HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT       #4678

PERIOD COVERED: 5am August 19 - 5am August 20, 2008 (DOY 232/0900z-233/0900z)

OBSERVATIONS SCHEDULED

NIC1 11205

The Effects of Multiplicity on the Evolution of Young Stellar Objects: A

NICMOS Imaging Study

We propose to use NICMOS to investigate the multiplicity of young

stellar objects (YSOs) in the Orion B molecular cloud. Previous

observations with the Spitzer Space Telescope have revealed a remarkable

star forming filament near the NGC 2068 reflection nebula. The

population of YSOs associated with the filament exhibit a surprisingly

wide range of circumstellar evolutionary states, from deeply embedded

protostars to T Tauri accretion disks. Many of the circumstellar disks

themselves show evidence for significant dust evolution, including grain

growth and settling and cleared inner holes, apparently in spite of the

very young age of these stars. We will estimate the binary fraction of a

representative sample of objects in these various stages of evolution in

order to test whether companions may play a significant role in that

evolution.

NIC1/NIC2/NIC3 11330

NICMOS Cycle 16 Extended Dark

This takes a series of Darks in parallel to other instruments.

NIC1/NIC2/NIC3 8795

NICMOS Post-SAA Calibration - CR Persistence Part 6

A new procedure proposed to alleviate the CR-persistence problem of

NICMOS. Dark frames will be obtained immediately upon exiting the SAA

contour 23, and every time a NICMOS exposure is scheduled within 50

minutes of coming out of the SAA. The darks will be obtained in parallel

in all three NICMOS Cameras. The POST-SAA darks will be non-standard

reference files available to users with a USEAFTER date/time mark. The

keyword 'USEAFTER=date/time' will also be added to the header of each

POST-SAA DARK frame. The keyword must be populated with the time, in

addition to the date, because HST crosses the SAA ~8 times per day so

each POST-SAA DARK will need to have the appropriate time specified, for

users to identify the ones they need. Both the raw and processed images

will be archived as POST-SAA DARKSs. Generally we expect that all NICMOS

science/calibration observations started within 50 minutes of leaving an

SAA will need such maps to remove the CR persistence from the science i

mages. Each observation will need its own CRMAP, as different SAA

passages leave different imprints on the NICMOS detectors.

NIC2 11548

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

Environment in Star Formation

We propose NICMOS 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.

WFPC2 11130

AGNs with Intermediate-mass Black Holes: Testing the Black Hole-Bulge

Paradigm, Part II

The recent progress in the study of central black holes in galactic

nuclei has led to a general consensus that supermassive {10^6-10^9 solar

mass} black holes are closely connected with the formation and

evolutionary history of large galaxies, especially their bulge

component. Two outstanding issues, however, remain unresolved. Can

central black holes form in the absence of a bulge? And does the mass

function of central black holes extend below 10^6 solar masses?

Intermediate-mass black holes {<10^6 solar masses}, if they exist, may

offer important clues to the nature of the seeds of supermassive black

holes. Using the SDSS, our group has successfully uncovered a new

population of AGNs with intermediate-mass black holes that reside in

low-luminosity galaxies. However, very little is known about the

detailed morphologies or structural parameters of the host galaxies

themselves, including the crucial question of whether they have bulges

or not. Surprisingly, the majority of the targets of our Cycle 14 pilot

program have structural properties similar to dwarf elliptical galaxies.

The statistics from this initial study, however, are really too sparse

to reach definitive conclusions on this important new class of black

holes. We wish to extend this study to a larger sample, by using the

Snapshot mode to obtain WFPC2 F814W images from a parent sample of 175

AGNs with intermediate- mass black holes selected from our final SDSS

search. We are particularly keen to determine whether the hosts contain

bulges, and if so, how the fundamental plane properties of the host

depend on the mass of their central black holes. We will also

investigate the environment of this unique class of AGNs.

WFPC2 11221

A Dark Core in Abell 520

We have recently disocovered that the rich cluster Abell 520 exhibits

truly extreme multi-wavelength characteristics. The data indicate that

the cluster is the site of a major merger. Our weak lensing analysis,

based on a deep CFHT image, suggests the presence of a massive dark core

that coincides with the central X-ray emission peak, while being largely

devoid of galaxies. Although a displacement between the X-ray gas and

the galaxy/dark matter distribution may be expected in a merger (e.g. as

in the bullet cluster), the dark matter peak without galaxies cannot be

easily explained within the current collisionless dark matter paradigm.

A higher resolution mass map is required to make further progress, as it

will enable us to examine the detailed structure of the dark matter

distribution, as well as improve the significance of the dark peak. We

propose a 3 x 3 WFPC2 mosaic of interlaced images, where each pointing

consists of two sets of F814W exposures offset by 5.5 pixels. This will

precisely pinpoint the locations of the highest lensing peaks, enhance

the comparison with the Chandra X-ray data, and test physical and

geometrical models for the spatial and thermal structure of this

remarkable cluster derived from our suite of gas+dark matter simulations

of head-on/off-axis cluster mergers.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports

of potential non-nominal performance that will be investigated.)

HSTARS:

11449 - GSacq(2,1,1) failed to RGA control

           At 232/23:58:32 the GSacq(2,1,1) scheduled at 232/23:55:35 failed to RGA

   control due to scan step limit exceeded on FGS 2.

   Observations affected: NIC 86 - 107 Proposal ID 11512

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                       SCHEDULED      SUCCESSFUL

FGS GSacq               08                  07  

FGS REacq               07                  07    

OBAD with Maneuver 30                  30    

SIGNIFICANT EVENTS: (None)