Daily Report #4591
Cooper, Joe
DAILY REPORT # 4591
PERIOD COVERED: UT April 16, 2008 (DOY 107)
OBSERVATIONS SCHEDULED
ACS/SBC/WFPC2 11230
HST FUV Observations of Brightest Cluster Galaxies: The Role of Star
Formation in Cooling Flows and BCG Evolution
The intracluster medium (ICM) now appears to be a very dynamic place where
heating and cooling processes vie for dominance and an uneasy equilibrium is
maintained. Since these same processes may operate during the process of
galaxy formation, the centers of clusters of galaxies provide low redshift
laboratories for studying the critical processes involved in galaxy
formation and black hole growth. At the present time, the main questions are
(1) How much gas is cooling out of the ICM? (2) How much star formation is
ongoing? (3) What is the impact of the gas and star formation on the central
BCG? In order to measure the current star formation in BCGs we have
undertaken a program of Spitzer IRAC and MIPS observations. We are in
process of obtaining observations of a sample of Brightest Cluster Galaxies
in 70 clusters selected from the ROSAT all sky survey. In about 25% of the
sources observed so far, we detect a mid-IR excess which we attribute to
dust heated by star formation. We propose to obtain ACS/SBC observations of
the Lyman Alpha emission line and the adjacent FUV continuum in 7 BCGs which
are in cooling core clusters of galaxies and have a large mid-IR excess. We
also propose WFPC2 F606W observations of the two clusters without high
resolution imaging to allow us to image the dust on the same scale as the
Far UV continuum. The FUV will allow us to confirm the presense of ongoing
starformation in these BCGs and will allow us to rule out an AGN as the
dominant contributer to the mid-IR. The morphology and spatial extent of the
young stars and the heated dust and CO will constrain the spatial scale over
which star formation occurs and thus where the cooling gas is deposited. The
combination of our FUV and IR observations will allow us to estimate the
star formation rates which must balance the rate at which cold gas is
deposited in the BCG. Our proposed FUV observations will produce unique
information about the cooling gas, the true mass accretion rates, and the
star formation rates in BCGs and its effect on the galaxy.
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 images. Each observation will need its own CRMAP, as
different SAA passages leave different imprints on the NICMOS detectors.
NIC3 11120
A Paschen-Alpha Study of Massive Stars and the ISM in the Galactic Center
The Galactic center (GC) is a unique site for a detailed study of a
multitude of complex astrophysical phenomena, which may be common to nuclear
regions of many galaxies. Observable at resolutions unapproachable in other
galaxies, the GC provides an unparalleled opportunity to improve our
understanding of the interrelationships of massive stars, young stellar
clusters, warm and hot ionized gases, molecular clouds, large scale magnetic
fields, and black holes. We propose the first large-scale hydrogen Paschen
alpha line survey of the GC using NICMOS on the Hubble Space Telescope. This
survey will lead to a high resolution and high sensitivity map of the
Paschen alpha line emission in addition to a map of foreground extinction,
made by comparing Paschen alpha to radio emission. This survey of the inner
75 pc of the Galaxy will provide an unprecedented and complete search for
sites of massive star formation. In particular, we will be able to (1)
uncover the distribution of young massive stars in this region, (2) locate
the surfaces of adjacent molecular clouds, (3) determine important physical
parameters of the ionized gas, (4) identify compact and ultra-compact HII
regions throughout the GC. When combined with existing Chandra and Spitzer
surveys as well as a wealth of other multi-wavelength observations, the
results will allow us to address such questions as where and how massive
stars form, how stellar clusters are disrupted, how massive stars shape and
heat the surrounding medium, and how various phases of this medium are
interspersed.
WFPC2 11125
The Dynamical Evolution of Globular Clusters
Globular clusters evolve through dynamical interactions, with primordial
binaries extending the time until core collapse by up to an order of
magnitude, depending on the initial binary fraction. These dynamical
interactions plus mass segregation causes the binary fraction to rise in the
core but fall at larger radii. We hope to eventually test these broad
predictions by comparing them to the binary properties for globular clusters
at different states of evolution, defined by the ratio of their age to the
dynamical relaxation time at the half-light radius. The most important
unknown aspects in the modeling process are the initial conditions of
binaries in the cluster. Here we propose to determine the initial binary
fraction as a function of radius by studying three of the dynamically
youngest globular clusters {NGC 5053, NGC 5466, and NGC 5897}. The presence
of binaries thickens the Main Sequence in a color-magnitude diagram, which
can be detected with deep multicolor images.
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.
WFPC2 11132
Constraining the age of the AB Dor system
The zero-age main sequence K-type star AB Dor, with an age of 25 to 125 Myr,
is the most active young star in the solar neighbourhood. It is part of a
quadruple system of young stars. The mass of AB Dor C, the closest and
lowest mass companion, has been derived from astrometric observations (with
the VLA and adaptive optics at the VLT) to 94+-3 times the mass of Jupiter.
The low mass (close to the hydrogen burning limit) combined with the young
age makes AB Dor C a unique calibration source for evolutionary tracks for
very low-mass stars and brown dwarfs, provided that a precise age estimate
can be derived for the system. We propose to use the HST planetary camera to
obtain resolved component photometry of the M-type pre-main sequence star AB
Dor Ba and Bb in order to derive individual spectral types and luminosities,
which will enable us to age-date the AB Dor system to better than +-20 Myr.
In addition, the observations will help to constrain the Ba/Bb orbit, and
hence to derive dynamical mass estimates as well.
WFPC2 11235
HST NICMOS Survey of the Nuclear Regions of Luminous Infrared Galaxies in
the Local Universe
At luminosities above 10^11.4 L_sun, the space density of far-infrared
selected galaxies exceeds that of optically selected galaxies. These
`luminous infrared galaxies' {LIRGs} are primarily interacting or merging
disk galaxies undergoing enhanced star formation and Active Galactic Nuclei
{AGN} activity, possibly triggered as the objects transform into massive S0
and elliptical merger remnants. We propose NICMOS NIC2 imaging of the
nuclear regions of a complete sample of 88 L_IR > 10^11.4 L_sun luminous
infrared galaxies in the IRAS Revised Bright Galaxy Sample {RBGS: i.e., 60
micron flux density > 5.24 Jy}. This sample is ideal not only in its
completeness and sample size, but also in the proximity and brightness of
the galaxies. The superb sensitivity and resolution of NICMOS NIC2 on HST
enables a unique opportunity to study the detailed structure of the nuclear
regions, where dust obscuration may mask star clusters, AGN and additional
nuclei from optical view, with a resolution significantly higher than
possible with Spitzer IRAC. This survey thus provides a crucial component to
our study of the dynamics and evolution of IR galaxies presently underway
with Wide-Field, HST ACS/WFC and Spitzer IRAC observations of these 88
galaxies. Imaging will be done with the F160W filter {H-band} to examine as
a function of both luminosity and merger stage {i} the luminosity and
distribution of embedded star clusters, {ii} the presence of optically
obscured AGN and nuclei, {iii} the correlation between the distribution of
1.6 micron emission and the mid- IR emission as detected by Spitzer IRAC,
{iv} the evidence of bars or bridges that may funnel fuel into the nuclear
region, and {v} the ages of star clusters for which photometry is available
via ACS/WFC observations. The NICMOS data, combined with the HST ACS,
Spitzer, and GALEX observations of this sample, will result in the most
comprehensive study of merging and interacting galaxies to date.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of
potential non-nominal performance that will be investigated.)
HSTARS:
11255 - GSAcq(2,1,2) failed to RGA Hold (Gyro Control)
Upon acquisition of siganl at 107/16:22:31, the GSAcq(2,1,2) scheduled at
107/15:08:24 - 15:16:29 failed to RGA Hold due to (QF1STOPF) stop flag
indication on FGS-1. Pre-acquisition OBADs (RSS) attitude correction values
are not available due to LOS. Post-acq OBAD/MAP had (RSS) value of 1373.29
arcseconds.
COMPLETED OPS REQUEST:
18225-0 - Modify RWA Spin Down Estimate Parameters @107/1314z
18054-0 - Preview KF Sun Vector Data via Telemetry Diags @107/1321z
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSacq 08 07
FGS REacq 04 04
OBAD with Maneuver 24 24
SIGNIFICANT EVENTS: (None)