NASA Hubble Space Telescope Daily Report #4939
HUBBLE SPACE TELESCOPE DAILY REPORT #4939
Continuing to Collect World Class Science
PERIOD COVERED: 5am September 25 – 5am September 28, 2009 (DOY 268/09:00z-271/09:00z)
OBSERVATIONS SCHEDULED
NIC1/NIC2/NIC3 8795
NICMOS Post-SAA Calibration – CR Persistence Part 6
This is 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 ‘Use After’ 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 darks. 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.
NIC1/NIC2/NIC3 11947
Extended Dark Monitoring
This program takes a series of darks to obtain darks (including amplifier glow, dark current, and shading profiles) for all three cameras in the read-out sequences used in Cycle 17. A set of 12 orbits will be observed every two months for a total of 72 orbits for a 12 month Cycle 17. This is a continuation of Cycle 16 program 11330 scaled down by ~80%.
The first orbit (Visit A0) should be scheduled in the NICMOS SMOV after the DC Transfer Test (11406) and at least 36h before the Filter Wheel Test (11407). Data download using fast track.
The following 28 orbits (visit A1-N2) should be scheduled AFTER the SMOV Proposal 11407 (Filter Wheel Test). This is done in order to monitor the dark current following an adjustment of the NCS set-point. These visits should be executed until the final temperature is reached during SMOV.
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/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 11907
UVIS Cycle 17 Contamination Monitor
The UV throughput of WFC3 during Cycle 17 is monitored via weekly standard star observations in a subset of key filters covering 200-600nm and F606W, F814W as controls on the red end. The data will provide a measure of throughput levels as a function of time and wavelength, allowing for detection of the presence of possible contaminants.
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).
ACS/WFC3 11879
CCD Daily Monitor (Part 1)
This program comprises basic tests for measuring the read noise and dark current of the ACS WFC and for tracking the growth of hot pixels. The recorded frames are used to create bias and dark reference images for science data reduction and calibration. This program will be executed four days per week (Mon, Wed, Fri, Sun) for the duration of Cycle 17. To facilitate scheduling, this program is split into three proposals. This proposal covers 352 orbits (22 weeks) from 31 August 2009 to 31 January 2010.
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/CCD 11844
CCD Dark Monitor Part 1
The purpose of this proposal is to monitor the darks for the STIS CCD.
WFC3/ACS/IR 11600
Star Formation, Extinction, and Metallicity at 0.7 < z < 1.5: H-Alpha Fluxes and Sizes from a Grism Survey of GOODS-N The global star formation rate (SFR) is ~10x higher at z=1 than today. This could be due to drastically elevated SFR in some fraction of galaxies, such as mergers with central bursts, or a higher SFR across the board. Either means that the conditions in z=1 star forming galaxies could be quite different from local objects. The next step beyond measuring the global SFR is to determine the dependence of SFR, obscuration, metallicity, and size of the star-forming region on galaxy mass and redshift. However, SFR indicators at z=1 typically apply local calibrations for UV, [O II] and far-IR, and do not agree with each other on a galaxy-by-galaxy basis. Extinction, metallicity, and dust properties cause uncontrolled offsets in SFR calibrations. The great missing link is Balmer H-alpha, the most sensitive probe of SFR. We propose a slitless WFC3/G141 IR grism survey of GOODS-N, at 2 orbits/pointing. It will detect Ha+[N II] emission from 0.7< z<1.5, to L(Ha) = 1.7 x 10^41 erg/sec at z=1, measuring H-alpha fluxes and sizes for > 600 galaxies, and a small number of higher-redshift emitters. This will produce: an emission-line redshift survey unbiased by magnitude and color selection; star formation rates as a function of galaxy properties, e.g. stellar mass and morphology/mergers measured by ACS; comparisons of SFRs from H-alpha to UV and far-IR indicators; calibrations of line ratios of H-alpha to important nebular lines such as [O II] and H-beta, measuring variations in metallicity and extinction and their effect on SFR estimates; and the first measurement of scale lengths of the H-alpha emitting, star-forming region in a large sample of z~1 sources.
WFC3/UVIS 11565
A Search for Astrometric Companions to Very Low-Mass, Population II Stars
We propose to carry out a Snapshot search for astrometric companions in a subsample of very low-mass, halo subdwarfs identified within 120 parsecs of the Sun. These ultra-cool M subdwarfs are local representatives of the lowest-mass H burning objects from the Galactic Population II. The expected 3-4 astrometric doubles that will be discovered will be invaluable in that they will be the first systems from which gravitational masses of metal-poor stars at the bottom of the main sequence can be directly measured.
COS/NUV/FUV/WFC3/UVIS/IR 11534
COS-GTO: Atmosphere of a Transiting Planet
COS observations of a transiting planet at different orbital locations will be useful in identifying the chemical content, size, temperature, and flows in the atmosphere of a transiting planet.
COS/FUV 11482
FUV Detector Dark
The purpose of this proposal is to measure the FUV detector dark rate by taking long science exposures with no light on the detector. The detector dark rate and spatial distribution of counts will be compared to pre-launch data in order to verify the nominal operation of the detector, and for use in the CalCOS calibration pipeline. Variations of count rate as a function of orbital position will be analyzed to find dependence of dark rate on proximity to the SAA.
This is SMOV Activity COS-24.
COS/NUV 11481
COS NUV High S/N Verification
The purpose of this proposal is to collect data at several central wavelengths for each NUV grating in Time-Tag mode, using multiple FP-POS positions, in order to verify that high signal-to-noise spectra can be obtained. All spectra will have enough counts to permit standard reduction techniques to be used to obtain spectra with a signal-to-noise ratio of at least 30. Very high signal-to-noise spectra will also be obtained in some medium resolution modes in order to demonstrate that a signal-to-noise ratio of at least 100 is possible.
COS/NUV 11477
COS NUV External Spectroscopic Performance – Part 2
The goal of this activity is to verify the spatial resolution of COS in the NUV and to characterize the interdependence of the spatial and spectral resolution of the instrument in that wavelength band. By stepping the source along the cross-dispersion direction out to the edge of the PSA, we will be able to quantify the variation of the spatial profile of the source with off-axis position, both by measuring the shape and width of the profile and by measuring the amount of flux transmitted through the aperture as the source is stepped past the edge of the aperture. Aside from measuring the spatial resolution of COS spectra, this study will be particularly useful for characterizing the contamination of sources near the targeted object in crowded stellar fields.
This test is ideally performed with a spatially unresolved point source with an emission line spectrum. Our observations with the PSA will target the Galactic symbiotic stars AG Draconis and He 2-38.
Our observations with the BOA will target another Galactic symbiotic star, RR Telescopii. This object exhibits similar line widths to AG Dra, but includes a rich array of Fe II emission lines as well.
WFC3/ACS/IR 11359
Panchromatic WFC3 Survey of Galaxies at Intermediate z: Early Release Science Program for Wide Field Camera 3
The unique panchromatic capabilities of WFC3 will be used to survey the structure and evolution of galaxies at the peak of the galaxy assembly epoch. Deep ultraviolet and near-IR imaging and slitless spectroscopy of existing deep multi-color ACS fields will be used to gauge star-formation and the growth of stellar mass as a function of morphology, structure and surrounding density in the critical epoch 1 < z < 4. Images in the F225W, F275W, and F336W filters will identify galaxies at z < 1.5 from their UV continuum breaks, and provide star-formation indicators tied directly to both local and z > 3 populations. Deep near-IR (F125W and F160W) images will probe the stellar mass function well below 10^9 Msun for mass-complete samples. Lastly, the WFC3 slitless UV and near-IR grisms will be used to measure redshifts and star-formation rates from H- alpha and rest-frame UV continuum slope. This WFC3 ERS program will survey one 4 x 2 mosaic for a total area of 50 square arcminutes to 5-sigma depths of m_AB = 27 in most filters from the mid-UV through the near-IR.
This multicolor high spatial resolution data set will allow the user to gauge the growth of galaxies through star-formation and merging. High precision photometric and low- resolution spectroscopic redshifts will allow accurate determinations of the faint-end of the luminosity and mass functions, and will shed light on merging and tidal disruption of stellar and gaseous disks. The WFC3 images will also allow detailed studies of the internal structure of galaxies, and the distribution of young and old stellar populations. This program will demonstrate the unique power of WFC3 by applying its many diverse modes and full panchromatic capability to a forefront problem in astrophysics.
WFC3/ACS/IR 11142
Revealing the Physical Nature of Infrared Luminous Galaxies at 0.3
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS:
12023 – REAcq(1,2,1) scheduled at 269/12:28:32 was observed to have succeeded. HST was guiding under two FGSs.There were no FGS indication(s) flag. One 486 ESB message “a0e” was received, indicating that “FGS Sequential Attitude Update failed because V1 error was too large to correct” (QDVEFGS1 mnemonic did not flag OOL at AOS).
The FGS-1 achieved initial FL-DV at 269/12:30:30, then returned to SSM Control at 269/12:31:18, then finally achieved FL-DV at 269/12:31:45.
The secondary FGS-2 achieved initial FL-DV at 269/12:31:01, then returned to SSM Control at 269/12:31:18, then finally achieved FL-DV at 269/12:32:23. There were no FGS indication(s) flag posted.
Observations possibly affected: COS 3 – 7, Proposal ID# 11481
COMPLETED OPS REQUEST: (None)
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSAcq 22 22
FGS REAcq 26 26
OBAD with Maneuver 14 14
SIGNIFICANT EVENTS: (None)
