NASA Hubble Space Telescope Daily Report #5055
HUBBLE SPACE TELESCOPE DAILY REPORT #5055
PERIOD COVERED: 5am March 17 – 5am March 18, 2010 (DOY 076/09:00z-077/09:00z)
OBSERVATIONS SCHEDULED
ACS/WFC 11995
CCD Daily Monitor (Part 2)
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 320 orbits (20 weeks) from 1 February 2010 to 20 June 2010.
ACS/WFC3 11882
CCD Hot Pixel Annealing
All the data for this program is acquired using internal targets (lamps) only, so all of the exposures should be taken during Earth occultation time (but not during SAA passages). This program emulates the ACS pre-flight ground calibration and post launch SMOV testing (program 8948), so that results from each epoch can be directly compared. Extended Pixel Edge Response (EPER) and First Pixel Response (FPR) data will be obtained over a range of signal levels for the Wide Field Channel (WFC). The High Resolution Channel (HRC) visits have been removed since it could not be repaired during SM4.
COS/NUV/FUV 11741
Probing Warm-Hot Intergalactic Gas at 0.5 < z < 1.3 with a Blind Survey for O VI, Ne VIII, Mg X, and Si XII Absorption Systems
Currently we can only account for half of the baryons (or less) expected to be found in the nearby universe based on D/H and CMB observations. This “missing baryons problem” is one of the highest-priority challenges in observational extragalatic astronomy. Cosmological simulations suggest that the baryons are hidden in low-density, shock-heated intergalactic gas in the log T = 5 – 7 range, but intensive UV and X-ray surveys using O VI, O VII, and O VIII absorption lines have not yet confirmed this prediction. We propose to use COS to carry out a sensitive survey for Ne VIII and Mg X absorption in the spectra of nine QSOs at z(QSO) > 0.89. For the three highest-redshift QSOs, we will also search for Si XII. This survey will provide more robust constraints on the quantity of baryons in warm-hot intergalactic gas at 0.5 < z < 1.3, and the data will provide rich constraints on the metal enrichment, physical conditions, and nature of a wide variety of QSO absorbers in addition to the warm-hot systems. By comparing the results to other surveys at lower redshifts (with STIS, FUSE, and from the COS GTO programs), the project will also enable the first study of how these absorbers evolve with redshift at z < 1. By combining the program with follow-up galaxy redshift surveys, we will also push the study of galaxy-absorber relationships to higher redshifts, with an emphasis on the distribution of the WHIM with respect to the large-scale matter distribution of the universe.
STIS/CC 11845
CCD Dark Monitor Part 2
Monitor the darks for the STIS CCD.
STIS/CC 11847
CCD Bias Monitor-Part 2
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.
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/ACS/UVIS 11613
GHOSTS: Stellar Outskirts of Massive Spiral Galaxies
We propose to continue our highly successful GHOSTS HST survey of the resolved stellar populations of nearby, massive disk galaxies using SNAPs. These observations provide star counts and color-magnitude diagrams 2-3 magnitudes below the tip of the Red Giant Branch of the outer disk and halo of each galaxy. We will measure the metallicity distribution functions and stellar density profiles from star counts down to very low average surface brightnesses, equivalent to ~32 V-mag per square arcsec.
This proposal will substantially improve our unique sampling of galaxy outskirts. Our targets cover a range in galaxy mass, luminosity, inclination, and morphology. As a function of these galaxy properties, this survey provides: – the most extensive, systematic measurement of radial light profiles and axial ratios of the diffuse stellar halos and outer disks of spiral galaxies; – a comprehensive analysis of halo metallicity distributions as function of galaxy type and position within the galaxy; – an unprecedented study of the stellar metallicity and age distribution in the outer disk regions where the disk truncations occur; – the first comparative study of globular clusters and their field stellar populations.
We will use these fossil records of the galaxy assembly process to test halo formation models within the hierarchical galaxy formation scheme.
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/IR 11644
A Dynamical-Compositional Survey of the Kuiper Belt: A New Window Into the Formation of the Outer Solar System
The eight planets overwhelmingly dominate the solar system by mass, but their small numbers, coupled with their stochastic pasts, make it impossible to construct a unique formation history from the dynamical or compositional characteristics of them alone. In contrast, the huge numbers of small bodies scattered throughout and even beyond the planets, while insignificant by mass, provide an almost unlimited number of probes of the statistical conditions, history, and interactions in the solar system. To date, attempts to understand the formation and evolution of the Kuiper Belt have largely been dynamical simulations where a hypothesized starting condition is evolved under the gravitational influence of the early giant planets and an attempt is made to reproduce the current observed populations. With little compositional information known for the real Kuiper Belt, the test particles in the simulation are free to have any formation location and history as long as they end at the correct point. Allowing compositional information to guide and constrain the formation, thermal, and collisional histories of these objects would add an entire new dimension to our understanding of the evolution of the outer solar system. While ground based compositional studies have hit their flux limits already with only a few objects sampled, we propose to exploit the new capabilities of WFC3 to perform the first ever large-scale dynamical-compositional study of Kuiper Belt Objects (KBOs) and their progeny to study the chemical, dynamical, and collisional history of the region of the giant planets. The sensitivity of the WFC3 observations will allow us to go up to two magnitudes deeper than our ground based studies, allowing us the capability of optimally selecting a target list for a large survey rather than simply taking the few objects that can be measured, as we have had to do to date. We have carefully constructed a sample of 120 objects which provides both overall breadth, for a general understanding of these objects, plus a large enough number of objects in the individual dynamical subclass to allow detailed comparison between and within these groups. These objects will likely define the core Kuiper Belt compositional sample for years to come. While we have many specific results anticipated to come from this survey, as with any project where the field is rich, our current knowledge level is low, and a new instrument suddenly appears which can exploit vastly larger segments of the population, the potential for discovery — both anticipated and not — is extraordinary.
WFC3/UVIS/IR 11702
Search for Very High-z Galaxies with WFC3 Pure Parallel
WFC3 will provide an unprecedented probe to the early universe beyond the current redshift frontier. Here we propose a pure parallel program using this new instrument to search for Lyman-break galaxies at 6.5
(1) We will use both the UVIS and the IR channels, and do not need to seek optical data from elsewhere.
(2) Our program will likely triple the size of the probable candidate samples at z~7 and z~8, and will complement other targeted programs aiming at the similar redshift range.
(3) Being a pure parallel program, our survey will only make very limited demand on the scarce HST resources. More importantly, as the pure parallel pointings will be at random sight-lines, our program will be least affected by the bias due to the large scale structure (“cosmic variance”).
(4) We aim at the most luminous LBG population, and will address the bright-end of the luminosity function at z~8 and z~7. We will constrain the value of L* in particular, which is critical for understanding the star formation process and the stellar mass assembly history in the first few hundred million years of the universe.
(5) The candidates from our survey, most of which will be the brightest ones that any surveys would be able to find, will have the best chance to be spectroscopically confirmed at the current 8–10m telescopes.
(6) We will also find a large number of extremely red, old galaxies at intermediate redshifts, and the fine spatial resolution offered by the WFC3 will enable us constrain their formation history based on the study of their morphology, and hence shed light on their connection to the very early galaxies in the universe.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS:
12222 – GSAcq(1,2,1) scheduled at 0676/15:09:28z – 15:16:59z failed to RGA Hold (gyro control) due to search radius limit exceeded on FGS-1.
Subsequent REAcq(1,2,1) at 076/16:38:43z failed to RGA Hold (gyro control) due to search radius limit exceeded on FGS-1.
Observations affected: WFC3 94 – 96 Proposal ID#11644.
HSTAR FOR DOY 071
12223 – GSAcq(1,2,1) at 071/09:26:46z required two attempts on FGS1 to successfully acquire the guide star and achieve FL-DV.
COMPLETED OPS REQUEST:
18825-0 – Clear GENSLEW Slot-10 for COS proposal 11639 @ 076/1830z
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSAcq 5 4
FGS REAcq 10 9
OBAD with Maneuver 3 2
SIGNIFICANT EVENTS: (None)
