HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

 

DAILY REPORT      #4961

 

PERIOD COVERED: 5am October 28 - 5am October 29, 2009 (DOY 301/09:00z-302/09:00z)

 

OBSERVATIONS SCHEDULED

 

ACS/WFC3 11879

 

CCD Daily Monitor (Part 1)

 

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 352 orbits (22 weeks) from 31 August 2009 to 31 January

2010.

 

ACS/WFC3 11882

 

CCD Hot Pixel Annealing

 

All the data for this program is acquired using internal targets (lamps)

only, so all of the exposures should be taken during Earth occultation

time (but not during SAA passages). This program emulates the ACS

pre-flight ground calibration and post launch SMOV testing (program

8948), so that results from each epoch can be directly compared.

Extended Pixel Edge Response (EPER) and First Pixel Response (FPR) data

will be obtained over a range of signal levels for the Wide Field

Channel (WFC). The High Resolution Channel (HRC) visits have been

removed since it could not be repaired during SM4.

 

COS/FUV 11524

 

COS-GTO: WARM AND HOT ISM IN AND NEAR THE MILKY WAY

 

COS G130M and G160M 20, 000 resolution observations will be obtained for

10 AGNs situated beyond Milky Way high velocity clouds. For all objects

good O VI line profile observations exist from FUSE and high velocity O

VI is detected. The COS observations will be used to obtain high quality

absorption line profiles (S/N ~ 30 to 40) for C IV, Si IV and N V in the

low and high velocity gas toward each AGN. The high ionization profiles

of O VI (from FUSE), N V, C IV, and Si IV will be compared to low

ionization profiles (O I, S II, Si II, Fe II, etc.) in order to evaluate

the physical conditions and origins of the highly ionized gas in and

near the Milky Way at low and high velocity. The HVCs include Complex C

(four lines of sight), Complex A, WD, WB, and several negative velocity

O VI HVCs. Other studies to be undertaken with this data set include

studies of the physical conditions and abundances in the cool and warm

HVC gas and studies of the physical conditions in low redshift IGM

systems detected along the 10 lines of sight.

 

COS/FUV 11526

 

COS-GTO: Sampling the Local ISM with Hot White Dwarfs

 

We shall use hot white dwarf stars located within 150pc of the Sun to

probe the absorption properties of the interstellar gas associated with

the local cavity. There is still much debate concerning the ionization

state of the local gas, since previously detected highly ionized lines

(such as CIV and SiIV) could be associated with the circumstellar

environments of hot white dwarfs. By using a priori knowledge of the

velocity structure of the interstellar sight-lines to these targets

(gained from high spectral resolution ground-based observations) in

conjunction with the UV absorption data gained with HST-COS, we shall be

able to better determine both the physical and chemical state of the

numerous diffuse interstellar clouds present within the local cavity.

 

COS/FUV 11541

 

COS-GTO: COOL, WARM AND HOT GAS IN THE COSMIC WEB AND IN GALAXY HALOS

 

COS G130M and G160M 20, 000 resolution observations will be obtained for

17 QSOs to study cool, warm and hot gas in the cosmic web and in galaxy

halos. 5 QSOs with z from 0.177 to 0.574 and sum z = 1.68 will be

observed with S/N = 40-50 per resolution element. 12 QSOs with z = 0.286

to 0.669 and sum z = 5.57 will be observed with S/N = 30-40. The

observations will allow a wide range of IGM studies including

determining the frequency of occurrence of the different types of

absorption systems detected, along with studies of the physical

conditions and elemental abundances in the different systems. Special

emphasis will be given to a study of the properties of highly ionized

IGM as traced by O VI, O V, O IV, N V, and C IV. The high S/N of the

observations will allow a search for broad Lyman alpha absorption and

weak metal line absorption that can be crucial for the evaluation of

physical conditions and elemental abundances. Supporting ground based

observations will allow studies of the association of the absorbers with

galaxy structures along the 17 lines of sight. The overall goal of the

program will be to obtain the information that will allow an assessment

of the baryonic content of the IGM as revealed by UV and EUV absorption

lines seen in the spectra of QSOs.

 

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.

 

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:

12057 - REAcq(2,1,1) at 301/09:03:25z and 301/10:39:19z failed to RGA

           Hold due to a search radius limit exceeded on FGS-2.

 

           Observations affected: COS 46-53, Proposal ID# 11541.

 

 

COMPLETED OPS REQUEST: (None)

 

COMPLETED OPS NOTES: (None)

 

                      SCHEDULED      SUCCESSFUL

FGS GSAcq               9                    9  

FGS REAcq               7                    5    

OBAD with Maneuver 7                    7                

 

SIGNIFICANT EVENTS: (None)