NASA Hubble Space Telescope Daily Report #4947

HUBBLE SPACE TELESCOPE DAILY REPORT #4947

Continuing to Collect World Class Science

PERIOD COVERED: 5am October 7 – 5am October 8, 2009 (DOY 280/09:00z-281/09:00z)

OBSERVATIONS SCHEDULED

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.

COS/FUV/ACS/WFC/WFC3/UV/ 11632 NUV The Gaseous Corona of M31

We propose to obtain ultraviolet spectroscopy of the halo of M31, to probe for a hot corona on scales of 30-40 pc from the galaxy. We seek to obtain absorption line spectra of O I, Mg II, Si II, C IV, and Si IV toward bright QSOs located behind the galaxy. One of the sightlines falls on the projection of Ibata’s giant stream. All background sources have been vetted with GALEX photometry and are therefore bright enough for observation. If hot gas is detected with this initial study, we will endeavor to use a grid of background sources to map the structure and kinematics of this gas in detail. M31 is the nearest major spiral galaxy for which such a study can be undertaken, other than our own Milky Way. Recent studies find a substantial population of HI high velocity clouds at distances form M31 of up to 50 kpc, and there is well documented evidence of disrupted satellites and tidal streams. These observations will shed light on the hot gaseous halo of M31, but also will help in interpreting QSO sightlines at high redshift.

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.

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.

NIC2/WFC3/IR 11548

Infrared Imaging of Protostars in the Orion A Cloud: The Role of Environment in Star Formation

We propose NICMOS and WFC3/IR observations of a sample of 252 protostars identified in the Orion A cloud with the Spitzer Space Telescope. These observations will image the scattered light escaping the protostellar envelopes, providing information on the shapes of outflow cavities, the inclinations of the protostars, and the overall morphologies of the envelopes. In addition, we ask for Spitzer time to obtain 55-95 micron spectra of 75 of the protostars. Combining these new data with existing 3.6 to 70 micron photometry and forthcoming 5-40 micron spectra measured with the Spitzer Space Telescope, we will determine the physical properties of the protostars such as envelope density, luminosity, infall rate, and outflow cavity opening angle. By examining how these properties vary with stellar density (i.e. clusters vs. groups vs. isolation) and the properties of the surrounding molecular cloud; we can directly measure how the surrounding environment influences protostellar evolution, and consequently, the formation of stars and planetary systems. Ultimately, this data will guide the development of a theory of protostellar evolution.

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/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/IR 11618

WFC3 Observations of VeLLOs and the Youngest Star Forming Environments

The Cores-to-Disks Spitzer Legacy team has discovered a number of extremely low luminosity sources embedded deep within nearby (< 300 pc) cores previously thought to be starless. With substellar masses, these low luminosity sources represent either the youngest low-mass protostars yet detected or the first embedded brown dwarfs. In either case, they represent a new observed class of sources referred to as VeLLOs (Very Low Luminosity Objects). We propose WFC3 F160W observations of a small sample of these sources, to be combined with deep ground-based observations at Ks, to address a broad set of issues concerning VeLLOs and the environments within which they are forming. First, the morphology of their outflow cavities will be traced, yielding estimates of the inclinations and opening angles of the cavities and the evolutionary stages of the VeLLOs. Second, our observations will reveal background stars seen through the densest regions of cores harboring these VeLLOs. The color-excesses of the background stars will yield the highest angular resolution extinction maps necessary to directly probe the inner density structure of these cores, found very soon after the onset of collapse, which would constrain the initial conditions of collapse within these isolated environments. In addition, we will construct similar maps of the dense pre-protostellar core L694-2 and the protostellar core B335. These maps will provide a snapshot of the evolution of the inner density structure of a core prior to low-mass star formation and soon thereafter, for comparison with the inner density structure of cores that have formed VeLLOs. Finally, these extinction maps will enable us to determine the core "centers", or positions of peak column densities. Comparison of these centers with the positions of the VeLLOs may yield insight regarding potential differences between the formation of low-mass stars and brown dwarfs. 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/IR 11664 The WFC3 Galactic Bulge Treasury Program: Populations, Formation History, and Planets Exploiting the full power of the Wide Field Camera 3 (WFC3), we propose deep panchromatic imaging of four fields in the Galactic bulge. These data will enable a sensitive dissection of its stellar populations, using a new set of reddening-free photometric indices we have constructed from broad-band filters across UV, optical, and near-IR wavelengths. These indices will provide accurate temperatures and metallicities for hundreds of thousands of individual bulge stars. Proper motions of these stars derived from multi-epoch observations will allow separation of pure bulge samples from foreground disk contamination. Our catalogs of proper motions and panchromatic photometry will support a wide range of bulge studies. Using these photometric and astrometric tools, we will reconstruct the detailed star-formation history as a function of position within the bulge, and thus differentiate between rapid- and extended-formation scenarios. We will also measure the dependence of the stellar mass function on metallicity, revealing how the characteristic mass of star formation varies with chemistry. Our sample of bulge stars with accurate metallicities will include 12 candidate hosts of extrasolar planets. Planet frequency is correlated with metallicity in the solar neighborhood; our measurements will extend this knowledge to a remote environment with a very distinct chemistry. Our proposal also includes observations of six well-studied globular and open star clusters; these observations will serve to calibrate our photometric indices, provide empirical population templates, and transform the theoretical isochrone libraries into the WFC3 filter system. Besides enabling our own program, these products will provide powerful new tools for a host of other stellar-population investigations with HST/WFC3. We will deliver all of the products from this Treasury Program to the community in a timely fashion. 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). FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTARS: 12038 – GSAcq(2,1,1) scheduled at 280/21:48:22 – 21:56:12 and REAcq(2,1,1) scheduled at 280/23:25:27, at 281/01:01:57, at 281/02:37:08 and at 281/04:12:59 all resulted in fine lock backup (2,0,2) using FGS-2 due to Scan Step Limit Exceeded on FGS-1. Observations possibly affected: WFC3 87-100 Proposal ID# 11664. STIS 23 Proposal ID# 11844. COMPLETED OPS REQUEST: (None) COMPLETED OPS NOTES: (None)

                        SCHEDULED      SUCCESSFUL

FGS GSAcq               06                  06

FGS REAcq               10                  10

OBAD with Maneuver      05                  05

SIGNIFICANT EVENTS: (None)