Search Publications
Diurnal Ejection of Boulder Clusters on Comet 67P Lasting beyond 3 au
Keller, Horst Uwe; Shi, Xian; Güttler, Carsten +6 more
Ejection of large boulder-like debris is a vigorous form of cometary activity that is unlikely induced by water ice out-gassing alone but rather associated with the sublimation of super-volatile ices. Though perceived on several comets, the actual pattern and mechanism of such activity are still unclear. Here we report on a specialized observation…
Next-generation Accretion Disk Reflection Model: High-density Plasma Effects
Kallman, Timothy R.; Bautista, Manuel; Harrison, Fiona A. +5 more
Luminous accretion disks around black holes are expected to have densities of ∼1015‑1022 cm‑3, which are high enough that plasma physics effects become important. Many of these effects have been traditionally neglected in the calculation of atomic parameters, and therefore in photoionization models and ultimately a…
Artificial Intelligence Assisted Inversion (AIAI): Quantifying the Spectral Features of 56Ni of Type Ia Supernovae
Wang, Lifan; Hu, Lei; Brown, Peter J. +1 more
Following our previous study of Artificial Intelligence Assisted Inversion (AIAI) of supernova analyses, we train a set of deep neural networks based on the 1D radiative transfer code TARDIS to simulate the optical spectra of Type Ia supernovae (SNe Ia) between 10 and 40 days after the explosion. The neural networks are applied to derive the mass …
Photometry of Saturated Stars with Neural Networks
Kochanek, Christopher S.; Winecki, Dominik
We use a multilevel perceptron (MLP) neural network to obtain photometry of saturated stars in the All-Sky Automated Survey for Supernovae (ASAS-SN). The MLP can obtain fairly unbiased photometry for stars from g ≃ 4 to 14 mag, particularly compared to the dispersion (15%–85% 1σ range around the median) of 0.12 mag for saturated (g < 11.5 mag) …
The Long-term Spin-down Trend of Ultraluminous X-Ray Pulsar M82 X-2
Liu, Jiren
The discovery in 2014 of the pulsation from the ultraluminous X-ray source (ULX) M82 X-2 has changed our view of ULXs. Because of the relatively short baseline over which pulsations have been detected so far, M82 X-2's spin state had been assumed to be in an equilibrium state. Using Chandra and XMM-Newton archive data, we are able to investigate t…
Turbulent Vortex with Moderate Dust Settling Probed by Scattering-induced Polarization in the IRS 48 System
Li, Zhi-Yun; Yang, Haifeng; Looney, Leslie W. +4 more
We investigate the crescent-shaped dust trap in the transition disk Oph IRS 48 using well-resolved (sub)millimeter polarimetric observations at ALMA Band 7 (870 µm). The dust polarization map reveals patterns consistent with dust-scattering-induced polarization. There is a relative displacement between the polarized flux and the total flux, …
TIC 290061484: A Triply Eclipsing Triple System with the Shortest Known Outer Period of 24.5 Days
Mitnyan, T.; Pál, A.; Vanderburg, A. +13 more
We have discovered a triply eclipsing triple-star system, TIC 290061484, with the shortest known outer period, P out, of only 24.5 days. This "eclipses" the previous record set by λ Tauri at 33.02 days, which held for 68 yr. The inner binary, with an orbital period of P in = 1.8 days, produces primary and secondary eclipses a…
Ages of Stars and Planets in the Kepler Field Younger than Four Billion Years
Howard, Andrew W.; Bouma, Luke G.; Hillenbrand, Lynne A. +3 more
Recent analyses of FGK stars in open clusters have helped clarify the precision with which a star's rotation rate and lithium content can be used as empirical indicators for its age. Here we apply this knowledge to stars observed by Kepler. Rotation periods are drawn from previous work; lithium is measured from new and archival Keck/HIRES spectra.…
Long-term Study of the 2020 Magnetar-like Outburst of the Young Pulsar PSR J1846-0258 in Kes 75
Campana, S.; Tiengo, A.; Götz, D. +14 more
Magnetar-like activity has been observed in a large variety of neutron stars. PSR J1846‑0258 is a young 327 ms radio-quiet pulsar with a large rotational power (∼8 × 1036 erg s‑1), and resides at the center of the supernova remnant Kes 75. It is one of the rare examples of a high-magnetic-field pulsar showing characteristics …
A JWST Medium-resolution MIRI Spectrum and Models of the Type Ia Supernova 2021aefx at +415 days
Suntzeff, N. B.; Wang, L.; Galbany, L. +39 more
We present a JWST MIRI medium-resolution spectrometer spectrum (5–27 µm) of the Type Ia supernova (SN Ia) SN 2021aefx at +415 days past B-band maximum. The spectrum, which was obtained during the iron-dominated nebular phase, has been analyzed in combination with previous JWST observations of SN 2021aefx to provide the first JWST time series…