Search Publications
A Census of Archival X-Ray Spectra for Modeling Tidal Disruption Events
Wen, Sixiang; Jonker, Peter G.; Stone, Nicholas C. +3 more
Tidal disruption events (TDEs) are highly energetic phenomena that occur when a star is tidally disrupted by the central massive black hole in a galaxy. Fitting the observed X-ray spectra of TDEs with a first-principles, general-relativistic slim-disk model for the emission from the inner accretion disk can constrain the black hole mass M •
Reaching Submillisecond Accuracy in Stellar Occultations and Artificial Satellite Tracking
Kamiński, K.; Marciniak, A.; Weber, C. +2 more
In recent years, there appeared a need for astronomical observations timed with submillisecond accuracy. These include, e.g., timing stellar occultations by small, subkilometer, or fast near-Earth asteroids and tracking artificial satellites in low-Earth orbit using optical sensors. Precise astrometry of fast-moving satellites and accurate timing …
Applied Machine-Learning Models to Identify Spectral Sub-Types of M Dwarfs from Photometric Surveys
Sithajan, Sirinrat; Meethong, Sukanya
M dwarfs are the most abundant stars in the Solar Neighborhood and they are prime targets for searching for rocky planets in habitable zones. Consequently, a detailed characterization of these stars is in demand. The spectral sub-type is one of the parameters that is used for the characterization and it is traditionally derived from the observed s…
The Potential of Detecting Nearby Terrestrial Planets in the HZ with Different Methods
Hui-Gen, Liu; Qiao-Yang, Hao; Shen-Wei, Zhou
Terrestrial planets in the habitable zone (hereafter HZ) around nearby stars are of great interest and provide a good sample to characterize their habitability. In this paper, we collect a nearby star catalog within 20 pc according to the Gaia Catalog of Nearby Stars, complete the physical parameters of the stars, and select stars that are not bro…
The MPI + CUDA Gaia AVU-GSR Parallel Solver Toward Next-generation Exascale Infrastructures
Bucciarelli, Beatrice; Vecchiato, Alberto; Cesare, Valentina +4 more
We ported to the GPU with CUDA the Astrometric Verification Unit-Global Sphere Reconstruction (AVU-GSR) Parallel Solver developed for the ESA Gaia mission, by optimizing a previous OpenACC porting of this application. The code aims to find, with a [10, 100] µarcsec precision, the astrometric parameters of ~108 stars, the attitude …
The Breakthrough Listen Search for Intelligent Life: Nearby Stars' Close Encounters with the Brightest Earth Transmissions
Isaacson, Howard; Derrick, Reilly
After having left the heliosphere, Voyager 1 and Voyager 2 continue to travel through interstellar space. The Pioneer 10, Pioneer 11, and New Horizons spacecraft are also on paths to pass the heliopause. These spacecraft have communicated with the Deep Station Network (DSN) radio antennas in order to download scientific data and telemetry data. Ou…
The First Photometric and Spectroscopic Studies of ASASSN-V J015428.67+204247.2 and its Relation to the Population of Low Mass Ratio Contact Binaries
Wang, Xi; Li, Kai; Gao, Xing +4 more
We performed photometric, spectroscopic and orbital period investigations of ASASSN-V J015428.67+204247.2 (hereafter, J015428) for the first time. The light curves of VRI bands were obtained. Through the analysis of Wilson-Devinney program, J015428 was found as an A-subtype medium contact binary system with a low-mass ratio (q = 0.129, f = 26.8%).…
Multiwavelength Analysis of a Nearby Heavily Obscured AGN in NGC 449
Fang, Guanwen; Gu, Qiusheng; Xu, Jun +5 more
We present the multiwavelength analysis of a heavily obscured active galactic nucleus (AGN) in NGC 449. We first constructed a broadband X-ray spectrum using the latest NuSTAR and XMM-Newton data. Its column density (≃1024 cm-2) and photon index (Γ ≃ 2.4) were reliably obtained by analyzing the broadband X-ray spectrum. Howev…
PDRs4All: A JWST Early Release Science Program on Radiative Feedback from Massive Stars
Hartigan, Patrick; Zhang, Yong; Gordon, Karl D. +134 more
Massive stars disrupt their natal molecular cloud material through radiative and mechanical feedback processes. These processes have profound effects on the evolution of interstellar matter in our Galaxy and throughout the universe, from the era of vigorous star formation at redshifts of 1-3 to the present day. The dominant feedback processes can …
Planetary Nebulae: Sources of Enlightenment
Henry, R. B. C.; Kwitter, Karen B.
In this review/tutorial we explore planetary nebulae as a stage in the evolution of low-to-intermediate-mass stars, as major contributors to the mass and chemical enrichment of the interstellar medium, and as astrophysical laboratories. We discuss many observed properties of planetary nebulae, placing particular emphasis on element abundance deter…