HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

 

DAILY REPORT      # 4622

 

PERIOD COVERED: 5am May 30 - 5am Jun 02, 2008 (DOY 151/0900z-154/0900z)

 

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.

 

NIC3 11332

 

NICMOS Cycle 16 Time Dependent Flat Fields

 

This proposal obtains sequences of NICMOS narrow, medium and broad band

filter flat fields for camera 1. In cameras 2 and 3, parallel

observations will allow us to obtain high S/N flats for all spectral

elements.

 

NIC1/NIC2/NIC3 11330

 

NICMOS Cycle 16 Extended Dark

 

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

 

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.

 

WFPC2 11227

 

The Orbital Period for an Ultraluminous X-ray Source in NGC1313

 

The ultraluminous X-ray sources {ULXs} are extragalactic point sources

with luminosities that exceed the Eddington luminosity for conventional

stellar-mass black holes by factors of 10 - 100. It has been hotly

debated whether the ULXs are just common stellar-mass black hole sources

with beamed emission or whether they are sub-Eddington sources that are

powered by the long-sought intermediate mass black holes {IMBH}. To

firmly decide this question, one must obtain dynamical mass measurements

through photometric and spectroscopic monitoring of the secondaries of

these system. The crucial first step is to establish the orbital period

of a ULX, and arguably the best way to achieve this goal is by

monitoring its ellipsoidal light curve. The extreme ULX NGC1313 X-2

provides an outstanding target for an orbital period determination

because its relatively bright optical counterpart {V = 23.5} showed a

15% variation between two HST observations separated by three months.

This level of variability is consistent with that expected for a tidally

distorted secondary star. Here we propose a set of 20 imaging

observations with HST/WFPC2 to define the orbital period. This would be

the first photometric measurement of the orbital period of a ULX binary.

Subsequently, we will propose to obtain spectroscopic observations to

obtain its radial velocity amplitude and thereby a dynamical estimate of

its mass.

 

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.

 

WFPC2 11218

 

Snapshot Survey for Planetary Nebulae in Globular Clusters of the Local

Group

 

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, 4, 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 more distant

than the Magellanic Clouds. These clusters, some of which may be much

younger than their counterparts in the Milky Way, 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.

 

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 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.

 

NIC2 11123

 

A NICMOS Survey for Proplyds in the RCW 38 Massive Embedded Cluster

 

We propose a search for line emission from photoevaporating

protoplanetary disks in the Massive Embedded Cluster RCW 38. These disks

would be analogous to the "proplyds" discovered in the Orion Nebula:

disks around young low mass stars which are being photoionized by a

nearby O star. We will search for these disks in RCW 38 using narrowband

imaging in the lines of Paschen alpha and molecular hydrogen (1-0) S(1)

with NICMOS. The RCW 38 region is an excellent target for determining

whether proplyds are observable in large numbers outside of Orion. It is

a young embedded cluster hosting a few hundred low mass young stars with

a large percentage showing infrared excess indicating the presence of

disks. About 100 of these stars are found within 0.1 pc of the central

O5 star, and the cluster is located within a cleared cavity 0.2 pc in

size, embedded within a molecular cloud, exposing the cluster members

directly to the UV radiation from the O star. Unlike Orion, but like

many other young clusters, RCW 38 is not seen in visible light, and

infrared imaging is needed. The best line in the infrared for revealing

proplyds is the Paschen alpha line, which is not detectable from the

ground. Only HST is able to perform these observations. From these

observations we will estimate the lifetime of the evaporating disks, and

ascertain whether these disks will survive long enough to form planets.

 

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 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.

 

WFPC2 11027

 

Visible Earth Flats

 

This proposal monitors flatfield stability. This proposal obtains

sequences of Earth streak flats to construct high quality flat fields

for the WFPC2 filter set. These flat fields will allow mapping of the

OTA illumination pattern and will be used in conjunction with previous

internal and external flats to generate new pipeline superflats. These

Earth flats will complement the Earth flat data obtained during cycles

4-14.

 

NIC2 10603

 

Multiwavelength Imaging of Edge-on Protoplanetary Disks: Quantifying the

Growth of Circumstellar Dust

 

Young, edge-on circumstellar disks are uniquely valuable laboratories

for the study of planet formation. In these objects, the central star is

occulted from direct view, significant PSF artifacts are absent, and the

disk is clearly seen as a central dust lane flanked by faint disk

reflected light. The detailed morphology of these nebulae and its

variation with wavelength provide crucial information on the disk

internal structure and the properties of its constituent dust grains. A

key observable is the slope defining the wavelength dependence of the

dust scattering opacity, which becomes shallower when grain growth has

taken place; multiwavelength resolved disk images are the key dataset

enabling such measurements. Recent analyses of three different edge-on

disks have revealed a diversity in their dust properties that is

indicative of different degrees of dust grain evolution having taken

place in each system. This characterization of disk grain growth, when

applied comparatively to a larger sample of these objects, would enable

the construction of an evolutionary sequence of young disks at

successive stages on the road to planet formation. In pursuit of this

goal, we have identified a sample of 15 edge-on disks previously

discovered by HST or groundbased telescopes, but for which high

fidelity, high spatial resolution images do not yet exist in both the

optical and near-infrared. We propose broad-band multicolor imaging with

NICMOS of all these targets, and ACS imaging of nine of these targets In

combination with existing data, the proposed images will form a complete

database of high resolution optical/near-IR images for these 15 disk

systems. Scattered light modeling will be used to derive the disk

structure and dust properties, yielding results that will be of

fundamental importance for our understanding of grain properties during

protoplanetary disk evolution.

 

NIC2 10487

 

A Search for Debris Disks in the Coeval Beta Pictoris Moving Group

 

Resolved observations of debris disks present us with the opportunity of

studying planetary evolution in other solar systems. We propose to

search for debris disks in the Beta Pictoris moving group {8-20 Myrs,

10-50 pc away} , which provides a coeval sample of multiple spectral

types, and it has already produced two magnificent resolved debris

disks: AU Mic and Beta Pic. Such coeval sample will provide us with a

snapshot of the crucial time in disk evolution in which the disk makes

the transition from optically thick to optically thin, and it will be

useful to study the stellar mass dependence of the disk evolution.

 

FLIGHT OPERATIONS SUMMARY:

 

Significant Spacecraft Anomalies: (The following are preliminary reports

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

 

HSTARS:

11325 - GSAcq(1,2,1) failed to RGA Hold (Gyro Control) @ 153/19:24:05

 

COMPLETED OPS REQUEST: (None)

 

COMPLETED OPS NOTES: (None)

 

                       SCHEDULED      SUCCESSFUL  

FGS GSacq               31                  30                 

FGS REacq               08                  08                      

OBAD with Maneuver 78                  78                                 

 

SIGNIFICANT EVENTS: (None)