Search Publications
Astro-COLIBRI-The COincidence LIBrary for Real-time Inquiry for Multimessenger Astrophysics
Becker Tjus, J.; Lefranc, V.; Schüssler, F. +4 more
Astro-COLIBRI is a novel tool that evaluates alerts of transient observations in real time, filters them by user-specified criteria, and puts them into their multiwavelength and multimessenger context. Through fast generation of an overview of persistent sources as well as transient events in the relevant phase space, Astro-COLIBRI contributes to …
Dating individual quasars with the He II proximity effect
Hennawi, Joseph F.; Worseck, Gábor; Prochaska, J. Xavier +2 more
Constraints on the time-scales of quasar activity are key to understanding the formation and growth of supermassive black holes (SMBHs), quasar triggering mechanisms, and possible feedback effects on their host galaxies. However, observational estimates of this so-called quasar lifetime are highly uncertain (tQ ~ 104-109…
Formation of a Solar Filament by Magnetic Reconnection, Associated Chromospheric Evaporation, and Subsequent Coronal Condensation
Yang, Bo; Yang, Jiayan; Bi, Yi +2 more
We present the first observation of a solar filament formed by magnetic reconnection, associated chromospheric evaporation, and subsequent coronal condensation. Driven by shearing motion during flux emergence, a sequential tether-cutting reconnection process occurred and resulted in an M1.3 confined flare accompanied by the formation of a sigmoid …
Revealing Efficient Dust Formation at Low Metallicity in Extragalactic Carbon-rich Wolf-Rayet Binaries
Moffat, Anthony F. J.; Smith, Nathan; Bond, Howard E. +6 more
We present Spitzer/InfraRed Array Camera observations of dust formation from six extragalactic carbon-rich Wolf-Rayet (WC) binary candidates in low-metallicity (Z ≲ 0.65 Z⊙) environments using multiepoch mid-infrared (IR) imaging data from the SPitzer InfraRed Intensive Transients Survey (SPIRITS). Optical follow-up spectroscopy of SPIR…
Carbon photochemical escape rates from the modern Mars atmosphere
Yelle, Roger V.; Lillis, Robert J.; Lo, Daniel Y. +1 more
We provide a comprehensive update of photochemical escape rates of atomic carbon from the present-day Martian atmosphere using a one-dimensional photochemical model and a Monte Carlo escape model. The photochemical model incorporates new results relevant to carbon photochemistry at Mars, including new cross sections for photodissociation of CO
The probabilistic random forest applied to the selection of quasar candidates in the QUBRICS survey
Grazian, Andrea; Boutsia, Konstantina; Cupani, Guido +5 more
The number of known, bright (i < 18), high-redshift (z > 2.5) QSOs in the Southern hemisphere is considerably lower than the corresponding number in the Northern hemisphere due to the lack of multiwavelength surveys at δ < 0. Recent works, such as the QUBRICS survey, successfully identified new, high-redshift QSOs in the South by means of…
Transients from the Cataclysmic Deaths of Cataclysmic Variables
Strader, Jay; Chomiuk, Laura; Shen, Ken J. +2 more
We explore the observational appearance of the merger of a low-mass star with a white dwarf (WD) binary companion. We are motivated by recent work finding that multiple tensions between the observed properties of cataclysmic variables (CVs) and standard evolution models are resolved if a large fraction of CV binaries merge as a result of unstable …
Large-scale asymmetry in galaxy spin directions: evidence from the Southern hemisphere
Shamir, Lior
Recent observations using several different telescopes and sky surveys showed patterns of asymmetry in the distribution of galaxies by their spin directions as observed from Earth. These studies were done with data imaged from the Northern hemisphere, showing excellent agreement between different telescopes and different analysis methods. Here, da…
A Wide Planetary Mass Companion Discovered through the Citizen Science Project Backyard Worlds: Planet 9
Debes, John H.; Gonzales, Eileen C.; Meisner, Aaron M. +22 more
Through the Backyard Worlds: Planet 9 citizen science project we discovered a late-type L dwarf co-moving with the young K0 star BD+60 1417 at a projected separation of 37″ or 1662 au. The secondary-CWISER J124332.12+600126.2 (W1243)-is detected in both the CatWISE2020 and 2MASS reject tables. The photometric distance and CatWISE proper motion bot…
Flare-forecasting Algorithms Based on High-gradient Polarity Inversion Lines in Active Regions
Piana, Michele; Benvenuto, Federico; Cicogna, Domenico +6 more
Solar flares emanate from solar active regions hosting complex and strong bipolar magnetic fluxes. Estimating the probability of an active region to flare and defining reliable precursors of intense flares are extremely challenging tasks in the space weather field. In this work, we focus on two metrics as flare precursors, the unsigned flux R, tes…