HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

 

DAILY REPORT       # 4588

 

PERIOD COVERED: UT April 11,12,13, 2008 (DOY 102,103,104)

 

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 11312

 

The Local Cluster Substructure Survey {LoCuSS}: Deep Strong Lensing

Observations with WFPC2

 

LoCuSS is a systematic and detailed investigation of the mass,

substructure, and thermodynamics of 100 X-ray luminous galaxy clusters

at 0.15<z<0.3. The primary goal is to test our recent suggestion that

this population is dominated by dynamically immature disturbed clusters,

and that the observed mass-temperature relation suffers strong

structural segregation. If confirmed, this would represent a paradigm

shift in our observational understanding of clusters, that were hitherto

believed to be dominated by mature, undisturbed systems. We propose to

complete our successful Cycle 15 program {SNAP:10881} which prior to

premature termination had delivered robust weak-lensing detections in 17

clusters, and candidate strongly-lensed arcs in 11 of these 17. These

strong and weak lensing signals will give an accurate measure of the

total mass and structure of the dark matter distribution that we will

subsequently compare with X-ray and Sunyaev Zeldovich Effect

observables. The broader applications of our project include 1} the

calibration of mass-temperature and mass-SZE scaling relations which

will be critical for the calibration of proposed dark energy

experiments, and 2} the low redshift baseline study of the demographics

of massive clusters to aid interpretation of future high redshift {z>1}

cluster samples. To complete the all-important high resolution imaging

component of our survey, we request deep WFPC2 observations of 20

clusters through the F606W filter, for which wide-field weak-lensing

data are already available from our Subaru imaging program. The

combination of deep WFPC2 and Subaru data for these 20 clusters will

enable us to achieve the science program approved by the Cycle 15 TAC.

 

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 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.

 

NIC3 11195

 

Morphologies of the Most Extreme High-Redshift Mid-IR-luminous Galaxies

II: The `Bump' Sources

 

The formative phase of some of the most massive galaxies may be

extremely luminous, characterized by intense star- and AGN-formation.

Till now, few such galaxies have been unambiguously identified at high

redshift, and thus far we have been restricted to studying the

low-redshift ultraluminous infrared galaxies as possible analogs. We

have recently discovered a sample of objects which may indeed represent

this early phase in galaxy formation, and are undertaking an extensive

multiwavelength study of this population. These objects are optically

extremely faint {R>26} but nevertheless bright at mid-infrared

wavelengths {F[24um] > 0.5 mJy}. Mid-infrared spectroscopy with

Spitzer/IRS reveals that they have redshifts z~2, implying luminosities

~1E13 Lsun. Their mid-IR SEDs fall into two broad, perhaps overlapping,

categories. Sources with brighter F[24um] exhibit power-law SEDs and SiO

absorption features in their mid-IR spectra characteristic of AGN,

whereas those with fainter F[24um] show a "bump" characteristic of the

redshifted 1.6um peak from a stellar population, and PAH emission

characteristic of starformation. We have begun obtaining HST images of

the brighter sources in Cycle 15 to obtain identifications and determine

kpc-scale morphologies for these galaxies. Here, we aim to target the

second class {the "bump" sources} with the goal of determining if these

constitute morphologically different objects, or simply a "low-AGN"

state of the brighter class. The proposed observations will help us

determine whether these objects are merging systems, massive obscured

starbursts {with obscuration on kpc scales!} or very reddened {locally

obscured} AGN hosted by intrinsically low-luminosity galaxies.

 

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.

 

NIC2/NIC1/NIC3 11159

 

The True Galactic Bulge Luminosity Function

 

We propose to obtain second epoch imaging of the deep Galactic bulge

field observed using NICMOS by Zoccali et al. (2000). The bulge

luminosity and mass function suffered from 30-50% contamination by

foreground disk stars, which was impossible to correct for in the

original study. Revisiting the field after 9 years, we propose to

segregate the foreground disk stars because they have large transverse

velocities, thus revealing the luminosity function of Galactic bulge low

mass stars to near the hydrogen burning limit. The slope of the mass

function has implications for galaxy formation and for understanding the

nature of microlensing in the Galactic bulge.

 

NIC3 11149

 

Characterizing the Stellar Populations in Lyman-Alpha Emitters and Lyman

Break Galaxies at 5.7<z<7 in the Subaru Deep Field

 

The epoch of reionization marks a major phase transition of the

Universe, during which the intergalactic space became transparent to UV

photons. Determining when this occurred and the physical processes

involved represents the latest frontier in observational cosmology. Over

the last few years, searches have intensified to identify the population

of high-redshift (z>6) galaxies that might be responsible for this

process, but the progress is hampered partly by the difficulty of

obtaining physical information (stellar mass, age, star formation

rate/history) for individual sources. This is because the number of z>6

galaxies that have both secure spectroscopic redshifts and high-quality

infrared photometry (especially with Spitzer/IRAC) is still fairly

small. Considering that only several photometric points are available

per source, and that many model SEDs are highly degenerate, it is

crucial to obtain as many observational constraints as possible for each

source to ensure the validity of SED modeling. To better understand the

physical properties of high-redshift galaxies, we propose here to

conduct HST/NICMOS (72 orbits) and Spitzer/IRAC (102 hours) imaging of

spectroscopically confirmed, bright (z<26 mag (AB)) Ly-alpha emitters

(LAEs) and Lyman-break galaxies (LBGs) at 5.7<z<7 selected from the

Subaru Deep Field. Spectroscopic redshifts remove one critical free

parameter from SED modeling while bright source magnitudes ensure

high-quality photometric data. By making accurate determinations of

stellar masses, ages, and star-formation histories, we will specifically

address the following major questions: (1) Do LAEs and LBGs represent

physically different galaxy populations at z>6 as suggested recently?

(2) Is Ly-alpha emission systematically suppressed at z>6 with respect

to continuum emission? (i.e., are we reaching the epoch of incomplete

reionization?), and (3) Do we see any sign of abnormally young stellar

population in any of the z>6 galaxies?

 

NIC2 11143

 

NICMOS imaging of submillimeter galaxies with CO and PAH redshifts

 

We propose to obtain F110W and F160W imaging of 10 z~2.4 submillimeter

galaxies {SMGs} whose optical redshifts have been confirmed by the

detection of millimeter CO and/or mid- infrared PAH emission. With the

4000A break falling within/between the two imaging filters, we will be

able to study these sources' spatially resolved stellar populations

{modulo extinction} in the rest-frame optical. SMGs' large luminosities

appear to be due largely to merger-triggered starbursts; high-resolution

NICMOS imaging will help us understand the stellar masses, mass ratios,

and other properties of the merger progenitors, valuable information in

the effort to model the mass assembly history of the universe.

 

NIC1/NIC2 11139

 

NICMOS Observations of the Microquasar GRS 1758-258

 

The galactic black hole candidate GRS 1758-258 is normally one of the

brightest persistent gamma-ray sources in the vicinity of the galactic

center. It is a microquasar with relativistic radio jets emanating from

a central variable source. Microquasars are excellent nearby test

laboratories for studying the complex accretion and outflow processes

that take place near black hole horizons. Despite an accurate location

provided by Chandra and the VLA and over a decade of careful

ground-based studies, the optical/infrared counterpart to GRS 1758-258

remains unknown. A stellar counterpart is expected, but the current

candidates are all more than 2 sigma from the center of the error

circle. The ground-based infrared flux limits are also right at the

values expected for the synchrotron emission from the outflow from the

black hole, and possibly for the emission from the accretion disk. This

leaves open the question as to what is powering this very energetic

persistent source. Here we propose to use NICMOS to perform broad-band

imaging of the GRS 1758- 258 error box. These images will be more than

three magnitudes more sensitive than the current ground-based ones. The

resulting spectra will reveal the thermal/non- thermal nature of the

sources in the region of the error box, and the high spatial resolution

images may reveal a jet structure. We propose to perform three visits of

two orbits each spanning the suggested 18.45 day binary orbital period

of the system: a correct counterpart identification should be confirmed

by its variability. We will also aim to support the HST observations

with X- and gamma-ray observations using Swift or INTEGRAL, and with

longer wavelength observations from the ground.

 

NIC3 11120

 

A Paschen-Alpha Study of Massive Stars and the ISM in the Galactic

Center

 

The Galactic center (GC) is a unique site for a detailed study of a

multitude of complex astrophysical phenomena, which may be common to

nuclear regions of many galaxies. Observable at resolutions

unapproachable in other galaxies, the GC provides an unparalleled

opportunity to improve our understanding of the interrelationships of

massive stars, young stellar clusters, warm and hot ionized gases,

molecular clouds, large scale magnetic fields, and black holes. We

propose the first large-scale hydrogen Paschen alpha line survey of the

GC using NICMOS on the Hubble Space Telescope. This survey will lead to

a high resolution and high sensitivity map of the Paschen alpha line

emission in addition to a map of foreground extinction, made by

comparing Paschen alpha to radio emission. This survey of the inner 75

pc of the Galaxy will provide an unprecedented and complete search for

sites of massive star formation. In particular, we will be able to (1)

uncover the distribution of young massive stars in this region, (2)

locate the surfaces of adjacent molecular clouds, (3) determine

important physical parameters of the ionized gas, (4) identify compact

and ultra-compact HII regions throughout the GC. When combined with

existing Chandra and Spitzer surveys as well as a wealth of other

multi-wavelength observations, the results will allow us to address such

questions as where and how massive stars form, how stellar clusters are

disrupted, how massive stars shape and heat the surrounding medium, and

how various phases of this medium are interspersed.

 

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.

 

WFPC2 11099

 

A "silver bullet" for the sources of reionization

 

Recent discoveries of z>6 galaxies have given us the first glimpse of

the Universe shortly after the era of reionization. The questions arose

whether these first galaxies can be made responsible for the

reionization process, and how long did it last. Neither observations nor

theory provide a clean answer. In particular observations give results

that are barely mutually consistent and need to be further tested.

Observing high redshift (z>7) sources is in general difficult, mostly

due to the high luminosity distance to these objects, and partly due to

the lower expected stellar masses compared to objects at moderate

redshifts.

 

We propose to use one of the most massive, merging cluster 1E0657-56

(z=0.295) as a cosmic telescopes to efficiently probe the high-redshift

universe. The gravitational potential well of this cluster provides

several magnitudes of magnification, enabling study of intrinsically

lower luminosity galaxies.As we discuss in the proposal, due to its

highly elongated mass distribution and ideal redshift the bullet cluster

is a prime candidate for this study. We propose deep NICMOS and WFPC2

observations; with much reduced observing time compared to e.g. NICMOS

UDF we expect an order of magnitude more (~5 candidates) z>7 objects.

They will also likely be multiply imaged, and since the geometry of

images depends upon the redshift, we will be able to confirm their

nature, thereby not requiring (often prohibitive at these magnitudes)

spectroscopic follow-up. This will enable us to count high-redshift

sources and constrain their luminosity function; a task made possible

with the help of gravitational lensing even in the pre-JWST era.

 

FLIGHT OPERATIONS SUMMARY:

 

Significant Spacecraft Anomalies: (The following are preliminary reports

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

 

HSTARS:

11249 - GSacq(2,1,2) failed to RGA control. @ 102/1514z

           During LOS GSaq(2,1,2) scheduled at 102/15:14:50 failed to RGA control.

           The GSacq failed due to receiving stop flag QF2STOPF on FGS 2. The Map

           at 15:23:32 showed errors of V1=17.15, V2=9.04, V3=3.75, and RSS=19.75.

 

 

11252 - OBAD Failed Identification (ESB 1902) @ 104/1625z

           At Acquisition of Signal (104/16:25:46) received three (3) 486 STB ESB

           1902 "OBAD Failed ID" messages. Vehicle was in RGA control, M2G mode

           with OBAD flag mnemonics showing GOBSTAT=255 (Attitude Determination

           Error) and GCHACL09=1 or (Failed State). OBAD Map at 15:40:16 showed

           errors of: V1 -32245.59, V2 6342.19, V3 -51499.65, RSS 61091.86

           arc-seconds. The GSAcquisition at 15:32:59 was not attempted as the #44

           commands had not updated. Ops Request 17543-2 was successfully executed

           and copies of the dump for tables 369 & 370 are attached. Awaiting next

           available engineering data dump to perform further analysis.

 

 

11253 - GSAcq (2,3,3) results in RGA Control @ 104/1625z

           At Acquisition of Signal (104/16:25:46) GSAcq (2,3,3) scheduled from

           (15:32:59-15:40:16) had not attempted due to both pre-acquisition OBAD's

           failing. GSAcq #44 commands did not update. OBAD #1 RSS error was

           61102.55 arc-seconds. OBAD #2 RSS error was 56101.50 arc-seconds. OBAD

           Map RSS error was 61091.86 arc-seconds.

 

 

COMPLETED OPS REQUEST:

17543-2 - Dump OBAD tables after failed OBAD (Generic) @ 104/1643z

 

COMPLETED OPS NOTES: (None)

 

                       SCHEDULED      SUCCESSFUL    

FGS GSacq               23                   21          

FGS REacq                11                  11                 

OBAD with Maneuver 70                   68   

 

SIGNIFICANT EVENTS:

 

Flash Report: FGS ITS Test

 

The ITS tests scheduled from 105:02:42 - 105:06:00 performed as

expected. The first ITS test was monitored in real time and no anomalous

behavior was seen. The other ITS tests occurred in ZOEs and the data

will be looked at when it is merged. There were no problems indicated in

telemetry when telemetry was reacquired after the tests were performed.

The subsequent guide star acquisitions have all been successful.

 

All SSR ENG data was dumped at 105/0749z