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Daily Report #5196



 
 
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Old October 6th 10, 03:43 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #5196


HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5196

PERIOD COVERED: 8:00pm October 4 - 7:59pm October 5, 2010 (DOY 278/00:00z-278/23:59z)

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

12452 - GSAcq(1,2,1) at 278/14:55:23z Resulted in Fine Lock Back-up on
FGS1.

Observations possibly affected: WFC3 1 Proposal ID#12344; WFC3 2-3
Proposal ID#12345; STIS 1 Proposal ID#12212

HSTARS FOR DOY 263, 265, 266, AND 267

12453 - REAcq(2,1,1) at 263/18:48z required two attempts to achieve
CT-DV.

Observations possibly affected: COS 23-28 Proposal ID#11997; COS 29
Proposal ID#11894

12454 - REAcq(1,2,1) at 265/13:58z required two attempts for FL-DV on
FGS2.

Observations possibly affected: COS 64-66 Proposal ID#11598

12455 - REAcq(2,1,1) at 266/15:18z required two attempts to achieve
CT-DV.

Observations possibly affected: WFC3 86-91 Proposal ID#12256

12456 - REAcq(1,2,1) at 267/21:54z required multiple attempts for
CT-DV on FGS1.

Observations possibly affected: WFC3 116-117 Proposal ID#11591


COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

Scheduled Successful
FGS GSAcq 10 10
FGS REAcq 06 06
OBAD with Maneuver 08 08

SIGNIFICANT EVENTS: (None)


OBSERVATIONS SCHEDULED:

ACS/WFC 12210

SLACS for the Masses: Extending Strong Lensing to Lower Masses and
Smaller Radii

Strong gravitational lensing provides the most accurate possible
measurement of mass in the central regions of early-type galaxies
(ETGs). We propose to continue the highly productive Sloan Lens ACS
(SLACS) Survey for strong gravitational lens galaxies by observing a
substantial fraction of 135 new ETG gravitational-lens candidates with
HST-ACS WFC F814W Snapshot imaging. The proposed target sample has
been selected from the seventh and final data release of the Sloan
Digital Sky Survey, and is designed to complement the distribution of
previously confirmed SLACS lenses in lens-galaxy mass and in the ratio
of Einstein radius to optical half-light radius. The observations we
propose will lead to a combined SLACS sample covering nearly two
decades in mass, with dense mapping of enclosed mass as a function of
radius out to the half-light radius and beyond. With this longer mass
baseline, we will extend our lensing and dynamical analysis of the
mass structure and scaling relations of ETGs to galaxies of
significantly lower mass, and directly test for a transition in
structural and dark-matter content trends at intermediate galaxy mass.
The broader mass coverage will also enable us to make a direct
connection to the structure of well-studied nearby ETGs as deduced
from dynamical modeling of their line-of-sight velocity distribution
fields. Finally, the combined sample will allow a more conclusive test
of the current SLACS result that the intrinsic scatter in ETG
mass-density structure is not significantly correlated with any other
galaxy observables. The final SLACS sample at the conclusion of this
program will comprise approximately 130 lenses with known foreground
and background redshifts, and is likely to be the largest confirmed
sample of strong-lens galaxies for many years to come.

COS/FUV 12212

What are the Locations and Kinematics of Mass Outflows in AGN?

Mass outflows of ionized gas in AGN, first revealed through
blueshifted UV and X-ray absorption lines, are likely important
feedback mechanisms for the enrichment of the IGM, self-regulation of
black-hole growth, and formation of structure in the early Universe.
To understand the origin, dynamics, and impact of the outflowing
absorbers on their surroundings, we need to know their locations
(radial positions and polar angles with respect to the AGN rotation
axes) and kinematics (radial and transverse velocities). We will use
COS high-resolution spectra of 11 Seyfert 1 galaxies to derive
velocity-dependent covering factors, ionic column densities, number
densities (via metastable lines or variability), and ionization
parameters (via photoionization models) of the UV absorbers, and
thereby determine their radial locations as we have done for NGC 4151.
We will use absorption variability over time scales of up to ~20
years, to determine transverse velocities and detect changes in radial
velocities. We will use STIS G430M long-slit spectra and WFC3 [OIII]
images to resolve the kinematics of the narrow-line region (NLR) and
determine the inclinations of the AGN, to investigate the connection
between nuclear absorption and NLR emission outflows and their
dependence on polar angle.

COS/NUV/FUV/WFC3/UV 12248

How Dwarf Galaxies Got That Way: Mapping Multiphase Gaseous Halos and
Galactic Winds Below L*

One of the most vexing problems in galaxy formation concerns how gas
accretion and feedback influence the evolution of galaxies. In high
mass galaxies, numerical simulations predict the initial fuel is
accreted through 'cold' streams, after which AGN suppress star
formation to leave galaxies red and gas-poor. In the shallow potential
wells that host dwarf galaxies, gas accretion can be very efficient,
and "superwinds" driven either by hot gas expelled by SNe or momentum
imparted by SNe and hot-star radiation are regarded as the likely
source(s) of feedback. However, major doubts persist about the physics
of gas accretion, and particularly about SN-driven feedback, including
their scalings with halo mass and their influence on the evolution of
the galaxies. While "superwinds" are visible in X-rays near the point
of their departure, they generally drop below detectable
surface-brightness limits at ~ 10 kpc. Cold clumps in winds can be
detected as blue-shifted absorption against the galaxy's own
starlight, but the radial extent of these winds are difficult to
constrain, leaving their energy, momentum, and ultimate fate
uncertain. Wind prescriptions in hydrodynamical simulations are
uncertain and at present are constrained only by indirect
observations, e.g. by their influence on the stellar masses of
galaxies and IGM metallicity. All these doubts lead to one conclusion:
we do not understand gas accretion and feedback because we generally
do not observe the infall and winds directly, in the extended gaseous
halos of galaxies, when it is happening. To do this effectively, we
must harness the power of absorption-line spectroscopy to measure the
density, temperature, metallicity, and kinematics of small quantities
of diffuse gas in galaxy halos. The most important physical
diagnostics lie in the FUV, so this is uniquely a problem for HST and
COS. We propose new COS G130M and G160M observations of 41 QSOs that
probe the gaseous halos of 44 SDSS dwarf galaxies well inside their
virial radii. Using sensitive absorption-line measurements of the
multiphase gas diagnostics Lya, CII/IV, Si II/III/IV, and other
species, supplemented by optical data from SDSS and Keck, we will map
the halos of galaxies with L = 0.02 - 0.3 L*, stellar masses M* =
10^(8-10) Msun, over impact parameter from 15 - 150 kpc. These
observations will directly constrain the content and kinematics of
accreting and outflowing material, provide a concrete target for
simulations to hit, and statistically test proposed galactic superwind
models. These observations will also inform the study of galaxies at
high z, where the shallow halo potentials that host dwarf galaxies
today were the norm. These observations are low-risk and routine for
COS, easily schedulable, and promise a major advance in our
understanding of how dwarf galaxies came to be.

WFC3/IR 12286

Hubble Infrared Pure Parallel Imaging Extragalactic Survey (HIPPIES)

WFC3 has demonstrated its unprecedented power in probing the early
universe. Here we propose to continue our pure parallel program with
this instrument to search for LBGs at z~6--8. Our program, dubbed as
the Hubble Infrared Pure Parallel Imaging Extragalactic Survey
("HIPPIES"), will carry on the HST pure parallel legacy in the new
decade. We request 205 orbits in Cycle-18, which will spread over ~ 50
high Galactic latitude visits (|b|20deg) that last for 3 orbits and
longer, resulting a total survey area of ~230 square arcmin. Combining
the WFC3 pure parallel observations in Cycle-17, HIPPIES will
complement other existing and forthcoming WFC3 surveys, and will make
unique contributions to the study in the new redshift frontier because
of the randomness of the survey fields. To make full use of the
parallel opportunities, HIPPIES will also take ACS parallels to study
LBGs at z~5--6. Being a pure parallel program, HIPPIES will only make
very limited demand on the scarce HST resources, but will have
potentially large scientific returns. As in previous cycle, we waive
all proprietary data rights, and will make the enhanced data products
public in a timely manner.

(1) The WFC3 part of HIPPIES aims at the most luminous LBG population
at z~8 and z~7. As its survey fields are random and completely
uncorrelated, the number counts of the bright LBGs from HIPPIES will
be least affected by the "cosmic variance", and hence we will be able
to obtain the best constraint on the bright-end of the LBG luminosity
function at z~8 and 7. Comparing the result from HIPPIES to the
hydrodynamic simulations will test the input physics and provide
insight into the nature of the early galaxies. (2) The z~7--8
candidates from HIPPIES, most of which will be the brightest ones that
any surveys would be able to find, will have the best chance to be
spectroscopically confirmed at the current 8--10m telescopes. (3) The
ACS part of HIPPIES will produce a significant number of candidate
LBGs at z~5 and z~6 per ACS field. Combining with the existing,
suitable ACS fields in the HST archive, we will be able to utilize the
random nature of the survey to quantify the cosmic variance and to
measure the galaxy bias at z~5--6, and therefore the galaxy halo
masses at these redshifts. (4) We will also find a large number of
extremely red, old galaxies at intermediate redshifts, and the fine
spatial resolution offered by the WFC3 will enable us constrain their
formation history based on the study of their morphology, and hence
shed light on their connection to the very early galaxies in the
universe.

WFC3/UV 12215

Searching for the Missing Low-Mass Companions of Massive Stars

Recent results on binary companions of massive O stars appear to
indicate that the distribution of secondary masses is truncated at low
masses. It thus mimics the distribution of companions of G dwarfs and
also the Initial Mass Function (IMF), except that it is shifted upward
by a factor of 20 in mass. These results, if correct, provide a
distribution of mass ratios that hints at a strong constraint on the
star-formation process. However, this intriguing result is derived
from a complex simulation of data which suffer from observational
incompleteness at the low-mass end.

We propose a snapshot survey to test this result in a very direct way.
HST WFC3 images of a sample of the nearest Cepheids (which were
formerly B stars of ~5 Msun) will search for low-mass companions down
to M dwarfs. We will confirm any companions as young stars, and thus
true physical companions, through follow-up Chandra X-ray images. Our
survey will show clearly whether the companion mass distribution is
truncated at low masses, but at a mass much higher than that of the
IMF or G dwarfs.

WFC3/UV 12344

Cycle 18: 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/UV 12345

UVIS Long Darks Test

Darks during SMOV showed a systematically lower global dark rate as
well as lower scatter when compared to the Cycle 17 darks. Those two
sets of exposures differ in exposure time - 1800 sec during SMOV and
900 sec during Cycle 17. Hypothetically, the effect could be caused by
short-duration stray light, say ~500-sec in duration. During the
latter part of Cycle 17, operation of WFC3 was changed to additionally
block the light path to the detector with the CSM. This program
acquires a small number of darks at the longer SMOV exposure times
(1800 sec) in order to check whether the effect repeats in the new
operating mode.

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.


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