Search Publications
The Role of Disk Tearing and Precession in the Observed Variability of Pleione
Carciofi, A. C.; Tycner, C.; Jones, C. E. +2 more
We acquired Hα spectroscopic observations from 2005 to 2019 showing Pleione has transitioned from a Be phase to a Be-shell phase during this period. Using the radiative transfer code HDUST, we created a grid of ~100,000 disk models for Pleione. We successfully reproduced the observed transition with a disk model that varies in inclination while ma…
The MASSIVE Survey. XVII. A Triaxial Orbit-based Determination of the Black Hole Mass and Intrinsic Shape of Elliptical Galaxy NGC 2693
Ma, Chung-Pei; Greene, Jenny E.; Blakeslee, John P. +5 more
We present a stellar dynamical mass measurement of a newly detected supermassive black hole (SMBH) at the center of the fast-rotating, massive elliptical galaxy NGC 2693 as part of the MASSIVE survey. We combine high signal-to-noise ratio integral field spectroscopy (IFS) from the Gemini Multi-Object Spectrograph with wide-field data from the Mitc…
Quasiperiodic Behavior in the γ-Ray Light Curve of the Blazar PKS 0405-385
Gong, Yunlu; Yuan, Min; Yi, Tingfeng +3 more
We analyze the quasiperiodic oscillation (QPO) of the historical light curve of flat-spectrum radio quasars PKS 0405-385 detected by the Fermi Large Area Telescope from 2008 August to 2021 November. To identify and determine the QPO signal of PKS 0405-385 in the γ-ray light curve, we use four time series analysis techniques based on frequency and …
What Are Those Tiny Things? A First Study of Compact Star Clusters in the SMACS0723 Field with JWST
Brammer, Gabriel; Toft, Sune; Faisst, Andreas L. +1 more
We use the unprecedented resolution and depth of the JWST NIRCam Early Release Observations at 1-5 µm to study the stellar mass, age, and metallicity of compact star clusters in the neighborhood of the host galaxies in the SMACS J0723.3-7327 galaxy cluster field at z = 0.39. The measured colors of these star clusters show a similar distribut…
A Library of Synthetic X-Ray Spectra for Fitting Tidal Disruption Events
Wen, Sixiang; Jonker, Peter G.; Stone, Nicholas C. +2 more
We present a tabulated version of our slim-disk model for fitting tidal disruption events (TDEs). We create a synthetic X-ray spectral library by ray-tracing stationary general relativistic slim disks and including gravitational redshift, Doppler, and lensing effects self-consistently. We introduce the library to reduce computational expense and i…
Bayesian Solar Wind Modeling with Pulsar Timing Arrays
Ransom, Scott M.; Zhu, Weiwei; Ray, Paul S. +29 more
Using Bayesian analyses we study the solar electron density with the NANOGrav 11 yr pulsar timing array (PTA) data set. Our model of the solar wind is incorporated into a global fit starting from pulse times of arrival. We introduce new tools developed for this global fit, including analytic expressions for solar electron column densities and open…
Anomalous Cosmic-Ray Oxygen Observations into 0.1 au
McComas, D. J.; Christian, E. R.; Leske, R. A. +10 more
The Integrated Science Investigation of the Sun instrument suite onboard NASA's Parker Solar Probe mission continues to measure solar energetic particles and cosmic rays closer to the Sun than ever before. Here, we present the first observations of cosmic rays into 0.1 au (21.5 solar radii), focusing specifically on oxygen from ~2018.7 to ~2021.2.…
Spectroastrometry and Reverberation Mapping: The Mass and Geometric Distance of the Supermassive Black Hole in the Quasar 3C 273
Zhang, Zhi-Xiang; Du, Pu; Hu, Chen +4 more
The quasar 3C 273 has been observed with infrared spectroastrometry (SA) of the broad Paα line and optical reverberation mapping (RM) of the broad Hβ line. SA delivers information about the angular size and structure of the Paα broad-line region (BLR), while RM delivers information about the physical size and structure of the Hβ BLR. Based on the …
The Unusually Weak and Exceptionally Steep Radio Relic in A2108
Lovisari, Lorenzo; Raychaudhury, Somak; Giacintucci, Simona +9 more
Mergers between galaxy clusters often drive shocks into the intracluster medium, the effects of which are sometimes visible via temperature and density jumps in the X-ray and via radio emission from relativistic particles energized by the shock's passage. A2108 was selected as a likely merger system through comparing the X-ray luminosity to the Pl…
Extremely Low-mass White Dwarf Stars Observed in Gaia DR2 and LAMOST DR8
Luo, Yangping; Németh, Péter; Wang, Kun +3 more
We present the first results from our ongoing project to study extremely low-mass (ELM) white dwarfs (WDs) (M ≤ 0.3M ⊙) with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) spectra. Based on the LAMOST DR8 spectral database, we analyzed 136 ELM WD candidates selected from Gaia DR2 data and 12 known objects previou…