![]() |
#1
|
|||
|
|||
![]()
HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science
DAILY REPORT****** #4761 PERIOD COVERED: 5am December 19 - 5am December 22, 2008 (DOY ************************** 354/1000z-357/1000z) OBSERVATIONS SCHEDULED WFPC2 11962 A New Supernova in the Antennae; Narrowing in on the Hubble Constant and Dark Energy A measurement of the Hubble constant to a precision of a few percent would be a powerful aid to the investigation of the nature of dark energy and a potent "end-to-end" test of the present cosmological model. In Cycle 15 we constructed a new, streamlined distance ladder utilizing high-quality type Ia supernova data and observations of Cepheids with HST in the near-IR to minimize the dominant sources of systematic uncertainty in past measurements of the Hubble constant and reduce its total uncertainty to a little under 5%. Here we propose to exploit this new route with a rare opportunity to begin reducing the remaining uncertainty. SN 2007sr in the Antennae (NGC 4038/9) is the rare SN Ia which is suitable for increasing the precision of small calibration sample of SNe Ia. Even rarer is that it is close enough that it's Cepheids are within range of observing with WFPC2 (and NICMOS, should it return to life). But we need to act fast as the window of long visibility and fixed orient runs from mid-early December 2008 to early March 2009. We request 34 orbits with WFPC2 to find the Cepheids in the SN host. We also request 16 orbits to observe the Cepheids we find with Camera 2, F160W if NICMOS becomes available by April 2009 . (If NICMOS does not return we would forgo these observations and ask the TTRB to let us make them with our own WFC3-IR allocation, though we much prefer the smaller pixel size of NIC2). FGS 11945 Asteroseismology of Extrasolar Planet Host Stars Detections of stellar oscillations, although a very demanding task in terms of observing time, offers a return of more accurate knowledge about the structure of stars than can be obtained in any other way. In particular, detecting the 10-15 highest amplitude modes in solar-like stars to signal-to-noise of just a few sigma each allows robust constraints on the stellar density to 1%, and the stellar age to within 5-10% of its main sequence lifetime. Ten day observing runs using the FGS as a photometer on any of the 5 best transiting planet systems would enable these asteroseismology returns. From more precisely observed transit shapes than can be obtained from the ground a completely independent constraint on stellar density to ~1% can be obtained. The long observation sets required for asteroseismology also provide an excellent opportunity of detecting transits from other planets, e.g. hypothesized inner -orbit Hot Earths, should any exist. WFPC2 11944 Binaries at the Extremes of the H-R Diagram We propose to use HST/Fine Guidance Sensor 1r to survey for binaries among some of the most massive, least massive, and oldest stars in our part of the Galaxy. FGS allows us to spatially resolve binary systems that are too faint to observe using ground-based, speckle or optical long baseline interferometry, and too close to resolve with AO. We propose a SNAP-style program of single orbit FGS TRANS mode observations of very massive stars in the cluster NGC 3603, luminous blue variables, nearby low mass main sequence stars, cool subdwarf stars, and white dwarfs. These observations will help us to (1) identify systems suitable for follow up studies for mass determination, (2) study the role of binaries in stellar birth and in advanced evolutionary states, (3) explore the fundamental properties of stars near the main sequence-brown dwarf boundary, (4) understand the role of binaries for X-ray bright systems, (5) find binaries among ancient and nearby subdwarf stars, and (6) help calibrate the white dwarf mass - radius relation. FGS 11943 Binaries at the Extremes of the H-R Diagram We propose to use HST/Fine Guidance Sensor 1r to survey for binaries among some of the most massive, least massive, and oldest stars in our part of the Galaxy. FGS allows us to spatially resolve binary systems that are too faint for ground-based, speckle or optical long baseline interferometry, and too close to resolve with AO. We propose a SNAP-style program of single orbit FGS TRANS mode observations of very massive stars in the cluster NGC 3603, luminous blue variables, nearby low mass main sequence stars, cool subdwarf stars, and white dwarfs. These observations will help us to (1) identify systems suitable for follow up studies for mass determination, (2) study the role of binaries in stellar birth and in advanced evolutionary states, (3) explore the fundamental properties of stars near the main sequence-brown dwarf boundary, (4) understand the role of binaries for X-ray bright systems, (5) find binaries among ancient and nearby subdwarf stars, and (6) help calibrate the white dwarf mass - radius relation. FGS 11870 Calibrating FGS1R's Optical Field Angle Distortion (OFAD), Second Epoch This proposal gathers the data needed to calibrate the optical field angle distortions in FGS1r to the level of accuracy required for astrometry science. Selected stars from the galactic cluster M35 are repeatedly observed in POSITION mode by FGS1r with F583W filter at a variety of spacecraft pointings and telescope roll angles. Ideally the observations are to occur at a time when this ecliptic star field is near the anti-sun direction so that HST's roll angle is unconstrained. Unfortunately this is not possible under two gyro operations. Therefore, the observations in this proposal are somewhat very constrained in roll. However, this test should suffice as an adequate update to the original FGS1r OFAD that executed in December 2000. For each visit, the desired telescope pointing is specified by POS TARG and ORIENT special requirements. FGS 11704 The Ages of Globular Clusters and the Population II Distance Scale Globular clusters are the oldest objects in the universe whose age can be accurately determined. The dominant error in globular cluster age determinations is the uncertain Population II distance scale. We propose to use FGS 1r to obtain parallaxes with an accuracy of 0.2 milliarcsecond for 9 main sequence stars with [Fe/H] -1.5. This will determine the absolute magnitude of these stars with accuracies of 0.04 to 0.06mag. This data will be used to determine the distance to 24 metal-poor globular clusters using main sequence fitting. These distances (with errors of 0.05 mag) will be used to determine the ages of globular clusters using the luminosity of the subgiant branch as an age indicator. This will yield absolute ages with an accuracy 5%, about a factor of two improvement over current estimates. Coupled with existing parallaxes for more metal-rich stars, we will be able to accurately determine the age for globular clusters over a wide range of metallicities in order to study the early formation history of the Milky Way and provide an independent estimate of the age of the universe. The Hipparcos database contains only 1 star with [Fe/H] -1.4 and an absolute magnitude error less than 0.18 mag which is suitable for use in main sequence fitting. Previous attempts at main sequence fitting to metal-poor globular clusters have had to rely on theoretical calibrations of the color of the main sequence. Our HST parallax program will remove this source of possible systematic error and yield distances to metal-poor globular clusters which are significantly more accurate than possible with the current parallax data. The HST parallax data will have errors which are 10 times smaller than the current parallax data. Using the HST parallaxes, we will obtain main sequence fitting distances to 11 globular clusters which contain over 500 RR Lyrae stars. This will allow us to calibrate the absolute magnitude of RR Lyrae stars, a commonly used Population II distance indicator. WFPC2 11316 HST Cycle 16 & Pre-SM4 Optical Monitor This is a continuation of the Cycle 15 & pre-SM4 Optical Monitor, 11020. Please see that proposal for a more complete description of the observing strategy. The 6 visits comprising this proposal observe two single standard stars with WFPC2/PC in order to establish overall OTA focal length for the purposes of focus maintenance. The goal of this monitoring before SM4 is to establish a best estimate of the OTA focus entering SMOV. 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. FGS 11213 Distances to Eclipsing M Dwarf Binaries We propose HST FGS observations to measure accurate distances of 5 nearby M dwarf eclipsing binary systems, from which model-independent luminosities can be calculated. These objects have either poor or no existing parallax measurements. FGS parallax determinations for these systems, with their existing dynamic masses determined to better than 0.5%, would serve as model-independent anchor points for the low-mass end of the mass-luminosity diagram. 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. WFPC2 11113 Binaries in the Kuiper Belt: Probes of Solar System Formation and Evolution The discovery of binaries in the Kuiper Belt and related small body populations is powering a revolutionary step forward in the study of this remote region. Three quarters of the known binaries in the Kuiper Belt have been discovered with HST, most by our snapshot surveys. The statistics derived from this work are beginning to yield surprising and unexpected results. We have found a strong concentration of binaries among low-inclination Classicals, a possible size cutoff to binaries among the Centaurs, an apparent preference for nearly equal mass binaries, and a strong increase in the number of binaries at small separations. We propose to continue this successful program in Cycle 16; we expect to discover at least 13 new binary systems, targeted to subgroups where these discoveries can have the greatest impact. ACS/HRC 10877 A Snapshot Survey of the Sites of Recent, Nearby Supernovae During the past few years, robotic {or nearly robotic} searches for supernovae {SNe}, most notably our Lick Observatory Supernova Search {LOSS}, have found hundreds of SNe, many of them in quite nearby galaxies {cz 4000 km/s}. Most of the objects were discovered before maximum brightness, and have follow-up photometry and spectroscopy; they include some of the best-studied SNe to date. We propose to conduct a snapshot imaging survey of the sites of some of these nearby objects, to obtain late-time photometry that {through the shape of the light and color curves} will help reveal the origin of their lingering energy. The images will also provide high-resolution information on the local environments of SNe that are far superior to what we can procure from the ground. For example, we will obtain color-color and color-magnitude diagrams of stars in these SN sites, to determine the SN progenitor masses and constraints on the reddening. Recovery of the SNe in the new HST images will also allow us to actually pinpoint their progenitor stars in cases where pre- explosion images exist in the HST archive. This proposal is an extension of our successful Cycle 13 snapshot survey with ACS. It is complementary to our Cycle 15 archival proposal, which is a continuation of our long-standing program to use existing HST images to glean information about SN environments. FLIGHT OPERATIONS SUMMARY: Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.) HSTARS: 11620 - NCC (NICMOS CRYO-COOLER) SAFED @ 354/1827z 11621 - GSAcq (2,3,2) Loss of Lock while guiding @ 356/1922 A Loss of Lock occurred on FGS 2 while guiding under FGSs 2 & 3. Observations affected: Astrometry Proposal # 11213 COMPLETED OPS REQUEST: 18376-0 - Off-Line +BB SPA Trim Relay 18377-0 - Lower FGS-1R K16 K-factor for Proposal 11945 COMPLETED OPS NOTES: (None) ************************ SCHEDULED***** SUCCESSFUL***** FAILURE TIMES FGS GSacq*************** 28***************** 28 FGS REacq*************** 13***************** 13 OBAD with Maneuver ***** 82***************** 82 LOSS of LOCK****************************************** 356/1922z SIGNIFICANT EVENTS: Flash Report: Off-Line +BB SPA Trim Relay (OR #18376) from Battery 3 @ 354/17:09z - this was in preparation for the upcoming hot period from DOY 348 until DOY 362. Flash Report: FGS-1R K16 K-factor lowered to a value of 4982 as preparation for 10 day Astrometry Proposal #11945 that started at 357/01:30z. |
Thread Tools | |
Display Modes | |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
Daily Report #4407 | Pataro, Pete | Hubble | 0 | July 19th 07 05:36 PM |
Daily Report #4385 | Cooper, Joe | Hubble | 0 | June 18th 07 02:55 PM |
Daily Report #4384 | Pataro, Pete | Hubble | 0 | June 15th 07 06:48 PM |
Daily Report | [email protected] | Hubble | 0 | October 29th 04 04:59 PM |
HST Daily Report 131 | George Barbehenn | Hubble | 0 | May 11th 04 02:48 PM |