probable candidate samples at z~7 and z~8, and will

complement other targeted programs aiming at the similar redshift range.

(3) Being a pure parallel program, our survey will only make very

limited demand on the scarce HST resources. More importantly, as the

pure parallel pointings will be at random sight-lines, our program will

be least affected by the bias due to the large scale structure ("cosmic

variance"). (4) We aim at the most luminous LBG population, and will

address the bright-end of the luminosity function at z~8 and z~7. We

will constrain the value of L* in particular, which is critical for

understanding the star formation process and the stellar mass assembly

history in the first few hundred million years of the universe. (5) The

candidates from our survey, most of which will be the brightest ones

that any surveys would be able to find, will have the best chance to be

spectroscopically confirmed at the current 8--10m telescopes. (6) We

will also find a large number of extremely red, old galaxies at

intermediate redshifts, and the fine spatial resolution offered by the

WFC3 will enable us constrain their formation history based on the study

of their morphology, and hence shed light on their connection to the

very early galaxies in the universe.

WFC3/IR 11712

Calibration of Surface Brightness Fluctuations for WFC3/IR

We aim to characterize galaxy surface brightness fluctuations (SBF), and

calibrate the SBF distance method, in the F110W and F160W filters of the

Wide Field Camera 3 IR channel. Because of the very high throughput of

F110W and the good match of F160W to the standard H band, we anticipate

that both of these filters will be popular choices for galaxy

observations with WFC3/IR. The SBF signal is typically an order of

magnitude brighter in the near-IR than in the optical, and the

characterisitics (sensitivity, FOV, cosmetics) of the WFC3/IR channel

will be enormously more efficient for SBF measurements than previously

available near-IR cameras. As a result, our proposed SBF calibration

will allow accurate distance derivation whenever an early-type or

bulge-dominated galaxy is observed out to a distance of 150 Mpc or more

(i.e., out to the Hubble flow) in the calibrated passbands. For

individual galaxy observations, an accurate distance is useful for

establishing absolute luminosities, black hole masses, linear sizes,

etc. Eventually, once a large number of galaxies have been observed

across the sky with WFC3/IR, this SBF calibration will enable accurate

mapping of the total mass density distribution in the local universe

using the data available in the HST archive. The proposed observations

will have additional important scientific value; in particular, we

highlight their usefulness for understanding the nature of multimodal

globular cluster color distributions in giant elliptical galaxies.

WFC3/UVI 11702