Search Publications
The role of cooling induced by mixing in the mass and energy cycles of the solar atmosphere
Hillier, Andrew; Snow, Ben; Arregui, Iñigo
In many astrophysical systems, mixing between cool and hot temperature gas/plasma through Kelvin-Helmholtz-instability-driven turbulence leads to the formation of an intermediate temperature phase with increased radiative losses that drive efficient cooling. The solar atmosphere is a potential site for this process to occur with interaction betwee…
Fundamental parameters for double-lined spectroscopic and detached eclipsing binary system J064726.39 + 223431.6
Han, Zhanwen; Kovalev, Mikhail; Chen, Xuefei +1 more
We present a study of the detached eclipsing binary J064726.39 + 223431.6 using spectra from the LAMOST medium-resolution spectra and Transiting Exoplanet Survey Satellite photometry. We use full-spectrum fitting to derive radial velocities and spectral parameters: ${T_{\rm eff}}_{A,B}=6177,\, 5820$ K, $V \sin {i}_{A,B}=59,\, 50~\, {\rm km}\, {\rm…
Radio transients and variables in the tenth Deeper, Wider, Faster observing run
Möller, A.; Abbott, T. M. C.; Zhang, J. +23 more
The Deeper, Wider, Faster (DWF) program coordinates observations with telescopes across the electromagnetic spectrum, searching for transients on time-scales of milliseconds to days. The tenth DWF observing run was carried out in near real-time during September 2021, and consisted of six consecutive days of observations of the NGC 6744 galaxy grou…
Exploring the origin of the extended main-sequence turn-off in M37 through the white dwarf cooling sequence
Salaris, M.; Anderson, J.; Bedin, L. R. +3 more
We use new observations from the Canada-France-Hawaii Telescope to study the white dwarf cooling sequence of the open cluster M37, a cluster that displays an extended main-sequence turn-off and, according to a recent photometric analysis, also a spread of initial chemical composition. By taking advantage of a first epoch collected in 1999 with the…
Detailed asteroseismic modelling of RR Lyrae stars with non-radial modes
Molnár, L.; Netzel, H.; Joyce, M.
Photometric observations from the last decade have revealed additional low-amplitude periodicities in many classical pulsators that are likely due to pulsations in non-radial modes. One group of multimode RR Lyrae stars, the so-called 0.61 stars, is particularly interesting. In these stars, the radial first overtone is accompanied by additional si…
Cold mode gas accretion on two galaxy groups at z ∼ 2
Zakamska, Nadia L.; Armus, Lee; Wright, Shelley A. +5 more
We present Keck Cosmic Web Imager (KCWI) integral field spectroscopy (IFS) observations of rest-frame UV emission lines $\rm Ly\alpha$, CIVλλ 1548 Å, 1550Å, and $\rm HeII$ 1640 Å observed in the circumgalactic medium (CGM) of two z = 2 radio-loud quasar host galaxies. We detect extended emission on 80-90 kpc scale in $\rm Ly\alpha$ in both systems…
Models for metal-poor stars with different initial abundances of C, N, O, Mg, and Si - III. Grids of isochrones for -2.5 ≤ [Fe/H] ≤ -0.5 and helium abundances Y = 0.25 and 0.29 at each metallicity
VandenBerg, Don A.
Stellar evolutionary tracks for $0.12 \le {\cal M}/{\cal M_{\odot }}\le 1.0$ have been computed for each of several variations in the abundances of C, N, and O, assuming mass-fraction helium abundances Y = 0.25 and 0.29, and 11 metallicities in the range -2.5 ≤ [Fe/H] ≤ -0.5, in 0.2-dex increments. Such computations are provided for mixtures with …
The impact of black hole scaling relation assumptions on the mass density of black holes
Simon, Joseph; Gültekin, Kayhan; Matt, Cayenne
We examine the effect of supermassive black hole (SMBH) mass scaling relation choice on the inferred SMBH mass population since redshift z ~ 3. To make robust predictions for the gravitational wave background (GWB), we must have a solid understanding of the underlying SMBH demographics. Using the SDSS and 3D-HST + CANDELS surveys for 0 < z <…
Periodic X-ray sources in the massive globular cluster 47 Tucanae: Evidence for dynamically formed cataclysmic variables
Li, Zhiyuan; Bao, Tong; Cheng, Zhongqun
We present a systematic study of periodic X-ray sources in the massive globular cluster 47 Tuc, utilizing deep archival Chandra observations that resolve the cluster core and recently available eROSITA observations that cover the cluster outskirt. By applying the Gregory-Loredo algorithm, we detect 20 periodic signals among 18 X-ray sources, rangi…
Inferred galaxy properties during Cosmic Dawn from early JWST photometry results
Wise, John H.; Brummel-Smith, Corey; Skinner, Danielle +3 more
Early photometric results from JWST have revealed a number of galaxy candidates above redshift 10. The initial estimates of inferred stellar masses and the associated cosmic star formation rates are above most theoretical model predictions up to a factor of 20 in the most extreme cases, while this has been moderated after the recalibration of NIRC…