Search Publications
Radio-loud Quasars above Redshift 4: Very Long Baseline Interferometry (VLBI) Imaging of an Extended Sample
Paragi, Zsolt; Krezinger, Máté; Frey, Sándor +7 more
High-redshift radio sources provide plentiful opportunities for studying the formation and evolution of early galaxies and supermassive black holes. However, the number of known radio-loud active galactic nuclei (AGN) above redshift 4 is rather limited. At high redshifts, it appears that blazars, with relativistically beamed jets pointing toward t…
First Census of Gas-phase Metallicity Gradients of Star-forming Galaxies in Overdense Environments at Cosmic Noon
Teplitz, Harry I.; Fan, Xiaohui; Cai, Zheng +8 more
We report the first spatially resolved measurements of gas-phase metallicity radial gradients in star-forming galaxies in overdense environments at z ≳ 2. The spectroscopic data are acquired by the MAMMOTH-Grism survey, a Hubble Space Telescope (HST) cycle 28 medium program. This program is obtaining 45 orbits of WFC3/IR grism spectroscopy in the …
Detection of Intracluster Globular Clusters in the First JWST Images of the Gravitational Lens Cluster SMACS J0723.3-7327 at z = 0.39
Lee, Myung Gyoon; Jang, In Sung; Bae, Jang Ho
We present a survey of globular clusters (GCs) in the massive gravitational lens cluster SMACS J0723.3-7327 at z = 0.39 based on the early released JWST/NIRCam images. In the color-magnitude diagrams of the point sources, we clearly find a rich population of intracluster GCs that are spread over a wide area of the cluster. Their ages, considering …
Phase-resolved spectroscopic analysis of the eclipsing black hole X-ray binary M33 X-7: System properties, accretion, and evolution
Massa, D.; Hamann, W. -R.; Postnov, K. A. +10 more
M33 X-7 is the only known eclipsing black hole high mass X-ray binary. The system is reported to contain a very massive O supergiant donor and a massive black hole in a short orbit. The high X-ray luminosity and its location in the metal-poor galaxy M33 make it a unique laboratory for studying the winds of metal-poor donor stars with black hole co…
Weak evidence for variable occultation depth of 55 Cnc e with TESS
Demory, B. -O.; Morris, B. M.; Schanche, N. +2 more
Context. 55 Cnc e is in a 0.73 day orbit transiting a Sun-like star. It has been observed that the occultation depth of this super-Earth, with a mass of 8 M⊕ and radius of 2 R⊕, changes significantly over time at mid-infrared wavelengths. Observations with Spitzer measured a change in its day-side brightness temperature of 12…
Updated Photometry of the Yellow Supergiant Progenitor and Late-time Observations of the Type IIb Supernova SN 2016gkg
Kilpatrick, Charles D.; Coulter, David A.; Foley, Ryan J. +4 more
We present Hubble Space Telescope (HST) observations of the Type IIb supernova (SN) SN 2016gkg at 652, 1698, and 1795 days from explosion with the Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3). Comparing to pre-explosion imaging from 2001 obtained with the Wide Field Planetary Camera 2, we demonstrate that SN 2016gkg is now fain…
Probing the Galactic halo with RR lyrae stars - III. The chemical and kinematic properties of the stellar halo
Tian, Haijun; Liu, Gaochao; Huang, Yang +3 more
Based on a large spectroscopic sample of ~4300 RR Lyrae stars with metallicity, systemic radial velocity, and distance measurements, we present a detailed analysis of the chemical and kinematic properties of the Galactic halo. Using this sample, the metallicity distribution function (MDF) as a function of r and the velocity anisotropy parameter β …
The K2-OjOS Project: New and revisited planets and candidates in K2 campaigns 5, 16, & 18
Bonavera, L.; González-Nuevo, J.; Korth, J. +28 more
We present the first results of K2-OjOS, a collaborative project between professional and amateur astronomers primarily aimed to detect, characterize, and validate new extrasolar planets. For this work, 10 amateur astronomers looked for planetary signals by visually inspecting the 20 427 light curves of K2 campaign 18 (C18). They found 42 planet c…
Solar Energetic Particles Produced during Two Fast Coronal Mass Ejections
Wang, Yuming; Guo, Jingnan; Li, Xiaolei +1 more
Two recent extremely fast coronal mass ejections (CMEs) are of particular interest. The first one originated from the southern hemisphere on 2021 October 28 and caused strong solar energetic particle (SEP) events over a wide longitude range from Earth, STEREO-A, to Mars. However, the other one, originating from the center of the Earth-viewed solar…
Data Fusion of Total Solar Irradiance Composite Time Series Using 41 Years of Satellite Measurements
Schmutz, W.; Haberreiter, M.; Dudok de Wit, T. +4 more
Since the late 1970s, successive satellite missions have been monitoring the sun's activity and recording the total solar irradiance (TSI). Some of these measurements have lasted for more than a decade. In order to obtain a seamless record whose duration exceeds that of the individual instruments, the time series have to be merged. Climate models …