HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

 

DAILY REPORT      #5024

 

PERIOD COVERED: 5am February 1 - 5am February 2, 2010 (DOY 032/10:00z-033/10:00z)

 

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.

 

ACS/WFC3 11604

 

The Nuclear Structure of OH Megamaser Galaxies

 

We propose a snapshot survey of a complete sample of 80 OH megamaser

galaxies. Each galaxy will be imaged with the ACS/WFC through F814W and

a linear ramp filter (FR656N or FR716N or FR782N or FR853N) allowing us

to study both the spheroid and the gas morphology in Halpha + [N II]. We

will use the 9% ramps FR647M (5370-7570 angstroms) centered at 7000

angstroms and FR914M (7570-10, 719 angstroms) 8000 angstroms for

continuum subtraction for the high and low z objects respectively. OH

megamaser galaxies (OHMG) form an important class of ultraluminous

IR-galaxies (ULIRGs) whose maser lines emit QSO-like luminosities.

ULIRGs in general are associated with recent mergers but it is often

unclear whether their power output is dominated by starbursts or a

hidden QSO because of the high absorbing columns which hide their nuclei

even at X-ray wavelengths. In contrast, OHMG exhibit strong evidence for

the presence of an energetically important and recently triggered active

nucleus. In particular it is clear that much of the gas must have

already collapsed to form a nuclear disk which may be the progenitor of

a circum-nuclear torus, a key element of the unified scheme of AGN. A

great advantage of studying OHMG systems over the general ULIRG

population, is that the circum-nuclear disks are effectively "fixed" at

an inner, edge on, orientation, eliminating varying inclination as a

nuisance parameter. We will use the HST observations in conjunction with

existing maser and spectroscopic data to construct a detailed picture of

the circum-nuclear regions of a hitherto relatively neglected class of

galaxy that may hold the key to understanding the relationship between

galaxy mergers, nuclear star-formation, and the growth of massive black

holes and the triggering of nuclear activity.

 

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.

 

NIC2/WFC3/IR 11548

 

Infrared Imaging of Protostars in the Orion A Cloud: The Role of

Environment in Star Formation

 

We propose NICMOS and WFC3/IR observations of a sample of 252 protostars

identified in the Orion A cloud with the Spitzer Space Telescope. These

observations will image the scattered light escaping the protostellar

envelopes, providing information on the shapes of outflow cavities, the

inclinations of the protostars, and the overall morphologies of the

envelopes. In addition, we ask for Spitzer time to obtain 55-95 micron

spectra of 75 of the protostars. Combining these new data with existing

3.6 to 70 micron photometry and forthcoming 5-40 micron spectra measured

with the Spitzer Space Telescope, we will determine the physical

properties of the protostars such as envelope density, luminosity,

infall rate, and outflow cavity opening angle. By examining how these

properties vary with stellar density (i.e. clusters vs. groups vs.

isolation) and the properties of the surrounding molecular cloud; we can

directly measure how the surrounding environment influences protostellar

evolution, and consequently, the formation of stars and Planetary

systems. Ultimately, this data will guide the development of a theory of

protostellar evolution.

 

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/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/ACS/WFC 12050

 

20th Anniversary of HST Launch

 

The 20th anniversary of HST's launch on April 24, 2010 will be a

significant milestone both in the Hubble mission and in the history of

U.S. space astronomy. Already plans are in place for many activities

surrounding this anniversary that take advantage of the "teachable

moment" afforded by this event. A new, high-impact image from Hubble is

a necessary component of this mix. We are proposing here to meet that

need with new observations of a dramatic region of the Carina Nebula

only partially observed previously with Hubble. The release of the large

mosaic of the Carina Nebula for HST's 17th anniversary was one of the

largest Hubble images ever released (Fig. 1). It contains numerous

dramatic details including the pillar containing HH 901 (Fig. 2) which

was itself released as a separate detail image. What is not widely

realized, however, is that the HST data in the Carina mosaic is limited

to H-alpha only. The oxygen (502 nm) and sulfur (673 nm) images were

obtained with the MOSAIC camera at CTIO. These low resolution images

were combined with the much higher resolution HST data to produce the

final color image composite. When the full mosaic is viewed, the loss of

resolution is an acceptable compromise. However, when zooming in on

details, the effect is noticeable. We have selected the most dramatic

portion to return to with WFC3 to obtain HST resolution in a complete

filter set. In order to highlight the new capabilities of WFC3 as well

as foreshadowing the capabilities of JWST, we will obtain a full 3-color

composite in the IR channel of WFC3 in addition

 

WFC3/UVIS 11714

 

Snapshot Survey for Planetary Nebulae in Local Group Globular Clusters

 

PLanetary nebulae (PNe) in globular clusters (GCs) raise a number of

interesting issues related to stellar and galactic evolution. The number

of PNe known in Milky Way GCs, four, is surprisingly low if one assumes

that all stars pass through a PN stage. However, it is likely that the

remnants of stars now evolving in galactic GCs leave the AGB so slowly

that any ejected nebula dissipates long before the star becomes hot

enough to ionize it. Thus there should not be ANY PNe in Milky Way

GCs--but there are four! It has been suggested that these Pne are the

result of mergers of binary stars within GCs, i.e., that they are

descendants of blue stragglers. The frequency of occurrence of PNe in

external galaxies poses more questions, because it shows a range of

almost an order of magnitude.

 

I propose a SNAPshot survey aimed at discovering PNe in the GC systems

of Local Group galaxies outside the Milky Way. These clusters, some of

which may be much younger than their counterparts in our galaxy, might

contain many more PNe than those of our own galaxy. I will use the

standard technique of emission-line and continuum imaging, which easily

discloses PNe. This proposal continues a WFPC2 program started in Cycle

16, but with the more powerful WFC3. As a by-product, the survey will

also produce color-magnitude diagrams for numerous clusters for the

first time, reaching down to the horizontal branch.

 

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 11644

 

A Dynamical-Compositional Survey of the Kuiper Belt: A New Window Into

the Formation of the Outer Solar System

 

The eight planets overwhelmingly dominate the solar system by mass, but

their small numbers, coupled with their stochastic pasts, make it

impossible to construct a unique formation history from the dynamical or

compositional characteristics of them alone. In contrast, the huge

numbers of small bodies scattered throughout and even beyond the

planets, while insignificant by mass, provide an almost unlimited number

of probes of the statistical conditions, history, and interactions in

the solar system. To date, attempts to understand the formation and

evolution of the Kuiper Belt have largely been dynamical simulations

where a hypothesized starting condition is evolved under the

gravitational influence of the early giant planets and an attempt is

made to reproduce the current observed populations. With little

compositional information known for the real Kuiper Belt, the test

particles in the simulation are free to have any formation location and

history as long as they end at the correct point. Allowing compositional

information to guide and constrain the formation, thermal, and

collisional histories of these objects would add an entire new dimension

to our understanding of the evolution of the outer solar system. While

ground based compositional studies have hit their flux limits already

with only a few objects sampled, we propose to exploit the new

capabilities of WFC3 to perform the first ever large-scale

dynamical-compositional study of Kuiper Belt Objects (KBOs) and their

progeny to study the chemical, dynamical, and collisional history of the

region of the giant planets. The sensitivity of the WFC3 observations

will allow us to go up to two magnitudes deeper than our ground based

studies, allowing us the capability of optimally selecting a target list

for a large survey rather than simply taking the few objects that can be

measured, as we have had to do to date. We have carefully constructed a

sample of 120 objects which provides both overall breadth, for a general

understanding of these objects, plus a large enough number of objects in

the individual dynamical subclass to allow detailed comparison between

and within these groups. These objects will likely define the core

Kuiper Belt compositional sample for years to come. While we have many

specific results anticipated to come from this survey, as with any

project where the field is rich, our current knowledge level is low, and

a new instrument suddenly appears which can exploit vastly larger

segments of the population, the potential for discovery -- both

anticipated and not -- is extraordinary.

 

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               10              10     

FGS REAcq               07              07     

OBAD with Maneuver 05              05     

 

SIGNIFICANT EVENTS: (None)