HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

 

DAILY REPORT    #5043

 

PERIOD COVERED: 5am March 1 - 5am March 2, 2010 (DOY 060/10:00z-061/10:00z)

 

OBSERVATIONS SCHEDULED

 

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.

 

ACS/WFC/WFC3/UV 11711

 

A Definitive Distance to the Coma Core Ellipticals

 

As the richest galaxy cluster in the local universe (cz < 10, 000 km/s),

the Coma cluster continues to serve as the standard of comparison for

numerous studies of galaxy properties and scaling relations in clusters.

The central importance of Coma has been recognized with two recent HST

large programs: a Treasury survey to study the dwarf galaxy population

by imaging 82 different ACS/WFC pointings, and a program to measure

Cepheid distances to two spiral galaxies projected within the Coma core

region. An accurate distance to the Coma core is essential for comparing

the galaxy luminosities and sizes to nearby galaxies in Virgo and

Fornax, while an accurate peculiar velocity is needed for correctly

tying to more distant clusters. However, experience dictates that

Cepheid distances to clusters must be carefully verified against

accurate measurements to the dominant early-type population, especially

for such an unprecedented effort as the Coma Cepheid search (the

completion of which remains uncertain). We propose to measure highly

accurate (3-4% internal error per galaxy) SBF distances to the two giant

Coma core ellipticals. The reliability of the SBF method with the

ACS/WFC has been repeatedly demonstrated, and it is so efficient that it

requires only 3% of the number of orbits dedicated to the two current

large Coma programs. The precise ACS SBF Coma core distance will also

provide a good constraint on the Coma peculiar velocity, thus improving

the accuracy of comparisons to distant clusters. Finally, our program

will answer some longstanding puzzles surrounding the rich globular

cluster population in the core of this archetypal galaxy cluster.

 

COS/FUV 11687

 

SNAPing Coronal Iron

 

This is a Snapshot Survey to explore two forbidden lines of highly

ionized iron in late-type coronal sources. Fe XII 1349 (T~ 2 MK) and Fe

XXI 1354 (T~ 10 MK) -- well known to Solar Physics -- have been detected

in about a dozen cool stars, mainly with HST/STIS. The UV coronal

forbidden lines are important because they can be observed with velocity

resolution of better than 15 km/s, whereas even the state-of-the-art

X-ray spectrometers on Chandra can manage only 300 km/s in the kilovolt

band where lines of highly ionized iron more commonly are found. The

kinematic properties of hot coronal plasmas, which are of great interest

to theorists and modelers, thus only are accessible in the UV at

present. The bad news is that the UV coronal forbidden lines are faint,

and were captured only in very deep observations with STIS. The good

news is that 3rd-generation Cosmic Origins Spectrograph, slated for

installation in HST by SM4, in a mere 25 minute exposure with its G130M

mode can duplicate the sensitivity of a landmark 25-orbit STIS E140M

observation of AD Leo, easily the deepest such exposure of a late-type

star so far. Our goal is to build up understanding of the properties of

Fe XII and Fe XXI in additional objects beyond the current limited

sample: how the lineshapes depend on activity, whether large scale

velocity shifts can be detected, and whether the dynamical content of

the lines can be inverted to map the spatial morphology of the stellar

corona (as in "Doppler Imaging''). In other words, we want to bring to

bear in the coronal venue all the powerful tricks of spectroscopic

remote sensing, well in advance of the time that this will be possible

exploiting the corona's native X-ray radiation. The 1290-1430 band

captured by side A of G130M also contains a wide range of key plasma

diagnostics that form at temperatures from below 10, 000 K (neutral

lines of CNO), to above 200, 000 K (semi-permitted O V 1371), including

the important bright multiplets of C II at 1335 and Si IV at 1400;

yielding a diagnostic gold mine for the subcoronal atmosphere. Because

of the broad value of the SNAP spectra, beyond the coronal iron project,

we waive the normal proprietary rights.

 

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.

 

STIS/CCD 11843

 

STIS CCD Performance Monitor

 

This activity measures the baseline performance and commandability of

the CCD subsystem. Only primary amplifier D is used. Bias and Flatfield

exposures are taken in order to measure bias level, read noise, CTE, and

gain. Numerous bias frames are taken to permit construction of

"superbias" frames in which the effects of read noise have been rendered

negligible. Full frame and binned observations are made, with binning

factors of 2 x 1, 1 x 2, 2 x 2. Bias frames are taken in subarray

readouts to check the bias level for ACQ and ACQ/PEAK observations. All

exposures are internals.

 

STIS/CCD 11844

 

CCD Dark Monitor Part 1

 

The purpose of this proposal is to monitor the darks for the STIS CCD.

 

STIS/CCD 11846

 

CCD Bias Monitor-Part 1

 

The purpose of this proposal is to 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.

 

WFC3/ACS/IR 11142

 

Revealing the Physical Nature of Infrared Luminous Galaxies at 0.3<z<2.7

Using HST and Spitzer

 

We aim to determine physical properties of IR luminous galaxies at

0.3<z<2.7 by requesting coordinated HST/NIC2 and MIPS 70um observations

of a unique, 24um flux-limited sample with complete Spitzer mid-IR

spectroscopy. The 150 sources investigated in this program have S(24um)

> 0.8mJy and their mid-IR spectra have already provided the majority

targets with spectroscopic redshifts (0.3<z<2.7). The proposed

150~orbits of NIC2 and 66~hours of MIPS 70um will provide the physical

measurements of the light distribution at the rest-frame ~8000A and

better estimates of the bolometric luminosity. Combining these

parameters together with the rich suite of spectral diagnostics from the

mid-IR spectra, we will (1) measure how common mergers are among LIRGs

and ULIRGs at 0.3<z<2.7, and establish if major mergers are the drivers

of z>1 ULIRGs, as in the local Universe, (2) study the co-evolution of

star formation and blackhole accretion by investigating the relations

between the fraction of starburst/AGN measured from mid-IR spectra vs.

HST morphologies, L(bol) and z, and (3) obtain the current best

estimates of the far-IR emission, thus L(bol) for this sample, and

establish if the relative contribution of mid-to-far IR dust emission is

correlated with morphology (resolved vs. unresolved).

 

WFC3/ACS/UVIS/IR 11570

 

Narrowing in on the Hubble Constant and Dark Energy

 

A measurement of the Hubble constant to a precision of a few percent

would be a powerful aid to the investigation of the nature of dark

energy and a potent "end-to end" test of the present cosmological model.

In Cycle 15 we constructed a new streamlined distance ladder utilizing

high- quality type Ia supernova data and observations of Cepheids with

HST in the near-IR to minimize the dominant sources of systematic

uncertainty in past measurements of the Hubble constant and reduce its

total uncertainty to a little under 5%. Here we propose to exploit this

new route to reduce the remaining uncertainty by more than 30%,

translating into an equal reduction in the uncertainty of the equation

of state of dark energy. We propose three sets of observations to reach

this goal: a mosaic of NGC 4258 with WFC3 in F160W to triple its sample

of long period Cepheids, WFC3/F160W observations of the 6 ideal SN Ia

hosts to triple their samples of Cepheids, and observations of NGC 5584

the host of a new SN Ia, SN 2007af, to discover and measure its Cepheids

and begin expanding the small set of SN Ia luminosity calibrations.

These observations would provide the bulk of a coordinated program aimed

at making the measurement of the Hubble constant one of the leading

constraints on dark energy.

 

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 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.

 

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).

 

FLIGHT OPERATIONS SUMMARY:

 

Significant Spacecraft Anomalies: (The following are preliminary reports

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

 

HSTARS: (None)

 

COMPLETED OPS REQUEST: (None)

 

COMPLETED OPS NOTES: (None)

 

                      SCHEDULED  SUCCESSFUL

FGS GSAcq               05             05      

FGS REAcq               12             12      

OBAD with Maneuver 05             05      

 

SIGNIFICANT EVENTS: (None)