Search Publications
Hubble Space Telescope observations of [O III] emission in nearby QSO2s: physical properties of the ionized outflows
Turner, T. J.; Kraemer, S. B.; Crenshaw, D. M. +14 more
We use Hubble Space Telescope/Space Telescope Imaging Spectrograph long-slit G430M and G750M spectra to analyse the extended [O III] λ5007 emission in a sample of 12 nearby (z < 0.12) luminous (Lbol > 1.6 × 1045 erg s-1) QSO2s. The purpose of the study is to determine the properties of the mass outflows of io…
TOI-1231 b: A Temperate, Neptune-sized Planet Transiting the Nearby M3 Dwarf NLTT 24399
Butler, R. Paul; Barclay, Thomas; Triaud, Amaury H. M. J. +59 more
We report the discovery of a transiting, temperate, Neptune-sized exoplanet orbiting the nearby (d = 27.5 pc), M3V star TOI-1231 (NLTT 24399, L 248-27, 2MASS J10265947-5228099). The planet was detected using photometric data from the Transiting Exoplanet Survey Satellite and followed up with observations from the Las Cumbres Observatory and the An…
Uncovering erosion effects on magnetic flux rope twist
Pal, Sanchita; Pomoell, Jens; Price, Daniel J. +2 more
Context. Magnetic clouds (MCs) are transient structures containing large-scale magnetic flux ropes from solar eruptions. The twist of magnetic field lines around the rope axis reveals information about flux rope formation processes and geoeffectivity. During propagation MC flux ropes may erode via reconnection with the ambient solar wind. Any eros…
Clumpy Star Formation and AGN Activity in the Dwarf-Dwarf Galaxy Merger Mrk 709
Deller, Adam T.; Stern, Daniel; Reines, Amy E. +2 more
Nearby, low-metallicity dwarf starburst galaxies hosting active galactic nuclei (AGNs) offer the best local analogs to study the early evolution of galaxies and their supermassive black holes (BHs). Here we present a detailed multiwavelength investigation of star formation and BH activity in the low-metallicity dwarf-dwarf galaxy merger Mrk 709. U…
Star Formation Timescales of the Halo Populations from Asteroseismology and Chemical Abundances
Shi, Jianrong; Xiang, Maosheng; Li, Haining +9 more
We combine asteroseismology, optical high-resolution spectroscopy, and kinematic analysis for 26 halo red giant branch stars in the Kepler field in the range of -2.5 < [Fe/H] < -0.6. After applying theoretically motivated corrections to the seismic scaling relations, we obtain an average mass of 0.97 ± 0.03 M⊙ for our sample of ha…
Stellar Population Astrophysics (SPA) with TNG. Atmospheric parameters of members of 16 unstudied open clusters
Vallenari, A.; Bragaglia, A.; Spina, L. +12 more
Context. Thanks to the modern understanding of stellar evolution, we can accurately measure the ages of open clusters (OCs). Given their position, they are ideal tracers of the Galactic disc. Gaia data release 2, besides providing precise parallaxes, led to the detection of many new clusters, opening a new era for the study of the Galactic disc. H…
Carbon stars as standard candles - II. The median J magnitude as a distance indicator
Rousseau-Nepton, Laurie; Heyl, Jeremy; Richer, Harvey +2 more
We introduce a new distance determination method using carbon-rich asymptotic giant branch stars (CS) as standard candles and the Large and Small Magellanic Clouds (LMC and SMC) as the fundamental calibrators. We select the samples of CS from the ((J - Ks)0, J0) colour-magnitude diagrams, as, in this combination of…
Observational and Theoretical Studies of 27 δ Scuti Stars with Investigation of the Period-Luminosity Relation
Davoudi, Fatemeh; Poro, Atila; Paki, Ehsan +11 more
The multi-color CCD photometric study of 27 δ Scuti stars is presented. By using approximately three years of photometric observations, we obtained the times of maxima and magnitude changes during the observation time interval for each star. The ephemerides of our δ Scuti stars were calculated based on the Markov Chain Monte Carlo (MCMC) method us…
Gaia GraL: Gaia DR2 Gravitational Lens Systems. VI. Spectroscopic Confirmation and Modeling of Quadruply Imaged Lensed Quasars
Djorgovski, S. G.; Stern, D.; Surdej, J. +23 more
Combining the exquisite angular resolution of Gaia with optical light curves and WISE photometry, the Gaia Gravitational Lenses group (GraL) uses machine-learning techniques to identify candidate strongly lensed quasars, and has confirmed over two dozen new strongly lensed quasars from the Gaia Data Release 2. This paper reports on the 12 quadrupl…
Plasma and Magnetic Field Turbulence in the Earth's Magnetosheath at Ion Scales
Rakhmanova, Liudmila; Riazantseva, Maria; Zastenker, Georgy
Crossing the Earth's bow shock is known to crucially affect solar wind plasma including changes in turbulent cascade. The present review summarizes results of more than 15 years of experimental exploration into magnetosheath turbulence. Great contributions to understanding turbulence development inside the magnetosheath was made by means of recent…