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Daily # 4211



 
 
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Old October 3rd 06, 11:23 PM posted to sci.astro.hubble
Joe Cooper
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Default Daily # 4211

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4211

PERIOD COVERED: UT October 02, 2006 (DOY 275)

OBSERVATIONS SCHEDULED

ACS/HRC/WFC 10758

ACS CCDs daily monitor

This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in ACS CCD detectors. The files, biases and dark will be used to
create reference files for science calibration. This programme will be
for the entire lifetime of ACS. Changes from cycle 13:- The default
gain for WFC is 2 e-/DN. As before bias frames will be collected for
both gain 1 and gain 2. Dark frames are acquired using the default
gain {2}. This program cover the period May, 31 2006- Oct, 1-2006. The
first half of the program has a different proposal number: 10729.

ACS/WFC 10763

The Guitar Nebula: A Bow Shock that Traces ISM Turbulence and
Accelerates Relativistic Particles

We propose joint Chandra and HST observations of the Guitar Nebula, an
extraordinary bow- shock nebula produced by a very high-velocity but
otherwise ordinary pulsar. Prior HST observations show epoch dependent
changes in shock structure that signify changing ISM conditions. An
enigmatic jet or filament is seen in a Chandra ACIS image {year 2000},
unlike jets from the Crab or other young pulsars. New Chandra
observations will reveal the relative motion of the jet and the pulsar
{which has moved by 0.9 arcsec} and thus determine if self confinement
or special structure in the ISM plays a dominant role in shaping the
jet, and will constrain the particle acceleration mechanism. We
request joint high-resolution HST observations to contemporaneously
determine the ISM density profile.

ACS/WFC 10813

MgII Absorption Line Systems: Galaxy Halos or the Metal-Enriched IGM?

MgII QSO absorption lines detected in the spectra of background QSOs
were used over a decade ago to infer that all redshift z 0.2
galaxies have gaseous halos of radius ~ 60 kpc. The actual size of the
halo was believed to be proportional to the luminosity of the galaxy.
However, these conclusions are now much harder to understand in light
of the results from numerical simulations which show how gas evolves
in the universe. These models predict that gas and galaxies merely
share the same filamentary structures defined by dark matter. If these
models are correct, how are MgII systems and galaxies really related?
We can better understand the distribution of absorbing gas if we FIRST
select galaxies close to QSO sightlines and THEN search for MgII
absorption at the redshift of the intervening galaxies. This is the
antithesis of the original experiments which sought to find absorbing
galaxies based on known MgII systems. The frequency with which we
detect MgII lines from randomly selected galaxies should enable us to
better understand if absorption arises in the halos of individual
galaxies, or if MgII merely arises in the same IGM that galaxies
inhabit. We have used ground-based telescopes to indentify twenty z =
0.31-0.55 galaxies within 14-51 kpc of a g 20 QSO, and to search for
MgII absorption at the galaxies' redshifts. Surprisingly, we find that
only 50% of our QSOs show MgII absorption. In this proposal, we seek
multi-color ACS images of twelve of the fields to i} correlate the
incidence of MgII with galaxy morphology; ii} determine if absorption
{or lack thereof} is related to galaxy disks or halos; iii} search for
signs of galaxy interactions which may explain the large
cross-sections of MgII systems; and iv} look for faint interloping
galaxies closer to the line of sight than the one we identified. An
important component of the program is to observe each field in the
SDSS g-, r- and i-bands, to permit an estimate of the photometric
redshift of any objects which lie closer to the QSO sightline than the
identified galaxy, and which might actually be responsible for the
absorption.

ACS/WFC 10876

SL2S: The Strong Lensing Legacy Survey

Strong Gravitational Lensing is an invaluable tool to constrain the
absolute mass distribution of structures irrespective of their light
distribution. Strong Lensing has successfully been applied to single
galaxies lensing quasars into multiple images, and to massive clusters
lensing background sources into giant arcs. More recently, the Sloan
Lens ACS Survey also found numerous examples of isolated, yet massive
ellipticals lensing background galaxies into Einstein rings. We have
started the Strong Lensing Legacy Survey {SL2S} looking for strong
lenses in the 170 sq. degree CFHT-Legacy Survey, using dedicated
automated search procedures, optimized for detection of arcs and
Einstein rings. Thanks to the unsurpassed combined depth, area and
image quality of the CFHT-LS, we uncovered a new population of lenses:
the intermediate mass halo and sub-halo lenses. This new population
effectively bridges the gap between single galaxies and massive
clusters. Here, we propose to obtain SNAPSHOT ACS images of the 50
first strong lens candidates with Einstein radii 2"Re9" {found in
the first 45 sq. degrees of CFHT-LS data released}. The ACS images
will allow us to model in details the mass distribution of this new
population of lensing groups under various lensing configurations.
Using ACS images, we ultimately hope to provide a better understanding
of the formation of structures by studying the lensing signatures of
the key population of galaxy groups.

ACS/WFC 10886

The Sloan Lens ACS Survey: Towards 100 New Strong Lenses

As a continuation of the highly successful Sloan Lens ACS {SLACS}
Survey for new strong gravitational lenses, we propose one orbit of
ACS-WFC F814W imaging for each of 50 high- probability strong
galaxy-galaxy lens candidates. These observations will confirm new
lens systems and permit immediate and accurate photometry, shape
measurement, and mass modeling of the lens galaxies. The lenses
delivered by the SLACS Survey all show extended source structure,
furnishing more constraints on the projected lens potential than
lensed-quasar image positions. In addition, SLACS lenses have lens
galaxies that are much brighter than their lensed sources,
facilitating detailed photometric and dynamical observation of the
former. When confirmed lenses from this proposal are combined with
lenses discovered by SLACS in Cycles 13 and 14, we expect the final
SLACS lens sample to number 80--100: an approximate doubling of the
number of known galaxy-scale strong gravitational lenses and an
order-of-magnitude increase in the number of optical Einstein rings.
By virtue of its homogeneous selection and sheer size, the SLACS
sample will allow an unprecedented exploration of the mass structure
of the early-type galaxy population as a function of all other
observable quantities. This new sample will be a valuable resource to
the astronomical community by enabling qualitatively new strong
lensing science, and as such we will waive all but a short {3-month}
proprietary period on the observations.

ACS/WFC/NIC2 10496

Decelerating and Dustfree: Efficient Dark Energy Studies with
Supernovae and Clusters

We propose a novel HST approach to obtain a dramatically more useful
"dust free" Type Ia supernovae {SNe Ia} dataset than available with
the previous GOODS searches. Moreover, this approach provides a
strikingly more efficient search-and-follow-up that is primarily pre-
scheduled. The resulting dark energy measurements do not share the
major systematic uncertainty at these redshifts, that of the
extinction correction with a prior. By targeting massive galaxy
clusters at z 1 we obtain a five-times higher efficiency in
detection of Type Ia supernovae in ellipticals, providing a
well-understood host galaxy environment. These same deep cluster
images then also yield fundamental calibrations required for future
weak lensing and Sunyaev-Zel'dovich measurements of dark energy, as
well as an entire program of cluster studies. The data will make
possible a factor of two improvement on supernova constraints on dark
energy time variation, and much larger improvement in systematic
uncertainty. They will provide both a cluster dataset and a SN Ia
dataset that will be a longstanding scientific resource.

ACS/WFC/NIC3 10632

Searching for galaxies at z6.5 in the Hubble Ultra Deep Field

We propose to obtain deep ACS {F606W, F775W, F850LP} imaging in the
area of the original Hubble Ultra Deep Field NICMOS parallel fields
and - through simultaneous parallel observations - deep NICMOS {F110W,
F160W} imaging of the ACS UDF area. Matching the extreme imaging depth
in the optical and near-IR bands will result in seven fields with
sufficiently sensitive multiband data to detect the expected typical
galaxies at z=7 and 8. Presently no such a field exist. Our combined
optical and near-IR ultradeep fields will be in three areas separated
by about 20 comoving Mpc at z=7. This will allow us to give a first
assessment of the degree of cosmic variance. If reionization is a
process extending over a large redshift interval and the luminosity
function doesn't evolve strongly beyond z=6, these data will allow us
to identify of the order of a dozen galaxies at 6.5z8.5 - using the
Lyman break technique - and to place a first constrain on the
luminosity function at z6.5. Conversely, finding fewer objects would
be an indication that the bulk of reionization is done by galaxies at
z=6. By spending 204 orbits of prime HST time we will capitalize on
the investment of 544 prime orbits already made on the Hubble Ultra
Deep Field {UDF}. We have verified that the program as proposed is
schedulable and that it will remain so even if forced to execute in
the 2-gyro mode. The data will be non-proprietary and the reduced
images will be made public within 2 months from the completion of the
observations.

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration - CR Persistence Part 5

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 images. Each observation will need its
own CRMAP, as different SAA passages leave different imprints on the
NICMOS detectors.

NIC2 10893

Sweeping Away the Dust: Reliable Dark Energy with an Infrared Hubble
Diagram

We propose building a high-z Hubble Diagram using type Ia supernovae
observed in the infrared rest-frame J-band. The infrared has a number
of exceptional properties. The effect of dust extinction is minimal,
reducing a major systematic tha may be biasing dark energy
measurements. Also, recent work indicates that type Ia supernovae are
true standard candles in the infrared meaning that our Hubble diagram
will be resistant to possible evolution in the Phillips relation over
cosmic time. High signal-to-noise measurements of 9 type Ia events at
z~0.4 will be compared with an independent optical Hubble diagram from
the ESSENCE project to test for a shift in the derived dark energy
equation of state due to a systematic bias. Because of the bright sky
background, H-band photometry of z~0.4 supernovae is not feasible from
the ground. Only the superb image quality and dark infrared sky seen
by HST makes this test possible. This experiment may also lead to a
better, more reliable way of mapping the expansion history of the
universe with the Joint Dark Energy Mission.

NIC3 11064

CYCLE 15 NICMOS SPECTROPHOTOMETRY CALIBRATION PROGRAM

Now that the spectrophotometric capabilities of the NICMOS grism have
been established, cycle 15 observations are needed to refine the
sensitivity estimates, to check for sensitivity loss with time, to
improve the accuracy of the linearity correction, to improve the
secondary flux standards by re-observation, and to expand the G206
data set now that the sky subtraction technique has been shown to
produce useful fluxes for some of the fainter secondary standards.
These faint secondary IR standards will be a significant step towards
establishing flux standards for JWST, as well as for SNAP, Spitzer,
and SOFIA. 1.Re-observe the 3 primary WDs GD71, G191B2b, & GD153 twice
each, once at the beginning and once near the end of the 18 month
cycle. To date, we have only 2 observation of each star, while the
corresponding STIS data set for these primary standards ranges from 6
to 23 obs. No observations exist for GD71 or GD153 with G206, so that
the current G206 sensitivity is defined solely by G191B2B. Purposes:
Refine sensitivities, measure sens losses. Orbits: 2 for each of 6
visits = 12 2. Re-observe WD1057 & WD1657 plus another P041C lamp-on
visit to improve the scatter in the non-lin measurements per Fig. 8 of
NIC ISR 2006-02. The WD stars require 2 orbits each, while the lamp-on
test is done in one. The very faintest and most crucial standard
WD1657 has 2 good visits already, so to substantially improve the S/N,
two visits of two orbits are needed. Include G206 for P041C in the
lamp-off baseline part of that orbit. Orbits: WD1057-2, WD1657-4,
P041C-1 -- 7 3. Re-observe 9 secondary standards to improve S/N of
the faint ones and to include G206 for all 9. BD+17 {3 obs} is not
repeated in this cycle. Four are bright enough to do in one orbit:
VB8, 2M0036+18, P330E, and P177D. Orbits:2*5+4=14 Grand Total orbits
over 18 month cycle 15 is 12+6+14=32 {Roelof will submit the P041C
lamp-on visit in a separate program.}

NIC3 11068

NICMOS A-Star Spectrophotometric Observations

Now that the Cohen A-star fluxes have been verified in the IR by the
four cycle 14 NICMOS grism observations from program 10754,
verification of four more of these Cohen SEDs will be done in Cycle
15. All 8 stars are selected from the Spitzer IRAC photometric
calibration target lists, {Tables 1-2} in Reach et al. 2005, PASP,
117,978; and all 8 A-stars are near the north ecliptic pole, ie near
the JWST continuous viewing zone. The baseline plan for JWST NIRSpec
calibration is to use the Cohen modeled flux beyond the 2.5micron
NICMOS limit. Because of intrinsic variation within the same spectral
type there is some statistical scatter expected in the precision of
the Cohen flux extrapolation that is based on models. Thus, the
ensemble JWST flux calibration based on an average over 8 stars should
be sqrt{8} more accurate than a sensitivity based on just one A-star.
In addition to JWST calibration, this program supports
spectrophotometric cross calibration of HST and Spitzer. The targets
are chosen to be faint enough for unsaturated observations with JWST
NIRSpec, yet still bright enough for high signal to noise in
relatively short observations with HST+NICMOS and with Spitzer+IRAC.

WFPC2 10748

WFPC2 CYCLE 14 Standard Darks

This dark calibration program obtains dark frames every week in order
to provide data for the ongoing calibration of the CCD dark current
rate, and to monitor and characterize the evolution of hot pixels.
Over an extended period these data will also provide a monitor of
radiation damage to the CCDs.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.)

HSTARS:

10457 - GSAcq(1,3,1) results in finelock backup (1,0,1)

The GSAcq(1,3,1) scheduled at 275/10:50:00 - 10:58:04 resulted to
finelock backup (1,0,1) using FGS-1 due to stop flag (QF3STOPF) on
FGS-3 at 275/10:54:39. Pre-acquisition OBADs had (RSS) attitude error
corrections values of 1200.58 and 11.32 arcseconds. Post-acquisition
OBAD/MAP had 3-axis (RSS) value of 11.32 a-s.

10458 - REAcq (2,1,2) failed to RGA control

REAcq (2,1,2) scheduled at 275/22:16:59-22:24:17 failed to RGA control
due to stop flag on FGS 2. No 486 ESB's were noted. OBAD #1: RSS=
18.64 a-s OBAD #2: RSS= 8.52 a-s OBAD MAP: RSS= 15.87 a-s

REAcq (2,1,2) scheduled at 275/23:59:04-276/00:06:21 failed to RGA
control due to stop flag on FGS 2. OBAD #1: RSS= 1557.75 a-s OBAD #2:
RSS= 4.06 a-s OBAD MAP was not scheduled

REAcq (2,1,2) scheduled at 276/01:40:10-01:47:27 failed to RGA control
due to stop flag on FGS 2. OBAD #1: RSS= 1516.12 a-s OBAD #2: RSS=
5.58 a-s OBAD MAP was not scheduled

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSacq 07 07
FGS REacq 07 04
OBAD with Maneuver 28 28

SIGNIFICANT EVENTS: (None)

 




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