Search Publications
Reconnection from a turbulence perspective
Eastwood, J. P.; Matthaeus, W. H.; Stawarz, J. E. +6 more
The spectral properties associated with laminar, anti-parallel reconnection are examined using a 2.5D kinetic particle in cell simulation. Both the reconnection rate and the energy spectrum exhibit three distinct phases: an initiation phase where the reconnection rate grows, a quasi-steady phase, and a declining phase where both the reconnection r…
Discovery of molecular gas fueling galaxy growth in a protocluster at z = 1.7
Prandoni, I.; Massardi, M.; Vignali, C. +16 more
Based on ALMA Band 3 observations of the CO(2→1) line transition, we report the discovery of three new gas-rich (MH2 ∼ 1.5 - 4.8 × 1010 M⊙) galaxies in an overdense region at z = 1.7 that already contains eight spectroscopically confirmed members. This leads to a total of 11 confirmed overdensity members…
Chemical diversity among A-B stars with low rotational velocities: non-LTE abundance analysis
Ryabchikova, T.; Sitnova, T.; Mashonkina, L. +2 more
We present accurate element abundance patterns based on the non-local thermodynamic equilibrium (non-LTE, NLTE) line formation for 14 chemical elements from He to Nd for a sample of nine A9 to B3-type stars with well-determined atmospheric parameters and low rotational velocities. We constructed new model atom of Zr II-III and updated model atoms …
Optical counterpart to Swift J0243.6+6124
Reig, P.; Alfonso-Garzón, J.; Fabregat, J.
Context. Swift J0243.6+6124 is a unique system. It is the first and only ultra-luminous X-ray source in our Galaxy. It is the first and only high-mass Be X-ray pulsar showing radio jet emission. It was discovered during a giant X-ray outburst in October 2017. While there are numerous studies in the X-ray band, very little is known about the optica…
The Outburst of the Young Star Gaia19bey
Lin, Chien-Cheng; Tonry, John; Magnier, Eugene +10 more
We report photometry and spectroscopy of the outburst of the young stellar object Gaia19bey. We have established the outburst light curve with archival Gaia "G," ATLAS "Orange," Zwicky Transient Facility r-band, and Pan-STARRS "rizy"-filter photometry, showing an outburst of ~4 yr duration, longer than typical EX Lupi objects but shorter than FU O…
Characterizing low-contrast Galactic open clusters with Gaia Data Release 2
Corradi, W. J. B.; Santos, J. F. C.; Angelo, M. S.
In this study, we characterized 16 objects previously classified as faint or low-contrast Galactic open clusters (OCs). We employed parameters associated with the dynamical evolution of the OCs: the core (rc), tidal (rt) and half-mass (rhm) radii, age and crossing time (tcr). Relations among these parame…
GRB 190114C in the nuclear region of an interacting galaxy. A detailed host analysis using ALMA, the HST, and the VLT
Covino, S.; Sánchez-Ramírez, R.; Salvaterra, R. +28 more
Context. For the first time, very high energy emission up to the TeV range has been reported for a gamma-ray burst (GRB). It is still unclear whether the environmental properties of GRB 190114C might have contributed to the production of these very high energy photons, or if it is solely related to the released GRB emission.
Aims: The relativ…
A full characterization of the supermassive black hole in IRAS-=09149-6206
Harrison, F. A.; Stern, D.; Fabian, A. C. +11 more
We present new broad-band X-ray observations of the type-I Seyfert galaxy IRAS 09149-6206, taken in 2018 with XMM-Newton, NuSTAR, and Swift. The source is highly complex, showing a classic 'warm' X-ray absorber, additional absorption from highly ionized iron, strong relativistic reflection from the innermost accretion disc and further reprocessing…
A Fast, Two-dimensional Gaussian Process Method Based on Celerite: Applications to Transiting Exoplanet Discovery and Characterization
Foreman-Mackey, Daniel; Gordon, Tyler A.; Agol, Eric
Gaussian processes (GPs) are commonly used as a model of stochastic variability in astrophysical time series. In particular, GPs are frequently employed to account for correlated stellar variability in planetary transit light curves. The efficient application of GPs to light curves containing thousands to tens of thousands of data points has been …
GG Tauri A: gas properties and dynamics from the cavity to the outer disk
Beck, T.; Chapillon, E.; Hersant, F. +13 more
Context. GG Tauri A is the prototype of a young triple T Tauri star that is surrounded by a massive and extended Keplerian outer disk. The central cavity is not devoid of gas and dust and at least GG Tauri Aa exhibits its own disk of gas and dust emitting at millimeter wavelengths. Its observed properties make this source an ideal laboratory for i…