Had I special: The Astronomical Contributions of the Herschel Family

НазваниеHad I special: The Astronomical Contributions of the Herschel Family
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Kepler Target Pixel Files

Susan E. Thompson1, S. McCauliff2, S. Bryson2, M. Still2, J. van Cleve2, J. Dotson2, J. Twicken2, T. Klaus2, M. Cote2, M. Fanelli2
1SETI Institute/NASA Ames, 2NASA Ames Research Center.

Exhibit Hall

In early 2011, the Kepler Mission will make available the pixel data for all observed targets, in addition to the aperture photometry light curves currently provided at the Multi-mission Archive at STScI (MAST). These target pixel files will contain images of the calibrated flux, the subtracted background, and the removed cosmic rays for the target at each cadence. Certain targets, such as highly variable stars, non-stellar targets, or saturated targets, require an analysis beyond fixed, optimal aperture photometry in order to retrieve all the information from the data. For a few cases we demonstrate the utility of the target pixel files in understanding the quality of the data and in performing specialized aperture photometry. Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA, Science Mission Directorate.


The Kepler Guest Observer Program

Martin D. Still1, M. Fanelli1, K. Kinemuchi1, Kepler Science Team
1NASA Ames Research Center.

Exhibit Hall

Kepler is a NASA Discovery mission to identify and characterize Earth-size planets within the habitable zone around nearby stars. The Kepler instrument also provides an unprecedented opportunity to test and refine a diverse range of astrophysical paradigms with high-precision, uniform and rapid cadence data, containing none of the diurnal or seasonal gaps that limit ground-based observations. Kepler provides open opportunities to exploit existing data and propose for new targets and science. This poster provides directions to resources and data at the Kepler data archive at MAST and the Kepler Guest Observer Office.


Finding Planets from Variable Star Pulsation Arrival Times with Kepler

Fergal Mullally1, K. Kinemuchi1, S. E. Thompson1, J. F. Rowe1
1Kepler Science Office.

Exhibit Hall

We examine the potential for planet detection using lightcurve arrival times around a variety of stars in the Kepler field. Arrival time analysis has been used to find planets around pulsars and sub-dwarf stars. When a variable star is orbiting the center of mass of a planetary system, its distance from the earth changes periodically. This change in distance is observed as a change in the observed arrival time of otherwise stable pulsations here on Earth. The sensitivity of the technique is set by the jitter of the pulsation period and phase, and the periods of detectable planets by the long term stability of the pulsation modes. We examine the limits that can be placed of a variety of variable stars using public data from the first quarter of observations by the Kepler space telescope.
Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA, Science Mission Directorate


An Update to the Kepler Eclipsing Binary Catalog: the use of Pixel Time Series to Identify Blended Eclipsing Binary Systems

Michael Rucker1, N. M. Batalha1, A. Prsa2, S. T. Bryson3, L. R. Doyle4, R. W. Slawson4, W. F. Welsh5, J. A. Orosz5
1Department of Physics and Astronomy, San Jose State University, 2Department of Astronomy and Astrophysics, Villanova University, 3NASA Ames Research Center, 4SETI Institute, 5Astronomy Department, San Diego State University.

Exhibit Hall

The Kepler telescope is providing a nearly seamless stream of photometric data of approximately 150,000 stars with unprecedented precision. The Kepler Eclipsing Binary (EB) catalog (based on the first 43 days of data; arXiv:1006.2815) is being continuously augmented as more data are collected and EBs are detected at longer periods. The catalog is expected to contain a small fraction of blends - cases where the eclipse signature is from a nearby source in the photometric aperture. In constructing the original catalog, obvious blends were identified and removed and/or reassigned to the appropriate point source. We build upon this work by performing pixel-level tests similar to those used to identify false positives amongst the Kepler exoplanet candidates. We summarize these tests here and provide examples that illustrate the types of blend scenarios that we have identified. Where appropriate and possible, we modified Kepler’s target list with the newly found Kepler star identification numbers. The changes reported here will affect the target lists which will go into effect on December 23, 2010 (start of Quarter 8). An updated version of the Kepler Eclipsing Binary catalog is available online at NASA’s Multimission Archive at STSci (MAST) website (http://archive.stsci.edu/kepler).


Pixel-Level Analysis Techniques for False-Positive Identification in Kepler Data

Steve Bryson1, J. Jenkins2, R. Gilliland3, N. Batalha4, T. N. Gautier5, J. Rowe1, E. Dunham6, D. Latham7, D. Caldwell2, J. Twicken2, P. Tenenbaum2, B. Clarke2, J. Li2, H. Wu2, E. Quintana2, D. Ciardi5, G. Torres7, J. Dotson1, M. Still1
1NASA Ames Research Center, 2SETI/NASA Ames Research Center, 3Space Telescope Science Institute, 4SJSU/NASA Ames Research Center, 5Jet Propulsion Laboratory, 6Lowell Observatory, 7Harvard-Smithsonian Center for Astrophysics.

Exhibit Hall

The Kepler mission seeks to identify Earth-size exoplanets by detecting transits of their parent star. The resulting transit signature will be small (~100 ppm). Several astrophysical phenomena can mimic an Earth-size transit signature, most notably background eclipsing binaries (BGEBs). As part of a larger false-positive identification effort, pixel-level analysis of the Kepler data has proven crucial in identifying the likelihood of these confounding signals. Pixel-level analysis is primarily useful for the case of the transit being a BGEB. Several analysis techniques are presented, including:
- measurement of centroid motion in and out of transit compared with detailed modeling of expected centroid motion, including an estimate of the transit source location
- transit source location determination through a high-precision PSF-fit of the difference between in- and out-of-transit pixels, directly measuring the location of the transit source
- source location determination through fitting the observed summed flux time series (or the light curve derived from the transit model) to each pixel's time series data.
These techniques have been automated and are being considered for inclusion in the Kepler Science Operations Center Data Analysis Pipeline. They are supplemented by various diagnostic plots of the Kepler data as well as comparison with background stars identified by the Kepler Follow-up Observing Program (FOP). The final determination of whether an observed transit is a false positive integrates several sources, including pixel-level analysis and FOP results. Pixel-level techniques can identify BGEBs that are separated from the Kepler target star by more than a certain radius, called the "radius of confusion". The determination of the radius of confusion, and the role it plays in assigning the probability of the transit being due to a planet, is briefly discussed. The statistics from the latest false-positive list are provided.
Funding for this mission provided by NASA's Discovery Program Office, SMD.


The Kepler Data Archive at MAST: What`s in it for me?

Dorothy A. Fraquelli1, R. Thompson1, S. Tseng1, M. Smith1
1Computer Sciences Corp..

Exhibit Hall

Hosted by MAST, the Multi-Mission Archive at Space Telescope, the Kepler Archive now contains over a year's worth of observations on more than 150,000 objects. The observations consist of light curves, both public and proprietary, target pixel files and full frame images (FFI). Supporting information includes data release notes, the Instrument Handbook, an Archive Manual and SPIE papers describing the instrument and data processing (in advance of the Kepler Data Hand Book). High level science products (HLSP) for the announced planets are available. The archive also contains the Kepler Input Catalog (KIC), the Kepler Target Catalog (KTC) and the Characteristics Table (CT).
We will show examples of how to search for and retrieve data, including FFIs and light curves, how Kepler GOs and science team members can download their data from an ftp area, how to view public light curves and FFIs, and, for Kepler proposers, how to locate objects in the KIC. We will discuss the different ways of retrieving Kepler data. A companion poster details MAST's GALEX-Kepler cross-match catalog, a unique product that supplies UV colors to complement the KIC's ground-based observations.
Demos of the web site are available at the STScI booth.


Public Kepler Data on the Bright Star Theta Cygni

Michael Robert Haas1, S. T. Bryson1, J. F. Rowe1, M. D. Still2
1NASA Ames Research Center, 2BAER Institute.

Exhibit Hall

The bright star Theta Cygni (Kepler ID 11918630) has been observed by Kepler in both short (59 sec) and long (29.4 min) cadence for a period of approximately 50 days starting on MJD 55410. These observations were made at the request of the Kepler Guest Observer Office and are intended for immediate public release. The purpose is to demonstrate Kepler’s exquisite photometric precision on bright, highly saturated targets. Theta Cygni is a F3V/M3V binary with a visual magnitude of 4.9/13.0. The short-cadence data show evidence of granulation (i.e., convection) out to about 1 mHz (~100 c/d) and clear detection of numerous p-modes with a peak near 1.8 mHz (~150 c/d). The high-frequency noise floor has a 3-sigma upper envelope of 0.4 ppm. The amplitude of the p-modes agrees with the stellar effective temperature, indicating that the star has a thin convective layer. Since a custom aperture was employed, the light curves will be constructed manually and placed on the Guest Observer website (http://keplergo.arc.nasa.gov/). The corresponding pixel-level data will be available from the Kepler archive (http://archive.stsci.edu/kepler/). The Kepler mission can accommodate a small number of such bright targets every quarter. Observing proposals can be submitted annually to the peer-reviewed Guest Observer Program, or much less formally on a quarterly basis for Director’s Discretionary Time (see http://keplergo.arc.nasa.gov/GOprogramDDT.shtml).
Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA, Science Mission Directorate.


Application of Bayesian Systematic Error Correction to Kepler Photometry

Jeffrey E. Van Cleve1, J. M. Jenkins1, J. D. Twicken1, J. C. Smith1, M. N. Fanelli2
1SETI Institute/NASA Ames Research Center,, 2Bay Area Environmental Research Institute.

Exhibit Hall

In a companion talk (Jenkins et al.), we present a Bayesian Maximum A Posteriori (MAP) approach to systematic error removal in Kepler photometric data, in which a subset of intrinsically quiet and highly correlated stars is used to establish the range of “reasonable” robust fit parameters, and hence mitigate the loss of astrophysical signal and noise injection on transit time scales (<3d), which afflict Least Squares (LS) fitting. In this poster, we illustrate the concept in detail by applying MAP to publicly available Kepler data, and give an overview of its application to all Kepler data collected through June 2010. We define the correlation function between normalized, mean-removed light curves and select a subset of highly correlated stars. This ensemble of light curves can then be combined with ancillary engineering data and image motion polynomials to form a design matrix from which the principal components are extracted by reduced-rank SVD decomposition. MAP is then represented in the resulting orthonormal basis, and applied to the set of all light curves. We show that the correlation matrix after treatment is diagonal, and present diagnostics such as correlation coefficient histograms, singular value spectra, and principal component plots. We then show the benefits of MAP applied to variable stars with RR Lyrae, harmonic, chaotic, and eclipsing binary waveforms, and examine the impact of MAP on transit waveforms and detectability. After high-pass filtering the MAP output, we show that MAP does not increase noise on transit time scales, compared to LS. We conclude with a discussion of current work selecting input vectors for the design matrix, representing and numerically solving MAP for non-Gaussian probability distribution functions (PDFs), and suppressing high-frequency noise injection with Lagrange multipliers. Funding for this mission is provided by NASA, Science Mission Directorate.


Validation of Candidate Multiple-Transiting Planet Systems and Assessing Possible False Positives based on Photometric Observables

Robert Morehead1, E. B. Ford1, Kepler Science Team
1University of Florida.

Exhibit Hall

Planetary systems with multiple planets that transit their host star are of great interest for studying the architecture of planetary systems (Steffen et al. 2010; Holman et al. 2010). Even space-based exoplanet transit surveys, such as CoRoT and Kepler, must be careful to exclude astrophysical false positives that can mimic the photometric signature of multiple-transiting planet system (MTPS). Due to large point spread functions, a putative MTPS might actually be: 1) a true MTPS, 2) a blend of an eclipsing binary and a star with a single transiting planet, 3) a blend of two eclipsing binaries, or 4) two stars each with a single transiting planet. Assessing the relative probability for each of these possibilities is important both for validating potential planets and for prioritizing the limited follow-up resources that can contribute to validation or confirmation of such systems.
We introduce new observable parameters based on ratios of the measured transit durations in MTPSs, as well as the measured orbital periods and (when available) impact parameters. We explore the utility of these parameters for validating candidate MTPSs and/or rejecting false positives. For multiple planets around the same star, these parameters have values near one. The distribution of these parameters for certain blend scenarios can be markedly different. We investigate these distributions through Monte Carlo simulations of three different types of blends; planet-binary, binary-binary, and planet-planet and compare these to the distribution for true MTPSs. We present results based on previously released Kepler data and simulations using multiple distributions for the orbital inclinations, eccentricities, and binary star population.
Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA, Science Mission Directorate

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