Search Publications
Detection of Superluminal Motion in the X-Ray Jet of M87
Cheung, C. C.; Jones, Christine; Meyer, Eileen T. +5 more
Chandra HRC observations are investigated for evidence of proper motion and brightness changes in the X-ray jet of the nearby radio galaxy M87. Using images spanning 5 yr, proper motion is measured in the X-ray knot HST-1, with a superluminal apparent speed of 6.3 ± 0.4c, or 24.1 ± 1.6 mas yr-1, and in Knot D, with a speed of 2.4 ± 0.6c…
The Relation between Galaxy ISM and Circumgalactic O VI Gas Kinematics Derived from Observations and ΛCDM Simulations
Charlton, Jane C.; Kacprzak, Glenn G.; Churchill, Christopher W. +8 more
We present the first galaxy-O VI absorption kinematic study for 20 absorption systems (EW > 0.1 Å) associated with isolated galaxies (0.15 ≤ z ≤ 0.55) that have accurate redshifts and rotation curves obtained using Keck/ESI. Our sample is split into two azimuthal angle bins: major axis (Φ < 25°) and minor axis (Φ > 33°). O VI absorption a…
Hypervelocity Stars from a Supermassive Black Hole-Intermediate-mass Black Hole Binary
Tagawa, Hiromichi; Rossi, Elena Maria; Fragione, Giacomo +4 more
In this paper we consider a scenario in which the currently observed hypervelocity stars in our Galaxy have been ejected from the Galactic center as a result of dynamical interactions with an intermediate-mass black hole (IMBH) orbiting the central supermassive black hole (SMBH). By performing three-body scattering experiments, we calculate the di…
The Quintuplet Cluster: Extended Structure and Tidal Radius
Rui, Nicholas Z.; Hosek, Matthew W., Jr.; Lu, Jessica R. +4 more
The Quintuplet star cluster is one of only three known young (<10 Myr) massive (M > 104 M ⊙) clusters within ∼100 pc of the Galactic center (GC). In order to explore star cluster formation and evolution in this extreme environment, we analyze the Quintuplet’s dynamical structure. Using the HST WFC3-IR instrument, we tak…
Source Imaging of a Moving Type IV Solar Radio Burst and Its Role in Tracking Coronal Mass Ejection from the Inner to the Outer Corona
Chen, Yao; Feng, Shiwei; Vasanth, V. +5 more
Source imaging of solar radio bursts can be used to track energetic electrons and associated magnetic structures. Here we present a combined analysis of data at different wavelengths for an eruption associated with a moving type IV (t-IVm) radio burst. In the inner corona, the sources are correlated with a hot and twisted eruptive EUV structure, w…
The Dust and Molecular Gas in the Brightest Cluster Galaxy in MACS 1931.8-2635
Donahue, Megan; Frye, Brenda; Liu, Hauyu Baobab +6 more
We present new Atacama Large Millimeter Array observations of the molecular gas and far-infrared continuum around the brightest cluster galaxy (BCG) in the cool-core cluster MACS 1931.8-2635. Our observations reveal (1.9 ± 0.3) × 1010 M ⊙ of molecular gas, on par with the largest known reservoirs of cold gas in a cluster core…
An Ongoing Mid-infrared Outburst in the White Dwarf 0145+234: Catching in Action the Tidal Disruption of an Exoasteroid?
Ge, Jian; Wright, Edward L.; Bauer, James +7 more
We report the detection of a large-amplitude MIR outburst in the white dwarf (WD) 0145+234 in the NEOWISE Survey data. The source had a stable MIR flux before 2018, and was brightened by about 1.0 magnitude in the W1 and W2 bands within half a year and has been continuously brightening since then. No significant variations are found in the optical…
Nature of Faint Radio Sources in GOODS-North and GOODS-South Fields. I. Spectral Index and Radio-FIR Correlation
Giavalisco, Mauro; Yun, Min S.; Kawabe, Ryohei +9 more
We present the first results from the deep and wide 5 GHz radio observations of the Great Observatories Origins Deep Survey (GOODS)-North (σ = 3.5 µJy beam-1, synthesized beam size θ = 1.″47 × 1.″42, and 52 sources over 109 arcmin2) and GOODS-South (σ = 3.0 µJy beam-1, θ = 0.″98 × 0.″45, and 88 sources …
Unusual Plasma and Particle Signatures at Mars and STEREO-A Related to CME-CME Interaction
Dumbović, Mateja; Temmer, Manuela; Veronig, Astrid +15 more
On 2017 July 25 a multistep Forbush decrease (FD) with a remarkable total amplitude of more than 15% was observed by Mars Science Laboratory/Radiation Assessment Detector at Mars. We find that these particle signatures are related to very pronounced plasma and magnetic field signatures detected in situ by STEREO-A on 2017 July 24, with a higher-th…
HALO7D II: The Halo Velocity Ellipsoid and Velocity Anisotropy with Distant Main-sequence Stars
Anderson, Jay; van der Marel, Roeland P.; Wetzel, Andrew +7 more
The Halo Assembly in Lambda Cold Dark Matter: Observations in 7 Dimensions (HALO7D) data set consists of Keck II/DEIMOS spectroscopy and Hubble Space Telescope-measured proper motions of Milky Way halo main-sequence turnoff stars in the CANDELS fields. In this paper, the second in the HALO7D series, we present the proper motions for the HALO7D sam…