NASA Hubble Space Telescope Daily Report #3976
HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science
DAILY REPORT # 3976
PERIOD COVERED: UT October 27, 2005 (DOY 300)
OBSERVATIONS SCHEDULED
ACS/HRC 10564
Resolving Ultracool White Dwarf Binaries
We propose an ACS/HRC imaging survey of the coolest white dwarfs known in order to search for binarity. Current models fail to match observed spectral energy distributions of these sub- 4000K stellar remnants, consistently predicting much lower luminosities than observed. A possible explanation is that they are binary in nature. Because these cool degenerates have no spectral features, the only way to investigate their apparent overluminosity is with very high resolution imaging, which can only be done with HST {these stars are far too faint to be observed with adaptive optics on the ground}. Optical wavelengths are ideal because the spectral energy distributions of these old degenerates peak near 600 nm. With the F435W filter we will be able to partially resolve equally luminous binaries as close as 0.02″, which corresponds to within 0.6 AU for over half of the 12 proposed target stars. The collected data will be critical in determining whether these stars represent the oldest white dwarfs in the solar neighborhood.
ACS/HRC/WFC 10548
Near-UV Snapshot Survey of Low Luminosity AGNs
Low-luminosity active galactic nuclei {LLAGNs} comprise ~30% of all bright galaxies {B<12.5} and are the most common type of AGN. These include low-luminosity Seyfert galaxies, LINERs, and transition-type objects {TOs, also called weak-[OI] LINERs}. What powers them is still at the forefront of AGN research. To unveil the nature of the central source we propose a near-UV snapshot survey of 50 nearby LLAGNs using ACS/HRC and the filter {F330W}, a configuration which is optimal to detect faint star forming regions around their nuclei. These images will complement optical and near-IR images available in the HST archive, providing a panchromatic atlas of the inner regions of these galaxies, which will be used to study their nuclear stellar population. Our main goals are to: 1} Investigate the presence of nuclear unresolved sources that can be attributed to an AGN; 2} Determine the frequency of nuclear and circumnuclear stellar clusters, and whether they are more common in Transition Objects {TOs} than in LINERs; 3} Characterize the sizes, colors, luminosities, masses and ages of these clusters; 4} Derive the luminosity function of star clusters and study their evaporation over time in the vicinity of AGNs. Finally, the results of this project will be combined with those of a previous similar one for Seyfert galaxies in order to compare the nature of the nuclear sources and investigate if there could be an evolution from Seyferts to TOs and LINERs. By adding UV images to the existing optical and near-IR ones, this project will also create an extremely valuable database for astronomers with a broad range of scientific interests.
ACS/SBC 10506
Coordinated observations of Saturn’s auroral dynamic morphology and Cassini plasma measurements
Planetary FUV aurora is the most spectacular signature of the electrodynamical coupling between the solar wind, the planet’s magnetic field, and its atmosphere. Saturn’s magnetosphere has similarities both with the Earth’s magnetosphere, which is ‘open’ to solar wind interaction and Jupiter’s relatively ‘closed’ case with its large internal sources of plasma. HST observations of Saturn’s aurora have shown a much more complex and dynamic morphology than anticipated: a frequent ‘spiral’ structure, a changing size of the oval in response to variations of the solar wind dynamics pressure, and large brightness changes in a few ten of minutes following compression of the magnetosphere by the solar wind. In addition, the global morphology and some spots move at 70% of the planetary co-rotation, while some other features appear nearly fixed in local time. Recently, ideas have emerged to account for Saturn’s aurora specificities, although many aspects are still not understood due to the paucity of observational data. Electric current models suggest that the main oval is located at the limit between closed and open magnetic field lines, near the magnetopause. The availability of Cassini in Saturn’s magnetic environment now offers a unique opportunity for collaborative science. We thus propose to test the relationship between the aurora and conditions at Saturn’s magnetopause {MP} boundary. We plan to image the FUV aurora with ACS at times of inbound Cassini crossing of the MP from the upstream solar wind/magnetosheath region into the middle magnetosphere during an inbound segment of a Cassini’s orbit. FUV images will also reveal whether the main oval changes its size over the interval, possibly indicating evidence for changes in the amount of open flux in the system. These HST images of the aurora simultaneous with in situ measurements of the plasma characteristics and electrodynamics inside the magnetosphere are critical to obtain key observational tests and constraints to future ideas and models of Saturn’s auroral precipitation and magnetospheric processes involved.
ACS/SBC 10739
Internal Flat Field Stability
The stability of the CCD flat fields will be monitored using the calibration lamps and a sub-sample of the filter set. For the SBC imaging filters, differences in the low-frequency flat field structure with wavelength will be assessed. New high signal P-flats will be obtained for the SBC prisms.
ACS/WFC 10588
The Host Galaxies of Post-Starburst Quasars
We propose to use ACS to conduct a snapshot imaging survey of post-starburst quasars now being discovered in signficant numbers by the Sloan Digital Sky Survey. Post-starburst quasars are broad-lined AGN that also possess Balmer jumps and high-n Balmer absorption lines indicative of luminous stellar populations on order of 100 Myr old. These objects, representing a few percent of the z < 0.5 quasar population, may be an evolutionary stage in the transition of ultraluminous infrared galaxies into normal quasars, or a type of galaxy interaction that triggers both star formation and nuclear activity. These sources may also illustrate how black hole mass/bulge mass correlations arise. Ground-based imaging of individual poststarburst quasars has revealed merger remnants, binary systems, and single point sources. Our ACS snapshots will enable us to determine morphologies and binary structure on sub-arcsecond scales {surely present in the sample and impossible to do without HST}, as well as basic host galaxy properties. We will be looking for relationships among morphology, particularly separation of double nuclei, the starburst age, the quasar black hole mass and accretion rate, that will lead to an understanding of the triggering activity and mutual evolution. This project will bring quantitative data and statistics to the previously fuzzy and anecdotal topic of the "AGN-starburst connection" and help test the idea that post-starburst quasars are an early evolutionary stage of normal quasars.
ACS/WFC/NIC3/WFPC2 10530
Probing Evolution And Reionization Spectroscopically {PEARS}
While imaging with HST has gone deep enough to probe the highest redshifts, e.g. the GOODS survey and the Ultra Deep Field, spectroscopic identifications have not kept up. We propose an ACS grism survey to get slitless spectra of all sources in a wide survey region {8 ACS fields} up to z =27.0 magnitude, and an ultradeep field in the HUDF reaching sources up to z =28 magnitude. The PEARS survey will: {1} Find and spectrocopically confirm all galaxies between z=4-7. {2} Probe the reionization epoch by robustly determining the luminosity function of galaxies and low luminosity AGNs at z = 4 – 6. With known redshifts, we can get a local measure of star formation and ionization rate in case reionization is inhomogeneous. {3} Study galaxy formation and evolution by finding galaxies in a contiguous redshift range between 4 < z < 7, and black hole evolution through a census of low-luminosity AGNs. {4} Get a robust census of galaxies with old stellar populations at 1 < z < 2.5, invaluable for checking consistency with heirarchical models of galaxy formation. Fitting these galaxies' spectra will yield age and metallicity estimates. {5} Study star-formation and galaxy assembly at its peak at 1< z < 2 by identifying emission lines in star-forming galaxies, old populations showing the 4000A break, and any combination of the two. {6} Constrain faint white dwarfs in the Galactic halo and thus measure their contribution to the dark matter halo. {7} Derive spectro-photometric redshifts by using the grism spectra along with broadband data. This will be the deepest unbiased spectroscopy yet, and will enhance the value of the multiwavelength data in UDF and the GOODS fields to the astronomical community. To this end we will deliver reduced spectra to the HST archives.
NIC1/NIC2/NIC3 8793
NICMOS Post-SAA calibration – CR Persistence Part 4
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.
NIC2 10620
Massive Star Formation and the Proper Motions of the OMC-1 Molecular Hydrogen Fingers
The Orion Molecular Cloud OMC-1 is by far the nearest region of massive star formation, and as such provides a laboratory for studying massive star formation with unprecedented detail. Using NICMOS, eight years ago our group discovered unique molecular hydrogen ‘fingers’ emanating from the IRc2 area. We propose new NICMOS imaging of the same region to compare with our earlier results. This will determine spatial motions to ~3 AU/year. Using the two data sets, we will: 1} bound the age range of the features and thus address whether all the molecular hydrogen features were produced in a single event – such as an explosion or a stellar merger – or in multiple events/steady outflow; 2} limit the location of the outflow source{s}, which remain to be identified despite sub-arcsecond imaging at thermal infrared wavelengths; and 3} characterize inhomogeneities on the 100 AU scale. Together these findings will significantly constrain how massive star formation proceeds in OMC-1. NICMOS achieves the highest quality, near-infrared images for diffuse objects in crowded regions. Because of the complexity of the OMC-1 region, and the difficulty in using Adaptive Optics to measure small position shifts for diffuse, low contrast objects, these high precision proper motion measurements require the stable PSF, high Strehl ratio, and low response in the PSF wings which HST/NICMOS uniquely provides.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS:
9986 – GSAcq (1,2,1) failed due to search radius limit exceeded on FGS1 @ 300/0913z
GSAcq (1,2,1) scheduled @ 300/09:08:18 failed due to search radius limit exceeded on FGS1. Received ESB “a05” Exceeded SRL.
OBAD 1 @ 300/08:40:52 = V1 -10.92, V2 -443.85, V3 -16.05, RSS 444.27
OBAD 2 @ 300/08:58:32 = V1 -18.45, V2 -15.73, V3 -10>92, RSS 26.60
Following MAP @ 300/09:15:38 = V1 15.83, V2 54.45, V3 20.14, RSS 60.18
9987 – GSAcq (1,2,1) failed due to search radius limit exceeded on FGS1 @ 300/1537z
GSacq(1,2,1) scheduled at 300/15:32:08 failed due to search radius limit exceeded on FGS 1. The OBADs showed errors of:
OBAD1 – V1= -842.94, V2= 4214.59, V3 = -1915.90 RSS= 4705.74
OBAD2 – V1= -57.97, V2= 27.22, V3= -51.87, RSS= 82.42
The map at 15:39:28 showed errors of: V1= 58.75, V2= 64.71, V3= 54.93, RSS= 103.23
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 10 9 300/1537z
(HSTAR 9987)
FGS
REacq 4 3 300/0913z
(HSTAR 9986)
OBAD with Maneuver 27 27
SIGNIFICANT EVENTS: (None)
