Search Publications
Progenitor, precursor, and evolution of the dusty remnant of the stellar merger M31-LRN-2015
Kozłowski, S.; Kochanek, C. S.; Johansson, J. +12 more
M31-LRN-2015 is a likely stellar merger discovered in the Andromeda Galaxy in 2015. We present new optical to mid-infrared photometry and optical spectroscopy for this event. Archival data show that the source started to brighten ~2 yr before the nova event. During this precursor phase, the source brightened by ~3 mag. The light curve at 6 and 1.5…
The Magnetic Field of the Active Planet-hosting M Dwarf AU Mic
Kochukhov, Oleg; Reiners, Ansgar
AU Mic is a young, very active M dwarf star with a debris disk and at least one transiting Neptune-size planet. Here we present a detailed analysis of the magnetic field of AU Mic based on previously unpublished high-resolution optical and near-infrared spectropolarimetric observations. We report a systematic detection of circular and linear polar…
Rotation periods for cool stars in the open cluster Ruprecht 147 (NGC 6774). Implications for gyrochronology
Gruner, D.; Barnes, S. A.
Context. Gyrochronology allows the derivation of ages for cool main sequence stars based on their observed rotation periods and masses, or a suitable proxy thereof. It is increasingly well-explored for FGK stars, but requires further measurements for older ages and K - M-type stars.
Aims: We study the 2.7 Gyr-old open cluster Ruprecht 147 to …
Ionospheric Multi-Spacecraft Analysis Tools
Lühr, Hermann; Dunlop, Malcolm Wray
Magnesium abundances in cool metal-polluted white dwarfs
Blouin, Simon
The accretion of rocky material is responsible for the presence of heavy elements in the atmospheres of a large fraction of white dwarf stars. Those objects represent a unique opportunity to infer the bulk composition of exoplanetesimals. This chemical characterization requires the use of detailed atmosphere models to determine the elemental abund…
J-PLUS: Unveiling the brightest end of the Lyα luminosity function at 2.0 < z < 3.3 over 1000 deg2
Hernández-Monteagudo, C.; Hernán-Caballero, A.; Varela, J. +22 more
We present the photometric determination of the bright end of the Lyα luminosity function (LF; at LLyα ≳ 1043.3 erg s-1) within four redshift windows (Δ z < 0.16) in the interval 2.2 ≲ z ≲ 3.3. Our work is based on the Javalambre Photometric Local Universe Survey (J-PLUS) first data release, which provides m…
Fundamental effective temperature measurements for eclipsing binary stars - I. Development of the method and application to AI Phoenicis
Maxted, P. F. L.; Smalley, B.; Miller, N. J.
Stars with accurate and precise effective temperature (Teff) measurements are needed to test stellar atmosphere models and calibrate empirical methods to determine Teff. There are few standard stars currently available to calibrate temperature indicators for dwarf stars. Gaia parallaxes now make it possible, in principle, to …
A Microlensing Accretion Disk Size Measurement in the Lensed Quasar WFI 2026-4536
Millon, Martin; Bonvin, Vivien; Bentz, Misty C. +4 more
We use 13 seasons of R-band photometry from the 1.2 m Leonard Euler Swiss Telescope at La Silla to examine microlensing variability in the quadruply imaged lensed quasar WFI 2026-4536. The lightcurves exhibit ∼0.2 mag of uncorrelated variability across all epochs and a prominent single feature of ∼0.1 mag within a single season. We analyze this va…
Amplification of Brightness Variability by Active-region Nesting in Solar-like Stars
Solanki, Sami K.; Shapiro, Alexander I.; Krivova, Natalie A. +1 more
Kepler observations revealed that hundreds of stars with near-solar fundamental parameters and rotation periods have much stronger and more regular brightness variations than the Sun. Here we identify one possible reason for the peculiar behavior of these stars. Inspired by solar nests of activity, we assume that the degree of inhomogeneity of act…
A Supernova Candidate at z = 0.092 in XMM-Newton Archival Data
Mereghetti, Sandro; Esposito, Paolo; Tiengo, Andrea +14 more
During a search for X-ray transients in the XMM-Newton archive within the EXTraS project, we discovered a new X-ray source that is detected only during an ∼5 min interval of an ∼21 hr-long observation performed on 2011 June 21 (EXMM 023135.0-603743, probability of a random Poissonian fluctuation: ∼1.4 × 10-27). With dedicated follow-up …