Search Publications
Formation of Clays, Ferrihydrite, and Possible Salts in Hydrae Chasma, Mars
Weitz, Catherine M.; Bishop, Janice L.
We used multiple orbital data sets to analyze the morphology, composition, and stratigraphy of clays and other hydrated deposits within Hydrae Chasma. Fe/Mg-smectites are concentrated along the lower floor of the chasma, adjacent to pit craters. There are at least two distinct smectites that vary in their morphology and spectral properties, with a…
A Supernova Remnant Counterpart for HESS J1832-085
Haberl, F.; Filipović, M. D.; Pühlhofer, G. +18 more
We examine the new Galactic supernova remnant (SNR) candidate, G23.11+0.18, as seen by the Murchison Widefield Array radio telescope. We describe the morphology of the candidate and find a spectral index of -0.63 ± 0.05 in the 70-170 MHz domain. Coincident TeV gamma-ray detection in High Energy Stereoscopic System (HESS) data supports the SNR natu…
High Spatial Resolution Thermal Infrared Spectroscopy with ALES: Resolved Spectra of the Benchmark Brown Dwarf Binary HD 130948BC
Spalding, Eckhart; Leisenring, Jarron; Woodward, Charles E. +6 more
We present 2.9-4.1 µm integral field spectroscopy of the L4+L4 brown dwarf binary HD 130948BC, obtained with the Arizona Lenslets for Exoplanet Spectroscopy (ALES) mode of the Large Binocular Telescope Interferometer. The HD 130948 system is a hierarchical triple system, in which the G2V primary is joined by two co-orbiting brown dwarfs. By …
Probing inhomogeneity in the helium ionizing UV background
Kim, Tae-Sun; Syphers, David; Pieri, Matthew M. +1 more
We present an analysis combining the simultaneous measurement of intergalactic absorption by hydrogen ({{H {I}}}), helium ({{He {II}}}), and oxygen ({{O {VI}}}) in UV and optical quasar spectra. The combination of the {{H {I}}} and {{He {II}}} Lyman-alpha forests through η (the ratio of column densities of singly ionized helium to neutral hydrogen…
Optical observations and CYCLOPS post-shock region modelling of the polar V348 Pav
Belloni, Diogo; Rodrigues, Claudia V.; Diaz, Marcos P. +3 more
Post-shock regions (PSR) of polar cataclysmic variables (CVs) produce most of their luminosity and give rise to high circular polarization in optical wavelengths and strong variability on the white dwarf (WD) rotation period, which are distinctive features of these systems. To investigate the polar candidate V348 Pav, we obtained a comprehensive o…
DBSCAN Clustering Algorithm for the Detection of Nearby Open Clusters Based on Gaia-DR2two
Gao, Xin-hua; Wang, Chao; Xu, Shou-kun +1 more
In this paper, we attempt to use the DBSCAN (Density-Based Spatial Clustering of Applications with Noise) clustering algorithm to detect nearby open clusters based on the Gaia Data Release 2 (Gaia-DR2). We select 594284 stars (within a distance of 100 pc to the Sun) from the Gaia-DR2 catalog, and construct a five-dimensional phase space (three-dim…
A New Einstein Cross Gravitational Lens of a Lyman-break Galaxy
Corradi, Romano L. M.; Vulcani, Benedetta; Negrello, Mattia +5 more
We report the study of an “Einstein Cross” configuration first identified in a set of HST images by Cerny et al. Deep spectroscopic observations obtained at the Spanish 10.4 m Gran Telescopio Canarias telescope, allowed us to demonstrate the lens nature of the system, that consists of a Lyman-break galaxy (LBG), not a quasi-stellar object as is us…
Neural Network for Solar Irradiance Modeling (NN-SIM)
Mauceri, Steffen; Coddington, Odele; Lyles, Danielle +1 more
An understanding of solar variability over a broad range of wavelengths and timescales is needed by scientists studying Earth's climate. While the current understanding of solar irradiance from measurements and models is maturing, there remain notable areas of discrepancy that highlight a lack of understanding of the variability in solar spectral …
Unveiling the nature of candidate high-mass young stellar objects in the Magellanic Clouds with near-IR spectroscopy
Meixner, Margaret; Reiter, Megan; Nayak, Omnarayani +1 more
As nearby neighbours to the Milky Way, the Large and Small Magellanic Clouds (LMC and SMC) provide a unique opportunity to study star formation in the context of their galactic ecosystems. Thousands of young stellar objects (YSOs) have been characterized with large-scale Spitzer and Herschel surveys. In this paper, we present new near-IR spectrosc…
Discovery of an Outbursting 12.8 Minute Ultracompact X-Ray Binary
Udalski, Andrzej; Mróz, Przemek; Skowron, Jan +2 more
We report the discovery of OGLE-UCXB-01, a 12.8 minute variable object located in the central field of Galactic bulge globular cluster Djorg 2. The presence of frequent, short-duration brightenings at such an ultrashort period in long-term OGLE photometry together with the blue color of the object in Hubble Space Telescope images and the detection…