HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5091

PERIOD COVERED: 5am May 6 - 5am May 7, 2010 (DOY 126/09:00z-127/09:00z)

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:

18854-3 – Recover STIS MAMA1 from HV shutoff @ 126/1914z

COMPLETED OPS NOTES: (None)

                      SCHEDULED  SUCCESSFUL

FGS GSAcq               6               6

FGS REAcq               9               9

OBAD with Maneuver 4               4

SIGNIFICANT EVENTS:

Ops Flash Report:

STIS MAMA1 HV ramp was successfully competed at 126/22:52z; the max

counts observed during the ramp was 158 cnts/secs.

OBSERVATIONS SCHEDULED

COS/NUV/FUV 11645

HST COS Observations of the Atmosphere and Airglow/Aurora of Enceladus

Recent observations from several instruments on the Cassini spacecraft

have revealed plumes of dust and water from the southern polar region,

and clearly shown that Enceladus contributes large amounts of plasma to

Saturn?s magnetosphere. This implies a global thin atmosphere containing

water and likely other species, and a local region with orders of

magnitude higher density near the plumes. While water and dust have been

identified from the plumes, the presence of many other species in the

atmosphere is possible and not yet ruled out. The identification of all

significant species in the atmosphere of Enceladus is of key importance

to speculation about the source of the water plumes, and the

implications for any form of life at or below the surface. In addition,

modeling suggests that Enceladus? mass loading region may be comparable

in extent to Io?s, and interacts strongly with Saturn?s corotating

magnetic field and plasma. We have recently concluded a search for an

auroral footprint of Enceladus in HST images, which set a low upper

limit implying that the magnetospheric interaction is concentrated near

Enceladus, rather than being communicated along field lines to Saturn?s

ionosphere. The next step will be to observe the interaction at the

satellite, and to learn whatever we can about the physics of the release

of the atmospheric gas. We propose here an exploratory set of spectral

observations with HST COS to measure the solar reflection spectrum over

a broad range of UV wavelengths for atmospheric absorption signatures.

This will at the same time measure the emission spectrum of the

atmosphere from both the leading and trailing hemispheres ? Enceladus

orbit apart, as was done in HST STIS observations of Io to study its

interaction at Jupiter. The higher sensitivity of COS will be needed to

study the much smaller and relatively weakly-interacting Enceladus, and

the outcome of these observations will determine the nature of future

studies of the atmosphere of Enceladus and its plasma interaction with

the Saturnian magnetosphere.

COS/NUV/FUV 11698

The Structure and Dynamics of Virgo's Multi-Phase Intracluster Medium

The dynamical flows of the intracluster medium (ICM) are largely

unknown. We propose to map the spatial and kinematic distribution of the

warm ICM of the nearby Virgo cluster using the Cosmic Origins

Spectrograph. 15 sightlines at a range of impact parameters within the

virial radius of the cluster (0.2 - 1.7 Mpc) will be probed for

Lyman-alpha absorption and the data compared to blind HI, dust and x-ray

surveys to create a multi-phase map of the cluster's ICM. Absorption

line sightlines are commonly 40-100 kpc from a galaxy, allowing the flow

of baryons between galaxies and the ICM to be assessed. The velocity

distribution of the absorbers will be directly compared to simulations

and used to constrain the turbulent motions of the ICM. This proposal

will result in the first map of a cluster's warm ICM and provide

important tests for our theoretical understanding of cluster formation

and the treatment of gas cooling in cosmological simulations.

COS/NUV/FUV 11720

Detailed Analysis of Carbon Atmosphere White Dwarfs

We propose to obtain UV spectra for the newly discovered white dwarf

stars with a carbon- dominated atmosphere. Model calculations show that

these stars emit most of their light in the UV part of the

electromagnetic spectrum and that an accurate determination of the flux

in this region is crucial for an accurate determination of the

atmospheric parameters. It will also provide a unique opportunity to

test the atomic data and broadening theory in stellar conditions never

met before. This will play a primordial role in our path to understand

the origin of these objects as well to obtain a better understanding of

the evolution of stars in general. The principal objective we hope to

achieve with these observations are 1) obtain accurate surface

gravity/mass for these stars, 2) constrain/determine the abundance of

other elements (O, He, Mg, Ne etc.), especially oxygen, 3) verify the

accuracy of the various theoretical atomic data used in the model

calculations, 4) understand the origin and evolution of carbon

atmosphere white dwarfs, in particular whether progenitor stars as

massive as 10.5 solar masses can produce white dwarfs, rather than

supernovae. We propose to observe 5 objects chosen carefully to cover

the range of observed properties among carbon atmosphere white dwarfs

(effective temperature, surface gravity, abundance of hydrogen/helium

and magnetic field).

STIS/CC 11845

CCD Dark Monitor Part 2

Monitor the darks for the STIS CCD.

STIS/CC 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 11606

Dynamical Hypermassive Black Hole Masses

We will use STIS spectra to derive the masses of 5 hypermassive black

holes (HMBHs). From the observed scaling relations defined by less

massive spheroids, these objects are expected to reside at the nuclei of

host galaxies with stellar velocity dispersions greater than 320 km/s.

These 5 targets have confirmed regular gas distributions on the scales

of the black hole sphere of influence. It is essential that the sphere

of influence is resolved for accurate determinations of black hole mass

(0.1"). These scales cannot be effectively observed from the ground.

Only two HMBHs have had their masses modeled so far; it is impossible to

draw any general conclusions about the connections between HMBH mass and

their massive host galaxies. With these 5 targets we will determine

whether these HMBHs deviate from the scaling relations defined by less

massive spheroids. A larger sample will allow us to firmly anchor the

high mass end of the correlation between black hole mass and stellar

velocity dispersion, and other scaling relations. Therefore we are also

conducting a SNAPshot program with which we expect to detect a further

24 HMBH candidates for STIS observation in future cycles. At the

completion of this project we will have populated the high mass end of

the scaling relations with the sample sizes enjoyed by less massive

spheroids.

STIS/MA 11856

MAMA Full Field Sensitivity Monitor & PSF Check

The purpose of this program is to monitor the sensitivity of the MAMA

detectors over the full field. This is achieved by observing globular

cluster NGC6681 once during Cycle 17. The data can be directly compared

with similar data obtained in Cycles 7, 8, 9, 10, 11, and 12.

STIS/MA1 11861

MAMA FUV Flats

This program will obtain FUV-MAMA observations of the STIS internal

Krypton lamp to construct an FUV flat applicable to all FUV modes.

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 11602

High-resolution imaging of three new UV-bright lensed arcs

We have identified and spectroscopically confirmed three new strongly

lensed, UV-bright star-forming galaxies at z ~ 2 that are similar to the

well-studied gravitationally lensed Lyman Break Galaxy (LBG)

MS1512-cB58, and are of comparable brightness to the ''8 O'Clock Arc''

(Allam et al. 2007) and ''Clone'' systems (Lin et al. 2008). The 8

O'Clock Arc and Clone have already been awarded 20 orbits for deep WFPC2

and NICMOS imaging in five bands (HST cycle 16, Program 11167, PI:

Allam). Adding these three recently discovered objects thus completes a

unique set of the brightest known strongly lensed galaxies at z ~ 2,

with magnitudes of r~20-21, and they provide a new window into the

detailed study of the properties of high redshift galaxies. We propose

21 orbits for deep WFC3 imaging in five bands (F475W, F606W, F814W,

F110W, and F160W) in order to construct detailed lensing models, to

probe the mass and light profiles of the lensing galaxies and their

environments, and to constrain the spectral energy distributions, star

formation histories, and morphologies of the lensed galaxies.

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.

WFC3/UVIS/IR 11662

Improving the Radius-Luminosity Relationship for Broad-Lined AGNs with a

New Reverberation Sample

The radius-luminosity (R-L) relationship is currently the fundamental

basis for all techniques used to estimate black hole masses in AGNs, in

both the nearby and distant universe. However, the current R-L

relationship is based on 34 objects that cover a limited range in black

hole mass and luminosity. To improve our understanding of black hole

growth and evolution, the R-L relationship must be extended to cover a

broader range of black hole masses using the technique known as

reverberation mapping. To this end, we have been awarded an

unprecedented 64 nights on the Lick Observatory 3-m telescope between

March 24 and May 31, 2008, to spectroscopically monitor 12 AGNs in order

to measure their black hole masses. To properly determine the

luminosities of these 12 AGNs, we must correct them for their

host-galaxy starlight contributions using high-resolution images.

Previous work by Bentz et al. (2006) has shown that the starlight

correction to AGN luminosity measurements is an essential component to

interpreting the R-L relationship. The correction will be substantial

for each of the 12 sources we will monitor, as the AGNs are relatively

faint and embedded in nearby, bright galaxies. Starlight corrections are

not possible with ground-based images, as the PSF and bulge

contributions become indistinguishable under typical seeing conditions,

and adaptive optics are not yet operational in the spectral range where

the corrections are needed. In addition, spectral decompositions are

very model-dependent and are limited by the degree of accuracy to which

we understand emission processes and stellar populations in galaxies.

Without correcting for starlight, we will be unable to apply the results

of our Spring 2008 campaign to the body of knowledge from previous

reverberation mapping work. Therefore, we propose to obtain high

resolution, high dynamic range images of the host galaxies of the 12

AGNs in our ground-based monitoring sample, as well as one white dwarf

which will be used as a PSF model.

WFC3/UVIS/IR 11700

Bright Galaxies at z>7.5 with a WFC3 Pure Parallel Survey

The epoch of reionization represents a special moment in the history of

the Universe as it is during this era that the first galaxies and star

clusters are formed. Reionization also profoundly affects the

environment where subsequent generations of galaxies evolve. Our

overarching goal is to test the hypothesis that galaxies are responsible

for reionizing neutral hydrogen. To do so we propose to carry out a pure

parallel WFC3 survey to constrain the bright end of the redshift z>7.5

galaxy luminosity function on a total area of 176 arcmin^2 of sky.

Extrapolating the evolution of the luminosity function from z~6, we

expect to detect about 20 Lyman Break Galaxies brighter than M_* at z~8

significantly improving the current sample of only a few galaxies known

at these redshifts. Finding significantly fewer objects than predicted

on the basis of extrapolation from z=6 would set strong limits to the

brightness of M_*, highlighting a fast evolution of the luminosity

function with the possible implication that galaxies alone cannot

reionize the Universe. Our observations will find the best candidates

for spectroscopic confirmation, that is bright z>7.5 objects, which

would be missed by small area deeper surveys. The random pointing nature

of the program is ideal to beat cosmic variance, especially severe for

luminous massive galaxies, which are strongly clustered. In fact our

survey geometry of 38 independent fields will constrain the luminosity

function like a contiguous single field survey with two times more area

at the same depth. Lyman Break Galaxies at z>7.5 down to m_AB=26.85 (5

sigma) in F125W will be selected as F098M dropouts, using three to five

orbits visits that include a total of four filters (F606W, F098M, F125W,

F160W) optimized to remove low-redshift interlopers and cool stars. Our

data will be highly complementary to a deep field search for high- z

galaxies aimed at probing the faint end of the luminosity function,

allowing us to disentangle the degeneracy between faint end slope and

M_* in a Schechter function fit of the luminosity function. We waive

proprietary rights for the data. In addition, we commit to release the

coordinates and properties of our z>7.5 candidates within one month from

the acquisition of each field.