Status Report

NASA Hubble Space Telescope Daily Report #4990

By SpaceRef Editor
December 22, 2009
Filed under , ,

PERIOD COVERED: 5am December 10 – 5am December 11, 2009 (DOY 344/10:00z-345/10:00z)


ACS/WFC3 11593

Dynamical Masses of the Coolest Brown Dwarfs

T dwarfs are excellent laboratories to study the evolution and the atmospheric physics of both brown dwarfs and extrasolar planets. To date, only a single T dwarf binary has a dynamical mass determination, and more are sorely needed. The prospects of measuring more dynamical masses over the next decade are limited to 6 known short- period T dwarf binaries. We propose here to obtain Long-Term HST/ACS monitoring for the 3 of the 6 binaries which cannot be resolved with AO from the ground. Upon completion, our program will substantially increase the number of T dwarf dynamical mass measurements and thereby provide key benchmarks for testing theoretical models of ultracool objects.

COS/FUV 12022

The Chemical Composition of AGN Outflows

We propose a simultaneous Chandra LETGS – HST/COS observation of the bright Seyfert 1 galaxy Mrk 509, within half a year from an approved large XMM-Newton monitoring campaign. Combining 180 ks LETGS time and 10 orbits of COS time with the XMM-Newton RGS spectrum, we will obtain accurate abundances of C, N, O, Ne, Si, S, and Fe over a broad range of ionization parameter. This allows us to determine directly the contributions from various supernova types and intermediate mass stars to the chemical enrichment processes in galaxy cores. It also will reveal directly the chemical composition of the outflow that enriches the surrounding diffuse medium. Our team has successfully executed a similar abundances campaign on Mrk 279.


The LMC as a QSO Absorption Line System

We propose to obtain high resolution, high signal-to-noise observations of QSOs behind the Large Magellanic Clouds. These QSOs are situated beyond the star forming disk of the galaxy, giving us the opportunity to study the distribution of metals and energy in regions lacking significant star formation. In particular, we will derive the metallicities and study the ionization characteristics of LMC gas at impact parameters 3-17 kpc. We will compare our results with high-z QSO absorption line systems.

NIC2 11166

The Mass-dependent Evolution of the Black Hole-Bulge Relations

In the local universe, the masses of giant black holes are correlated with the luminosities, masses and velocity dispersions of their host galaxy bulges. This indicates a surprisingly close connection between the evolution of galactic nuclei (on parsec scales) and of stars on kpc scales. A key observational test of proposed explanations for these correlations is to measure how they have evolved over cosmic time. Our ACS imaging of 20 Seyfert 1 galaxies at z=0.37 showed them to have smaller bulges (by a factor of 3) for a given central black hole mass than is found in galaxies in the present-day universe. However, since all our sample galaxies had black hole masses in the range 10^8.0–8.5 Msun, we could only measure the OFFSET in black hole mass to bulge luminosity ratios from the present epoch. By extending this study to black hole masses another factor of 10 lower, we propose to determine the full CORRELATION of black hole mass with host galaxy properties at a lookback time of 4 Gyrs and to test mass-dependency of the evolution. We have selected 14 Seyfert galaxies from SDSS DR5 whose narrow Hbeta emission lines (and estimated nuclear luminosities) imply that they have black hole masses around 10^7 Msuns. We will soon complete our Keck spectroscopic measures of their bulge velocity dispersions. We need a 1-orbit NICMOS image of each galaxy to separate its nonstellar luminosity from its bulge and disk. This will allow us to make the first determination of the full black hole/bulge relations at z=0.37 (e.g. M-L and M-sigma), as well as a test of whether active galaxies obey the Fundamental Plane relation at that epoch.

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.

WFC3/IR 11712

Calibration of Surface Brightness Fluctuations for WFC3/IR

We aim to characterize galaxy surface brightness fluctuations (SBF), and calibrate the SBF distance method, in the F110W and F160W filters of the Wide Field Camera 3 IR channel. Because of the very high throughput of F110W and the good match of F160W to the standard H band, we anticipate that both of these filters will be popular choices for galaxy observations with WFC3/IR. The SBF signal is typically an order of magnitude brighter in the near-IR than in the optical, and the characteristics (sensitivity, FOV, cosmetics) of the WFC3/IR channel will be enormously more efficient for SBF measurements than previously available near-IR cameras. As a result, our proposed SBF calibration will allow accurate distance derivation whenever an early-type or bulge- dominated galaxy is observed out to a distance of 150 Mpc or more (i.e., out to the Hubble flow) in the calibrated passbands. For individual galaxy observations, an accurate distance is useful for establishing absolute luminosities, black hole masses, linear sizes, etc. Eventually, once a large number of galaxies have been observed across the sky with WFC3/IR, this SBF calibration will enable accurate mapping of the total mass density distribution in the local universe using the data available in the HST archive. The proposed observations will have additional important scientific value; in particular, we highlight their usefulness for understanding the nature of multimodal globular cluster color distributions in giant elliptical galaxies.

WFC3/IR 11928

WFC3/IR Low-Frequency Flat and Geometric Distortion

Multiple observations of globular cluster Omega Cen at multiple infrared wavelengths of IR detector will be used to derive filter dependency of low-frequency sensitivity (L_flat fields) across of IR detector and its time variation. Additionally, the same data will be also used to derive filter-dependant geometric distortion of the detector and its time- dependency.

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/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 11909

UVIS Hot Pixel Anneal

The on-orbit radiation environment of WFC3 will continually generate new hot pixels. This proposal performs the procedure required for repairing those hot pixels in the UVIS CCDs. During an anneal, the two-stage thermo-electric cooler (TEC) is turned off and the four-stage TEC is used as a heater to bring the UVIS CCDs up to ~20 deg. C. As a result of the CCD warmup, a majority of the hot pixels will be fixed; previous instruments such as WFPC2 and ACS have seen repair rates of about 80%. Internal UVIS exposures are taken before and after each anneal, to allow an assessment of the procedure’s effectiveness in WFC3, provide a check of bias, global dark current, and hot pixel levels, as well as support hysteresis (bowtie) monitoring and CDBS reference file generation. One IR dark is taken after each anneal, to provide a check of the IR detector.


Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)

HSTARS: (None)



FGS GSAcq 7 7
FGS REAcq 8 8
OBAD with Maneuver 6 6


SpaceRef staff editor.