Status Report

NASA Hubble Space Telescope Daily Report #5119

By SpaceRef Editor
June 21, 2010
Filed under , ,


Continuing to Collect World Class Science

PERIOD COVERED: 5am June 16 – 5am June 17, 2010 (DOY 167/09:00z-168/09:00z)


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


For DOY 159

12305 – GSAcq(1,2,1) at 159/4:46:39z required five attempts to achieve CT-DV on FGS1. The acquisition was successful.

Observations possibly affected WFC3 43 & 44, ACS 10-13, Proposal ID#11613.

For DOY 163

12306 – GSAcq(1,2,1) at 163/13:05z initially failed FL walk down with scan step limit exceeded on FGS1. The second attempt was successful.

Observations possibly affected COS 93-96, Proposal ID#11997; WFC 31 & 61, Proposal ID#11929.



FGS GSAcq 9 9
FGS REAcq 6 6
OBAD with Maneuver 4 4



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.

COS/NUV 11705

Physical Properties of Quasar Outflows: From BALs to Mini-BALs

Accretion disk outflows are important components of quasar environments. They might play a major role in facilitating accretion, regulating star formation in the host galaxies and distributing metals to the surrounding gas. They reveal themselves most conspicuously via broad absorption lines (BALs), but they appear even more frequently in other guises such as the weaker and narrower “mini-BALs.” How are these diverse outflow features related? Are mini-BALs really just “mini” versions of the BALs, or do they represent a fundamentally different type of outflow, with different degrees of ionization, column densities, mass loss rates, physical origins, etc.?

We propose HST-COS spectroscopy to make the first quantitative assessment of the outflow physical conditions across the full range of weak/narrow mini-BALs to strong/broad BALs. Our strategy is to measure key diagnostic lines (SVI, OVI, CIII, SIV, PV, etc.) at 930A – 1130A (rest- frame) in a sample of 7 outflow quasars with known mini-BALs through weak BALs. We will then 1) combine the COS data with ground-based spectra of the same quasars to include more lines (CIV, SiIV) at longer wavelengths, and 2) include in our analysis a nearly identical UV/optical dataset obtained previously for a sample of quasars with strong BALs. Our study of this combined dataset will be an essential next step toward a more global understanding of quasar outflows.


The Structure and Dynamics of Virgo’s Multi-Phase Intracluster Medium

The dynamical flows of the intracluster medium (ICM) are largely unknown. We propose to map the spatial and kinematic distribution of the warm ICM of the nearby Virgo cluster using the Cosmic Origins Spectrograph. 15 sightlines at a range of impact parameters within the virial radius of the cluster (0.2 – 1.7 Mpc) will be probed for Lyman-alpha absorption and the data compared to blind HI, dust and x-ray surveys to create a multi-phase map of the cluster’s ICM. Absorption line sightlines are commonly 40-100 kpc from a galaxy, allowing the flow of baryons between galaxies and the ICM to be assessed. The velocity distribution of the absorbers will be directly compared to simulations and used to constrain the turbulent motions of the ICM. This proposal will result in the first map of a cluster’s warm ICM and provide important tests for our theoretical understanding of cluster formation and the treatment of gas cooling in cosmological simulations.


Detailed Analysis of Carbon Atmosphere White Dwarfs

We propose to obtain UV spectra for the newly discovered white dwarf stars with a carbon- dominated atmosphere. Model calculations show that these stars emit most of their light in the UV part of the electromagnetic spectrum and that an accurate determination of the flux in this region is crucial for an accurate determination of the atmospheric parameters. It will also provide a unique opportunity to test the atomic data and broadening theory in stellar conditions never met before. This will play a primordial role in our path to understand the origin of these objects as well to obtain a better understanding of the evolution of stars in general. The principal objective we hope to achieve with these observations are 1) obtain accurate surface gravity/mass for these stars, 2) constrain/determine the abundance of other elements (O, He, Mg, Ne etc.), especially oxygen, 3) verify the accuracy of the various theoretical atomic data used in the model calculations, 4) understand the origin and evolution of carbon atmosphere white dwarfs, in particular whether progenitor stars as massive as 10.5 solar masses can produce white dwarfs, rather than supernovae. We propose to observe 5 objects chosen carefully to cover the range of observed properties among carbon atmosphere white dwarfs (effective temperature, surface gravity, abundance of hydrogen/helium and magnetic field).


UV Spectroscopy of Local Lyman Break Galaxy Analogs: New Clues to Galaxy Formation in the Early Universe

Much of our information about galaxy evolution and the interaction between galaxies and the IGM at high-z has been provided by the Lyman Break Galaxies (LBGs). However, it is difficult to investigate these faint and distant objects in detail. To address this, we have used the GALEX All-Sky Imaging Survey and the SDSS to identify for the first time a rare population of low- redshift galaxies with properties remarkably similar to the high-redshift LBGs. These local “Lyman Break Analogs” (LBAs) resemble LBGs in terms of morphology, size, UV luminosity, star formation rate, UV surface brightness, stellar mass, velocity dispersion, metallicity, and dust content. We are assembling a wide range of data on these objects with the goal of using them as local laboratories for better understanding the relevant astrophysical processes in LBGs. These data include HST imaging (95 orbits in Cy15 and 16), Spitzer photometry and spectroscopy, Chandra and XMM X-ray imaging and spectroscopy, and near-IR integral field spectroscopy (VLT, Keck, and Gemini). In this proposal we are requesting the most important missing puzzle piece: far-UV spectra with a signal-to-noise and spectral resolution significantly better than available for typical LBGs. We will use these spectra to study the LBA’s galactic winds, probe the processes that regulate the escape of Ly-a and Lyman continuum radiation, determine chemical abundances for the stars and gas, and constrain the form of the high-end of the Initial Mass Function. Adding these new COS data will give us vital information about these extraordinary sites of star formation in the local universe. In so-doing it will also shed new light on the processes that led to the formation of stars, the building of galaxies, and the enrichment and heating of the IGM in the early 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.

STIS/CCD 11849

STIS CCD Hot Pixel Annealing

This purpose of this activity is to repair radiation induced hot pixel damage to the STIS CCD by warming the CCD to the ambient instrument temperature and annealing radiation-damaged pixels.

Radiation damage creates hot pixels in the STIS CCD Detector. Many of these hot pixels can be repaired by warming the CCD from its normal operating temperature near -83 deg. C to the ambient instrument temperature (~ +5 deg. C) for several hours. The number of hot pixels repaired is a function of annealing temperature. The effectiveness of the CCD hot pixel annealing process is assessed by measuring the dark current behavior before and after annealing and by searching for any window contamination effects.

WFC3/ACS/IR 11731

Studying Cepheid Systematics in M81: H-Band Observations

The local value of the Hubble Constant remains one of the most important constraints in cosmology, but improving on the 10% accuracy of the HST Key Project is challenging. No improvements will be convincing until the metallicity dependence is well constrained and blending effects are fully understood. M81 and its dwarf companion Holmberg IX are superb laboratories for studying Cepheid systematics because they contain large numbers of bright Cepheids with a good spread in metallicity lying at a common, relatively close distance. We have identified 180 126 to the close of the galaxy- building era at z~0.3.Pure parallel observations with the grisms have proven to be efficient for identifying line emission from galaxies across a broad range of redshifts. The G102 grism on WFC3 was designed to extend this capability to search for Ly-alpha emission from the first galaxies. Using up to 250 orbits of pure parallel WFC3 spectroscopy, we will observe about 40 deep (4-5 orbit) fields with the combination of G102 and G141, and about 20 shallow (2-3 orbit) fields with G141 alone.

Our primary science goals at the highest redshifts are: (1) Detect Lya in ~100 galaxies with z>5.6 and measure the evolution of the Lya luminosity function, independent of of cosmic variance; 2) Determine the connection between emission line selected and continuum-break selected galaxies at these high redshifts, and 3) Search for the proposed signature of neutral hydrogen absorption at re-ionization. At intermediate redshifts we will (4) Detect more than 1000 galaxies in Halpha at 0.5

SpaceRef staff editor.