NASA Hubble Space Telescope Daily Report #4439


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Notice: Due to the conversion of some ACS WFC or HRC observations into WFPC2, or NICMOS observations after the loss of ACS CCD science capability in January, there may be an occasional discrepancy between a proposal's listed (and correct) instrument usage and the abstract that follows it.

HUBBLE SPACE TELESCOPE DAILY REPORT # 4439

- Continuing to collect World Class Science

PERIOD COVERED: UT August 31, September 01, 02, 03, 2007 (DOY 243, 244, 245, 246)

OBSERVATIONS SCHEDULED

ACS/SBC 10840

The FUV fluxes of Tauri stars in the Taurus molecular cloud Present and forthcoming ground-based and space surveys of the T Tauri stars in the Taurus molecular cloud will provide information from high energy stellar and accretion radiation to low energy solid state and molecular emission from the disk, making those stars perfect laboratories to carry out self-consistent studies of disk physics and evolution. We propose to complete this wealth of information by obtaining ACS/FUV spectra for a significant sample of Taurus T Tauri stars, covering a range of accretion properties and dust evolutionary stages. FUV fluxes carry ~ 10 - 100 more energy than X-rays into these disks and are thus crucial gas heating agents and key to disk dispersal by photoevaporation. These observations are a pre-requisite to interpret observations with Spitzer, SOFIA, Herschel, and ALMA, and will become one of the important legacies of HST to the star formation community.

FGS 11210

The Architecture of Exoplanetary Systems

Are all planetary systems coplanar? Concordance cosmogony makes that prediction. It is, however, a prediction of extrasolar planetary system architecture as yet untested by direct observation for main sequence stars other than the Sun. To provide such a test, we propose to carry out FGS astrometric studies on four stars hosting seven companions. Our understanding of the planet formation process will grow as we match not only system architecture, but formed planet mass and true distance from the primary with host star characteristics for a wide variety of host stars and exoplanet masses. We propose that a series of FGS astrometric observations with demonstrated 1 millisecond of arc per- observation precision can establish the degree of coplanarity and component true masses for four extrasolar systems: HD 202206 {brown dwarf+planet}; HD 128311 {planet+planet}, HD 160691 = mu Arae {planet+planet}, and HD 222404AB = gamma Cephei {planet+star}.  In each case the companion is identified as such by assuming that the minimum mass is the actual mass. For the last target, a known stellar binary system, the companion orbit is stable only if coplanar with the AB binary orbit.

FGS 11212

Filling the Period Gap for Massive Binaries

The current census of binaries among the massive O-type stars is seriously incomplete for systems in the period range from years to millennia because the radial velocity variations are too small and the angular separations too close for easy detection. Here we propose to discover binaries in this observational gap through a Faint Guidance Sensor SNAP survey of relatively bright targets listed in the Galactic O Star Catalog. Our primary goal is to determine the binary frequency among those in the cluster/association, field, and runaway groups.  The results will help us assess the role of binaries in massive star formation and in the processes that lead to the ejection of massive stars from their natal clusters. The program will also lead to the identification of new, close binaries that will be targets of long term spectroscopic and high angular resolution observations to determine their masses and distances. The results will also be important for the interpretation of the spectra of suspected and newly identified binary and multiple systems.

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration - CR Persistence Part 5

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 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 10897

Coronagraphic imaging of the submillimeter debris disk of a 200Myr old M-dwarf

A recent sub-millimeter survey has unambiguously discovered a new debris disk around the M0.5 dwarf GJ842.2 which is 200 Myr old. Reanalysis of the IRAS data has shown that there is also a 25 micron excess toward this star indicating warm dust close to the star. It is also only the second debris disk found among M-dwarfs that constitute 70 % of the stars in the Galaxy. Collisional and Poynting-Roberston timescale arguments indicate that the cold grains detected in the sub-mm are ``primordial'', i.e. original grains from the protoplanetary phase. The disk around GJ842.2 is thus unique in terms of the presence of dust at such a late stage of evolution and presents two conundrums: why did it retain so much primordial dust at large distances, and why does it continue to produce dust close to the star? We propose to conduct high contrast NICMOS coronagraphic imaging of GJ842.2 to determine the spatial distribution of the small reflecting grains and test the various scenarios which might explain the IRAS and sub-mm data e.g.resonant trapping of dust by planets or ``sandblasting'' by interstellar medium grains working more aggressively on a low-luminosity star than on an A-type star like Beta Pic. Also, we would search for an evolutionary sequence between GJ842.2 and the only other M-dwarf with a disk resolved by HST, the 10 Myr old AU Mic system.

WFPC2 10818

Very Young Globular Clusters in M31 ?

We propose to use HST's unique high spatial resolution imaging capabilities to conclusively confirm or refute the presence of alleged very young globular clusters in M31. Such young globular clusters with ages < 3 Gyr are not present in our galaxy, and, if real, would lead to a striking difference in the age distribution of the GCs between M31 and the Milky Way. If the apparent presence of very young globular clusters in M31 is confirmed through our proposed ACS imaging {now WFPC2 imaging} with HST, this would suggest major differences in the history of assembly of the two galaxies, with probable substantial late accretion into M31 which did not occur in our own galaxy.

WFPC2 10787

Modes of Star Formation and Nuclear Activity in an Early Universe Laboratory

Nearby compact galaxy groups are uniquely suited to exploring the mechanisms of star formation amid repeated and ongoing gravitational encounters, conditions similar to those of the high redshift universe. These dense groups host a variety of modes of star formation, and they enable fresh insights into the role of gas in galaxy evolution. With Spitzer mid-IR observations in hand, we have begun to obtain high quality, multi-wavelength data for a well- defined sample of 12 nearby {<4500km/s} compact groups covering the full range of evolutionary stages. Here we propose to obtain sensitive BVI images with the ACS/WFC, deep enough to reach the turnover of the globular cluster luminosity function, and WFPC2 U-band and ACS H-alpha images of Spitzer-identified regions hosting the most recent star formation. In total, we expect to detect over 1000 young star clusters forming inside and outside galaxies, more than 4000 old globular clusters in >40 giant galaxies {including 16 early-type galaxies}, over 20 tidal

features, approximately 15 AGNs, and intragroup gas in most of the 12 groups. Combining the proposed ACS images with Chandra observations, UV GALEX observations, ground-based H-alpha imaging, and HI data, we will conduct a detailed study of stellar nurseries, dust, gas kinematics, and AGN.

WFPC2 10818

Very Young Globular Clusters in M31 ?

We propose to use HST's unique high spatial resolution imaging capabilities to conclusively confirm or refute the presence of alleged very young globular clusters in M31. Such young globular clusters with ages < 3 Gyr are not present in our galaxy, and, if real, would lead to a striking difference in the age distribution of the GCs between M31 and the Milky Way. If the apparent presence of very young globular clusters in M31 is confirmed through our proposed ACS imaging {now WFPC2 imaging} with HST, this would suggest major differences in the history of assembly of the two galaxies, with probable substantial late accretion into M31 which did not occur in our own galaxy.

WFPC2 11022

WFPC2 Cycle 15 Decontaminations and Associated Observations

This proposal is for the WFPC2 decons. Also included are instrument monitors tied to decons: photometric stability check, focus monitor, pre- and post-decon internals {bias, intflats, kspots, & darks}, UV throughput check, VISFLAT sweep, and internal UV flat check.

WFPC2 11028

WFPC2 Cycle 15 UV Earth Flats

Monitor flat field stability. This proposal obtains sequences of earth streak flats to improve the quality of pipeline flat fields for the WFPC2 UV filter set. These Earth flats will complement the UV earth flat data obtained during cycles 8-14.

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.

WFPC2 11206

At the cradle of the Milky Way: Formation of the most massive field disk galaxies at z>1

We propose to obtain 2 orbit WFPC2 F814W images of a sample of the 15 most massive galaxies found at $1 < z < 1.3$. These were culled from over 20,000 Keck spectra collected as part of DEEP and are unique among high redshift massive galaxy samples in being kinematically selected. Through a recent HST NICMOS-2 imaging program {GO- 10532}, we have confirmed that these galaxies have regular stellar disks, and their emission line kinematics are not due to gradients from merging components. These potentially very young galaxies are likely precursors to massive local disks, assuming no further merging. The proposed WFPC2 and existing NIC-2 data provide colors, stellar masses, and ages of bulge and disk subcomponents, to assess whether old stellar bulges and disks are in place at that time or still being built, and constrain their formation epochs. Finally, this sample will yield the first statistically significant results on the $z > 1$ evolution of the size-velocity-luminosity scaling relations, for massive galaxies at different wavelengths, and constrain whether this evolution reflects stellar mass growth, or passive evolution, of either bulge or disk components.

WFPC2 11289

SL2S: The Strong Lensing Legacy Survey

Recent systematic surveys of strong galaxy-galaxy lenses {CLASS, SLACS, GOODS, etc.} are producing spectacular results for galaxy masses roughly below a transition mass M~10^13 Mo. The observed lens properties and their evolution up to z~0.2, consistent with numerical simulations, can be described by isothermal elliptical potentials. In contrast, modeling of giant arcs in X-ray luminous clusters {halo masses M >~10^13 Mo} favors NFW mass profiles, suggesting that dark matter halos are not significantly affected by baryon cooling. Until recently, lensing surveys were neither deep nor extended enough to probe the intermediate mass density regime, which is fundamental for understanding the assembly of structures. The CFHT Legacy Survey now covers 125 square degrees, and thus offers a large reservoir of strong lenses probing a large range of mass densities up to z~1. We have extracted a list of 150 strong lenses using the most recent CFHTLS data release via automated procedures. Following our first SNAPSHOT proposal in cycle 15, we propose to continue the Hubble follow-up targeting a larger list of 130 lensing candidates. These are intermediate mass range candidates {between galaxies and clusters} that are selected in the redshift range of 0.2-1 with no a priori X-ray selection. The HST resolution is necessary for confirming the lensing candidates, accurate modeling of the lenses, and probing the total mass concentration in galaxy groups up to z~1 with the largest unbiased sample available to date.

WFPC2 11292

The Ring Plane Crossings of Uranus in 2007

The rings of Uranus turn edge-on to Earth in May and August 2007. In between, we will have a rare opportunity to see the unlit face of the rings. With the nine optically thick rings essentially invisible, we will observe features and phenomena that are normally lost in their glare. We will use this opportunity to search thoroughly for the embedded "shepherd" moons long believed to confine the edges of the rings, setting a mass limit roughly 10 times smaller than that of the smallest shepherd currently known, Cordelia. We will measure the vertical thicknesses of the rings and study the faint dust belts only known to exist from a single Voyager image. We will also study the colors of the newly-discovered faint, outer rings; recent evidence suggests that one ring is red and the other blue, implying that each ring is dominated by a different set of physical processes. We will employ near- edge-on photometry from 2006 and 2007 to derive the particle filling factor within the rings, to observe how ring epsilon responds to the "traffic jam" as particles pass through its narrowest point, and to test the latest models for preserving eccentricities and apse alignment within the rings. Moreover, this data set will allow us to continue monitoring the motions of the inner moons, which have been found to show possibly chaotic orbital variations; by nearly doubling the time span of the existing Hubble astrometry, the details of the variations will become much clearer.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS:

10968 - ZERO GYRO SAFEMODE ENTRY

HST entered Zero Gyro Software Sunpoint at 243/23:01:54 Z due to failure of Gyro 2(GRG1_2MC) current reading 0.00ma. ACS safed in ZGSP. Two Gyro Configuration Test failed at 243/23:01:54.

10970 - OTA Temperatures Out of Limits

At 244/16:45:27 EMRA1T began breaking high yellow limit at -7.79134.
At 244/16:47:23 ESPID6T began breaking high yellow at -15.7403.
At 244/17:44:02 ESPID3T began breaking high yellow limit at -11.5197.
10972 - NICMOS safed @ 245/0258z

NICMOS safed at 245/02:58:50 with two status buffer messages: Exec 323, P=120712, T=16922
NICMOS 671, P=160145, T=16922
("NED_AD_DATAFIFO_EMPTY").
An Engineering Data Report MSERPROC was also received.

COMPLETED OPS REQUEST:

18123-1 - Power On Gyro 6
18124-1 - ZGSP Recovery
18130-0 - Uplink N02Z8260B, Set ATP Pointer, and Clear ENGREPs
18129-0 - 2nd LBBIAS post G6 Insertion
18128-0 - Bias update post G6 insertion
18127-1 - Modify T2G Rate Damp Timer and Rate Damping Moving Target Limit
18126-0 - PSEA RGA configuration following the failure of RGA-2
18125-1 - FSW Gyro Reconfiguration due to Gyro 2 Failure
18134-1 - Enable FSW Gyro Bias Correction for Slot B (G6)
18132-0 - Perform RGA Bias Update Using LBBIAS
18136-1 - Perform RGA Bias Update using OBSINT
18137-0 - Update on-board gyro bias limit
18141-0 - LBBIAS after long M2G interval

COMPLETED OPS NOTES:

1636-0 - Adjust Structure Current Limit in ZGSP
1638-0 - Temporarily Change Primary Mirror Temperature Limits
1637-0 - Limit Modifications for Gyro 2 Failure and Gyro 6 Power On
1635-0 - Temporarily Change OTA Baffle Temperature Limits
1639-0 - Adjust Safing Limits for Gyro 2 Failure
1640-1 - Adjust PCS Limits for Gyro 2 Failure
1636-2 - Adjust Structure Current Limit in ZGSP
1609-4 - Change JERRCNT Limit

                          SCHEDULED      SUCCESSFUL 
FGS GSacq                 11              11 
FGS REacq                 07              07 
OBAD with Maneuver        44              44 

SIGNIFICANT EVENTS:

FLASH REPORT: Zero Gyro Software Sunpoint entry

At 243/23:01:54 UTC Gyro 2 disparity counts exceeded limits during an LOS period and HST entered Zero Gyro Software Sun Point. The vehicle was in M2G mode in orbit night with a vehicle slew in progress when this occurred. Gyro 2's motor current and digital data were zero after telemetry was reestablished.

FLASH REPORT: Gyro 6 power on

After examination of the Gyro 2 failure data, Project gave the go ahead for the power on of Gyro 6. Ops Request 18123-1 was executed at 2007/244 05:55. Gyro turn on was nominal.

Zero Gyro Status Briefing Flash Report - Sept 1, 2007

On Saturday, September 1st at 9am EST a Zero Gyro Entry (Gyro 2 failure) Status Briefing was held with the Mission Operations Team, Science Institute and HST Project. Status of each subsystem was provided. PCS confirmed Gyro 2 failure and that Gyro 6 was powered on at 244/0554 GMT. Other subsystems are performing nominally and as expected. TCS did change yellow limits on the OTA Baffle temperature to the SM limits (w/AD closed). EPS reported a change in the structure current profile following the anomaly. An Ops Note was issued to increase structure current ground limits by 0.4 amps (5.4 to 5.8A). There was an increase of up to 1.5 amps in the structure current profile which EPS is monitoring.

The team reviewed Safemode Procedure 10 TGS Zero Gyro Sunpoint Safemode Response and authority to proceed with the recovery was granted. A telecon was held with the STScI to coordinate the delivery of the Health & Safety (H&S) SMS and the Science Intercept SMS. STScI reported that the two SMSs will be generated in parallel and all products should be delivered around the same time.

Flash Report - Health and Safety Load

The Health and Safety Load for recovering for the ZGSP safe mode recovery was uplinked at 245/06:30, and started executing nominally at 245/08:00 GMT.

Flash Report NICMOS Safing - STB 671

NICMOS Safed at 2007/245/02:58:50 UTC with a NICMOS 671 status buffer message indicating the NED A/D data collection FIFO register was empty. At the time of the event, HST was in orbit day and not passing through the SAA. ACS remains in Safe and all other SIs are continuing to operate nominally.

Since that time, HST has commenced operations on the Health & Safety SMS at 245/08:02:46 UTC. NICMOS commanding later in this SMS will not be executed until and unless the instrument is recovered. Flash Report:  Commenced Execution of Science Intercept SMS Execution of the 486 and NSSC-1 Science Intercept SMS loads commenced as planned on Sunday September 2nd at 8 pm. EST (i.e., 246/00:00:00 UTC).

Flash Report:

All Acquisitions beginning the 246 SMS have been successful through 246/1800. No LOL events have been observed. PCS and FSW are actively working issues with gyro bias updates. These issues will be discussed at the 5:00 PM meeting this evening.

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