Status Report

NASA Hubble Space Telescope Daily Report #4224

By SpaceRef Editor
October 23, 2006
Filed under , ,
NASA Hubble Space Telescope Daily Report #4224


Continuing to collect World Class Science

PERIOD COVERED: UT October 20,21,22, 2006 (DOY 293,294,295)


NIC1/NIC2/NIC3 8793

NICMOS Post-SAA calibration – CR Persistence Part 4

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 USEAFTER 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 DARKSs. 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 11063

NICMOS Focus Monitoring

This program is a version of the standard focus sweep used since cycle 7. It has been modified to go deeper and uses more narrow filters for improved focus determination. For Cycle14 a new source has been added in order to accomodate 2-gyro mode: the open cluster NGC1850. The old target, the open cluster NGC3603, will be used whenever available and the new target used to fill the periods when NGC3603 is not visible. Steps: a} Use refined target field positions as determined from cycle 7 calibrations b} Use MULTIACCUM sequences of sufficient dynamic range to account for defocus c} Do a 17-point focus sweep, +/- 8mm about the PAM mechanical zeropoint for each cameras 1 and 2, in 1.0mm steps. d} Use PAM X/Y tilt and OTA offset slew compensations refined from previous focus monitoring/optical alignment activities

WFPC2 11029

WFPC2 CYCLE 15 Intflat Linearity Check and Filter Rotation Anomaly Monitor

Intflat observations will be taken to provide a linearity check: the linearity test consists of a series of intflats in F555W, in each gain and each shutter. A combination of intflats, visflats, and earthflats will be used to check the repeatability of filter wheel motions. {Intflat sequences tied to decons, visits 1-18 in prop 10363, have been moved to the cycle 15 decon proposal xxxx for easier scheduling.} Note: long-exposure WFPC2 intflats must be scheduled during ACS anneals to prevent stray light from the WFPC2 lamps from contaminating long ACS external exposures.

FGS 10989

Astrometric Masses of Extrasolar Planets and Brown Dwarfs

We propose observations with HST/FGS to estimate the astrometric elements {perturbation orbit semi-major axis and inclination} of extra-solar planets orbiting six stars. These companions were originally detected by radial velocity techniques. We have demonstrated that FGS astrometry of even a short segment of reflex motion, when combined with extensive radial velocity information, can yield useful inclination information {McArthur et al. 2004}, allowing us to determine companion masses. Extrasolar planet masses assist in two ongoing research frontiers. First, they provide useful boundary conditions for models of planetary formation and evolution of planetary systems. Second, knowing that a star in fact has a plantary mass companion, increases the value of that system to future extrasolar planet observation missions such as SIM PlanetQuest, TPF, and GAIA.

NIC3/ACS/WFC 10921

Tangential Velocities of Objects in the Orion Nebula and Locating the Embedded Outflow Sources.

The Orion Nebula is arguably the Rosetta Stone for studying a very young star cluster and how the radiation and outflowing plasma from its stars interact with ambient material. It has been the subject of numerous HST imaging studies, which means that there is good opportunity for determining tangential velocities by obtaining second epoch images during Cycle 15, which may be the last cycle for which the WFPC2 is available. These velocities in the plane-of-the-sky will allow us to determine the patterns of outflow from micro-jets smaller than the Solar System to jet driven shocks more than a parsec from their sources. Combined with radial velocities, we’ll obtain spatial velocities, which are critical to determining where the embedded sources are located that produce the numerous HH objects coming from the Orion-S and BN-KL regions. We’ll also be able to determine the physics that is operating in the LL Ori type of outflows {where a bipolar jet is being distorted by a slow wind coming from the nebula}. We will also be able to search for runaway stars caused by the disintegration of young multiple-star systems. All of this is possible because the long-time base of the WFPC2 and ACS observations allow a new level of astrometric precision to be obtained and to be done efficiently by making coordinated parallel observations with all images.

WFPC2 10914

HST Observations of Astrophysically Important Visual Binaries

This is a continuation of a project begun in Cycle 7 and continued up through Cycle 14. The program consists of annual FGS or WFPC2 observations of three visual binary stars that will yield fundamental astrophysical results, once their orbits and masses are determined. Our targets are the following: {1} Procyon {P = 40.9 yr}, for which our first WFPC2 images yielded an extremely accurate angular separation of the bright F star and its much fainter white-dwarf companion. Combined with ground-based astrometry of the bright star, our observation significantly revised downward the derived masses, and brought Procyon A into much better agreement with theoretical evolutionary masses for the first time. With the continued monitoring proposed here, we will obtain masses to an accuracy of better than 1%, providing a testbed for theories of both Sun-like stars and white dwarfs. {2} G 107-70, a close double white dwarf {P = 18.5 yr} that promises to add two accurate masses to the tiny handful of white-dwarf masses that are directly known from dynamical measurements. {3} Mu Cas {P = 20.8 yr}, a famous nearby metal-deficient G dwarf for which accurate masses will lead to the stars’ helium contents, with cosmological implications. For all three stars, we will also be setting increasingly stringent limits on the presence of planetary-mass bodies in the systems.

NIC1 10889

The Nature of the Halos and Thick Disks of Spiral Galaxies

We propose to resolve the extra-planar stellar populations of the thick disks and halos of seven nearby, massive, edge-on galaxies using ACS, NICMOS, and WFPC2 in parallel. These observations will provide accurate star counts and color-magnitude diagrams 1.5 magnitudes below the tip of the Red Giant Branch sampled along the two principal axes and one intermediate axis 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. These observations will provide the definitive HST study of extra-planar stellar populations of spiral galaxies. Our targets cover a range in galaxy mass, luminosity, and morphology and as function of these galaxy properties we will provide: – The first systematic study of the radial and isophotal shapes of the diffuse stellar halos of spiral galaxies – The most detailed comparative study to date of thick disk morphologies and stellar populations – A comprehensive analysis of halo and thick disk metallicity distributions as a function of galaxy type and position within the galaxy. – A sensitive search for tidal streams – The first opportunity to directly relate globular cluster systems to their field stellar population We will use these fossil records of the galaxy assembly process preserved in the old stellar populations to test halo and thick disk formation models within the hierarchical galaxy formation scheme. We will test LambdaCDM predictions on sub-galactic scales, where it is difficult to test using CMB and galaxy redshift surveys, and where it faces its most serious difficulties.

ACS/WFC 10816

The Formation History of Andromeda’s Extended Metal-Poor Halo

We propose deep ACS imaging in the outer spheroid of the Andromeda galaxy, in order to measure the star formation history of its true halo. For the past 20 years, nearly all studies of the Andromeda “halo” were focused on the spheroid within 30 kpc of the galaxy’s center, a region now known to host significant substructure and populations with high metallicity and intermediate ages. However, two groups have recently discovered an extended metal-poor halo beyond 30 kpc; this population is distinct in its surface-brightness profile, abundance distribution, and kinematics. In earlier cycles, we obtained deep images of the inner spheroid {11 kpc on the minor axis}, outer disk {25 kpc on the major axis}, and giant tidal stream, yielding the complete star formation history in each field. We now propose deep ACS imaging of 4 fields bracketing this 30 kpc transition point in the spheroid, so that the inner spheroid and the extended halo populations can be disentangled, enabling a reconstruction of the star formation history in the halo. A wide age distribution in the halo, as found in the inner spheroid, would imply the halo was assembled through ongoing accretion of satellite galaxies, while a uniformly old population would be a strong indication that the halo was formed during the early rapid collapse of the Andromeda proto-galaxy.

ACS/WFC 10803

Detecting the progenitors of core-collapse supernovae

Modern supernova searches in the nearby Universe are discovering large numbers of SNe which have massive star progenitors {Types II, Ib and Ic}. The extensive HST image archive within ~20Mpc enables the indvidual bright stellar content of starforming galaxies to be resolved. As massive, evolved stars are the most luminous single objects in a galaxy, the progenitors of core-collapse SNe are often directly detectable on pre-explosion archive images. We have discovered three progenitors of recent type II-Plateau SNe, showing them to be red supergiants of 8-12 solar masses. This is the first direct evidence that red supergiants do indeed produce normal type II explosions. We have set upper mass limits on a further 7 progenitor stars and suggest that faint type II supernovae are unlikely to come from the collapse of very massive stars which form black holes. These discoveries are providing strong constraints on theoretical models of pre-supernova evolution, explosion models and the origin of the supernova types. We request time to continue this successful project and require ACS observations of future SNe which are discovered in galaxies closer than 20Mpc and which have pre-explosion HST archive images available. This will allow the SNe to be precisely positioned on the pre-explosion images. We have set a final goal for this project of determining masses and types, or setting restrictive mass-limits, for 30 supernovae over the remainder of HST’s project life.

ACS/WFC 10766

A Deep X-ray Survey of the Small Magellanic Cloud

We request deep observations of 2 representative fields in the Small Magellanic Cloud with Chandra and HST,with the primary goal of measuring the luminosity function and space density of X-ray binaries and other sources down to an unprecedented faint luminosity limit of 2x10E32 erg/s. This will be the faintest XLF ever obtained for any galaxy, including our own. HST photometry to 24th magnitude in V and I filters will identify the sources and provide Fx/Fopt, which will be vital in quantifying the LMXB population and in measuring the properties of the first coronally active stars ever detected in an external galaxy.


ACS CCDs daily monitor

This program consists of a set of basic tests to monitor, the read noise, the development of hot pixels and test for any source of noise in ACS CCD detectors. The files, biases and dark will be used to create reference files for science calibration. This programme will be for the entire lifetime of ACS. Changes from cycle 13:- The default gain for WFC is 2 e-/DN. As before bias frames will be collected for both gain 1 and gain 2. Dark frames are acquired using the default gain {2}. This program cover the period May, 31 2006- Oct, 1-2006. The first half of the program has a different proposal number: 10729.

ACS/HRC 10738

Earth Flats

Sky flats will be obtained by observing the bright Earth with the HRC and WFC. These observations will be used to verify the accuracy of the flats currently in the pipeline and to monitor any changes. Weekly coronagraphic monitoring is required to assess the changing position of the spots.

NIC2 10716

The Unique Cluster Lens SDSS1004+4112

SDSS1004+4112 is a unique example of a cluster lens because of its relatively high lens redshift {zlens=0.68}, the existence of multiply imaged quasars for which time delays are measured, the presence of a significant number of multiply imaged background galaxies, and a quasar host galaxy that is so magnified that it can be observed in the mid?IR. By combining a deep 4?channel IRAC image with a NICMOS mosaic of the central, multiply?imaged region of the cluster, we will study the quasar host galaxy, search for low?mass substructure in the cluster, obtain accurate photometric redshifts for lensed arcs, discover very red lensed arcs and develop an accurate mass model for the cluster. Then we will combine all the data to obtain a competitive constraint on the cosmological model.

NIC2 10540

Imaging Nearby Dusty Disks

Images of circumstellar debris disks around young stars display complex structures that suggest they harbor forming planets. Disks around stars of nearly the same age and mass show dramatically different morphologies including rings with brightness asymmetries and multiple warps. The reasons for this heterogeneity are not understood, nor given the small sample of imaged disks, can we be sure we have yet observed all possible outcomes of the planet formation process. Disk imaging programs have demonstrated that the Hubble Space Telescope is the only excellent platform for the high-contrast detection of scattered light disks in the presence of their bright parent stars. Therefore, we propose a NICMOS imaging survey of the nearest, youngest, stars to Earth with substantial disks known from infrared excess emission.

NIC2 10527

Imaging Scattered Light from Debris Disks Discovered by the Spitzer Space Telescope Around 20 Sun-like Stars

We propose to use the high contrast capability of the NICMOS coronagraph to image a sample of newly discovered circumstellar disks associated with sun-like stars. These systems were identified by their strong thermal infrared emission with the Spitzer Space Telescope as part of the Spitzer Legacy Science program titled, “The Formation and Evolution of Planetary Systems {FEPS}.” Modelling of the thermal excess emission in the form of spectral energy distributions alone cannot distinguish between narrowly confined high opacity disks and broadly distributed, low opacity disks. However, our proposed NICMOS observations can, by imaging the light scattered from this material. Even non- detections will place severe constraints on the disk geometry, ruling out models with high optical depth. Unlike previous disk imaging programs, our program contains a well defined sample of solar mass stars covering a range of ages from ~10Myrs to a few Gyrs, allowing us to study the evolution of disks from primordial to debris for the first time. These results will greatly improve our understanding of debris disks around Sun- like stars at stellar ages nearly 10x older than any previous investigation. Thus we will have fit a crucial piece into the puzzle concerning the formation and evolution of our own solar system.


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


10476 – REacq(2,1,1) failed to RGA Control Upon acquisition of signal at 293/13:54:00, REacq(2,1,1) scheduled at 293/13:38:16 – 13:46:20 was observed to have failed to RGA Hold due to search radius limit exceeded on FGS-2. Pre-acquisition OBADs had (RSS) attitude error corrections values of 10.39 and 133.07 arcseconds. Post-acquisition OBAD/MAP at 293/14:17:00 had (RSS) value of 119.47 arcseconds.

10479 – GSACQ(1,2,1) Fine Lock Backup on FGS 1

GSACQ(1,2,1) at 294/04:18:11 failed to Fine Lock Backup on FGS 1 at 04:22:06 with QF2STOPF on FGS 2.

10482 – GSAcq(1,3,1) failed to RGA Control

Upon acquisition of signal at 295/11:20:31, GSAcq(1,3,1) scheduled at 295/10:48;06 – 10:56:10 was observed to have failed to RGA Hold due to search radius limit exceeded on FGS-3. Pre-acquisition OBADs (RSS) attitude error corrections values not available pending future ETR Dump. Post-acquisition OBAD/MAP had 3-axis (RSS) value of 21.29 arcseconds. Subsequent REacq(1,3,1) at 295/12:16:15 failed to RGA Hold due to search radius limit exceeded on FGS-3. Pre-acquisition OBADs had (RSS) values of 1159.58 and 11.34 a-s. Post-acquisition OBAD/MAP had (RSS) value of 7.33 a-s.


17940-0 – Genslew for proposal 10895 – slot 7 17941-0 – Genslew for proposal 10895 – slot 8

17942-0 – Genslew for proposal 10895 – slot 9


                         SCHEDULED      SUCCESSFUL
FGS GSacq                24                    23
FGS REacq                18                    16
OBAD with Maneuver   84                    84


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