NASA Hubble Space Telescope Daily Report #4955
HUBBLE SPACE TELESCOPE DAILY REPORT #4955
Continuing to Collect World Class Science
PERIOD COVERED: 5am October 20 – 5am October 21, 2009 (DOY293/09:00z-294/09:00z)
OBSERVATIONS SCHEDULED
FGS 11785
Trigonometric Calibration of the Distance Scale for Classical Novae
The distance scale for classical novae is important for understanding the stellar physics of their thermonuclear runaways, their contribution to Galactic nucleosynthesis, and their use as extragalactic standard candles. Although it is known that there is a relationship between their absolute magnitudes at maximum light and their subsequent rates of decline–the well-known maximum-magnitude rate-of-decline (MMRD) relation–it is difficult to set the zero-point for the MMRD because of the very uncertain distances of Galactic novae.
We propose to measure precise trigonometric parallaxes for the quiescent remnants of the four nearest classical novae. We will use the Fine Guidance Sensors, which are proven to be capable of measuring parallaxes with errors of ~0.2 mas, well below what is possible from the ground.
NIC 11417
NICMOS Detector Read noise and Dark Current
The NICMOS detector characteristics will be monitored during the entire extent of the SMOV4 through a set of dark exposures. This will also allow a determination of the detector temperature from bias measurements. The data should be obtained in SAA-free orbits, approximately every 24 hours. In addition, the detector read noise and the detector shading profiles will be measured once a week.
NIC1/NIC2/NIC3 11820
NICMOS Post-SAA Calibration – CR Persistence Part 7
Internals for CR persistence
NIC2 11148
High Contrast Imaging of Dusty White Dwarfs
For the past 18 years, only one white dwarf with a circumstellar dust disk was known to exist. In the last two years, six new disks have been discovered. Since all material inwards of a few AU should be scoured clean during post main sequence evolution, the primary explanation is the presence of a planetary system that is perturbing relic planetesimals into the tidal disruption radius of the white dwarf. Dusty disks around white dwarfs should be markers for planets and we propose to use high contrast imaging to search for faint companions down to 6 M_$J$ that may be feeding the disks. White dwarfs are uniquely suited for planet searches, where the planet/white dwarf contrast is less than for main sequence stars.
STIS/CCD 11844
CCD Dark Monitor Part 1
The purpose of this proposal is to monitor the darks for the STIS CCD.
STIS/CCD 11846
CCD Bias Monitor-Part 1
The purpose of this proposal is to monitor the bias in the 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1, and 1×1 at gain = 4, to build up high-S/N superbiases and track the evolution of hot columns.
STIS/MA1/MA2 11857
STIS Cycle 17 MAMA Dark Monitor
This proposal monitors the behavior of the dark current in each of the MAMA detectors.
The basic monitor takes two 1380s ACCUM darks each week with each detector. However, starting Oct 5, pairs are only included for weeks that the LRP has external MAMA observations planned. The weekly pairs of exposures for each detector are linked so that they are taken at opposite ends of the same SAA free interval. This pairing of exposures will make it easier to separate long and short term temporal variability from temperature dependent changes.
For both detectors, additional blocks of exposures are taken once every six months. These are groups of five 1314s FUV-MAMA Time-Tag darks or five 3x315s NUV ACCUM darks distributed over a single SAA-free interval. This will give more information on the brightness of the FUV MAMA dark current as a function of the amount of time that the HV has been on, and for the NUV MAMA will give a better measure of the short term temperature dependence.
WFC3/ACS/UVIS 11360
Star Formation in Nearby Galaxies
Star formation is a fundamental astrophysical process; it controls phenomena ranging from the evolution of galaxies and nucleosynthesis to the origins of planetary systems and abodes for life. The WFC3, optimized at both UV and IR wavelengths and equipped with an extensive array of narrow-band filters, brings unique capabilities to this area of study. The WFC3 Scientific Oversight Committee (SOC) proposes an integrated program on star formation in the nearby universe which will fully exploit these new abilities. Our targets range from the well-resolved R136 in 30 Dor in the LMC (the nearest super star cluster) and M82 (the nearest starbursting galaxy) to about half a dozen other nearby galaxies that sample a wide range of star-formation rates and environments. Our program consists of broad band multiwavelength imaging over the entire range from the UV to the near-IR, aimed at studying the ages and metallicities of stellar populations, revealing young stars that are still hidden by dust at optical wavelengths, and showing the integrated properties of star clusters. Narrow-band imaging of the same environments will allow us to measure star-formation rates, gas pressure, chemical abundances, extinction, and shock morphologies. The primary scientific issues to be addressed are: (1) What triggers star formation? (2) How do the properties of star-forming regions vary among different types of galaxies and environments of different gas densities and compositions? (3) How do these different environments affect the history of star formation? (4) Is the stellar initial mass function universal or determined by local conditions?
WFC3/IR 11108
Near Infrared Observations of a Sample of z~6.5-6.7 Galaxies
The majority of the most distant galaxies discovered to date have been found by strong Lyman alpha emission at red optical wavelengths. An accurate estimate of the star formation rates for these objects requires a measurement of the line-free UV continuum, which must be taken at infrared wavelengths. Here we propose to obtain imaging with WFC3 in the F140W filter for a sample of 9 Lyman alpha galaxies with redshifts z~6.5 up to z=6.740 from a complete, flux- limited widefield narrowband and multi-color survey conducted on the 8-m Subaru Telescope. This program will investigate galaxy morphologies and star formation for a uniform sample of the highest redshift galaxies now known.
WFC3/IR/S/C 11929
IR Dark Current Monitor
Analyses of ground test data showed that dark current signals are more reliably removed from science data using darks taken with the same exposure sequences as the science data, than with a single dark current image scaled by desired exposure time. Therefore, dark current images must be collected using all sample sequences that will be used in science observations. These observations will be used to monitor changes in the dark current of the WFC3-IR channel on a day-to-day basis, and to build calibration dark current ramps for each of the sample sequences to be used by GOs in Cycle 17. For each sample sequence/array size combination, a median ramp will be created and delivered to the calibration database system (CDBS).
WFC3/UV/ACS/WFC 11688
Exploring the Bottom End of the White Dwarf Cooling Sequence in the Open Cluster NGC6819
The recent discovery by our group of an unexpectedly bright end of the white-dwarf (WD) luminosity function (LF) of the metal-rich, old open cluster NGC 6791 casts serious doubts on our understanding of the physical process which rules the formation and the cooling of WDs. It is clear at this point that the theory badly needs more observations. Here we propose WFC3/UVIS and ACS/WFC HST observations reaching the bottom end of the WD LF, for the first time in a solar-metallicity, 2.5-Gyr-old, populous open cluster: NGC 6819.
WFC3/UVIS 11657
The Population of Compact Planetary Nebulae in the Galactic Disk
We propose to secure narrow- and broad-band images of compact planetary nebulae (PNe) in the Galactic Disk to study the missing link of the early phases of post-AGB evolution. Ejected AGB envelopes become PNe when the gas is ionized. PNe expand, and, when large enough, can be studied in detail from the ground. In the interim, only the HST capabilities can resolve their size, morphology, and central stars. Our proposed observations will be the basis for a systematic study of the onset of morphology. Dust properties of the proposed targets will be available through approved Spitzer/IRS spectra, and so will the abundances of the alpha- elements. We will be able thus to explore the interconnection of morphology, dust grains, stellar evolution, and populations. The target selection is suitable to explore the nebular and stellar properties across the galactic disk, and to set constraints on the galactic evolutionary models through the analysis of metallicity and population gradients.
WFC3/UVIS 11905
WFC3 UVIS CCD Daily Monitor
The behavior of the WFC3 UVIS CCD will be monitored daily with a set of full-frame, four-amp bias and dark frames. A smaller set of 2Kx4K subarray biases are acquired at less frequent intervals throughout the cycle to support subarray science observations. The internals from this proposal, along with those from the anneal procedure (Proposal 11909), will be used to generate the necessary superbias and superdark reference files for the calibration pipeline (CDBS).
WFC3/UVIS 11908
Cycle 17: UVIS Bowtie Monitor
Ground testing revealed an intermittent hysteresis type effect in the UVIS detector (both CCDs) at the level of ~1%, lasting hours to days. Initially found via an unexpected bowtie-shaped feature in flatfield ratios, subsequent lab tests on similar e2v devices have since shown that it is also present as simply an overall offset across the entire CCD, i.e., a QE offset without any discernable pattern. These lab tests have further revealed that overexposing the detector to count levels several times full well fills the traps and effectively neutralizes the bowtie. Each visit in this proposal acquires a set of three 3×3 binned internal flatfields: the first unsaturated image will be used to detect any bowtie, the second, highly exposed image will neutralize the bowtie if it is present, and the final image will allow for verification that the bowtie is gone.
WFC3/UVIS 11925
UVIS Detector Linearity
This proposal will measure the in-orbit linear response of the UVIS detectors by sampling over the response curve through saturation. This program uses exposures of a standard star field (NGC 1850) to measure the absolute values, and exposures of a tungsten lamp to measure positional variations in response, following a similar procedure as the ground tests.
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 11 11
FGS REAcq 07 07
OBAD with Maneuver 07 07
SIGNIFICANT EVENTS: (None)
