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Daily Report #5077



 
 
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Old April 19th 10, 04:37 PM posted to sci.astro.hubble
Cooper, Joe
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Default Daily Report #5077

HUBBLE SPACE TELESCOPE - Continuing to Collect World Class Science

DAILY REPORT #5077

PERIOD COVERED: 5am April 16 - 5am April 19, 2010 (DOY 106/09:00z-109/09:00z)

OBSERVATIONS SCHEDULED

WFC3/UVIS 12018

Ultra-Luminous X-Ray Sources in the Most Metal-Poor Galaxies

There is growing observational and theoretical evidence to suggest
that Ultra-Luminous X-ray sources (ULX) form preferentially in low
metallicity environments. Here we propose a survey of 27 nearby (
30Mpc) star-forming Extremely Metal Poor Galaxies (Z5% solar). There
are almost no X-ray observations of such low abundance galaxies (3 in
the Chandra archive). These are the most metal-deficient galaxies
known, and a logical place to find ULX if they favor metal-poor
systems. We plan to test recent population synthesis models which
predict that ULX should be very numerous in metal-poor galaxies. We
will also test the hypothesis that ULX form in massive young star
clusters, and ask for HST time to obtain the necessary imaging data.

ACS/WFC 12017

The Proper Motion of SNR E0519-69.0

We propose to measure independently the proper motion expansions of
the ejecta and forward shock in SNR E0519-69.0. The metal-enriched
reverse-shock-heated ejecta emits only in X-rays, while the forward
shock is traced to high precision by H alpha emission. The proposed
measurements require the unique high resolution imaging capabilities
of Chandra and Hubble. The optical (forward shock) and X-ray (ejecta)
results will yield important constraints on the remnant's evolutionary
state; we will search in particular for evidence of cosmic-ray
modified dynamics. An important component of this project is an
integrated theoretical investigation using realistic models of SN Ia
explosions evolved to the remnant stage.

COS/FUV 11997

FUV Internal/External Wavelength Scale Monitor

This program monitors the offsets between the wavelength scale set by
the internal wavecal versus that defined by absorption lines in
external targets. This is accomplished by observing two external
targets in the SMC: SK191 with G130M and G160M and Cl* NGC 330 ROB B37
with G140L (SK191 is too bright to be observed with G140L). The
cenwaves observed in this program are a subset of the ones used during
Cycle 17. Observing all cenwaves would require a considerably larger
number of orbits. Constraints on scheduling of each target are placed
so that each target is observed once every ~2-3 months. Observing the
two targets every month would also require a considerably larger
number of orbits.

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 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 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.

FGS 11874

Monitoring FGS2R2 S-Curves after SMOV4

This proposal satisfies the near-term requirement associated with
SMOV4 activity OTA/FGS-10, as well as the long term Cycle 17
requirement to monitor the post SM4 evolution of the FGS2R2 S-curves
stability during its first year on orbit. The S curves will be
obtained from Trans mode observations of stars (point sources) at
several locations in the FGS2R2 FOV in order to monitor both global
and differential (i.e., field-dependent) changes. At each location,
both F583W and PUPIL S-curves will be obtained. Stars in the M35
cluster will be used for this proposal since the field lies very near
the ecliptic and can therefore be observed by HST at two Orients from
August to May.

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.

ACS/WFC/WFC3/IR 11802

WFC3/IR Observations of Strongly Lensing Clusters

We propose WFC3/IR observations of the massive lensing clusters Abell
1689 and Abell 1703 to constrain the properties of both cluster and
background field galaxies. The dataset will also help constrain the
photometric redshift of A1689-zD1, the bright galaxy candidate at
z~7.6.

ACS/WFC3 11735

The LSD Project: Dynamics, Merging and Stellar Populations of a Sample
of Well-Studied LBGs at z~3

A large observational effort with the ground-based ESO/VLT telescopes
allowed us to obtain deep, spatially-resolved, near-IR spectra of
complete sample of 11 Lyman-Break Galaxies at z~3.1. These
observations were used to obtain, for the first time, the metallicity
and the dynamical properties of a sample of objects that, albeit
small, is representative of the total population of the LBGs. We
propose to use HST to obtain high-resolution optical and near-IR
images of this sample of LBGs in order to study the broad-band
morphology and the stellar light distribution of these galaxies. These
images, exploiting the superior spatial resolution of HST images and
the low-background : 1- will allow a precise measure of the dynamical
mass from the velocity field derived with spectroscopy; 2- will permit
a comparison of the distribution of star formation (from the line
emission) with the underlying stellar population, and, 3- will be used
to check if the complex velocity field and the multiple line-emitting
regions detected in most targets can be ascribed to on-going mergers.
This accurate study will shed light on a number of unsolved problems
still affecting the knowledge of the LBGs.

ACS/WFC 11715

The Luminous Galactic Cepheid RS Puppis: A Geometric Distance from its
Nested Light Echoes

RS Puppis is one of the most luminous Cepheids in the Milky Way (P =
41.4 days) and an analog of the bright Cepheids used to measure
extragalactic distances. An accurate distance would help anchor the
zero-point of the bright end of the period-luminosity relation, but at
a distance of about 2 kpc it is too far away for a trigonometric
parallax with existing instrumentation.

RS Pup is unique in being surrounded by a reflection nebula, whose
brightness varies as pulses of light from the Cepheid propagate
outwards. Members of our team have used ground-based imaging of the
nebula to derive phase lags in the light variations of individual
features in the nebula, and have inferred a seemingly very precise
geometric distance to the star. However, there is an unavoidable
ambiguity involving the cycle counts, which was resolved by assuming
that the features lie in the plane of the sky. If this assumption is
incorrect, a large systematic error would be introduced into the
distance measurement.

We show that polarimetric imaging using the high spatial resolution of
ACS/WFC and its ability to image close to the star can resolve this
ambiguity and yield a reliable geometric distance to RS Pup. We will
also obtain a wide-field multicolor image of the nebula, in order to
study its morphology and the mass-loss history of the Cepheid.

WFC3/IR 11712

Calibration of Surface Brightness Fluctuations for WFC3/IR

We aim to characterize galaxy surface brightness fluctuations (SBF),
and calibrate the SBF distance method, in the F110W and F160W filters
of the Wide Field Camera 3 IR channel. Because of the very high
throughput of F110W and the good match of F160W to the standard H
band, we anticipate that both of these filters will be popular choices
for galaxy observations with WFC3/IR. The SBF signal is typically an
order of magnitude brighter in the near-IR than in the optical, and
the characteristics (sensitivity, FOV, cosmetics) of the WFC3/IR
channel will be enormously more efficient for SBF measurements than
previously available near-IR cameras. As a result, our proposed SBF
calibration will allow accurate distance derivation whenever an
early-type or bulge-dominated galaxy is observed out to a distance of
150 Mpc or more (i.e., out to the Hubble flow) in the calibrated
passbands. For individual galaxy observations, an accurate distance is
useful for establishing absolute luminosities, black hole masses,
linear sizes, etc. Eventually, once a large number of galaxies have
been observed across the sky with WFC3/IR, this SBF calibration will
enable accurate mapping of the total mass density distribution in the
local universe using the data available in the HST archive. The
proposed observations will have additional important scientific value;
in particular, we highlight their usefulness for understanding the
nature of multimodal globular cluster color distributions in giant
elliptical galaxies.

WFC3/ACS/IR 11600

Star Formation, Extinction, and Metallicity at 0.7z1.5: 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 0.7z1.5, 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 11595

Turning Out the Light: A WFC3 Program to Image z2 Damped Lyman Alpha
Systems

We propose to directly image the star-forming regions of z2 damped
Lya systems (DLAs) using the WFC3/UVIS camera on the Hubble Space
Telescope. In contrast to all previous attempts to detect the galaxies
giving rise to high redshift DLAs, we will use a novel technique that
completely removes the glare of the background quasar. Specifically,
we will target quasar sightlines with multiple DLAs and use the higher
redshift DLA as a ``blocking filter'' (via Lyman limit absorption) to
eliminate all FUV emission from the quasar. This will allow us to
carry out a deep search for FUV emission from the lower redshift DLA,
shortward of the Lyman limit of the higher redshift absorber. The
unique filter set and high spatial resolution afforded by WFC3/UVIS
will then enable us to directly image the lower redshift DLA and thus
estimate its size, star- formation rate and impact parameter from the
QSO sightline. We propose to observe a sample of 20 sightlines,
selected primarily from the SDSS database, requiring a total of 40 HST
orbits. The observations will allow us to determine the first FUV
luminosity function of high redshift DLA galaxies and to correlate the
DLA galaxy properties with the ISM characteristics inferred from
standard absorption-line analysis to significantly improve our
understanding of the general DLA population.

ACS/SBC/COS/NUV/FUV 11579

The Difference Between Neutral- and Ionized-Gas Metal Abundances in
Local Star-Forming Galaxies with COS

The metallicity of galaxies and its evolution with redshift is of
paramount importance for understanding galaxy formation. Abundances in
the interstellar medium (ISM) are typically determined using
emission-line spectroscopy of HII regions. However, since HII regions
are associated with recent SF they may not have abundances typical for
the galaxy as a whole. This is true in particular for star-forming
galaxies (SFGs), in which the bulk of the metals may be contained in
the neutral gas. It is therefore important to directly probe the metal
abundances in the neutral gas. This can be done using absorption lines
in the Far UV. We have developed techniques to do this in SFGs, where
the absorption is measured for sightlines toward bright SF regions
within the galaxy itself. We have successfully applied this technique
to a sample of galaxies observed with FUSE. The results have been very
promising, suggesting in I Zw 18 that abundances in the neutral gas
may be up to 0.5 dex lower than in the ionized gas. However, the
interpretation of the FUSE data is complicated by the very large FUSE
aperture (30 arcsec), the modest S/N, and the limited selection of
species available in the FUSE bandpass. The advent of COS on HST now
allows a significant advance in all of these areas. We will therefore
obtain absorption line spectroscopy with G130M in the same sample for
which we already have crude constraints from FUSE. We will obtain
ACS/SBC images to select the few optimal sightlines to target in each
galaxy. The results will be interpreted through line-profile fitting
to determine the metal abundances constrained by the available lines.
The results will provide important new insights into the metallicities
of galaxies, and into outstanding problems at high redshift such as
the observed offset between the metallicities of Lyman Break Galaxies
and Damped Lyman Alpha systems.

NIC2/WFC3/IR 11219

Active Galactic Nuclei in Nearby Galaxies: A New View of the Origin of
the Radio-Loud Radio- Quiet Dichotomy?

Using archival HST and Chandra observations of 34 nearby early-type
galaxies (drawn from a complete radio selected sample) we have found
evidence that the radio-loud/radio-quiet dichotomy is directly
connected to the structure of the inner regions of their host galaxies
in the following sense: [1] Radio-loud AGN are associated with
galaxies with shallow cores in their light profiles [2] Radio-quiet
AGN are only hosted by galaxies with steep cusps. Since the brightness
profile is determined by the galaxy's evolution, through its merger
history, our results suggest that the same process sets the AGN
flavor. This provides us with a novel tool to explore the co-evolution
of galaxies and supermassive black holes, and it opens a new path to
understand the origin of the radio-loud/radio-quiet AGN dichotomy.
Currently our analysis is statistically incomplete as the brightness
profile is not available for 82 of the 116 targets. Most galaxies were
not observed with HST, while in some cases the study is obstructed by
the presence of dust features. We here propose to perform an infrared
NICMOS snapshot survey of these 82 galaxies. This will enable us to i)
test the reality of the dichotomic behavior in a substantially larger
sample; ii) extend the comparison between radio-loud and radio-quiet
AGN to a larger range of luminosities.

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 21 21
FGS REAcq 22 22
OBAD with Maneuver 16 16

SIGNIFICANT EVENTS:

Flash Reports:

The new acquisition PLCP groups were used at the start of the 109 SMS.
All indications are that the first two acquisitions were successful.



 




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