HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

 

DAILY REPORT       #4954

 

PERIOD COVERED: 5am October 19 - 5am October 20, 2009 (DOY292/09:00z-293/09:00z)

 

OBSERVATIONS SCHEDULED

 

ACS/WFC3 11879

 

CCD Daily Monitor (Part 1)

 

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 352 orbits (22 weeks) from 31 August 2009 to 31 January

2010.

 

COS/FUV 11895

 

FUV Detector Dark Monitor

 

The purpose of this proposal is to monitor the FUV detector dark rate by

taking long science exposures without illuminating 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.

 

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.

 

NIC 11410

 

NICMOS Aperture Locations

 

The position of NICMOS apertures in the HST focal plane is measured in

the V2-V3 plane.

 

NIC 11416

 

NICMOS Parallel Thermal Background

 

Characterize the stability of the HST+NCS+Instrument thermal emission as

seen by NICMOS on secular scales. The data will be obtained using NIC3

and the F222M filter and will run throughout the SMOV4 activities as a

pure parallel program.

 

NIC 11417

 

NICMOS Detector Read Noise and Dark Current

 

The NICMOS detector characteristics will be monitored during the entire

extent of the SMOV4 through a set of dark exposures. This will also

allow a determination of the detector temperature from bias

measurements. The data should be obtained in SAA-free orbits,

approximately every 24 hours. In addition, the detector read noise and

the detector shading profiles will be measured once a week.

 

NIC1/NIC2/NIC3 11820

 

NICMOS Post-SAA Calibration - CR Persistence Part 7

 

Internals for CR persistence

 

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 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.

 

STIS/CCD 11852

 

STIS CCD Spectroscopic Flats C17

 

The purpose of this proposal is to obtain pixel-to-pixel lamp flat

fields for the STIS CCD in spectroscopic mode.

 

STIS/CCD/MA1 11737

 

The Distance Dependence of the Interstellar N/O Abundance Ratio: A Gould

Belt Influence?

 

The degree of elemental abundance homogeneity in the interstellar medium

is a function of the enrichment and mixing processes that govern

galactic chemical evolution. Observations of young stars and the

interstellar gas within ~500 pc of the Sun have revealed a local ISM

that is so well-mixed it is having an impact on ideas regarding the

formation of extrasolar planets. However, the situation just beyond the

local ISM is not so clear. Sensitive UV absorption line measurements

have recently revealed a pattern of inhomogeneities in the interstellar

O, N, and Kr gas-phase abundances at distances of ~500 pc and beyond

that appear nucleosynthetic in origin rather than due to dust depletion.

In particular, based on a sample of 13 sightlines, Knauth et al. (2006)

have found that the nearby stars (d < 500 pc) exhibit a mean

interstellar N/O abundance ratio that is significantly higher (0.18 dex)

than that toward the more distant stars. Interestingly, all of their

sightlines lie in the sky vicinity of the Gould Belt of OB associations,

molecular clouds, and diffuse gas encircling the Sun at a distance of

~400 pc. Is it possible that mixing processes have not yet smoothed out

the recent ISM enrichment by massive stars in the young Belt region? By

measuring the interstellar N/O ratios in a strategic new sample of

sightlines with STIS, we propose to test the apparent N/O homogeneity

inside the Gould Belt and determine if the apparent decline in the N/O

ratio with distance is robust and associated with the Belt region.

 

STIS/MA1/MA2 11857

 

STIS Cycle 17 MAMA Dark Monitor

 

This proposal monitors the behavior of the dark current in each of the

MAMA detectors.

 

The basic monitor takes two 1380s ACCUM darks each week with each

detector. However, starting Oct 5, pairs are only included for weeks

that the LRP has external MAMA observations planned. The weekly pairs of

exposures for each detector are linked so that they are taken at

opposite ends of the same SAA free interval. This pairing of exposures

will make it easier to separate long and short term temporal variability

from temperature dependent changes.

 

For both detectors, additional blocks of exposures are taken once every

six months. These are groups of five 1314s FUV-MAMA Time-Tag darks or

five 3x315s NUV ACCUM darks distributed over a single SAA-free interval.

This will give more information on the brightness of the FUV MAMA dark

current as a function of the amount of time that the HV has been on, and

for the NUV MAMA will give a better measure of the short term

temperature dependence.

 

WFC3/IR 11108

 

Near Infrared Observations of a Sample of z~6.5-6.7 Galaxies

 

The majority of the most distant galaxies discovered to date have been

found by strong Lyman alpha emission at red optical wavelengths. An

accurate estimate of the star formation rates for these objects requires

a measurement of the line-free UV continuum, which must be taken at

infrared wavelengths. Here we propose to obtain imaging with WFC3 in the

F140W filter for a sample of 9 Lyman alpha galaxies with redshifts z~6.5

up to z=6.740 from a complete, flux- limited widefield narrowband and

multi-color survey conducted on the 8-m Subaru Telescope. This program

will investigate galaxy morphologies and star formation for a uniform

sample of the highest redshift galaxies now known.

 

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!

 

WFC3/UV 11906

 

WFC3 UVIS CCD Gain

 

The absolute gain of each quadrant of the WFC3 UVIS detector will be

measured for the nominal detector readout configuration and at the

on-orbit operating temperature.

 

WFC3/UVIS 11707

 

Detecting Isolated Black Holes through Astrometric Microlensing

 

This proposal aims to make the first detection of isolated stellar-mass

black holes (BHs) in the Milky Way, and to determine their masses. Until

now, the only directly measured BH masses have come from radial-velocity

measurements of X-ray binaries. Our proposed method uses the astrometric

shifts that occur when a galactic-bulge microlensing event is caused by

a BH lens. Out of the hundreds of bulge microlensing events found

annually by the OGLE and MOA surveys, a few are found to have very long

durations (>200 days). It is generally believed that the majority of

these long-duration events are caused by lenses that are isolated BHs.

 

To test this hypothesis, we will carry out high-precision astrometry of

5 long-duration events, using the ACS/HRC camera. The expected

astrometric signal from a BH lens is >1.4 mas, at least 7 times the

demonstrated astrometric precision attainable with the HRC.

 

This proposal will thus potentially lead to the first unambiguous

detection of isolated stellar-mass BHs, and the first direct mass

measurement for isolated stellar-mass BHs through any technique.

Detection of several BHs will provide information on the frequency of

BHs in the galaxy, with implications for the slope of the IMF at high

masses, the minimum mass of progenitors that produce BHs, and

constraints on theoretical models of BH formation.

 

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               11                   11                  

FGS REAcq               04                   04                

OBAD with Maneuver 06                   06              

 

SIGNIFICANT EVENTS: (None)