HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

 

DAILY REPORT       # 4509

 

PERIOD COVERED: UT December 17, 2007 (DOY 351)

 

OBSERVATIONS SCHEDULED

 

ACS/SBC 11225

 

The Wavelength Dependence of Accretion Disk Structure

 

We can now routinely measure the size of quasar accretion disks using

gravitational microlensing of lensed quasars. The next step to testing

accretion disk models is to measure the size of accretion disks as a

function of wavelength, particularly at the UV and X-ray wavelengths

that should probe the inner, strong gravity regime. Here we focus on two

four-image quasar lenses that already have optical {R band} and X-ray

size measurements using microlensing. We will combine the HST

observations with ground-based monitoring to measure the disk size as a

function of wavelength from the near-IR to the UV. We require HST to

measure the image flux ratios in the ultraviolet continuum near the

Lyman limit of the quasars. The selected targets have estimated black

hole masses that differ by an order of magnitude, and we should find

wavelength scalings for the two systems that are very different because

the Blue/UV wavelengths should correspond to parts of the disk near the

inner edge for the high mass system but not in the low mass system. The

results will be modeled using a combination of simple thin disk models

and complete relativistic disk models. While requiring only 18 orbits,

success for one system requires observations in both Cycles 16 and 17.

 

FGS 11018

 

Long Term Stability of FGS1r in Position Mode

 

It is known from our experience with FGS3, and later with FGS1r, that an

FGS on orbit experiences long term evolution, presumably due to

disorption of water from the instrument's graphite epoxy composits. This

manifests principly as a change in the plate scale and secondarily as a

change in the geometric distortions. These effects are well modeled by

adjustments to the rhoA and kA parameters which are used to transform

the star selector servo angles into FGS {x, y} detector space

coordinates. By observing the relative positions of selected stars in a

standard cluster at a fixed telescope pointing and orientation, the

evolution of rhoA and kA can be monitored and calibrated to preserve the

astrometric performance of FGS1r.

 

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 11219

 

Active Galactic Nuclei in nearby galaxies: a new view of the origin of

the radio-loud radio- quiet dichotomy?

 

Using archival HST and Chandra observations of 34 nearby early-type

galaxies {drawn from a complete radio selected sample} we have found

evidence that the radio-loud/radio-quiet dichotomy is directly connected

to the structure of the inner regions of their host galaxies in the

following sense: [1] Radio-loud AGN are associated with galaxies with

shallow cores in their light profiles [2] Radio-quiet AGN are only

hosted by galaxies with steep cusps. Since the brightness profile is

determined by the galaxy's evolution, through its merger history, our

results suggest that the same process sets the AGN flavour. This

provides us with a novel tool to explore the co-evolution of galaxies

and supermassive black holes, and it opens a new path to understand the

origin of the radio-loud/radio-quiet AGN dichotomy. Currently our

analysis is statistically incomplete as the brightness profile is not

available for 82 of the 116 targets. Most galaxies were not observed

with HST, while in some cases the study is obstructed by the presence of

dust features. We here propose to perform an infrared NICMOS snapshot

survey of these 82 galaxies. This will enable us to i} test the reality

of the dichotomic behaviour in a substantially larger sample; ii} extend

the comparison between radio-loud and radio-quiet AGN to a larger range

of luminosities.

 

NIC3 11107

 

Imaging of Local Lyman Break Galaxy Analogs: New Clues to Galaxy

Formation in the Early Universe

 

We have used the ultraviolet all-sky imaging survey currently being

conducted by the Galaxy Evolution Explorer {GALEX} to identify for the

first time a rare population of low- redshift starbursts with properties

remarkably similar to high-redshift Lyman Break Galaxies {LBGs}. These

"compact UV luminous galaxies" {UVLGs} resemble LBGs in terms of size,

SFR, surface brightness, mass, metallicity, kinematics, dust, and color.

The UVLG sample offers the unique opportunity of investigating some very

important properties of LBGs that have remained virtually inaccessible

at high redshift: their morphology and the mechanism that drives their

star formation. Therefore, in Cycle 15 we have imaged 7 UVLGs using ACS

in order to 1} characterize their morphology and look for signs of

interactions and mergers, and 2} probe their star formation histories

over a variety of timescales. The images show a striking trend of

small-scale mergers turning large amounts of gas into vigorous

starbursts {a process referred to as dissipational or "wet" merging}.

Here, we propose to complete our sample of 31 LBG analogs using the

ACS/SBC F150LP {FUV} and WFPC2 F606W {R} filters in order to create a

statistical sample to study the mechanism that triggers star formation

in UVLGs and its implications for the nature of LBGs. Specifically, we

will 1} study the trend between galaxy merging and SFR in UVLGs, 2}

artificially redshift the FUV images to z=1-4 and compare morphologies

with those in similarly sized samples of LBGs at the same rest-frame

wavelengths in e.g. GOODS, UDF, and COSMOS, 3} determine the presence

and morphology of significant stellar mass in "pre-burst" stars, and 4}

study their immediate environment. Together with our Spitzer

{IRAC+MIPS}, GALEX, SDSS and radio data, the HST observations will form

a unique union of data that may for the first time shed light on how the

earliest major episodes of star formation in high redshift galaxies came

about. This proposal was adapted from an ACS HRC+WFC proposal to meet

the new Cycle 16 observing constraints, and can be carried out using the

ACS/SBC and WFPC2 without compromising our original science goals.

 

WFPC2 10915

 

ACS Nearby Galaxy Survey

 

Existing HST observations of nearby galaxies comprise a sparse and

highly non-uniform archive, making comprehensive comparative studies

among galaxies essentially impossible. We propose to secure HST's

lasting impact on the study of nearby galaxies by undertaking a

systematic, complete, and carefully crafted imaging survey of ALL

galaxies in the Local Universe outside the Local Group. The resulting

images will allow unprecedented measurements of: {1} the star formation

history {SFH} of a >100 Mpc^3 volume of the Universe with a time

resolution of Delta[log{t}]=0.25; {2} correlations between spatially

resolved SFHs and environment; {3} the structure and properties of thick

disks and stellar halos; and {4} the color distributions, sizes, and

specific frequencies of globular and disk clusters as a function of

galaxy mass and environment. To reach these goals, we will use a

combination of wide-field tiling and pointed deep imaging to obtain

uniform data on all 72 galaxies within a volume-limited sample extending

to ~3.5 Mpc, with an extension to the M81 group. For each galaxy, the

wide-field imaging will cover out to ~1.5 times the optical radius and

will reach photometric depths of at least 2 magnitudes below the tip of

the red giant branch throughout the limits of the survey volume. One

additional deep pointing per galaxy will reach SNR~10 for red clump

stars, sufficient to recover the ancient SFH from the color-magnitude

diagram. This proposal will produce photometric information for ~100

million stars {comparable to the number in the SDSS survey} and uniform

multi- color images of half a square degree of sky. The resulting

archive will establish the fundamental optical database for nearby

galaxies, in preparation for the shift of high- resolution imaging to

the near-infrared.

 

WFPC2 11169

 

Collisions in the Kuiper belt

 

For most of the 15 year history of observations of Kuiper belt objects,

it has been speculated that impacts must have played a major role in

shaping the physical and chemical characteristics of these objects, yet

little direct evidence of the effects of such impacts has been seen. The

past 18 months, however, have seen an explosion of major new discoveries

giving some of the first insights into the influence of this critical

process. From a diversity of observations we have been led to the

hypotheses that: {1} satellite- forming impacts must have been common in

the Kuiper belt; {2} such impacts led to significant chemical

modification; and {3} the outcomes of these impacts are sufficiently

predictable that we can now find and study these impact-derived systems

by the chemical and physical attributes of both the satellites and the

primaries. If our picture is correct, we now have in hand for the first

time a set of incredibly powerful tools to study the frequency and

outcome of collisions in the outer solar system. Here we propose three

linked projects that would answer questions critical to the multiple

prongs of our hypothesis. In these projects we will study the chemical

effects of collisions through spectrophotometric observations of

collisionally formed satellites and through the search for additional

satellites around primaries with potential impact signatures, and we

will study the physical effects of impacts through the examination of

tidal evolution in proposed impact systems. The intensive HST program

that we propose here will allow us to fully test our new hypotheses and

will provide the ability to obtain the first extensive insights into

outer solar system impact processes.

 

WFPC2 11178

 

Probing Solar System History with Orbits, Masses, and Colors of

Transneptunian Binaries

 

The recent discovery of numerous transneptunian binaries {TNBs} opens a

window into dynamical conditions in the protoplanetary disk where they

formed as well as the history of subsequent events which sculpted the

outer Solar System and emplaced them onto their present day heliocentric

orbits. To date, at least 47 TNBs have been discovered, but only about a

dozen have had their mutual orbits and separate colors determined,

frustrating their use to investigate numerous important scientific

questions. The current shortage of data especially cripples scientific

investigations requiring statistical comparisons among the ensemble

characteristics. We propose to obtain sufficient astrometry and

photometry of 23 TNBs to compute their mutual orbits and system masses

and to determine separate primary and secondary colors, roughly tripling

the sample for which this information is known, as well as extending it

to include systems of two near-equal size bodies. To make the most

efficient possible use of HST, we will use a Monte Carlo technique to

optimally schedule our observations.

 

WFPC2 11202

 

The Structure of Early-type Galaxies: 0.1-100 Effective Radii

 

The structure, formation and evolution of early-type galaxies is still

largely an open problem in cosmology: how does the Universe evolve from

large linear scales dominated by dark matter to the highly non-linear

scales of galaxies, where baryons and dark matter both play important,

interacting, roles? To understand the complex physical processes

involved in their formation scenario, and why they have the tight

scaling relations that we observe today {e.g. the Fundamental Plane}, it

is critically important not only to understand their stellar structure,

but also their dark-matter distribution from the smallest to the largest

scales. Over the last three years the SLACS collaboration has developed

a toolbox to tackle these issues in a unique and encompassing way by

combining new non-parametric strong lensing techniques, stellar

dynamics, and most recently weak gravitational lensing, with

high-quality Hubble Space Telescope imaging and VLT/Keck spectroscopic

data of early-type lens systems. This allows us to break degeneracies

that are inherent to each of these techniques separately and probe the

mass structure of early-type galaxies from 0.1 to 100 effective radii.

The large dynamic range to which lensing is sensitive allows us both to

probe the clumpy substructure of these galaxies, as well as their

low-density outer haloes. These methods have convincingly been

demonstrated, by our team, using smaller pilot-samples of SLACS lens

systems with HST data. In this proposal, we request observing time with

WFPC2 and NICMOS to observe 53 strong lens systems from SLACS, to obtain

complete multi-color imaging for each system. This would bring the total

number of SLACS lens systems to 87 with completed HST imaging and

effectively doubles the known number of galaxy-scale strong lenses. The

deep HST images enable us to fully exploit our new techniques, beat down

low-number statistics, and probe the structure and evolution of

early-type galaxies, not only with a uniform data-set an order of

magnitude larger than what is available now, but also with a fully

coherent and self-consistent methodological approach!

 

WFPC2 11361

 

Hubble Heritage Observations of Mars at 2007 Opposition

 

We will obtain images of Mars at opposition in December 2007.

 

FLIGHT OPERATIONS SUMMARY:

 

Significant Spacecraft Anomalies: (The following are preliminary reports

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

 

HSTARS:

11105 - Firefox on SMORWS7 cannot install updates

           When Firefox is opened on SMORWS7, it complains that it cannot install

           the updates that it had previously downloaded because Admin access is

           needed.

 

11106 - GSAcq(2,12) failed to RGA Hold(Gyro Control)

           GSAcq(2,1,2) scheduled at 352/02:00:12 - 02:08:17 failed to RGA Hold due

           to (QF2STOPF) sto flag indication on FGS-2 during acquisition walkdown.

           Pre-acquisition OBADs had (RSS) values of 1136.36 and 9.50 arseconds.

           Post-acq OBAD/MAP had 3-axis (RSS) value of 0.70 arcseconds. This

           acquisition is in On Orbit FSW/FGE Hybrid Test Mode scheduled.

 

11107 - GSAcq(1,2,2) requires multiple attempts to achieve CT-DV

           OTA SE review of PTAS processing data revealed that GSAcq(1,2,2)

           required four attempts to achieve CT-DV on FGS1.

 

11108 - GSAcq(1,2,2) requires multiple attempts to achieve CT-DV

           OTA SE review of PTAS processing revealed GSAcq(1,2,2) at 342/05:27:40

           required several attempts to achieve CT-DV. The acquisition was

           successful.

 

11109 - GSAcq(1,2,2) requires multiple attempts to achieve CT-DV

           OTA SE review of PTAS processing reveals that GSAcq(1,2,2) at 342/07:02

           required multiple attempts to achieve CT-DV. The acquisition was

           successful.

 

 

COMPLETED OPS REQUEST:

18054-0 - Preview KF Sun Vector Data via Telemetry Diags - 2 times

18164-0 - FSW/FGE hybrid mode on-orbit test commanding

17597-9 - FHST Stuck-on-Bottom Macro Execution

 

 

COMPLETED OPS NOTES: (None)

 

                       SCHEDULED      SUCCESSFUL  

FGS GSacq               08                 07                                                                                           

FGS REacq               06                 06                               

OBAD with Maneuver 28                 28                    

 

SIGNIFICANT EVENTS:

 

The FGS Hybrid mode was enabled in FSW at 351/12:50 this morning and the

first FGS-2R Hybrid mode acquisition was successful at 351/13:20.

 

FGS-2R performed Hydrid mode acquisitions throughout the day.

At 352/05:03 the FGE/FSW Hybrid Mode was disabled via Ops Request 18164.

The TMDIAG locations were then restored to their nominal values for the

KF sun vector data via generic ops request 18054. Nine of the 10 hybrid

mode acquisitions were successful. The one failure was unrelated to

hybrid mode performance. Initial analysis indicates that the hybrid mode

acquisitions executed as expected. Additional data analysis will be

performed by the OTA group and presented at the GSAWG meeting on

Wednesday. The first post-hybrid acquisition at 352/05:14 was

successful.