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Daily 3637



 
 
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Old June 22nd 04, 01:56 PM
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Default Daily 3637

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 3637

PERIOD COVERED: DOYs 170-172

OBSERVATIONS SCHEDULED

NIC3 9998

NICMOS Cycle 12 Grism Calibration and Standard Stars to 2.5microns

This is the grism calibration proposal.

NIC/NIC3/STIS/CCD 9877

A test of the foreground proximity effect at z=1.2

The diffuse UV background flux J is a crucial component for
cosmological evolution models, though few determinations have been
made. The proximity effect, the thinning out of the Lyman alpha forest
near a sight- line's background quasar and explained at least partly
by the enhanced ionization from the quasar, is a key method to measure
J. A foreground proximity effect {FPE} should exist from quasars close
on the sky but at different z; it can constrain J and test the
enhanced ionization model. Galaxy clustering around the quasar may
modify the effect, but knowing the galaxy density around the Lya
forest should allow for corrections. We propose to measure the FPE at
z=1.2, which is advantageous because 1} the diffuse UV flux is lower,
and thus contrast with the UV flux of neighboring quasars is higher,
and 2} galaxies are easier to identify at z=1.2. We have good
knowledge of the physical volume we wish to study through surveys for
quasars, MgII absorbers and galaxies, to constrain the
redshift-dependent galaxy density along the line of sight. We will
analyze the results based on pixel opacities, which is more sensitive
to fluctuations in J than traditional line counting, and will compare
our results with cosmological simulations to derive estimates of the
UV background in the context of available physical models.

NIC/NIC3 9865

The NICMOS Parallel Observing Program

We propose to continue managing the NICMOS pure parallel program.
Based on our experience, we are well prepared to make optimal use of
the parallel opportunities. The improved sensitivity and efficiency of
our observations will substantially increase the number of
line-emitting galaxies detected. As our previous work has
demonstrated, the most frequently detected line is Halpha at
0.7z1.9, which provides an excellent measure of current star
formation rate. We will also detect star-forming and active galaxies
in other redshift ranges using other emission lines. The grism
observations will produce by far the best available Halpha luminosity
functions over the crucial--but poorly observed--redshift range where
galaxies appear to have assembled most of their stellar mass. This key
process of galaxy evolution needs to be studied with IR data; we found
that observations at shorter wavelengths appear to have missed a large
fraction of the star-formation in galaxies, due to dust reddening. We
will also obtain deep F110W and F160W images, to examine the space
densities and morphologies of faint red galaxies. In addition to
carrying out the public parallels, we will make the fully reduced and
calibrated images and spectra available on-line, with some
ground-based data for the deepest parallel fields included.

STIS/CCD 9854

Anomalous Flux Ratios in Quadruple Gravitationally Lensed QSOs

We propose to observe eight {8} gravitationally lensed systems which
exhibit quadruple images of the background high redshift quasars.
Models invoking a smooth potential fit the observed image positions
accurately, in most cases better than 5 milliarcseconds. But the same
models dramatically fail to predict the observed flux ratios. These
anomalous flux ratios can be attributed to micro- or milli-lensing in
the massive lensing halo. In this proposal, we will isolate the source
of the anomalous flux ratios by using the superior resolution of
HST/STIS to obtain spectrophotometric data and compare the emission
line flux ratio of the QSOs to the continuum flux ratios. Due to the
much larger size of the broad emission line regions, the flux ratios
in the emission lines should only be affected by milli-lensing if the
sub-halos are comparable or larger in projected size than the source
region. That is, flux ratios observed in the QSO continuum are
sensitive to substructure on all scales {both micro- and
milli-lensing}, while the broad emission lines are insensitive to
micro-lensing due to the larger physical size of the source emission
region. This sample of eight quasars will provide the definitive
evidence to distinguish between possible sources causing the observed
anomalous flux ratios.

NIC2 9845

NICMOS Confirmation of a Young Planetary-Mass Companion

We have recently discovered a strong candidate for a planetary-mass
{~10 Mjup} companion to a young Sun-like star, based on near-IR
imaging and spectroscopy with the Keck and Subaru adaptive optics {AO}
systems. While the ground-based data strongly suggest that the
candidate has a very low effective temperature, and hence a very low
mass, they are not definitive. We propose to obtain NICMOS
coronagraphy to measure the companion's 1.9um water-band absorption.
This feature is a distinct signature of very cool objects and is
unobservable from the ground. The combined ground-based and
space-based data set will determine whether the companion has a very
low temperature, and hence if it is the lowest mass companion found to
date by direct imaging.

ACS/WFC/WFPC2 9837

Stellar Populations in the Outskirts of M33: A Unique Probe of Disk
Galaxy Formation

The fossil record of galaxy formation and evolution is imprinted on
the structure and composition of galactic stellar populations. We have
recently completed an extensive ground-based imaging survey of the low
mass Local Group spiral, M33. Our analysis of the global structure of
M33 suggests it is a 'pure disk' galaxy, with no discernible stellar
halo. Furthermore, the disk surface brightness declines very abruptly
beyond ~5 scalelengths. We propose here to obtain deep ACS imagery of
two fields in the far outer disk of M33, located at 4.5 and 6
exponential scalelengths. Deep colour-magnitude diagrams reaching main
sequence turn-offs of ~8 Gyr {corresponding to star formation episodes
since z 1} will be constructed and used for quantitative modelling of
the star formation history. State-of-the-art cosmological simulations
of galaxy formation predict stars in the outer regions of galactic
disks should be predominantly young-to-intermediate age. The data we
propose to obtain will directly test this idea, and provide a
much-needed observational constraint on the epoch at which disk
galaxies were assembled. The proposed observations will provide an
excellent complement to an ongoing Cycle 11 program to study the outer
disk of the more massive system, M31.

STIS/CCD/MA2 9807

Rotation in Jets from Young Stars: investigating NUV lines with very
high Spectral Resolution

Optical STIS spectra of the jets from DG Tau, RW Aur, TH 28 and LkHa
231 obtained by us {prop IDs. 7311, 9435} show systematic transverse
radial velocity shifts in the region where the flow has just been
accelerated and collimated {Bacciotti et al, 2002}, i.e. within about
100 AU from the source. We interpret such shifts as evidence for jet
rotation. Whether YSO jets rotate is a fundamental question in star
formation because it has been suggested that jets might be the way
excess angular momentum is removed from the star/disk system, thereby
allowing the star to accrete. In particular it is important to know if
observed toroidal velocities are in agreement with predictions of
magneto-centrifugal jet launching models. The limited spatial and
spectral resolution of STIS in the optical however, only allows one to
say qualitatively that the observed rotational velocities are in rough
agreement with theory. Moreover only the resolved peripheral regions
of the flow can be studied. We are proposing here to exploit the
higher spatial and spectral resolution of STIS in the NUV to measure
transverse jet velocity profiles. To measure the velocity profiles, we
will observe the Mg II doublet at 2800 Angstrom {using the E230M
echelle and the 6 X 0.2 slit transverse to the flow}. In comparison to
the optical, the NUV affords us double the spatial resolution and we
will be able to detect velocity differences across the jet down to 2
km/s. Not only should we be able to determine for the first time the
detailed rotational velocity profile across a jet but we also expect
to spatially resolve the high velocity axial core of the jet in the
NUV. Finally we add that as very few NUV observations of the initial
jet beam of YSO jets are available, our datasets should be a valuable
contribution to the HST archive.

STIS 9786

The Next Generation Spectral Library

We propose to continue the Cycle 10 snapshot program to produce a Next
Generation Spectral Library of 600 stars for use in modeling the
integrated light of galaxies and clusters. This program is using the
low dispersion UV and optical gratings of STIS. The library will be
roughly equally divided among four metallicities, very low {[Fe/H] lt
-1.5}, low {[Fe/H] -1.5 to -0.5}, near-solar {[Fe/H] -0.3 to 0.1}, and
super-solar {[Fe/H] gt 0.2}, well-sampling the entire HR-diagram in
each bin. Such a library will surpass all extant compilations and have
lasting archival value, well into the Next Generation Space Telescope
era. Because of the universal utility and community-broad nature of
this venture, we waive the entire proprietary period.

NIC3 9780

NIC3 Imaging of z~6 Candidates in a Deep ACS Parallel Field: Finding
the reionizing population and their LF

A fundamental cosmological question is when and how the universe was
reionized. It is now generally believed that the reionization ended by
z=6. There is evidence that QSO/AGN cannot provide enough photons to
keep the universe ionized at that epoch. In Yan et al. {2003}, we
presented a first statistically significant sample of 6.0z6.5 galaxy
candidates, 30 objects in total found in a deep ACS/WFC parallel field
by using the "drop-out" technique, and argued that the contamination
due to possible contaminators was minimal. We concluded that young,
star-forming galaxies did exist in large number as expected from our
earlier work {Yan et al. 2002}, and that they could have contributed
most of the reionizing photons. The candidates in our sample have a
median magnitude of AB=27.4 mag, beyond the spectroscopic capability
of any existing facilities. Any effort of acquiring a large sample of
galaxies around z=6 will have the vast majority of candidates at such
a faint brightness level. Thus near-IR imaging is the only practical
way to further confirm the nature and the redshifts of these
candidates until the launch of the JWST in 2010. Here we propose to
use the NIC3 of the NICMOS to image 43% of our sample in the F110W and
F160W bands to unambiguously confirm their nature. We will image 13-14
of our candidates with two NIC3 fields, and request 16 orbits of
observation in total. With this data set, we will be able to determine
the surface density of galaxies at the crucial epoch around z=6, and
derive photometric redshift for our candidates. Our result will set
stringent limits to the faint-end slope of the luminosity function
{LF} and the star formation rate at z=6, and thus provide essential
constraints to a series of questions regarding the reionization of the
universe.

ACS/WFC/WFPC2 9774

Young Massive Clusters in Spiral Galaxies and the Connection with Open
Clusters

We propose to carry out a census of star clusters in the disks of the
nearby spiral galaxies NGC 45, NGC 1313, NGC 4395, NGC 5236 and NGC
7793. Using ACS, we will identify much fainter and older star clusters
than possible in previous ground-based surveys, or even in HST imaging
of more distant galaxies. For the first time, we will directly explore
the connection between young "massive'' {or "super''} star clusters
{YMCs} and lower-mass "open'' clusters in different star forming
environments. We will test the universality of the luminosity- and
mass functions of stellar clusters and establish whether the presence
of YMCs is a result of a top-heavy cluster luminosity function, or
follows from generally richer cluster systems. Our target galaxies
span a range of morphological properties, surface brightness and star
formation rate. Some of them are known from ground-based studies to
host large numbers of YMCs while others have more modest cluster
populations. However, previous ground-based data were restricted to
luminous clusters younger than about 500 Myr. Here we will extend the
search to clusters formed throughout the entire lifetime of each
galaxy and reach clusters with properties typical of the Milky Way
open clusters. This will allow us to close the gap between studies of
extragalactic and Galactic disk clusters.

ACS/WFC/HRC 9771

The local Hubble flow and the density field within 6 Mpc

Great progress has been made recently in accurate distance
measurements of nearby galaxies beyond the Local Group based on the
luminosity of the tip of the red giant branch {TRGB}. Over the last
three years, snapshot surveys with HST have provided us with the TRGB
distances for more than a hundred nearby galaxies obtained with an
accuracy of about 10%. The local velocity field within 5 Mpc exhibits
a significant anisotropy which disagrees with a spherical
Virgo-centric flow. The local Hubble flow is very cold, with 1-D rms
deviations of ~30 km/s. Cosmological simulations with Cold Dark Matter
can only realize such low dispersions with a combination of a low mean
density of matter and a substantial component with negative pressure.
There may be a constraint on the equation of state w=-p/rho. Our
observations will concentrate on 116 galaxies whose expected distances
lie within 4 - 6 Mpc, allowing us to trace a Dark Matter distribution
in the Local Volume with twice the information currently available.
The program is a good one for SNAP mode because the order and rate
that the observations are made are not very important, as long as
there is good completion over several years.

ACS/HRC 9746

Binary systems in the Kuiper Belt

The properties of the orbits of Kuiper belt object {KBO} satellites
hold keys to fundamental insight into masses and densities of KBOs,
the interaction history of the early solar system, the internal
structure of distant ice-rock bodies, and even the genesis of the
Pluto-Charon binary. Within the past 18 months, 9 KBO satellite
systems have been discovered, allowing for the first time the
possibility of characterizing a sample of KBO satellite orbital
properties. We propose HRC observations to determine satellite orbits
in the 6 best cases. We have carefully devised a strategy for each of
these 6 systems to make maximum use of ground-based observations,
previous HST observations, and the smallest possible number of new HST
observations. Our proposed observations will efficiently provide
highly reliable orbital solutions which are critical to achieving the
scientific promise available from the study of these systems. Our
strategy relies heavily on extensive Monte Carlo simulations to define
optimal times of observing such that each new point obtained gives
maximum leverage for refining the orbital solution. We find that with
this strategy we can provide mass solutions for all 6 systems to an
accuracy of better than 10% using only 25 new HST observations. This
highly efficient program provides extreme scientific output with
optimal use of scarce resources.

ACS/HRC/WFC 9728

Tracing the History of Cosmic Expansion to z~2 with Type Ia Supernovae

Type Ia supernovae {SNe Ia} provide the only direct evidence for an
accelerating universe, an extraordinary result that needs the most
rigorous test. The case for cosmic acceleration rests on the
observation that SNe Ia at z = 0.5 are about 0.25 mag fainter than
they would be in a universe without acceleration. A powerful and
straightforward way to assess the reliability of the SN Ia measurement
and the conceptual framework of its interpretation is to look for
cosmic deceleration at z 1. This would be a clear signature of a
mixed dark-matter and dark-energy universe. Systematic errors in the
SNe Ia result attributed to grey dust or cosmic evolution of the SN Ia
peak luminosity would not show this change of sign. We have obtained a
toehold on this putative ``epoch of deceleration'' with SN 1997ff at z
= 1.7, and 3 more at z 1 from our Cycle 11 program, all found and
followed by HST. However, this is too important a test to rest on just
a few objects, anyone of which could be subject to a lensed
line-of-sight or misidentification. Here we propose to extend our
measurement with observations of twelve SNe Ia in the range 1.0 z
1.5 or 6 such SNe Ia and 1 ultradistant SN Ia at z = 2, that will be
discovered as a byproduct from proposed Treasury and DD programs.
These objects will provide a much firmer foundation for a conclusion
that touches on important questions of fundamental physics.

NIC1/NIC2/NIC3 8792

NICMOS Post-SAA calibration - CR Persistence Part 3

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.

WFPC2 10075

WFPC2 CYCLE 12 Intflat and Viflat Sweeps and Filter Rotation Anomaly
Monitor

Using intflat observations, this WFPC2 proposal is designed to monitor
the pixel-to-pixel flatfield response and provide a linearity check.
The intflat sequences, to be done once during the year, are similar to
those from the Cycle 11 program 9597. The images will provide a backup
database in the event of complete failure of the visflat lamp as well
as allow monitoring of the gain ratios. The sweep is a complete set of
internal flats, cycling through both shutter blades and both gains.
The linearity test consists of a series of intflats in F555W, in each
gain and each shutter. As in Cycle 11, we plan to continue to take
extra visflat, intflat, and earthflat exposures to test the
repeatability of filter wheel motions.

WFPC2 10071

WFPC2 CYCLE 12 Supplemental Darks Part 3/3

This dark calibration program obtains 3 dark frames every day to
provide data for monitoring and characterizing the evolution of hot
pixels.

ACS/HRC/WFC 10060

CCD Daily Monitor

This program consists of basic tests to monitor, the read noise, the
development of hot pixels and test for any source of noise in ACS CCD
detectors. This programme will be executed once a day for the entire
lifetime of ACS.

ACS/SBC 10047

ACS UV Contamination Monitor

A standard star field {NGC6681} is observed every three months,
alternating between after and before annealing operations, through all
the ACS broad band UV filters. NGC6681 hosts several UV spectro -
photometric standard stars for which accurate spectra have been {and
will continue to be} measured with STIS. Two SBC dark current
exposures taken as the last exposure of each SBC sequence. Also, to
minimize SBS turn-on/turn-off cycles and in order to check the lab
flats for the SBC detector, internal observations using the deuterium
lamp with F125LP are being taken inflight, following the UV monitor
observations. The internal flats have been taken ~monthly since SMOV,
and the degradation of the lamp has been monitored. The total exposure
time to date is ~15 hours giving a total of 8600 counts/pixel. The
goal is 10, 000 counts/pixel such that the resulting pipeline flat has
uncertainties of ~1% due to poison counting statistics. Thus,
approximately 3 additional hours of observation are required.

ACS/WFC 10046

CCD Hot Pixel Annealing

Hot pixel annealing will be performed once every 4 weeks. The CCD TECs
will be turned off and heaters will be activated to bring the detector
temperatures to about +20C. This state will be held for approximately
12 hours, after which the heaters are turned off, the TECs turned on,
and the CCDs returned to normal operating condition. To assess the
effectiveness of this procedure, a bias and two dark images will be
taken after the annealing procedure for both WFC and HRC. The HRC
darks are taken in parallel with the WFC darks.

STIS/CCD 10037

STIS Cycle 12 Faint Standard Extension: FASTEX

WD 1657+343 is the faintest of four pure hydrogen WD stars that
comprised the original FASTEX program and has been observed thrice in
2000 and once in 2002 to firmly establish the absolute flux levels.
Annual revisits of one orbit should occur to monitor our predictions
of the CTE correction, which is increasing with time on orbit. G430L
at both the standard and E1 aperture position are required at the
exposure times already established as standard. The remaining time in
the orbit will be spent extending the wavelength coverage using G750L.
To date, HST has not provided any faint solar analog stars to
compliment the three V=12-13.5 mag solar analogs provided by M. Rieke
for NICMOS calibration. As instrumentation in space and on the ground
becomes more sensitive, fainter flux standards are required. A solar
analog in a field with low reddening is an excellent choice for a
fainter standard, because unreddened pure hydrogen WDs are rare beyond
V=16, because Solar absolute fluxes are well measured at all
wavelengths, and because the fluxes do not fall off as fast as the hot
WDs at longer wavelengths. A 16.5 G star may not be faint enough for
most JWST modes but will provide a significant step in the right
direction. The SNAP program requires such a spectrophotometric
standard, which lies at the bright limit of its spectroscopy mode.
NICMOS grism observation of this standard are planned for cycle 12 and
STIS spectra are required to establish the standard over the full
range from 0.3-2 microns.

STIS/CCD 10020

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/CCD 10018

CCD Dark Monitor-Part 2

Monitor the darks for the STIS CCD.

ACS/HRC/WFC 10004

The Physics of Relativistic Jets: Chandra Imaging of Extended Jets in
Gamma-loud Blazars

Extended jets have been a key target for Chandra yet only recently has
the kpc-scale jet physics been compared to that of the inner,
parsec-scale jets. Such a comparison reveals the jet deceleration,
power dissipation, pressure gradient, and confinement mechanism ---
all essential ingredients for understanding the relativistic jets that
characterize radio- loud AGN. Currently, few data exist to make this
comparison. We propose to double the sample, with Chandra observations
of 4 gamma-loud blazars: 0954+556 and 1229-021, the only 2 bright
radio jets not yet observed by Chandra; and 0208-512 and 3C 454.3,
observed in A03 with much too short exposures. We also propose HST
multi-band ACS imaging of jet knots in 0208-512, 0954+556 and 3C
454.3.

FLIGHT OPERATIONS SUMMARY:

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

HSTAR 9451: GS Acquisition (1,2,2) @ 171/08:42Z failed to RGA control
due to SRLE on FGS 1. Prior FHST FM Updates showed ATT ERR of V1 =
-0.701, V2 = 11.243. V3 = -13.929 and V1 = -1.629, V2 = 0.418, V3 =
-2.164. The FHST Map @ 171/09:22:25Z showed attitude vehicle axis
errors of 2.517, -2.027, 8.720 arcsec. Under investigation.

COMPLETED OPS REQs:
17198-0 FHST Intensity Data Collection (See comment section) @170/1302z
17199-1 FHST Rate Control Data Collection (See comment section) 170/1623z

OPS NOTES EXECUTED:
1245-0 Change Limits MAMA1 Threshold Voltage @171/1550z(closed @172/2335z)

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS
GSacq 25 24 171/0847z
(HSTAR 9451)
FGS REacq 18 18
FHST Update 47 47
LOSS of LOCK

SIGNIFICANT EVENTS:

The third and final group of FHST Intensity and Rate Control Data
collections were successfully completed per Ops Request 17198 and
[email protected] 170/13:02Z and 16:23Z, respectively. Sections K and L, of
the consolidated script, were executed collecting one additional
Intensity period and one additional Rate Control period.


 




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