Search Publications
The 3D Kinematics of the Orion Nebula Cluster. II. Mass-dependent Kinematics of the Inner Cluster
Lu, Jessica R.; Kim, Dongwon; Hsu, Chih-Chun +3 more
We present the kinematic analysis of 246 stars within $4^{\prime} $ from the center of Orion Nebula Cluster (ONC), the closest massive star cluster with active star formation across the full mass range, which provides valuable insights in the formation and evolution of star cluster on an individual-star basis. High-precision radial velocities and …
Radial Distribution of Electron Quasi-thermal Noise in the Outer Heliosphere
Chen, Ling; Li, Yi-Lun; Wu De, Jin
Voyager 1 and 2 are only the two spacecraft that have arrived and passed through the heliospheric boundaries. Based on the plasma data from the Voyager 2 spacecraft, the electron quasi-thermal noise (QTN) is investigated by using of the electron population model consisting of a core with Maxwellian distribution and a halo with kappa distribution. …
Protoplanetary Disks around Sun-like Stars Appear to Live Longer When the Metallicity is Low
Hirschauer, Alec S.; Fahrion, Katja; Lenkić, Laura +17 more
Previous Hubble Space Telescope observations of the star-forming cluster NGC 346 in the Small Magellanic Cloud (SMC) revealed a large population of pre-main-sequence (PMS) candidates, characterized by Hα excess emission in their photometry. However, without access to spectroscopy, the nature of these objects remained unclear. Using the NIRSpec ins…
Energetic Electrons Accelerated and Trapped in a Magnetic Bottle above a Solar Flare Arcade
Krucker, Säm; Chen, Bin; Yu, Sijie +6 more
Where and how flares efficiently accelerate charged particles remains an unresolved question. Recent studies revealed that a "magnetic bottle" structure, which forms near the bottom of a large-scale reconnection current sheet above the flare arcade, is an excellent candidate for confining and accelerating charged particles. However, further unders…
A Detailed Survey of the Parallel Mean Free Path of Solar Energetic Particle Protons and Electrons
Ruffolo, D.; Dresing, N.; Bandyopadhyay, R. +4 more
In this work, more than a dozen solar energetic particle (SEP) events are identified where the source region is magnetically well connected to at least one spacecraft at 1 au. The observed intensity–time profiles, for all available proton and electron energy channels, are compared to results computed using a numerical one-dimensional SEP transport…
JWST Photometry of Globular Clusters in A2744. II. Luminosity and Color Distributions
Harris, William E.; Reina-Campos, Marta
Deep JWST imaging of the giant galaxy cluster A2744, at redshift z = 0.308, is used to explore the features of its rich population of globular clusters (GCs), building on our initial survey of the system. We use the photometry of more than 10,000 GCs over a 3 mag range to construct the GC luminosity function and color distribution. These results n…
Halfway to the Peak: The JWST MIRI 5.6 µm Number Counts and Source Population
Veilleux, Sylvain; Marchesini, Danilo; Alberts, Stacey +9 more
We present an analysis of eight JWST Mid-Infrared Instrument (MIRI) 5.6 µm images with 5σ depths of ≈0.1 µJy. We detect 2854 sources within our combined area of 18.4 arcmin2. We compute the MIRI 5.6 µm number counts, including an analysis of the field-to-field variation. Compared to earlier published MIRI 5.6 µm …
How Small-scale Jetlike Solar Events from Miniature Flux Rope Eruptions Might Produce the Solar Wind
Panesar, Navdeep K.; Moore, Ronald L.; Sterling, Alphonse C.
We consider small-scale jetlike events that might make the solar wind, as has been suggested in recent studies. We show that the events referred to as "coronal jets" and as "jetlets" both fall on a power-law distribution that also includes large-scale eruptions and spicule-sized features; all of the jetlike events could contribute to the solar win…
The Remarkable X-Ray Spectra and Variability of the Ultraluminous Weak-line Quasar SDSS J1521+5202
Brandt, W. N.; Yu, Zhibo; Zou, Fan +5 more
We present a focused X-ray and multiwavelength study of the ultraluminous weak-line quasar (WLQ) SDSS J1521+5202, one of the few X-ray weak WLQs that is amenable to basic X-ray spectral and variability investigations. J1521+5202 shows striking X-ray variability during 2006–2023, by up to a factor of ≈32 in 0.5–2 keV flux, and our new 2023 Chandra …
Linking High-z and Low-z: Are We Observing the Progenitors of the Milky Way with JWST?
Marconi, Alessandro; Salvadori, Stefania; Rusta, Elka +2 more
The recent JWST observation of the Firefly Sparkle at z = 8.3 offers a unique opportunity to link the high- and the low-z Universe. Indeed, the claim of it being a Milky Way (MW) type of assembly at the cosmic dawn opens the possibility of interpreting the observation with locally calibrated galaxy-formation models. Here, we use the a state-of-the…