Search Publications
The R-process Alliance: The Peculiar Chemical Abundance Pattern of RAVE J183013.5-455510
Whitten, Devin D.; Beers, Timothy C.; Placco, Vinicius M. +14 more
We report on the spectroscopic analysis of RAVE J183013.5-455510, an extremely metal-poor star, highly enhanced in CNO, and with discernible contributions from the rapid neutron-capture process. There is no evidence of binarity for this object. At $[\mathrm{Fe}/{\rm{H}}]$ = -3.57, this star has one of the lowest metallicities currently observed, w…
The Fifth Candidate for an Intermediate-mass Black Hole in the Galactic Center
Oka, Tomoharu; Tsujimoto, Shiho; Iwata, Yuhei +2 more
We report the results of high-resolution molecular line observations of the high-velocity compact cloud HCN-0.085-0.094 with the Atacama Large Millimeter/submillimeter Array. The HCN J = 4-3, HCO+ J = 4-3, and CS J = 7-6 line images reveal that HCN-0.085-0.094 consists mainly of three small clumps with extremely broad velocity widths. E…
Broadband Selection, Spectroscopic Identification, and Physical Properties of a Population of Extreme Emission-line Galaxies at 3 < z < 3.7
Harikane, Yuichi; Shibuya, Takatoshi; Suzuki, Tomoko L. +7 more
We present the selection, spectroscopic identification, and physical properties of extreme emission-line galaxies (EELGs) at 3 < z < 3.7, aiming at studying physical properties of an analog population of star-forming galaxies (SFGs) at the epoch of reionization. The sample is selected based on the excess in the observed Ks broadband flux rel…
MCR-TRGB: A Multiwavelength-covariant, Robust Tip of the Red Giant Branch Measurement Method
Dalcanton, J. J.; Boyer, M. L.; Williams, B. F. +2 more
We present a new method to measure colors and magnitudes of the tip of the red giant branch (TGRB) in multiple bandpasses simultaneously by fitting an n-dimensional Gaussian to photometry of candidate tip stars. We demonstrate that this method has several advantages over traditional edge detection, particularly in regimes where the TRGB magnitude …
Hyper Suprime-Cam Low Surface Brightness Galaxies. II. A Hubble Space Telescope Study of the Globular Cluster Systems of Ultradiffuse Galaxies in Groups
Greene, Jenny E.; Goulding, Andy D.; Beaton, Rachael L. +4 more
We increase the sample of ultradiffuse galaxies (UDGs) in lower-density environments with characterized globular cluster (GC) populations using new Hubble Space Telescope observations of nine UDGs in group environments. While the bulk of our UDGs have GC abundances consistent with normal dwarf galaxies, two of these UDGs have excess GC populations…
Imaging and Spectral Study on the Null Point of a Fan-spine Structure During a Solar Flare
Yang, Shuhong; Zhang, Jun; Zhong, Ze +3 more
Using the multi-instrument observations, we make the first simultaneous imaging and spectral study on the null point of a fan-spine magnetic topology during a solar flare. When magnetic reconnection occurs at the null point, the fan-spine configuration brightens in the (extreme-)ultraviolet channels. In the Hα images, the fan-spine structure is pa…
Revealing the Dark Threads of the Cosmic Web
Tripp, Todd M.; Prochaska, J. Xavier; Tejos, Nicolas +4 more
Modern cosmology predicts that matter in our universe today has assembled into a vast network of filamentary structures colloquially termed the "cosmic web." Because this matter is either electromagnetically invisible (I.e., dark) or too diffuse to image in emission, tests of this cosmic web paradigm are limited. Wide-field surveys do reveal web-l…
Binary Fraction Estimation of Main-sequence Stars in 12 Open Clusters: Based on the Homogeneous Data of LAMOST Survey and Gaia DR2
Wang, Jiaxin; Fu, Jianning; Niu, Hubiao
Based on the homogeneous low-resolution spectra data observed by Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and the Gaia Data Release 2 (Gaia DR2) photometric data, we chose 12 open clusters (OCs) to study their fundamental parameters and binary fractions (BFs). For each OC, more than 20 cluster members were observed by LAM…
A Gravitational Redshift Measurement of the White Dwarf Mass-Radius Relation
Cheng, Sihao; Zakamska, Nadia L.; Chandra, Vedant +1 more
The mass-radius relation of white dwarfs is largely determined by the equation of state of degenerate electrons, which causes the stellar radius to decrease as mass increases. Here we observationally measure this relation using the gravitational redshift effect, a prediction of general relativity that depends on the ratio between stellar mass and …
ALMA Observations of Quasar Host Galaxies at z ≃ 4.8
Maiolino, Roberto; Trakhtenbrot, Benny; Netzer, Hagai +4 more
We present ALMA Band 7 data of the [C II] $\lambda 157.74\,\mu {\rm{m}}$ emission line and underlying far-IR (FIR) continuum for 12 luminous quasars at $z\simeq 4.8$ powered by fast-growing supermassive black holes (SMBHs). Our total sample consists of 18 quasars, 12 of which are presented here for the first time. The new sources consist of six He…