HUBBLE
SPACE TELESCOPE - Continuing to collect World Class Science
DAILY
REPORT #4653
PERIOD
COVERED: 5am July 15 - 5am July 16, 2008 (DOY 197/0900z-198/0900z)
OBSERVATIONS
SCHEDULED
NIC1/NIC2/NIC3
8795
NICMOS Post-SAA Calibration - CR Persistence Part 6
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 i
mages.
Each observation will need its own CRMAP, as different SAA
passages
leave different imprints on the NICMOS detectors.
NIC2
11197
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 that 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 Phillip's relation over
cosmic
time. High signal-to-noise measurements of 16 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. In Cycle 15 we obtained
NICMOS
photometry of 8 ESSENCE supernovae and are awaiting template
observations
to place them on the IR Hubble diagram. Here we request
another
8 supernovae be studied in the final season of the ESSENCE
search.
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.
NIC2
11237
The
Origin of the Break in the AGN Luminosity Function
We
propose to use NICMOS imaging to measure rest-frame optical
luminosities
and morphological properties of a complete sample of faint
AGN
host galaxies at redshifts z ~ 1.4. The targets are drawn from the
VLT-VIMOS
Deep Survey, and they constitute a sample of the lowest
luminosity
type 1 AGN known at z > 1. The spectroscopically estimated
black
hole masses are up to an order of magnitude higher than expected
given
their nuclear luminosities, implying highly sub-Eddington
accretion
rates. This exactly matches the prediction made by recent
theoretical
models of AGN evolution, according to which the faint end of
the
AGN luminosity function is populated mainly by big black holes that
have
already exhausted a good part of their fuel. In this proposal we
want
to test further predictions of that hypothesis, by focusing on the
host
galaxy properties of our low-luminosity, low- accretion AGN. If the
local
ratio between black hole and bulge masses holds at least
approximately
at these redshifts, one expects most of these
low-luminosity
AGN to reside in fairly big ellipticals with stellar
masses
around and above 10^11 solar masses (in contrast to the Seyfert
phenomenon
in the local universe). With NICMOS imaging we will find out
whether
that is true, implying also a sensitive test for the validity of
the
M_BH/M_bulge relation at z ~ 1.4.
NIC2
11547
Characterizing
Pre-Main Sequence Populations in Stellar Associations of
the
Large Magellanic Cloud
The
Large Magellanic Cloud (LMC) offers an extremely rich sample of
resolved
low-mass stars (below 1 Solar Mass) in the act of formation
that
has not been explored sufficiently yet. These pre-main sequence
(PMS)
stars provide a unique snapshot of the star formation process, as
it
is being recorded for the last ~20 Myr, and they give important
information
on the low-mass Initial Mass Function (IMF) of their host
stellar
systems. Studies of young, rich LMC clusters like 30 Doradus are
crowding
limited, even at the angular resolution facilitated by HST in
the
optical. To learn more about low-mass PMS stars in the LMC, one has
to
study less crowded regions like young stellar associations. We propose
to
employ WFPC2 to obtain deep photometry (V ~ 25.5 mag) of four
selected
LMC stellar associations in order to perform an original
optical
analysis of their red PMS and blue bright MS stellar
populations.
With these observations we aim at a comprehensive study,
which
will add substantial information on the most recent star formation
and
the IMF in the LMC. The data reduction and analysis will be
performed
with a 2D photometry software package especially developed by
us
for WFPC2 imaging of extended stellar associations with variable
background.
Our targets have been selected optimizing a combination of
criteria,
namely spatial resolution, crowding, low extinction, nebular
contamination,
and background confusion in comparison to other regions
in
the Local Group. Parallel NICMOS imaging will provide additional
information
on near-infrared properties of the stellar population in the
regions
surrounding these systems.
NIC2
11799
NICMOS
Non-linearity Calibration for Faint Objects
NICMOS
has played a key role in probing the deep near infrared regime
for
a decade. It has been the only instrument available to observe
objects
in the near infrared that are not visible from the ground. In
particular,
it has played a major role in the SN Ia observations at
redshifts
z>1. However, the calibration of NICMOS has turned out to be
difficult
due to the apparent non-linearity of the detectors. The NICMOS
calibration
team has described the non-linearity as a power law based on
data
in the range of ~50-5000 ADU/s. The correction relies on an
extrapolation
of two orders of magnitude in flux at count rates close to
the
sky level (0.1 ADU/s) where space observations are particularly
prized
- and where SN Ia observations are made. Precise measurements of
faint
objects require us to reduce the uncertainties from this
extrapolation.
Here we propose to derive the absolute calibration in the
sky
limited regime and to characterize the non-linearity over the entire
dynamic
range for the camera/filter combination: NIC2/F110W.
NIC3
11545
A
NICMOS Survey of Newly-Discovered Young Massive Clusters
We
are on the cusp of a revolution in massive star research triggered by
2MASS
and Spitzer/GLIMPSE, and now is the ideal time to capitalize on
these
projects by performing the first survey of massive stars in young
stellar
clusters throughout the Galactic plane. A search of the 2MASS
and
GLIMPSE surveys has produced over 450 newly-identified massive
stellar
cluster candidates in the Galactic plane which are hidden from
our
view at optical wavelengths due to extinction. Here we propose a
program
of 29 orbits to image the most promising candidate clusters in
broad
and narrow band filters using HST/NICMOS. We will be complementing
these
observations with approved Spitzer and Chandra programmes,
numerous
approved and planned ground-based spectroscopic observations,
and
state-of-the-art modelling. We expect to substantially increase the
numbers
of massive stars known in the Galaxy, including main sequence
stars
and post-main sequence stars in the Red Supergiant, Luminous Blue
Variable
and Wolf-Rayet stages. Ultimately, this programme will address
many
of the fundamental topics in astrophysics: the slope to the initial
mass
function (IMF), an upper-limit to the masses of stars, the
formation
and evolution of the most massive stars, gamma-ray burst (GRB)
progenitors,
the chemical enrichment of the interstellar medium, and
nature
of the first stars in the Universe.
WFPC2
11130
AGNs
with Intermediate-mass Black Holes: Testing the Black Hole-Bulge
Paradigm,
Part II
The
recent progress in the study of central black holes in galactic
nuclei
has led to a general consensus that supermassive {10^6-10^9 solar
mass}
black holes are closely connected with the formation and
evolutionary
history of large galaxies, especially their bulge
component.
Two outstanding issues, however, remain unresolved. Can
central
black holes form in the absence of a bulge? And does the mass
function
of central black holes extend below 10^6 solar masses?
Intermediate-mass
black holes {<10^6 solar masses}, if they exist, may
offer
important clues to the nature of the seeds of supermassive black
holes.
Using the SDSS, our group has successfully uncovered a new
population
of AGNs with intermediate-mass black holes that reside in
low-luminosity
galaxies. However, very little is known about the
detailed
morphologies or structural parameters of the host galaxies
themselves,
including the crucial question of whether they have bulges
or
not. Surprisingly, the majority of the targets of our Cycle 14 pilot
program
have structural properties similar to dwarf elliptical galaxies.
The
statistics from this initial study, however, are really too sparse
to reach
definitive conclusions on this important new class of black
holes.
We wish to extend this study to a larger sample, by using the
Snapshot
mode to obtain WFPC2 F814W images from a parent sample of 175
AGNs
with intermediate-mass black holes selected from our final SDSS
search.
We are particularly keen to determine whether the hosts contain
bulges,
and if so, how the fundamental plane properties of the host
depend
on the mass of their central black holes. We will also
investigate
the environment of this unique class of AGNs.
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
08
08
FGS
REacq
06
06
OBAD
with Maneuver 28
28
SIGNIFICANT
EVENTS: (None)