Search Publications
A Decade of MWC 758 Disk Images: Where Are the Spiral-arm-driving Planets?
Debes, John H.; Schneider, Glenn; Esposito, Thomas M. +10 more
Large-scale spiral arms have been revealed in scattered light images of a few protoplanetary disks. Theoretical models suggest that such arms may be driven by and corotate with giant planets, which has called for remarkable observational efforts to look for them. By examining the rotation of the spiral arms for the MWC 758 system over a 10 year ti…
Rotating network jets in the quiet Sun as observed by IRIS
Srivastava, A. K.; Murawski, K.; Dwivedi, B. N. +1 more
Aims: We perform a detailed observational analysis of network jets to understand their kinematics, rotational motion, and underlying triggering mechanism(s). We analyzed the quiet-Sun (QS) data.
Methods: IRIS high-resolution imaging and spectral observations (slit-jaw images: Si IV 1400.0 Å; raster: Si IV 1393.75 Å) were used to analyze …
Galactic binaries can explain the Fermi Galactic centre excess and 511 keV emission
Calore, F.; Bartels, R.; Storm, E. +1 more
The Fermi-LAT Galactic Centre excess and the 511 keV positron-annihilation signal from the inner Galaxy bear a striking morphological similarity. We propose that both can be explained through a scenario in which millisecond pulsars produce the Galactic Centre excess and their progenitors, low-mass X-ray binaries, the 511 keV signal. As a proof of …
The Penn State - Toruń Centre for Astronomy Planet Search stars. IV. Dwarfs and the complete sample
Nowak, G.; Adamów, M.; Niedzielski, A. +3 more
Context. Our knowledge of the intrinsic parameters of exoplanets is as precise as our determinations of their stellar hosts parameters. In the case of radial velocity searches for planets, stellar masses appear to be crucial. But before estimating stellar masses properly, detailed spectroscopic analysis is essential. With this paper we conclude a …
The chemical composition of the oldest nearby open cluster Ruprecht 147
Fu, Xiaoting; Mucciarelli, Alessio; Bragaglia, Angela +2 more
Context. Ruprecht 147 (NGC 6774) is the closest old open cluster, with a distance of less than 300 pc and an age of about 2.5 Gyr. It is therefore well suited for testing stellar evolution models and for obtaining precise and detailed chemical abundance information.
Aims: We combined photometric and astrometric information coming from literat…
Reconnection in the Post-impulsive Phase of Solar Flares
Reeves, Katharine K.; Forbes, Terry G.; Seaton, Daniel B.
Using a recently developed analytical procedure, we determine the rate of magnetic reconnection in the “standard” model of eruptive solar flares. During the late phase, the neutral line is located near the lower tip of the reconnection current sheet, and the upper region of the current sheet is bifurcated into a pair of Petschek-type shocks. Despi…
Dynamical ages of the young local associations with Gaia
Miret-Roig, N.; Figueras, F.; Antoja, T. +1 more
Context. The young local associations (YLAs) constitute an excellent sample for the study of a variety of astrophysical topics, especially the star formation process in low-density environments. Data from the Gaia mission allows us to undertake studies of the YLAs with unprecedented accuracy.
Aims: We determine the dynamical age and place of …
A predicted astrometric microlensing event by a nearby white dwarf
McGill, Peter; Smith, Leigh C.; Belokurov, Vasily +2 more
We used the Tycho-Gaia Astrometric Solution catalogue, part of Gaia Data Release 1, to search for candidate astrometric microlensing events expected to occur within the remaining lifetime of the Gaia satellite. Our search yielded one promising candidate. We predict that the nearby DQ type white dwarf LAWD 37 (WD 1142-645) will lens a background st…
The Optical/Near-infrared Extinction Law in Highly Reddened Regions
Hosek, Matthew W., Jr.; Lu, Jessica R.; Clarkson, William I. +6 more
A precise extinction law is a critical input when interpreting observations of highly reddened sources such as young star clusters and the Galactic Center (GC). We use Hubble Space Telescope observations of a region of moderate extinction and a region of high extinction to measure the optical and near-infrared extinction law (0.8-2.2 µm). Th…
Outflowing OH+ in Markarian 231: The Ionization Rate of the Molecular Gas
Sturm, E.; Veilleux, S.; Ashby, M. L. N. +6 more
The oxygen-bearing molecular ions OH+, H2O+, and H3O+ are key species that probe the ionization rate of (partially) molecular gas that is ionized by X-rays and cosmic-rays permeating the interstellar medium. We report Herschel far-infrared and submillimeter spectroscopic observations of OH