HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

 

DAILY REPORT      #5047

 

PERIOD COVERED: 5am March 5 - 5am March 8, 2010 (DOY 064/10:00z-067/10:00z)

 

OBSERVATIONS SCHEDULED

 

WFC3/UV/ACS/WFC 12050

 

20th Anniversary of HST Launch

 

The 20th anniversary of HST's launch on April 24, 2010 will be a

significant milestone both in the Hubble mission and in the history of

U.S. space astronomy. Already plans are in place for many activities

surrounding this anniversary that take advantage of the "teachable

moment" afforded by this event. A new, high-impact image from Hubble is

a necessary component of this mix. We are proposing here to meet that

need with new observations of a dramatic region of the Carina Nebula

only partially observed previously with Hubble. The release of the large

mosaic of the Carina Nebula for HST's 17th anniversary was one of the

largest Hubble images ever released (Fig. 1). It contains numerous

dramatic details including the pillar containing HH 901 (Fig. 2) which

was itself released as a separate detail image. What is not widely

realized, however, is that the HST data in the Carina mosaic is limited

to H-alpha only. The oxygen (502 nm) and sulfur (673 nm) images were

obtained with the MOSAIC camera at CTIO. These low resolution images

were combined with the much higher resolution HST data to produce the

final color image composite. When the full mosaic is viewed, the loss of

resolution is an acceptable compromise. However, when zooming in on

details, the effect is noticeable. We have selected the most dramatic

portion to return to with WFC3 to obtain HST resolution in a complete

filter set. In order to highlight the new capabilities of WFC3 as well

as foreshadowing the capabilities of JWST, we will obtain a full 3-color

composite in the IR channel of WFC3 in addition

 

S/C 12046

 

COS FUV DCE Memory Dump

 

Whenever the FUV detector high voltage is on, count rate and current

draw information is collected, monitored, and saved to DCE memory. Every

10 msec the detector samples the currents from the HV power supplies

(HVIA, HVIB) and the AUX power supply (AUXI). The last 1000 samples are

saved in memory, along with a histogram of the number of occurrences of

each current value.

 

In the case of a HV transient (known as a "crackle" on FUSE), where one

of these currents exceeds a preset threshold for a persistence time, the

HV will shut down, and the DCE memory will be dumped and examined as

part of the recovery procedure. However, if the current exceeds the

threshold for less than the persistence time (a "mini-crackle" in FUSE

parlance), there is no way to know without dumping DCE memory. By

dumping and examining the histograms regularly, we will be able to

monitor any changes in the rate of "mini-crackles" and thus learn

something about the state of the detector.

 

ACS/WFC 11995

 

CCD Daily Monitor (Part 2)

 

This program comprises basic tests for measuring the read noise and dark

current of the ACS WFC and for tracking the growth of hot pixels. The

recorded frames are used to create bias and dark reference images for

science data reduction and calibration. This program will be executed

four days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To

facilitate scheduling, this program is split into three proposals. This

proposal covers 320 orbits (20 weeks) from 1 February 2010 to 20 June

2010.

 

WFC3/IR/S/C 11929

 

IR Dark Current Monitor

 

Analyses of ground test data showed that dark current signals are more

reliably removed from science data using darks taken with the same

exposure sequences as the science data, than with a single dark current

image scaled by desired exposure time. Therefore, dark current images

must be collected using all sample sequences that will be used in

science observations. These observations will be used to monitor changes

in the dark current of the WFC3-IR channel on a day-to-day basis, and to

build calibration dark current ramps for each of the sample sequences to

be used by Gos in Cycle 17. For each sample sequence/array size

combination, a median ramp will be created and delivered to the

calibration database system (CDBS).

 

WFC3/UVIS 11912

 

UVIS Internal Flats

 

This proposal will be used to assess the stability of the flat field

structure for the UVIS detector throughout the 15 months of Cycle 17.

The data will be used to generate on-orbit updates for the delta-flat

field reference files used in the WFC3 calibration pipeline, if

significant changes in the flat structure are seen.

 

WFC3/UVIS 11908

 

Cycle 17: UVIS Bowtie Monitor

 

Ground testing revealed an intermittent hysteresis type effect in the

UVIS detector (both CCDs) at the level of ~1%, lasting hours to days.

Initially found via an unexpected bowtie-shaped feature in flatfield

ratios, subsequent lab tests on similar e2v devices have since shown

that it is also present as simply an overall offset across the entire

CCD, i.e., a QE offset without any discernable pattern. These lab tests

have further revealed that overexposing the detector to count levels

several times full well fills the traps and effectively neutralizes the

bowtie. Each visit in this proposal acquires a set of three 3x3 binned

internal flatfields: the first unsaturated image will be used to detect

any bowtie, the second, highly exposed image will neutralize the bowtie

if it is present, and the final image will allow for verification that

the bowtie is gone.

 

WFC3/UVIS 11907

 

UVIS Cycle 17 Contamination Monitor

 

The UV throughput of WFC3 during Cycle 17 is monitored via weekly

standard star observations in a subset of key filters covering 200-600nm

and F606W, F814W as controls on the red end. The data will provide a

measure of throughput levels as a function of time and wavelength,

allowing for detection of the presence of possible contaminants.

 

WFC3/UVIS 11905

 

WFC3 UVIS CCD Daily Monitor

 

The behavior of the WFC3 UVIS CCD will be monitored daily with a set of

full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K

subarray biases are acquired at less frequent intervals throughout the

cycle to support subarray science observations. The internals from this

proposal, along with those from the anneal procedure (Proposal 11909),

will be used to generate the necessary superbias and superdark reference

files for the calibration pipeline (CDBS).

 

WFC3/UVIS 11903

 

UVIS Photometric Zero Points

 

This proposal obtains the photometric zero points in 53 of the 62

UVIS/WFC3 filters: the 18 broad-band filters, 8 medium-band filters, 16

narrow-band filters, and 11 of the 20 quad filters (those being used in

cycle 17). The observations will be primary obtained by observing the

hot DA white dwarf standards GD153 and G191-B2B. A redder secondary

standard, P330E, will be observed in a subset of the filters to provide

color corrections. Repeat observations in 16 of the most widely used

cycle 17 filters will be obtained once per month for the first three

months, and then once every second month for the duration of cycle 17,

alternating and depending on target availability. These observations

will enable monitoring of the stability of the photometric system.

Photometric transformation equations will be calculated by comparing the

photometry of stars in two globular clusters, 47 Tuc and NGC 2419, to

previous measurements with other telescopes/instruments.

 

COS/NUV 11894

 

NUV Detector Dark Monitor

 

The purpose of this proposal is to measure the NUV detector dark rate by

taking long science exposures with no light on the detector. The

detector dark rate and spatial distribution of counts will be compared

to pre-launch and SMOV data in order to verify the nominal operation of

the detector. Variations of count rate as a function of orbital position

will be analyzed to find dependence of dark rate on proximity to the

SAA. Dependence of dark rate as function of time will also be tracked.

 

ACS/WFC3 11887

 

CCD Stability Monitor

 

This program will verify that the low frequency flat fielding, the

photometry, and the geometric distortion are stable in time and across

the field of view of the CCD arrays. A moderately crowded stellar field

in the cluster 47 Tuc is observed with the ACS (at the cluster core) and

WFC3 (6 arcmin West of the cluster core) using the full suite of broad

and narrow band imaging filters. The positions and magnitudes of objects

will be used to monitor local and large scale variations in the plate

scale and the sensitivity of the detectors and to derive an independent

measure of the detector CTE. The UV sensitivity for the SBC and ACS will

be addressed in the UV contamination monitor program (11886, PI=Smith).

 

One additional orbit will be obtained at the beginning of the cycle will

allow a verification of the CCD gain ratios for WFC3 using gain 2.0,

1.4, 1.0, 0.5 and for ACS using gain 4.0 and 2.0. In addition, one

subarray exposure with the WFC3 will allow a verification that

photometry obtained in full-frame and in sub-array modes are repeatable

to better than 1%. This test is important for the ACS Photometric

Cross-Calibration program (11889, PI=Bohlin) which uses sub-array

exposures.

 

ACS/SBC 11886

 

UV Contamination Monitor

 

The observations consist of imaging and spectroscopy with SBC and HRC of

the cluster NGC 6681 in order to monitor the temporal evolution of the

UV sensitivity of the SBC and the HRC.

 

STIS/CC 11847

 

CCD Bias Monitor-Part 2

 

Monitor the bias in the 1x1, 1x2, 2x1, and 2x2 bin settings at gain=1,

and 1x1 at gain = 4, to build up high-S/N superbiases and track the

evolution of hot columns.

 

STIS/CC 11845

 

CCD Dark Monitor Part 2

 

Monitor the darks for the STIS CCD.

 

COS/NUV/FUV 11728

 

The Impact of Starbursts on the Gaseous Halos of Galaxies

 

Perhaps the most important (yet uncertain) aspects of galaxy evolution

are the processes by which galaxies accrete gas and by which the

resulting star formation and black hole growth affects this accreting

gas. It is believed that both the form of the accretion and the nature

of the feedback change as a function of the galaxy mass. At low mass the

gas comes in cold and the feedback is provided by massive stars. At high

mass, the gas comes in hot, and the feedback is from an AGN. The

changeover occurs near the mass where the galaxy population transitions

from star-forming galaxies to red and dead ones. The population of red

and dead galaxies is building with cosmic time, and it is believed that

feedback plays an important role in this process: shutting down star

formation by heating and/or expelling the reservoir of cold halo gas. To

investigate these ideas, we propose to use COS far-UV spectra of

background QSOs to measure the properties of the halo gas in a sample of

galaxies near the transition mass that have undergone starbursts within

the past 100 Myr to 1 Gyr. The galactic wind associated with the

starburst is predicted to have affected the properties of the gaseous

halo. To test this, we will compare the properties of the halos of the

post-starburst galaxies to those of a control sample of galaxies matched

in mass and QSO impact parameter. Do the halos of the post-starburst

galaxies show a higher incidence rate of Ly-Alpha and metal

absorption-lines? Are the kinematics of the halo gas more disturbed in

the post-starbursts? Has the wind affected the ionization state and/or

the metallicity of the halo? These data will provide fresh new insights

into the role of feedback from massive stars on the evolution of

galaxies, and may also offer clues about the properties of the QSO metal

absorption-line systems at high-redshift .

 

WFC3/IR 11696

 

Infrared Survey of Star Formation Across Cosmic Time

 

We propose to use the unique power of WFC3 slitless spectroscopy to

measure the evolution of cosmic star formation from the end of the

reionization epoch at z>6 to the close of the galaxy- building era at

z~0.3.Pure parallel observations with the grisms have proven to be

efficient for identifying line emission from galaxies across a broad

range of redshifts. The G102 grism on WFC3 was designed to extend this

capability to search for Ly-alpha emission from the first galaxies.

Using up to 250 orbits of pure parallel WFC3 spectroscopy, we will

observe about 40 deep (4-5 orbit) fields with the combination of G102

and G141, and about 20 shallow (2-3 orbit) fields with G141 alone.

 

Our primary science goals at the highest redshifts are: (1) Detect Lya

in ~100 galaxies with z>5.6 and measure the evolution of the Lya

luminosity function, independent of of cosmic variance; 2) Determine the

connection between emission line selected and continuum-break selected

galaxies at these high redshifts, and 3) Search for the proposed

signature of neutral hydrogen absorption at re-ionization. At

intermediate redshifts we will (4) Detect more than 1000 galaxies in

Halpha at 0.5<z<1.8 to measure the evolution of the extinction-corrected

star formation density across the peak epoch of star formation. This is

over an order-of-magnitude improvement in the current statistics, from

the NICMOS Parallel grism survey. (5) Trace ``cosmic downsizing" from

0.5<z<2.2; and (6) Estimate the evolution in reddening and metallicty in

star- forming galaxies and measure the evolution of the Seyfert

population. For hundreds of spectra we will be able to measure one or

even two line pair ratios -- in particular, the Balmer decrement and

[OII]/[OIII] are sensitive to gas reddening and metallicity. As a bonus,

the G102 grism offers the possibility of detecting Lya emission at

z=7-8.8.

 

To identify single-line Lya emitters, we will exploit the wide

0.8--1.9um wavelength coverage of the combined G102+G141 spectra. All

[OII] and [OIII] interlopers detected in G102 will be reliably separated

from true LAEs by the detection of at least one strong line in the G141

spectrum, without the need for any ancillary data. We waive all

proprietary rights to our data and will make high-level data products

available through the ST/ECF.

 

WFC3/UV/IR 11664

 

The WFC3 Galactic Bulge Treasury Program: Populations, Formation

History, and Planets

 

Exploiting the full power of the Wide Field Camera 3 (WFC3), we propose

deep panchromatic imaging of four fields in the Galactic bulge. These

data will enable a sensitive dissection of its stellar populations,

using a new set of reddening-free photometric indices we have

constructed from broad-band filters across UV, optical, and near-IR

wavelengths. These indices will provide accurate temperatures and

metallicities for hundreds of thousands of individual bulge stars.

Proper motions of these stars derived from multi-epoch observations will

allow separation of pure bulge samples from foreground disk

contamination. Our catalogs of proper motions and panchromatic

photometry will support a wide range of bulge studies.

 

Using these photometric and astrometric tools, we will reconstruct the

detailed star-formation history as a function of position within the

bulge, and thus differentiate between rapid- and extended-formation

scenarios. We will also measure the dependence of the stellar mass

function on metallicity, revealing how the characteristic mass of star

formation varies with chemistry. Our sample of bulge stars with accurate

metallicities will include 12 candidate hosts of extrasolar planets.

Planet frequency is correlated with metallicity in the solar

neighborhood; our measurements will extend this knowledge to a remote

environment with a very distinct chemistry.

 

Our proposal also includes observations of six well-studied globular and

open star clusters; these observations will serve to calibrate our

photometric indices, provide empirical population templates, and

transform the theoretical isochrone libraries into the WFC3 filter

system. Besides enabling our own program, these products will provide

powerful new tools for a host of other stellar-population investigations

with HST/WFC3. We will deliver all of the products from this Treasury

Program to the community in a timely fashion.

 

WFC3/IR/ACS/WFC 11663

 

Formation and Evolution of Massive Galaxies in the Richest Environments

at 1.5 < z < 2.0

 

We propose to image seven 1.5<z<2 clusters and groups from the IRAC

Shallow Cluster Survey with WFC3 and ACS in order to study the formation

and evolution of massive galaxies in the richest environments in the

Universe in this important redshift range. We will measure the evolution

of the sizes and morphologies of massive cluster galaxies, as a function

of redshift, richness, radius and local density. In combination with

allocated Keck spectroscopy, we will directly measure the dry merger

fraction in these clusters, as well as the evolution of Brightest

Cluster Galaxies (BCGs) over this redshift range where clear model

predictions can be confronted. Finally we will measure both the epoch of

formation of the stellar populations and the assembly history of that

stellar mass, the two key parameters in the modern galaxy formation

paradigm.

 

WFC3/UVIS 11657

 

The Population of Compact Planetary Nebulae in the Galactic Disk

 

We propose to secure narrow- and broad-band images of compact planetary

nebulae (PNe) in the Galactic Disk to study the missing link of the

early phases of post-AGB evolution. Ejected AGB envelopes become PNe

when the gas is ionized. PNe expand, and, when large enough, can be

studied in detail from the ground. In the interim, only the HST

capabilities can resolve their size, morphology, and central stars. Our

proposed observations will be the basis for a systematic study of the

onset of morphology. Dust properties of the proposed targets will be

available through approved Spitzer/IRS spectra, and so will the

abundances of the alpha- elements. We will be able thus to explore the

interconnection of morphology, dust grains, stellar evolution, and

populations. The target selection is suitable to explore the nebular and

stellar properties across the galactic disk, and to set constraints on

the galactic evolutionary models through the analysis of metallicity and

population gradients.

 

ACS/WFC3 11604

 

The Nuclear Structure of OH Megamaser Galaxies

 

We propose a snapshot survey of a complete sample of 80 OH megamaser

galaxies. Each galaxy will be imaged with the ACS/WFC through F814W and

a linear ramp filter (FR656N or FR716N or FR782N or FR853N) allowing us

to study both the spheroid and the gas morphology in Halpha + [N II]. We

will use the 9% ramps FR647M (5370-7570 angstroms) centered at 7000

angstroms and FR914M (7570-10, 719 angstroms) 8000 angstroms for

continuum subtraction for the high and low z objects respectively. OH

megamaser galaxies (OHMG) form an important class of ultraluminous

IR-galaxies (ULIRGs) whose maser lines emit QSO-like luminosities.

ULIRGs in general are associated with recent mergers but it is often

unclear whether their power output is dominated by starbursts or a

hidden QSO because of the high absorbing columns which hide their nuclei

even at X-ray wavelengths. In contrast, OHMG exhibit strong evidence for

the presence of an energetically important and recently triggered active

nucleus. In particular it is clear that much of the gas must have

already collapsed to form a nuclear disk which may be the progenitor of

a circum-nuclear torus, a key element of the unified scheme of AGN. A

great advantage of studying OHMG systems over the general ULIRG

population, is that the circum-nuclear disks are effectively "fixed" at

an inner, edge on, orientation, eliminating varying inclination as a

nuisance parameter. We will use the HST observations in conjunction with

existing maser and spectroscopic data to construct a detailed picture of

the circum-nuclear regions of a hitherto relatively neglected class of

galaxy that may hold the key to understanding the relationship between

galaxy mergers, nuclear star-formation, and the growth of massive black

holes and the triggering of nuclear activity.

 

WFC3/ACS/IR 11600

 

Star Formation, Extinction, and Metallicity at 0.7<z<1.5: H-Alpha Fluxes

and Sizes from a Grism Survey of GOODS-N

 

The global star formation rate (SFR) is ~10x higher at z=1 than today.

This could be due to drastically elevated SFR in some fraction of

galaxies, such as mergers with central bursts, or a higher SFR across

the board. Either means that the conditions in z=1 star forming galaxies

could be quite different from local objects. The next step beyond

measuring the global SFR is to determine the dependence of SFR,

obscuration, metallicity, and size of the star-forming region on galaxy

mass and redshift. However, SFR indicators at z=1 typically apply local

calibrations for UV, [O II] and far-IR, and do not agree with each other

on a galaxy-by-galaxy basis. Extinction, metallicity, and dust

properties cause uncontrolled offsets in SFR calibrations. The great

missing link is Balmer H-alpha, the most sensitive probe of SFR. We

propose a slitless WFC3/G141 IR grism survey of GOODS-N, at 2

orbits/pointing. It will detect Ha+[N II] emission from 0.7<z<1.5, to

L(Ha) = 1.7 x 10^41 erg/sec at z=1, measuring H-alpha fluxes and sizes

for > 600 galaxies, and a small number of higher-redshift emitters. This

will produce: an emission-line redshift survey unbiased by magnitude and

color selection; star formation rates as a function of galaxy

properties, e.g. stellar mass and morphology/mergers measured by ACS;

comparisons of SFRs from H-alpha to UV and far-IR indicators;

calibrations of line ratios of H-alpha to important nebular lines such

as [O II] and H-beta, measuring variations in metallicity and extinction

and their effect on SFR estimates; and the first measurement of scale

lengths of the H-alpha emitting, star- forming region in a large sample

of z~1 sources.

 

COS/NUV/FUV 11598

 

How Galaxies Acquire their Gas: A Map of Multiphase Accretion and

Feedback in Gaseous Galaxy Halos

 

We propose to address two of the biggest open questions in galaxy

formation - how galaxies acquire their gas and how they return it to the

IGM - with a concentrated COS survey of diffuse multiphase gas in the

halos of SDSS galaxies at z = 0.15 - 0.35. Our chief science goal is to

establish a basic set of observational facts about the physical state,

metallicity, and kinematics of halo gas, including the sky covering

fraction of hot and cold material, the metallicity of infall and

outflow, and correlations with galaxy stellar mass, type, and color -

all as a function of impact parameter from 10 - 150 kpc. Theory suggests

that the bimodality of galaxy colors, the shape of the luminosity

function, and the mass-metallicity relation are all influenced at a

fundamental level by accretion and feedback, yet these gas processes are

poorly understood and cannot be predicted robustly from first

principles. We lack even a basic observational assessment of the

multiphase gaseous content of galaxy halos on 100 kpc scales, and we do

not know how these processes vary with galaxy properties. This ignorance

is presently one of the key impediments to understanding galaxy

formation in general. We propose to use the high-resolution gratings

G130M and G160M on the Cosmic Origins Spectrograph to obtain sensitive

column density measurements of a comprehensive suite of multiphase ions

in the spectra of 43 z < 1 QSOs lying behind 43 galaxies selected from

the Sloan Digital Sky Survey. In aggregate, these sightlines will

constitute a statistically sound map of the physical state and

metallicity of gaseous halos, and subsets of the data with cuts on

galaxy mass, color, and SFR will seek out predicted variations of gas

properties with galaxy properties. Our interpretation of these data will

be aided by state-of-the-art hydrodynamic simulations of accretion and

feedback, in turn providing information to refine and test such models.

We will also use Keck, MMT, and Magellan (as needed) to obtain optical

spectra of the QSOs to measure cold gas with Mg II, and optical spectra

of the galaxies to measure SFRs and to look for outflows. In addition to

our other science goals, these observations will help place the Milky

Way's population of multiphase, accreting High Velocity Clouds (HVCs)

into a global context by identifying analogous structures around other

galaxies. Our program is designed to make optimal use of the unique

capabilities of COS to address our science goals and also generate a

rich dataset of other absorption-line systems

 

WFC3/UVIS 11588

 

Galaxy-Scale Strong Lenses from the CFHTLS Survey

 

We aim to investigate the origin and evolution of early-type galaxies

using gravitational lensing, modeling the mass profiles of objects over

a wide range of redshifts. The low redshift (z = 0.2) sample is already

in place following the successful HST SLACS survey; we now propose to

build up and analyze a sample of comparable size (~50 systems) at high

redshift (0.4 < z < 0.9) using HST WFC3 Snapshot observations of lens

systems identified by the SL2S collaboration in the CFHT legacy survey.

 

WFC3/UV 11581

 

Searching for Pulsations from a Helium White Dwarf Companion to a

Millisecond Pulsar

 

The low mass white dwarf (WD) companion to the 3.26 ms pulsar PSR

J1911-5958A offers an unprecedented opportunity for seismological study

of the interior of a helium core WD. While much more massive

carbon/oxygen core WDs are observed to pulsate in normal modes of

oscillation called g-modes (known as ZZ Ceti stars), no helium core

pulsator is known. By extrapolating the boundaries of the ZZ Ceti

instability strip downward in surface gravity by a factor of 20 below

any known pulsator, we find that the effective temperature of this WD

makes it an excellent candidate to search for pulsation. Detection of

g-mode pulsations in the lightcurve would have a transformative effect

on the field of WD pulsations, as this would allow the first

seismological study of the interior of a helium core WD, and the low

gravity strongly constrains theories for the driving and amplitudes of

pulsations. We show that with 3 orbits of HST, we will detect

photometric variations with amplitudes of 1%, lower than typically seen

in other hydrogen-dominated ZZ Ceti stars. A set of measured mode

periods would also constrain the thickness of the presumed stably

hydrogen burning shell, and help us determine its age more securely.

 

STIS/CCD/MA2 11568

 

A SNAPSHOT Survey of the Local Interstellar Medium: New NUV Observations

of Stars with Archived FUV Observations

 

We propose to obtain high-resolution STIS E230H SNAP observations of

MgII and FeII interstellar absorption lines toward stars within 100

parsecs that already have moderate or high-resolution far-UV (FUV),

900-1700 A, observations available in the MAST Archive. Fundamental

properties, such as temperature, turbulence, ionization, abundances, and

depletions of gas in the local interstellar medium (LISM) can be

measured by coupling such observations. Due to the wide spectral range

of STIS, observations to study nearby stars also contain important data

about the LISM embedded within their spectra. However, unlocking this

information from the intrinsically broad and often saturated FUV

absorption lines of low-mass ions, (DI, CII, NI, OI), requires first

understanding the kinematic structure of the gas along the line of

sight. This can be achieved with high resolution spectra of high-mass

ions, (FeII, MgII), which have narrow absorption lines, and can resolve

each individual velocity component (interstellar cloud). By obtaining

short (~10 minute) E230H observations of FeII and MgII, for stars that

already have moderate or high- resolution FUV spectra, we can increase

the sample of LISM measurements, and thereby expand our knowledge of the

physical properties of the gas in our galactic neighborhood. STIS is the

only instrument capable of obtaining the required high resolution data

now or in the foreseeable future.

 

NIC2/WFC3/IR 11548

 

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

Environment in Star Formation

 

We propose NICMOS and WFC3/IR 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.

 

WFC3/IR 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

WFC3 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!

 

FLIGHT OPERATIONS SUMMARY:

 

Significant Spacecraft Anomalies: (The following are preliminary reports

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

 

HSTARS:

12210 - GSAcq(1,2,1) 064/12:03:43z acquired fine lock backup on FGS 2 due

           to Scan Step Limit on FGS 1.

 

           Observations possibly affected: STIS 63, Proposal ID#11568

 

 

12211 - REAcq(1,0,1) at 065/04:14:20z failed due to Scan Step Limit

           Exceeded at 064/04:16:14z. Previous GSAcq(1,0,1) at 065/02:52z was

           successful.

 

           Observations affected: ACS 89-91 & WFC3 126-129, Proposal ID#11663

 

 

12212 - GSAcq(2,3,3) scheduled at 065/16:58:34z required two attempts to

           achieve Coarse Track Data Valid CT-DV).

           Subsequent REAcq(2,3,3) at 065/18:31:07z was successful.

 

 

COMPLETED OPS REQUEST: (None)

 

COMPLETED OPS NOTES: (None)

 

                     SCHEDULED  SUCCESSFUL

FGS GSAcq              24             24

FGS REAcq               24            23       

OBAD with Maneuver 17            17       

 

SIGNIFICANT EVENTS:

 

FLASH REPORT:  COS, STIS and ACS newly installed FSW was successfully

activated at ~067/00:23z. The STIS OFINDSLT macro will first be used

at 067/16:54z.