NASA Hubble Space Telescope Daily Status Report #4402
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 # 4402
– Continuing to collect World Class Science
PERIOD COVERED: UT July 11, 2007 (DOY 192)
OBSERVATIONS SCHEDULED
FGS 11210
SCHEDULED SUCCESSFUL
FGS GSacq 8 6
FGS REacq 6 4
OBAD with Maneuver 28 28
COMPLETED OPS NOTES: (None)
SIGNIFICANT EVENTS: (None)
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 11211
An Astrometric Calibration of Population II Distance Indicators
In 2002 HST produced a highly precise parallax for RR Lyrae. That measurement resulted in an absolute magnitude, M{V}= 0.61+/-0.11, a useful result, judged by the over ten refereed citations each year since. It is, however, unsatisfactory to have the direct, parallax-based, distance scale of Population II variables based on a single star. We propose, therefore, to obtain the parallaxes of four additional RR Lyrae stars and two Population II Cepheids, or W Vir stars. The Population II Cepheids lie with the RR Lyrae stars on a common K-band Period-Luminosity relation. Using these parallaxes to inform that relationship, we anticipate a zero-point error of 0.04 magnitude. This result should greatly strengthen confidence in the Population II distance scale and increase our understanding of RR Lyrae star and Pop II Cepheid astrophysics.
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.
NIC2 10893
Sweeping Away the Dust: Reliable Dark Energy with an Infrared Hubble Diagram
We propose building a high-z Hubble Diagram using type Ia supernovae observed in the infrared rest-frame J-band. The infrared has a number of exceptional properties. The effect of dust extinction is minimal, reducing a major systematic tha may be biasing dark energy measurements. Also, recent work indicates that type Ia supernovae are true standard candles in the infrared meaning that our Hubble diagram will be resistant to possible evolution in the Phillips relation over cosmic time. High signal-to-noise measurements of 9 type Ia events at z~0.4 will be compared with an independent optical Hubble diagram from the ESSENCE project to test for a shift in the derived dark energy equation of state due to a systematic bias. Because of the bright sky background, H-band photometry of z~0.4 supernovae is not feasible from the ground. Only the superb image quality and dark infrared sky seen by HST makes this test possible. This experiment may also lead to a better, more reliable way of mapping the expansion history of the universe with the Joint Dark Energy Mission.
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 Millky 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 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 11079
Treasury Imaging of Star Forming Regions in the Local Group: Complementing the GALEX and NOAO Surveys
We propose to use WFPC2 to image the most interesting star-forming regions in the Local Group galaxies, to resolve their young stellar populations. We will use a set of filters including F170W, which is critical to detect and characterize the most massive stars, to whose hot temperatures colors at longer wavelengths are not sensitive. WFPC2’s field of view ideally matches the typical size of the star-forming regions, and its spatial resolution allows us to measure indvidual stars, given the proximity of these galaxies. The resulting H-R diagrams will enable studies of star- formation properties in these regions, which cover largely differing metallicities {a factor of 17, compared to the factor of 4 explored so far} and characteristics. The results will further our understanding of the star-formation process, of the interplay between massive stars and environment, the properties of dust, and will provide the key to interpret integrated measurements of star-formation indicators {UV, IR, Halpha} available for several hundreds more distant galaxies. Our recent deep surveys of these galaxies with GALEX {FUV, NUV} and ground-based imaging {UBVRI, Halpha, [OIII] and [SII]} provided the identification of the most relevant SF sites. In addition to our scientific analysis, we will provide catalogs of HST photometry in 6 bands, matched corollary ground-based data, and UV, Halpha and IR integrated measurements of the associations, for comparison of integrated star-formation indices to the resolved populations. We envisage an EPO component.
WFPC2 11175
UV Imaging to Determine the Location of Residual Star Formation in Galaxies Recently Arrived on the Red Sequence
We have indentified a sample of low-redshift {z = 0.04 – 0.10} galaxies that are candidates for recent arrival on the red sequence. They have red optical colors indicative of old stellar populations, but blue UV-optical colors that could indicate the presence of a small quantity of continuing or very recent star formation. However, their spectra lack the emission lines that characterize star-forming galaxies. We propose to use ACS/SBC to obtain high-resolution imaging of the UV flux in these galaxies, in order to determine the spatial distribution of the last episode of star formation. WFPC2 imaging will provide B, V, and I photometry to measure the main stellar light distribution of the galaxy for comparison with the UV imaging, as well as to measure color gradients and the distribution of interstellar dust. This detailed morphological information will allow us to investigate the hypothesis that these galaxies have recently stopped forming stars and to compare the observed distribution of the last star formation with predictions for several different mechanisms that may quench star formation in galaxies.
WFPC2 11178
Probing Solar System History with Orbits, Masses, and Colors of Transneptunian Binaries
The recent discovery of numerous transneptunian binaries {TNBs} opens a window into dynamical conditions in the protoplanetary disk where they formed as well as the history of subsequent events which sculpted the outer Solar System and emplaced them onto their present day heliocentric orbits. To date, at least 47 TNBs have been discovered, but only about a dozen have had their mutual orbits and separate colors determined, frustrating their use to investigate numerous important scientific questions. The current shortage of data especially cripples scientific investigations requiring statistical comparisons among the ensemble characteristics. We propose to obtain sufficient astrometry and photometry of 23 TNBs to compute their mutual orbits and system masses and to determine separate primary and secondary colors, roughly tripling the sample for which this information is known, as well as extending it to include systems of two near-equal size bodies. To make the most efficient possible use of HST, we will use a Monte Carlo technique to optimally schedule our observations.
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)
HSTARS:
#10888 GSAcq(2,0,2) failed to RGA Hold (Gyro Control)
Upon acquisition of signal (AOS) at 192/11:43:01, the GSAcq(2,0,2) scheduled at 192/10:55:18 – 11:01:35 had failed to RGA Hold due to (QF2STOPF) stop flag indication on FGS-2. Scheduled Astrometry FGS1 did not attempt. Pre-acquisition OBADs attitude correction values not available due to LOS. Post-acq OBAD/MAP had (RSS) value of 15.71 arcseconds.
#10889 REAcq (1,2,1) failed due to Search Radius Limit Exceeded on FGS 1
At 192/20:54:28 REAcq (1,2,1) scheduled from 20:49:36-20:57:04 had failed due to search radius limit exceeded on FGS 1. At 20:48:31 F2SOB (FHST2 Stuck on Bottom) showed OOL. Unable to execute Ops Request 17597-9 due to forward not available. OBAD #1: V1 -29.22, V2 2604.20, V3 0.32, RSS 2604.36 OBAD #2: V1 -3.09, V2 -14.18, V3 172.41, RSS 173.02 OBAD MAP: V1 3.34, V2 4.95, V3 -151.58, RSS 151.70
#10890 GSAcq (1,2,1) failed due to Search Radius Limit Exceeded on FGS 1
At AOS 192/22:47:30 observed that GSAcq (1,2,1)scheduled from 22:30:10-22:37:22 had failed due to search radius limit exceeded on FGS 1. OBAD data unavailable until next scheduled engineering dump. OBAD MAP: v1 -78.32, V2 26.00, V3 -145.71, RSS 167.46
At AOS 193/00:03:45 REAcq (1,2,1) scheduled from 00:03:46-00:10:58 failed due to search radius limit exceeded on FGS 1. OBAD data unavailable due to LOS. Awaiting next scheduled engineering dump. OBAD MAP RSS: V1 4.74, V2 -8.31, V3 -63.96, RSS 64.67
COMPLETED OPS REQUEST: (None)
