Search Publications
BESTP - An automated Bayesian modeling tool for asteroseismology
Gizon, Laurent; Jiang, Chen
Asteroseismic observations are crucial to constrain stellar models with precision. Bayesian Estimation of STellar Parameters (BESTP) is a tool that utilizes Bayesian statistics and nested sampling Monte Carlo algorithm to search for the stellar models that best match a given set of classical and asteroseismic constraints from observations. The com…
Detecting Reconnection Sites Using the Lorentz Transformations for Electromagnetic Fields
Lapenta, Giovanni
We take a pragmatic definition of reconnection to find locations where a reconnection electric field causes an E × B drift that carries two components of the magnetic field toward their elimination. With this in mind as our target, we observe that such locations can be found using a new indicator: the velocity of the Lorentz transformation that el…
Ground-based Transmission Spectroscopy with VLT FORS2: Evidence for Faculae and Clouds in the Optical Spectrum of the Warm Saturn WASP-110b
Madhusudhan, Nikku; Nikolov, Nikolay; Maciejewski, Gracjan +12 more
We present a ground-based optical transmission spectrum for the warm Saturn-mass exoplanet WASP-110b from two transit observations made with the FOcal Reducer and Spectrograph on the Very Large Telescope. The spectrum covers the wavelength range from 4000-8333 Å, which is binned in 46 transit depths measured to an averaged precision of 220 parts p…
The Age-Metallicity-Specific Orbital Energy Relation for the Milky Way's Globular Cluster System Confirms the Importance of Accretion for Its Formation
Schlaufman, Kevin C.; Woody, Turner
Globular clusters can form inside their host galaxies at high redshift when gas densities are higher and gas-rich mergers are common. They can also form inside lower-mass galaxies that have since been accreted and tidally disrupted, leaving their globular cluster complement bound to higher-mass halos. We argue that the age-metallicity-specific orb…
A compact core-jet structure in the changing-look Seyfert NGC 2617
Paragi, Zsolt; Yang, Jun; An, Tao +9 more
The nearby face-on spiral galaxy NGC 2617 underwent an unambiguous 'inside-out' multiwavelength outburst in Spring 2013, and a dramatic Seyfert-type change probably between 2010 and 2012, with the emergence of broad optical emission lines. To search for the jet activity associated with this variable accretion activity, we carried out multiresoluti…
On the nature of the anomalous event in 2021 in the dwarf nova SS Cygni and its multi-wavelength transition
Maehara, Hiroyuki; Enoto, Teruaki; Shidatsu, Megumi +20 more
SS Cyg has long been recognized as the prototype of a group of dwarf novae that show only outbursts. However, this object has entered a quite anomalous event in 2021, which at first appeared to be standstill, i.e., an almost constant luminosity state observed in Z Cam-type dwarf novae. This unexpected event gives us a great opportunity to reconsid…
Near-infrared Studies of Nova V1674 Herculis: A Shocking Record Breaker
Banerjee, D. P. K.; Starrfield, S.; Page, K. L. +3 more
We present near-infrared spectroscopy of Nova Herculis 2021 (V1674 Her), obtained over the first 70 days of its evolution. This fastest nova on record displays a rich emission line spectrum, including strong coronal line emission with complex structures. The hydrogen line fluxes, combined with a distance of ${4.7}_{-1.0}^{+1.3}$ kpc, give an upper…
Inhomogeneity in the early Galactic chemical enrichment exposed by beryllium abundances in extremely metal-poor stars
Pasquini, L.; Smiljanic, R.; Zych, M. G.
Context. Abundances of beryllium in metal-poor stars scale linearly with metallicity down to [Fe/H] ∼ -3.0. In the stars where Be has been detected at this extremely metal-poor regime, an increased abundance scatter has been previously reported in the literature. This scatter could indicate a flattening of the relation between Be abundances and me…
Searching for gravitational waves via Doppler tracking by future missions to Uranus and Neptune
Saha, Prasenjit; D'Orazio, Daniel J.; Soyuer, Deniz +1 more
The past year has seen numerous publications underlining the importance of a space mission to the ice giants in the upcoming decade. Proposed mission plans involve a ∼10 yr cruise time to the ice giants. This cruise time can be utilized to search for low-frequency gravitational waves (GWs) by observing the Doppler shift caused by them in the Earth…
Evolution of the truncated disc and inner hot-flow of GX 339-4
Chainakun, P.; Young, A. J.; Luangtip, W. +2 more
Aims: We study the changes in geometry of the truncated disc and the inner hot-flow of GX 339-4 by analysing the power spectral density (PSD) extracted from six XMM-Newton observations taken at the very end of an outburst.
Methods: We developed a theoretical model of the PSD of GX 339-4 in the 0.3-0.7 keV (thermal-reverberation-dominated…