Search Publications
Verifying reddening and extinction for Gaia DR1 TGAS giants
Gontcharov, George A.; Mosenkov, Aleksandr V.
Gaia DR1 Tycho-Gaia Astrometric Solution parallaxes, Tycho-2 photometry, and reddening/extinction estimates from nine data sources for 38 074 giants within 415 pc from the Sun are used to compare their position in the Hertzsprung-Russell diagram with theoretical estimates, which are based on the PARSEC and MIST isochrones and the TRILEGAL model of…
Observing and modeling the poloidal and toroidal fields of the solar dynamo
Schüssler, M.; Schunker, H.; Duvall, T. L. +1 more
Context. The solar dynamo consists of a process that converts poloidal magnetic field to toroidal magnetic field followed by a process that creates new poloidal field from the toroidal field.
Aims: Our aim is to observe the poloidal and toroidal fields relevant to the global solar dynamo and to see if their evolution is captured by a Babcock-…
A NLTE line formation for neutral and singly ionized calcium in model atmospheres of B-F stars
Sitnova, T. M.; Mashonkina, L. I.; Ryabchikova, T. A.
We present non-local thermodynamic equilibrium (NLTE) line formation calculations for Ca I and Ca II in B-F stars. The sign and the magnitude of NLTE abundance corrections depend on line and stellar parameters. We determine calcium abundances for nine stars with reliable stellar parameters. For all stars, where the lines of both species could be m…
ALMA view of RX J1131-1231: Sub-kpc CO (2-1) mapping of a molecular disk in a lensed star-forming quasar host galaxy
Rybak, M.; Vegetti, S.; McKean, J. P. +8 more
We present ALMA 2-mm continuum and CO (2-1) spectral line imaging of the gravitationally lensed z = 0.654 star-forming/quasar composite RX J1131-1231 at 240-400 mas angular resolution. The continuum emission is found to be compact and coincident with the optical emission, whereas the molecular gas forms a complete Einstein ring, which shows strong…
Star Formation in the Sh 2-53 Region Influenced by Accreting Molecular Filaments
Tamura, M.; Tachihara, Kengo; Dewangan, L. K. +6 more
We present a multiwavelength analysis of a ∼30‧ × 30‧ area around the Sh 2-53 region (hereafter S53 complex), which is associated with at least three H II regions, two mid-infrared bubbles (N21 and N22), and infrared dark clouds. The 13CO line data trace the molecular content of the S53 complex in a velocity range of 36-60 km s-1
A Comprehensive Study of 94 Open Clusters Based on the Data from IPHAS, GAIA DR2, and Other Sky Surveys
Dambis, A. K.; Yalyalieva, L. N.; Glushkova, E. V. +2 more
We determine the color excesses, photometric distances, ages, astrometric parallaxes and proper motions for 94 open clusters in the northern part of the Milky Way. We estimate the color excesses and photometric distances based on the data from IPHAS photometric survey of the northern Galactic plane using individual total-to-selective extinction ra…
Ionospheric Responses to CME- and CIR-Driven Geomagnetic Storms Along 30°E-40°E Over the African Sector From 2001 to 2015
Matamba, Tshimangadzo Merline; Habarulema, John Bosco
In this paper, we present the responses of the ionospheric total electron content (TEC) to coronal mass ejection (CME)- and corotating interaction region (CIR)-driven storms using stations that lie within 30°E-40°E geographic longitude in middle, low, and equatorial latitudes over the African sector. CIR-driven storms are generally weak (-50 nT &l…
Mapping the neutral atomic hydrogen gas outflow in the restarted radio galaxy 3C 236
Morganti, R.; Schulz, R.; Nyland, K. +3 more
The energetic feedback that is generated by radio jets in active galactic nuclei (AGNs) has been suggested to be able to produce fast outflows of atomic hydrogen (H I) gas, which can be studied in absorption at high spatial resolution. We have used the Very Large Array (VLA) and a global very long baseline interferometry (VLBI) array to locate and…
Investigating the Structure of Vela X
Chevalier, R. A.; Miceli, M.; Bocchino, F. +9 more
Vela X is a prototypical example of a pulsar wind nebula whose morphology and detailed structure have been affected by interaction with the reverse shock of its host supernova remnant. The resulting complex of filamentary structure and mixed-in ejecta embedded in a nebula that is offset from the pulsar provides the best example we have of this mid…
Fragile Detection of Solar g -Modes by Fossat et al.
Gizon, Laurent; Gaulme, Patrick; Schou, Jesper +1 more
The internal gravity modes of the Sun are notoriously difficult to detect, and the claimed detection of gravity modes presented by Fossat et al. (Astron. Astrophys.604, A40, 2017) is thus very exciting. Given the importance of these modes for understanding solar structure and dynamics, the results must be robust. While Fossat et al. described thei…