Search Publications
Interstellar Extinction in the Direction of the Young Open Cluster NGC 6530
Topasna, G. A.; Kaltcheva, N. T.; Jones, R. H.
We present UBVRI polarization observations of 12 B-type stars in the direction of the young open cluster NGC 6530, nine of them confirmed as probable members. The maximum degree of polarization for our target stars ranges from 0.16% to 2.84%, with an average value of 1.1%. We note variations of the polarization vector orientations across the clust…
Comparison of Multi-class and Binary Classification Machine Learning Models in Identifying Strong Gravitational Lenses
Bottrell, Connor; Fabbro, Sebastien; Teimoorinia, Hossen +1 more
Typically, binary classification lens-finding schemes are used to discriminate between lens candidates and non-lenses. However, these models often suffer from substantial false-positive classifications. Such false positives frequently occur due to images containing objects such as crowded sources, galaxies with arms, and also images with a central…
HST/FGS Trigonometric Parallaxes of M-dwarf Eclipsing Binaries
Schaefer, Gail H.; Nelan, Edmund P.; Ciardi, David R. +5 more
Hubble Space Telescope (HST) Fine Guidance Sensor (FGS) trigonometric parallax observations were obtained to directly determine distances to five nearby M-dwarf/M-dwarf eclipsing binary systems. These systems are intrinsically interesting as benchmark systems for establishing basic physical parameters for low-mass stars, such as luminosity L, and …
Evryscope-South Survey of Upper- and Pre-main Sequence Solar Neighborhood Stars
Law, Nicholas M.; Corbett, Hank; Gonzalez, Ramses +5 more
Using photometric data collected by Evryscope-South, we search for nearby young variable systems on the upper main sequence (UMS) and pre-main sequence (PMS). The Evryscopes are all-sky high-cadence telescope arrays operating in the Northern and Southern hemispheres. We base our search on a Gaia-selected catalog of young neighborhood upper- and pr…
Pixel-based Spectral Characterization of Mid-infrared Si Array Detectors for Astronomical Observations in Space
Kaneda, Hidehiro; Ishihara, Daisuke; Wada, Takehiko +2 more
Mid-infrared (IR) array detectors have been used for astronomical observations in space. However, the uniformities of their spectral response curves have not been investigated in detail, the understanding of which is important for spectroscopic observations using large array formats. We characterize the spectral responses of all the pixels in IR a…
Absolute Magnitudes of Early-type Supergiants from uvbyβ Photometry and Parallax Data
Paunzen, Ernst; Prišegen, Michal; Kaltcheva, Nadia +2 more
We combine Strömgren-Crawford uvbyβ photometry with Gaia-DR2 parallaxes for a sample of 880 supergiants of O-B9 spectral types to explore the potential of these data in providing physical parameters of such stars. We obtained reddening corrections and photometric absolute magnitudes via the existing uvbyβ calibrations. We calculated Gaia-based abs…
An AGB Star with a Thick Circumstellar Shell
Wang, Lifan; Durré, Mark; Mould, Jeremy +1 more
The Asymptotic Giant Branch is the terminal phase of red giant evolution with timescales of millions of years and a total mass lost from the star that is a significant fraction of the initial mass. Investigation of one of these stars, WISEA J173046.10-344455.5, a kpc in the direction of the center of the Galaxy, reveals a cool oxygen rich star wit…
The Faint Optical Counterparts Catalog at 19.4 < r < 22 mag from Herschel-ATLAS SDP Field
Wu, Hong; Zhu, Yi-Nan; Zhou, Zhi-Min +2 more
We carry out a spectroscopic survey with Hectospec mounted on the 6.5 m Multiple Mirror Telescope to obtain redshifts of optical counterparts of the Herschel-ATLAS sources in the science demonstration phase field. Our work concerns counterparts with a magnitude range at $19.4\lt {r}_{\mathrm{SDSS}}\lt 22$ mag. The observation covers two $\sim 1\ {…
The Zwicky Transient Facility: Data Processing, Products, and Archive
Cenko, S. Bradley; Riddle, Reed; Van Sistine, Angela +46 more
The Zwicky Transient Facility (ZTF) is a new robotic time-domain survey currently in progress using the Palomar 48-inch Schmidt Telescope. ZTF uses a 47 square degree field with a 600 megapixel camera to scan the entire northern visible sky at rates of ∼3760 square degrees/hour to median depths of g ∼ 20.8 and r ∼ 20.6 mag (AB, 5σ in 30 sec). We d…
Models and Simulations for the Photometric LSST Astronomical Time Series Classification Challenge (PLAsTiCC)
Galbany, L.; Brown, P. J.; González-Gaitán, S. +28 more
We describe the simulated data sample for the Photometric Large Synoptic Survey Telescope (LSST) Astronomical Time Series Classification Challenge (PLAsTiCC), a publicly available challenge to classify transient and variable events that will be observed by the LSST, a new facility expected to start in the early 2020s. The challenge was hosted by K…