HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

 

DAILY REPORT       # 4563

 

PERIOD COVERED: UT March 07,08,09, 2008 (DOY 067,068,069)

 

OBSERVATIONS SCHEDULED

 

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.

 

WFPC2 11235

 

HST NICMOS Survey of the Nuclear Regions of Luminous Infrared Galaxies

in the Local Universe

 

At luminosities above 10^11.4 L_sun, the space density of far-infrared

selected galaxies exceeds that of optically selected galaxies. These

`luminous infrared galaxies' {LIRGs} are primarily interacting or

merging disk galaxies undergoing enhanced star formation and Active

Galactic Nuclei {AGN} activity, possibly triggered as the objects

transform into massive S0 and elliptical merger remnants. We propose

NICMOS NIC2 imaging of the nuclear regions of a complete sample of 88

L_IR > 10^11.4 L_sun luminous infrared galaxies in the IRAS Revised

Bright Galaxy Sample {RBGS: i.e., 60 micron flux density > 5.24 Jy}.

This sample is ideal not only in its completeness and sample size, but

also in the proximity and brightness of the galaxies. The superb

sensitivity and resolution of NICMOS NIC2 on HST enables a unique

opportunity to study the detailed structure of the nuclear regions,

where dust obscuration may mask star clusters, AGN and additional nuclei

from optical view, with a resolution significantly higher than possible

with Spitzer IRAC. This survey thus provides a crucial component to our

study of the dynamics and evolution of IR galaxies presently underway

with Wide-Field, HST ACS/WFC and Spitzer IRAC observations of these 88

galaxies. Imaging will be done with the F160W filter {H-band} to examine

as a function of both luminosity and merger stage {i} the luminosity and

distribution of embedded star clusters, {ii} the presence of optically

obscured AGN and nuclei, {iii} the correlation between the distribution

of 1.6 micron emission and the mid- IR emission as detected by Spitzer

IRAC, {iv} the evidence of bars or bridges that may funnel fuel into the

nuclear region, and {v} the ages of star clusters for which photometry

is available via ACS/WFC observations. The NICMOS data, combined with

the HST ACS, Spitzer, and GALEX observations of this sample, will result

in the most comprehensive study of merging and interacting galaxies to

date.

 

FGS 11212

 

Filling the Period Gap for Massive Binaries

 

The current census of binaries among the massive O-type stars is

seriously incomplete for systems in the period range from years to

millennia because the radial velocity variations are too small and the

angular separations too close for easy detection. Here we propose to

discover binaries in this observational gap through a Faint Guidance

Sensor SNAP survey of relatively bright targets listed in the Galactic O

Star Catalog. Our primary goal is to determine the binary frequency

among those in the cluster/association, field, and runaway groups. The

results will help us assess the role of binaries in massive star

formation and in the processes that lead to the ejection of massive

stars from their natal clusters. The program will also lead to the

identification of new, close binaries that will be targets of long term

spectroscopic and high angular resolution observations to determine

their masses and distances. The results will also be important for the

interpretation of the spectra of suspected and newly identified binary

and multiple systems.

 

FGS 11211

 

An Astrometric Calibration of Population II Distance Indicators

 

In 2002 HST produced a highly precise parallax for RR Lyrae. That

measurement resulted in an absolute magnitude, M{V}= 0.61+/-0.11, a

useful result, judged by the over ten refereed citations each year

since. It is, however, unsatisfactory to have the direct,

parallax-based, distance scale of Population II variables based on a

single star. We propose, therefore, to obtain the parallaxes of four

additional RR Lyrae stars and two Population II Cepheids, or W Vir

stars. The Population II Cepheids lie with the RR Lyrae stars on a

common K-band Period-Luminosity relation. Using these parallaxes to

inform that relationship, we anticipate a zero-point error of 0.04

magnitude. This result should greatly strengthen confidence in the

Population II distance scale and increase our understanding of RR Lyrae

star and Pop II Cepheid astrophysics.

 

FGS 11210

 

The Architecture of Exoplanetary Systems

 

Are all planetary systems coplanar? Concordance cosmogony makes that

prediction. It is, however, a prediction of extrasolar planetary system

architecture as yet untested by direct observation for main sequence

stars other than the Sun. To provide such a test, we propose to carry

out FGS astrometric studies on four stars hosting seven companions. Our

understanding of the planet formation process will grow as we match not

only system architecture, but formed planet mass and true distance from

the primary with host star characteristics for a wide variety of host

stars and exoplanet masses. We propose that a series of FGS astrometric

observations with demonstrated 1 millisecond of arc per-observation

precision can establish the degree of coplanarity and component true

masses for four extrasolar systems: HD 202206 {brown dwarf+planet}; HD

128311 {planet+planet}, HD 160691 = mu Arae {planet+planet}, and HD

222404AB = gamma Cephei {planet+star}. In each case the companion is

identified as such by assuming that the minimum mass is the actual mass.

For the last target, a known stellar binary system, the companion orbit

is stable only if coplanar with the AB binary orbit.

 

WFPC2 11206

 

At the cradle of the Milky Way: Formation of the most massive field disk

galaxies at z>1

 

We propose to obtain 2 orbit WFPC2 F814W images of a sample of the 15

most massive galaxies found at $1 < z < 1.3$. These were culled from

over 20,000 Keck spectra collected as part of DEEP and are unique among

high redshift massive galaxy samples in being kinematically selected.

Through a recent HST NICMOS-2 imaging program {GO-10532}, we have

confirmed that these galaxies have regular stellar disks, and their

emission line kinematics are not due to gradients from merging

components. These potentially very young galaxies are likely precursors

to massive local disks, assuming no further merging. The proposed WFPC2

and existing NIC-2 data provide colors, stellar masses, and ages of

bulge and disk subcomponents, to assess whether old stellar bulges and

disks are in place at that time or still being built, and constrain

their formation epochs. Finally, this sample will yield the first

statistically significant results on the $z > 1$ evolution of the

size-velocity-luminosity scaling relations, for massive galaxies at

different wavelengths, and constrain whether this evolution reflects

stellar mass growth, or passive evolution, of either bulge or disk

components.

 

WFPC2 11180

 

The Morphology of the Post-Red Supergiant IRC+10420's Circumstellar

Ejecta

 

The extremely luminous post-red supergiant and powerful OH/IR source IRC

+10420 is surrounded by a complex circumstellar nebula. Numerous small

condensations, arcs, jet-like rays of knots, and intriguing

semi-circular structures are easily visible in our previous WFPC2

images. We have suggested that these spatially recognizable features may

be evidence for episodic mass loss events possibly from localized active

regions. We now propose to obtain second epoch WFPC2 images with the

Planetary Camera to measure the transverse motions of these ejecta.

Spatially resolved spectra from STIS showed that the embedded arcs are

kinematically distinct from the spherically expanding diffuse

nebulosity. The transverse motions in combination with radial velocities

from the STIS spectra, will let us determine the morphology of IRC

+10420's nebula and the structures embedded in it, its mass loss

history, and provide clues to the mass loss mechanism responsible for

the discrete ejections.

 

NIC2 11168

 

The IMF in the Hidden Galactic Starburst W49A

 

W49A is one of the most luminous and prolific massive star formation

regions in the disk of our Milky Way. Given the presence of several very

massive OB clusters as well as an unusually high concentration of many

young ultra-compact HII regions (UCHIIR) -- all embedded in about 1

million solar masses of molecular gas -- it is arguably the best

Galactic template for a luminous starburst region. We propose to obtain

NICMOS imaging of the central part of W49A, covering a strip from the

central, massive OB cluster to the ring of UCHIIRs. Our goals are to

resolve and characterize the central star cluster and determine its IMF

down to about 1 solar mass. We want to characterize the distribution of

intermediate-mass YSOs, and identify the NIR counterparts to the

UCHIIRs. The combination of the proposed HST/NICMOS data with our

recently obtained Spitzer observations would allow a great step forward

in the understanding of massive star and cluster formation.

 

NIC2 11157

 

NICMOS Imaging Survey of Dusty Debris Around Nearby Stars Across the

Stellar Mass Spectrum

 

Association of planetary systems with dusty debris disks is now quite

secure, and advances in our understanding of planet formation and

evolution can be achieved by the identification and characterization of

an ensemble of debris disks orbiting a range of central stars with

different masses and ages. Imaging debris disks in starlight scattered

by dust grains remains technically challenging so that only about a

dozen systems have thus far been imaged. A further advance in this field

needs an increased number of imaged debris disks. However, the technical

challenge of such observations, even with the superb combination of HST

and NICMOS, requires the best targets. Recent HST imaging investigations

of debris disks were sample-limited not limited by the technology used.

We performed a search for debris disks from a IRAS/Hipparcos cross

correlation which involved an exhaustive background contamination check

to weed out false excess stars. Out of ~140 identified debris disks, we

selected 22 best targets in terms of dust optical depth and disk angular

size. Our target sample represents the best currently available target

set in terms of both disk brightness and resolvability. For example, our

targets have higher dust optical depth, in general, than newly

identified Spitzer disks. Also, our targets cover a wider range of

central star ages and masses than previous debris disk surveys. This

will help us to investigate planetary system formation and evolution

across the stellar mass spectrum. The technical feasibility of this

program in two-gyro mode guiding has been proven with on-orbit

calibration and science observations during HST cycles 13, 14, and 15.

 

ACS/SBC 11154

 

Optical-UV Spectrum of the Middle-aged Pulsar B1055-52

 

The middle-aged radio, X-ray and gamma-ray pulsar B1055-52 is one of the

few pulsars that allow a multiwavelength study of pulsar radiation. An

optical counterpart of the pulsar has been detected with the HST FOC,

but it was observed in only one filter (F342W, m=24.9). To understand

the nature of the pulsar radiation, its spectrum must be measured in a

broad wavelength range. We propose imaging observations of the pulsar's

counterpart with WFPC2 in the red part of the spectrum and ACS/SBC in

the UV part to measure the broadband spectral distribution, compare it

with the X-ray spectrum, and investigate the thermal and magnetospheric

components of the pulsar's radiation.

 

WFPC2 11138

 

The Physics of the Jets of Powerful Radio Galaxies and Quasars

 

We propose to obtain HST polarimetry of the jets of the quasars 1150+497

and PKS 1136-135. Our goal is to solve the riddle of their high-energy

emission mechanism, and tackle issues such as particle acceleration and

jet dynamics. Our targets are the optically brightest quasar jets, and

they span the range of luminosities and beaming parameters seen in these

objects. Recent observations with Spitzer, HST and Chandra have shed new

light on the spectral morphology of quasar jets, throwing wide open the

question of the nature of their optical and X-ray emission. Three

mechanisms are possible, including synchrotron emission as well as two

Comptonization processes. Polarimetry can uniquely determine which of

these mechanisms operates in the optical. We will compare the optical

polarimetry to in- hand radio polarimetry as well as in-hand and new

Spitzer, HST and Chandra imaging to gain new insights on the structure

of these jets, as well as particle acceleration mechanisms and jet

dynamics.

 

WFPC2 11124

 

The Origin of QSO Absorption Lines from QSOs

 

We propose using WFPC2 to image the fields of 10 redshift z ~ 0.7

foreground {FG} QSOs which lie within ~29-151 kpc of the sightlines to

high-z background {BG} QSOs. A surprisingly high fraction of the BG QSO

spectra show strong MgII {2796,2803} absorption lines at precisely the

same redshifts as the FG QSOs. The high resolution capabilities of WFPC2

are needed to understand the origin of these absorption systems, in two

ways. First, we wish to explore the FG QSO environment as close as

possible to the position of the BG QSO, to search for interloping group

or cluster galaxies which might be responsible for the absorption, or

irregularly shaped post-merger debris between the FG and BG QSO which

may indicate the presence of large amount of disrupted gas along a

sightline. Similarly, high resolution images are needed to search for

signs of tidal interactions between any galaxies which might be found

close to the FG QSO. Such features might provide evidence of young

merging events causing the start of QSO duty cycles and producing

outflows from the central AGN. Such winds may be responsible for the

observed absorption lines. Second, we seek to measure the intrinsic

parameters of the FG QSO host galaxy, such as luminosity and morphology,

to correlate with the properties of the MgII absorption lines. We wish

to observe each field through the F814W filter, close to the rest- frame

B-band of the FG QSO. These blue data can reveal enhanced star formation

regions close to the nucleus of the host galaxy, which may be indicative

of galaxy mergers with the FG QSO host. The FG QSO environment offers

quite a different set of phenomena which might be responsible for MgII

absorption, providing an important comparison to studies of MgII

absorption from regular field galaxies.

 

WFPC2 11113

 

Binaries in the Kuiper Belt: Probes of Solar System Formation and

Evolution

 

The discovery of binaries in the Kuiper Belt and related small body

populations is powering a revolutionary step forward in the study of

this remote region. Three quarters of the known binaries in the Kuiper

Belt have been discovered with HST, most by our snapshot surveys. The

statistics derived from this work are beginning to yield surprising and

unexpected results. We have found a strong concentration of binaries

among low-inclination Classicals, a possible size cutoff to binaries

among the Centaurs, an apparent preference for nearly equal mass

binaries, and a strong increase in the number of binaries at small

separations. We propose to continue this successful program in Cycle 16;

we expect to discover at least 13 new binary systems, targeted to

subgroups where these discoveries can have the greatest impact.

 

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 11103

 

A Snapshot Survey of The Most Massive Clusters of Galaxies

 

We propose the continuation of our highly successful SNAPshot survey of

a sample of 125 very X-ray luminous clusters in the redshift range

0.3-0.7. As demonstrated by the 25 snapshots obtained so far in Cycle14

and Cycle15 these systems frequently exhibit strong gravitational

lensing as well as spectacular examples of violent galaxy interactions.

The proposed observations will provide important constraints on the

cluster mass distributions, the physical nature of galaxy-galaxy and

galaxy-gas interactions in cluster cores, and a set of optically bright,

lensed galaxies for further 8-10m spectroscopy. All of our primary

science goals require only the detection and characterization of

high-surface-brightness features and are thus achievable even at the

reduced sensitivity of WFPC2. Because of their high redshift and thus

compact angular scale our target clusters are less adversely affected by

the smaller field of view of WFPC2 than more nearby systems.

Acknowledging the broad community interest in this sample we waive our

data rights for these observations. Due to a clerical error at STScI our

approved Cycle15 SNAP program was barred from execution for 3 months and

only 6 observations have been performed to date - reinstating this SNAP

at Cycle16 priority is of paramount importance to reach meaningful

statistics.

 

WFPC2 11029

 

WFPC2 CYCLE 15 Intflat Linearity Check and Filter Rotation Anomaly

Monitor

 

Intflat observations will be taken to provide a linearity check: the

linearity test consists of a series of intflats in F555W, in each gain

and each shutter. A combination of intflats, visflats, and earthflats

will be used to check the repeatability of filter wheel motions.

{Intflat sequences tied to decons, visits 1-18 in prop 10363, have been

moved to the cycle 15 decon proposal xxxx for easier scheduling.} Note:

long-exposure WFPC2 intflats must be scheduled during ACS anneals to

prevent stray light from the WFPC2 lamps from contaminating long ACS

external exposures.

 

FLIGHT OPERATIONS SUMMARY:

 

Significant Spacecraft Anomalies: (The following are preliminary reports

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

 

HSTARS:

11214 - NICMOS Detector #2 VSRC Voltage (ND2VSRCV) Limit Violation

           The NICMOS Detector #2 VSRC Voltage (ND2VSRCV) flagged OOL high 5.19

           volts for one sample starting at 068/21:58:46 and return within its

           nominal (~5.1) range about 30 seconds later at 068/21:59:15. Similar

           occurrence documented in HSTARs 9586, 9728.

 

 

11215 - NICMOS Suspend

           At 069/02:46:03 NICMOS Suspended with a status buffer message NICMOS

           632, P = 225, T = 34342, indicating "MECH_2_MAX_RETRIES_EXCEEDED". The

           number of positioning error retries attempted during a Filter Wheel 2

           movement exceeded the maximum limit.

 

           At 069/08:46:45 received Exec 272 status buffer message P=0, T=10871.

 

           At acquisition of signal, 069/09:22:30, an Exec 272 status buffer

           message had been received at 069/08:59:01, P=0, T=16759.

 

 

COMPLETED OPS REQUEST:

18212-0 - Dump NICMOS Memory Following Suspend @ 069/0511z

18213-0 - NICMOS Suspend Recovery @ 069/1515z

 

 

COMPLETED OPS NOTES: (None)

 

                       SCHEDULED      SUCCESSFUL

FGS GSacq               20                   20                 

FGS REacq               18                  18                 

OBAD with Maneuver 70                  70                

 

SIGNIFICANT EVENTS:

 

Flash Report:

NICMOS suspended on 2008/069/02:46:03 due to filter wheel #2 exceeding

its maximum allotted number of retries (HSTAR# 11215). Data analysis was

performed and the suspend event was attributed to known noise in the

filter wheel #2 electronics.

 

Flash Report:

NICMOS was successfully recovered and has successfully completed the

first observation set. NICMOS was recovered to operate at 069/13:59 via

Ops Request 18213 and the PAMs were moved to the chronographic position

(PAMC) at 069/15:14 to intercept the SMS. The first science observations

were complete at 069/17:06. HST was in a ZOE at the time, but upon

acquisition of data, there were no error messages and NICMOS was

operating as expected