Search Publications
M-subdwarf Research. I. Identification, Modified Classification System, and Sample Construction
Qin, Li; Luo, A. -Li; Zhang, Shuo +7 more
We propose a revision of the system developed by Lépine et al. for spectroscopic M-subdwarf classification. Based on an analysis of subdwarf spectra and templates from Savcheva et al., we show that the CaH1 feature originally proposed by Gizis is important in selecting reliable cool subdwarf spectra. This index should be used in combination with t…
An Atlas of Coronal Electron Density at 5R ⊙. II. A Spherical Harmonic Method for Density Reconstruction
Morgan, Huw
This is the second of a series of three papers that present a methodology with the aim of creating a set of maps of the coronal density over a period of many years. This paper describes a method for reconstructing the coronal electron density based on spherical harmonics. By assuming a radial structure to the corona at the height of interest, line…
Swift-XRT Follow-up of Gravitational-wave Triggers in the Second Advanced LIGO/Virgo Observing Run
Troja, E.; Cenko, S. B.; Sakamoto, T. +37 more
The Neil Gehrels Swift Observatory carried out prompt searches for gravitational-wave (GW) events detected by the LIGO/Virgo Collaboration (LVC) during the second observing run (“O2”). Swift performed extensive tiling of eight LVC triggers, two of which had very low false-alarm rates (GW170814 and the epochal GW170817), indicating a high confidenc…
Exoplanets in the Antarctic Sky. II. 116 Transiting Exoplanet Candidates Found by AST3-II (CHESPA) within the Southern CVZ of TESS
Wittenmyer, Robert A.; Wang, Lifan; Yang, Ming +37 more
We report first results from the CHinese Exoplanet Searching Program from Antarctica (CHESPA)—a wide-field high-resolution photometric survey for transiting exoplanets carried out using telescopes of the AST3 (Antarctic Survey Telescopes times 3) project. There are now three telescopes (AST3-I, AST3-II, and CSTAR-II) operating at Dome A—the highes…
Spitzer Catalog of Herschel-selected Ultrared Dusty Star-forming Galaxies
Serjeant, Stephen; Dunne, Loretta; Ashby, Matthew L. N. +24 more
The largest Herschel extragalactic surveys, H-ATLAS and HerMES, have selected a sample of “ultrared” dusty star-forming galaxies (DSFGs) with rising SPIRE flux densities (S 500 > S 350 > S 250; the so-called “500 µm risers”) as an efficient way for identifying DSFGs at higher redshift (z > 4). In thi…
Cassini Composite Infrared Spectrometer (CIRS) Observations of Titan 2004-2017
Bézard, Bruno; Vinatier, Sandrine; Lellouch, Emmanuel +16 more
From 2004 to 2017, the Cassini spacecraft orbited Saturn, completing 127 close flybys of its largest moon, Titan. Cassini’s Composite Infrared Spectrometer (CIRS), one of 12 instruments carried on board, profiled Titan in the thermal infrared (7-1000 µm) throughout the entire 13 yr mission. CIRS observed on both targeted encounters (flybys) …
A New Automatic Tool for CME Detection and Tracking with Machine-learning Techniques
Zhang, Yan; Feng, Li; Lu, Lei +7 more
With the accumulation of coronal mass ejection (CME) observations by coronagraphs, automatic detection and tracking of CMEs has proven to be crucial. The excellent performance of the convolutional neural network in image classification, object detection, and other computer vision tasks motivates us to apply it to CME detection and tracking as well…
Identifying Spectral Lines to Study Coronal Mass Ejection Evolution in the Lower Corona
Landi, Enrico; Rivera, Yeimy J.; Lepri, Susan T.
As prominences propagate away from the Sun via a coronal mass ejection (CME), they expand, accelerate, and are strongly heated. The heating is substantial enough to continuously ionize the prominence plasma, making it difficult to follow its dynamic evolution with a single extreme ultraviolet (EUV) narrow-band channel or a white light instrument. …
Nonlinear Color-Metallicity Relations of Globular Clusters. VIII. Reproducing Color Distributions of Individual Globular Cluster Systems in the Virgo and Fornax Galaxy Clusters
Chung, Chul; Lee, Sang-Yoon; Yoon, Suk-Jin
The color distributions of globular clusters (GCs) in individual early-type galaxies show great diversity in their morphology. Based on the conventional “linear” relationship between the colors and metallicities of GCs, the GC metallicity distributions inferred from colors and in turn their formation histories, should be as diverse as they appear.…
The Ultraviolet Detection of Diffuse Gas in Galaxy Groups
Danforth, Charles W.; Stocke, John T.; Jannuzi, Buell +5 more
A small survey of the UV-absorbing gas in 12 low-z galaxy groups has been conducted using the Cosmic Origins Spectrograph on board the Hubble Space Telescope. Targets were selected from a large, homogeneously selected sample of groups found in the Sloan Digital Sky Survey. A critical selection criterion excluded sight lines that pass close (<1.…