HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT      #4962

PERIOD COVERED: 5am October 29 - 5am October 30, 2009 (DOY 302/09:00z-303/09:00z)

OBSERVATIONS SCHEDULED

ACS/WFC 11689

Direct Observations of Dark Matter from a Second Bullet: The Spectacular

Abell 2744

Vigorous cluster mergers provide a unique opportunity to directly "see"

dark matter and to probe its properties through the analysis of the

segregation of the baryonic and non-baryonic components. This is

accomplished through detailed comparison of the mass distributions as

traced by X-ray emitting gas and by gravitational lensing. This

condition is rare and so far only one cluster has met these

requirements, the so-called "bullet" cluster, producing exciting results

and placing constraints to the properties of dark matter. These

constraints have a broad impact on models for formation of structure and

on galaxy evolution. This multi-wavelength analysis has the potential

confront alternative gravity models such as MOND. Therefore, it is

crucial to find new bullet clusters to corroborate and improve

previous measurements. This is the most direct way to constrain dark

matter properties and A2744 is ideal for corroborating this study since

it maximizes all the requirements for this analysis. Here, we propose to

carry out such analysis through combined ACS and Chandra observations of

the cluster merger Abell 2744.

COS/NUV 11900

NUV Internal/External Wavelength Scale Monitor

This program monitors the offsets between the wavelength scale set by

the internal wavecal versus that defined by absorption lines in external

targets. This is accomplished by observing two external radial velocity

standard targets: HD187691 with G225M and G285M and HD6655 with G285M

and G230L. The two standard targets have little flux in the wavelength

range covered by G185M and so Feige 48 (sdO) is observed with this

grating. Both Feige 48 and HD6655 are also observed in SMOV. The

cenwaves observed in this program are a subset of the ones used during

Cycle 17. Observing all cenwaves would require a considerably larger

number of orbits. Constraints on scheduling of each target are placed so

that each target is observed once every ~2-3 months. Observing the three

targets every month would also require a considerably larger number of

orbits.

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 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/CCD 11653

SAINTS - Supernova 1987A INTensive Survey

SAINTS is a program to observe SN 1987A, the brightest supernova since

1604, as it matures into the youngest supernova remnant at age 21. HST

is the essential tool for resolving SN1987A's many physical components.

A violent encounter is underway between the fastest-moving debris and

the circumstellar ring: shocks excite "hotspots." Radio, optical,

infrared and X-ray fluxes have been rising rapidly: we have organized

Australia Telescope, HST, VLT, Spitzer, and Chandra observations to

understand the several emission mechanisms at work. Photons from the

shocked ring will excite previously invisible gas outside the ring,

revealing the true extent of the mass loss that preceded the explosion

of Sanduleak -69 202. This will help test ideas for the progenitor of SN

1987A. The inner debris, excited by radioactive isotopes from the

explosion, is now resolved and seen to be aspherical, providing direct

evidence on the shape of the explosion itself. Questions about SN 1987A

remain unanswered. A rich and unbroken data set from SAINTS will help

answer these central questions and will build an archive for the future

to help answer questions we have not yet thought to ask.

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/UV/ACS/WFC 11688

Exploring the Bottom End of the White Dwarf Cooling Sequence in the Open

Cluster NGC6819

The recent discovery by our group of an unexpectedly bright end of the

white-dwarf (WD) luminosity function (LF) of the metal-rich, old open

cluster NGC 6791 casts serious doubts on our understanding of the

physical process which rules the formation and the cooling of WDs. It is

clear at this point that the theory badly needs more observations. Here

we propose WFC3/UVIS and ACS/WFC HST observations reaching the bottom

end of the WD LF, for the first time in a solar-metallicity,

2.5-Gyr-old, populous open cluster: NGC 6819.

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 11657

The Population of Compact Planetary Nebulae in the Galactic Disk

We propose to secure narrow- and broad-band images of compact planetary

nebulae (PNe) in the Galactic Disk to study the missing link of the

early phases of post-AGB evolution. Ejected AGB envelopes become PNe

when the gas is ionized. PNe expand, and, when large enough, can be

studied in detail from the ground. In the interim, only the HST

capabilities can resolve their size, morphology, and central stars. Our

proposed observations will be the basis for a systematic study of the

onset of morphology. Dust properties of the proposed targets will be

available through approved Spitzer/IRS spectra, and so will the

abundances of the alpha- elements. We will be able thus to explore the

interconnection of morphology, dust grains, stellar evolution, and

populations. The target selection is suitable to explore the nebular and

stellar properties across the galactic disk, and to set constraints on

the galactic evolutionary models through the analysis of metallicity and

population gradients.

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).

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               11                  11                 

FGS REAcq               06                  06                                                                                               

OBAD with Maneuver 06                  06                

SIGNIFICANT EVENTS: (None)