HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4652
PERIOD COVERED: 5am July 14 - 5am July 15, 2008 (DOY 196/0900z-197/0900z)
OBSERVATIONS SCHEDULED
ACS/SBC 11151
Evaluating the Role of Photoevaporation of Protoplanetary Disk Dispersal
Emission produced by accretion onto the central star leads to
photoevaporation, which may play a fundamental role in disk dispersal.
Models of disk photoevaporation by the central star are challenged by
two potential problems: the emission produced by accretion will be
substantially weaker for low-mass stars, and photoevaporation must
continue as accretion slows. Existing FUV spectra of CTTSs are biased to
solar-mass stars with high accretion rates, and are therefore
insufficient to address these problems. We propose use HST/ACS SBC
PR130L to obtain FUV spectra of WTTSs and of CTTSs at low masses and
mass accretion rates to provide crucial data to evaluate
photoevaporation models. We will estimate the FUV and EUV luminosities
of low-mass CTTSs with small mass accretion rates, CTTSs with transition
disks and slowed accretion, and of magnetically-active WTTSs.
ACS/SBC 11158
HST Imaging of UV emission in Quiescent Early-type Galaxies
We have constructed a sample of early type galaxies at z~0.1 that have
blue UV-optical colors, yet also show no signs of optical emission, or
extended blue light. We have cross- correlated the SDSS catalog and the
Galaxy Evolution Explorer Medium Imaging Survey to select a sample of
galaxies where this UV emission is strongest. The origin of the UV
rising flux in these galaxies continues to be debated, and the
possibility that some fraction of these galaxies may be experiencing low
levels of star formation cannot be excluded. There is also a possibility
that low level AGN activity {as evidenced by a point source} is
responsible We propose to image the UV emission using the HST/SBC and to
explore the morphology of the UV emission relative to the optical light.
WFPC2 11024
WFPC2 CYCLE 15 INTERNAL MONITOR
This calibration proposal is the Cycle 15 routine internal monitor for
WFPC2, to be run weekly to monitor the health of the cameras. A variety
of internal exposures are obtained in order to provide a monitor of the
integrity of the CCD camera electronics in both bays {both gain 7 and
gain 15 -- to test stability of gains and bias levels}, a test for
quantum efficiency in the CCDs, and a monitor for possible buildup of
contaminants on the CCD windows. These also provide raw data for
generating annual super-bias reference files for the calibration
pipeline.
NIC1/NIC2/NIC3 11330
NICMOS Cycle 16 Extended Dark
This takes a series of Darks in parallel to other instruments.
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 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 flavour. 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 behaviour in a substantially larger sample; ii} extend
the comparison between radio-loud and radio-quiet AGN to a larger range
of luminosities.
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 developped 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 programs,
numerous approved and planned ground-based spectroscopic observations,
and state-of-the-art modeling. 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 program 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.
WEPC2 11196
An Ultraviolet Survey 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 starbursts and creating/fueling central AGN. We
propose far {ACS/SBC/F140LP} and near {WFPC2/PC/F218W} UV imaging of a
sample of 27 galaxies drawn from the complete IRAS Revised Bright Galaxy
Sample {RBGS} LIRGs sample and known, from our Cycle 14 B and I-band ACS
imaging observations, to have significant numbers of bright {23 < B < 21
mag} star clusters in the central 30 arcsec. The HST UV data will be
combined with previously obtained HST, Spitzer, and GALEX images to {i}
calculate the ages of the clusters as function of merger stage, {ii}
measure the amount of UV light in massive star clusters relative to
diffuse regions of star formation, {iii} assess the feasibility of using
the UV slope to predict the far-IR luminosity {and thus the star
formation rate} both among and within IR-luminous galaxies, and {iv}
provide a much needed catalog of rest-frame UV morphologies for
comparison with rest-frame UV images of high-z LIRGs and Lyman Break
Galaxies. These observations will achieve the resolution required to
perform both detailed photometry of compact structures and spatial
correlations between UV and redder wavelengths for a physical
interpretation our IRX-Beta results. The HST UV data, combined with the
HST ACS, Spitzer, Chandra, and GALEX observations of this sample, will
result in the most comprehensive study of luminous starburst galaxies to
date.
WFPC2 11070
WFPC2 CYCLE 15 Standard Darks - part II
This dark calibration program obtains dark frames every week in order to
provide data for the ongoing calibration of the CCD dark current rate,
and to monitor and characterize the evolution of hot pixels. Over an
extended period these data will also provide a monitor of radiation
damage to the CCDs.
WFPC2 11113
Binaries in the Kuiper Belt: Probes of Solar System Formation and
Evolution
The discovery of binaries in the Kuiper Belt and related small body
populations is powering a revolutionary step forward in the study of
this remote region. Three quarters of the known binaries in the Kuiper
Belt have been discovered with HST, most by our snapshot surveys. The
statistics derived from this work are beginning to yield surprising and
unexpected results. We have found a strong concentration of binaries
among low-inclination Classicals, a possible size cutoff to binaries
among the Centaurs, an apparent preference for nearly equal mass
binaries, and a strong increase in the number of binaries at small
separations. We propose to continue this successful program in Cycle 16;
we expect to discover at least 13 new binary systems, targeted to
subgroups where these discoveries can have the greatest impact.
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:
11391 - GSAcq (1,2,1) failed due to Search Radius Limit Exceeded on FGS 1
At Acquisition of
Signal, 196/13:35:00, GSAcq (1,2,1) scheduled from
13:22:30 - 13:29:48
had failed to RGA control due to Search Radius Limit
Exceeded on FGS 1.
Received one 486 ESB message "a07", C Timeout - DV.
Possible
observations affected: NICMOS proposal 11545, observations 21 -28.
11392 - GSAcq (2,3,3) failed due to Search Radius Limit Exceeded on FGS 2
GSAcq (2,3,3)
scheduled from 197/15:20:39 - 15:28:07 failed due to
Search Radius Limit
Exceeded on FGS 2. At Acquisition of Signal (AOS) at
15:17:00, received
486 ESB message "1806" T2G open loop timer expired.
Vehicle was in T2G
Attitude Hold mode at AOS.
At 15:45:27 ,
received an additional 486 ESB message "1806" T2G open
loop timer expired.
Possible
observations affected: WFPC Proposal 11113, Observations 27-30
11395 - REACQ(2,1,1) failed while LOS
REACQ(2,1,1) at
197/01:04:08 failed to RGA control while vehicle was
LOS, with QF2STOPF
and QSTOP flags set. #44 commands did not change
since previous
acquisition.
One 486 ESB message
1805 (T2G_MOVING_TARGET_DETECTED) and one message
1808 (TxG FHST
Sanity Check Failed) were observed at AOS. Two NSSCI
status buffer
messages ACS 779 ("Fold Mechanism Move was Blocked") were
received at
01:13:04 and 01:31:38 due to take data flag being down when
the fold mechanism
move was commanded.
Observation
affected: ACS 2, Proposal 11151.
COMPLETED OPS REQUEST:
18251-0 - Place +BB SPA Trim Relay Back On-line @ 196/1409z
COMPLETED OPS NOTES: (None)
SCHEDULED
SUCCESSFUL
FGS GSacq
09
07
FGS REacq
03
02
OBAD with Maneuver 24
24
SIGNIFICANT EVENTS:
Place +BB SPA Back On-Line Flash Report:
On DOY 2008/196 at approximately 14:08 GMT, Ops Request 18251 (Place +BB
SPA Trim Relay back On-Line) was successfully executed to place the +BB
SPA trim relay back on-line in FSW. Nominal system performance was
observed the following orbit.