Search Publications
M Dwarf Activity in the Pan-STARRS1 Medium-Deep Survey: First Catalog and Rotation Periods
Berger, E.; Rest, A.; Chambers, K. C. +10 more
We report on an ongoing project to investigate activity in the M dwarf stellar population observed by the Pan-STARRS1 Medium-Deep Survey (PS1-MDS). Using a custom-built pipeline, we refine an initial sample of ∼4 million sources in PS1-MDS to a sample of 184,148 candidate cool stars using color cuts. Motivated by the well-known relationship betwee…
A Perturbative Analysis of Synchrotron Spectral Index Variation over the Microwave Sky
Aluri, Pavan K.; Saha, Rajib
In this paper, we implement a perturbative approach, first proposed by Bouchet & Gispert, to estimate the variation of the spectral index of galactic polarized synchrotron emission, using a linear combination of simulated Stokes Q polarization maps of selected frequency bands from WMAP and Planck observations on a region of sky dominated by th…
Isolating the Young Stellar Population in the Outer Disk of NGC 300
Dolphin, Andrew E.; Skillman, Evan D.; Williams, Benjamin F. +2 more
The recent star formation history (SFH) in the outer disk of NGC 300 is presented through the analysis of color-magnitude diagrams (CMDs). We analyze resolved stellar photometry by creating CMDs from four Hubble Space Telescope fields containing a combination of images from the Advanced Camera for Surveys and the UVIS imager aboard the Wide Field …
Of Genes and Machines: Application of a Combination of Machine Learning Tools to Astronomy Data Sets
Kumar, S.; Chambers, K. C.; Flewelling, H. +8 more
We apply a combination of genetic algorithm (GA) and support vector machine (SVM) machine learning algorithms to solve two important problems faced by the astronomical community: star-galaxy separation and photometric redshift estimation of galaxies in survey catalogs. We use the GA to select the relevant features in the first step, followed by op…
Panchromatic Imaging of a Transitional Disk: The Disk of GM Aur in Optical and FUV Scattered Light
Apai, D.; Hamaguchi, K.; Henning, Th. +18 more
We have imaged GM Aurigae with the Hubble Space Telescope, detected its disk in scattered light at 1400 and 1650 Å, and compared these with observations at 3300 Å, 5550 Å, 1.1 µm, and 1.6 µm. The scattered light increases at shorter wavelengths. The radial surface brightness profile at 3300 Å shows no evidence of the 24 au radius cavit…
High-contrast Imaging of Intermediate-mass Giants with Long-term Radial Velocity Trends
Henning, Thomas; Terada, Hiroshi; Usuda, Tomonori +62 more
A radial velocity (RV) survey for intermediate-mass giants has been in operation for over a decade at Okayama Astrophysical Observatory (OAO). The OAO survey has revealed that some giants show long-term linear RV accelerations (RV trends), indicating the presence of outer companions. Direct-imaging observations can help clarify what objects genera…
Quantifying the Interstellar Medium and Cosmic Rays in the MBM 53, 54, and 55 Molecular Clouds and the Pegasus Loop Using Fermi-LAT Gamma-ray Observations
Mizuno, T.; Okumura, A.; Fukui, Y. +4 more
A study of the interstellar medium (ISM) and cosmic rays (CRs) using Fermi Large Area Telescope (LAT) data, in a region encompassing the nearby molecular clouds MBM 53, 54, and 55 and a far-infrared loop-like structure in Pegasus, is reported. By comparing the Planck dust thermal emission model with Fermi-LAT γ-ray data, it was found that neither …
Comparison of CME/Shock Propagation Models with Heliospheric Imaging and In Situ Observations
Lu, Lei; Feng, Xueshang; Liu, Ying D. +3 more
The prediction of the arrival time for fast coronal mass ejections (CMEs) and their associated shocks is highly desirable in space weather studies. In this paper, we use two shock propagation models, I.e., Data Guided Shock Time Of Arrival (DGSTOA) and Data Guided Shock Propagation Model (DGSPM), to predict the kinematical evolution of interplanet…
Properties of Interstellar Medium In Infrared-bright QSOs Probed by [O I] 63 um and [C II] 158 um Emission Lines
Tsai, Chao-Wei; Zhao, Yinghe; Yan, Lin
We present a study of the interstellar medium (ISM) in the host galaxies of nine QSOs at 0.1 < z < 0.2 with black hole masses of 3× {10}7 {M}⊙ to 3× {10}9 {M}⊙ based on the far-IR spectroscopy taken with Herschel Space Observatory. We detect the [O I] 63 µm ([C II] 158 µm) emission in…
Search for Gamma-Ray Emission from AE Aquarii with Seven Years of Fermi-LAT Observations
Rea, Nanda; Torres, Diego F.; Li, Jian +4 more
AE Aquarii (AE Aqr) is a cataclysmic binary hosting one of the fastest rotating ({P}{spin} = 33.08 s) white dwarfs (WDs) known. Based on seven years of Fermi Large Area Telescope (LAT) Pass 8 data, we report on a deep search for gamma-ray emission from AE Aqr. Using X-ray observations from ASCA, XMM-Newton, Chandra, Swift, Suzaku, and N…