Search Publications
Vertical Electric Currents in Active Regions: Calculation Methods and Relation to the Flare Index
Fursyak, Yu. A.
In the scope of the performed work, two problems are solved. The first is the analysis of two existing methods for calculating vertical electric currents, differential and integral. The integral method has some advantages compared to the differential method. Among them, one can mention there is no need to differentiate the magnetic field and a goo…
Visibility and Origin of Compact Interplanetary Radio Type IV Bursts
Pohjolainen, Silja; Talebpour Sheshvan, Nasrin
We have analyzed radio type IV bursts in the interplanetary (IP) space at decameter-hectometer (DH) wavelengths to determine their source origin and a reason for the observed directivity. We used radio dynamic spectra from the instruments on three different spacecraft, STEREO-A, Wind, and STEREO-B, which were located approximately 90 degrees apart…
Cospatial Star Formation and Supermassive Black Hole Growth in z ∼ 3 Galaxies: Evidence for In Situ Co-evolution
Elbaz, D.; Ivison, R. J.; Smolčić, V. +7 more
We present a sub-kiloparsec localization of the sites of supermassive black hole (SMBH) growth in three active galactic nuclei (AGNs) at z ∼ 3 in relation to the regions of intense star formation in their hosts. These AGNs are selected from Karl G. Jansky Very Large Array (VLA) and Atacama Large Millimeter/submillimeter Array (ALMA) observations i…
Constraining the star formation rate with the extragalactic background light
Rubtsov, G. I.; Korochkin, A. A.
The present day spectrum of the extragalactic background light (EBL) in UV, optical, and IR wavelengths is the integral result of multiple astrophysical processes going on throughout the evolution of the Universe. The relevant processes include star formation, stellar evolution, light absorption, and emission by the cosmic dust. The properties of …
Habitability in the Omega Centauri Cluster
Kane, Stephen R.; Deveny, Sarah J.
The search for exoplanets has encompassed a broad range of stellar environments, from single stars in the solar neighborhood to multiple stars and various open clusters. The stellar environment has a profound effect on planet formation and stability evolution and is thus a key component of exoplanetary studies. Dense stellar environments, such as …
Complex optical/UV and X-ray variability of the Seyfert 1 galaxy 1H 0419-577
Dewangan, Gulab C.; Naik, Sachindra; Kembhavi, Ajit K. +2 more
We present detailed broad-band UV/optical to X-ray spectral variability of the Seyfert 1 galaxy 1H 0419-577 using six XMM-Newton observations performed during 2002-2003. These observations covered a large amplitude variability event in which the soft X-ray (0.3-2 keV) count rate increased by a factor of ∼4 in six months. The X-ray spectra during t…
Aeolian slipface dynamics and grainflow morphologies on Earth and Mars
Bourke, Mary C.; Cornwall, Carin; Jackson, Derek W. T. +1 more
In 2015, an active dune field on Mars was visited up close by the Curiosity rover in Gale Crater providing the first high resolution ground images of fine scale windblown features not previously resolved from orbital-based imagery. For the first time, these images allow for direct comparison with terrestrial aeolian dynamics and provide critical g…
Eclipsing spotted giant star with K2 and historical photometry
Vanderburg, A.; Rappaport, S.; Bieryla, A. +15 more
Context. Stars can maintain their observable magnetic activity from the pre-main sequence (PMS) to the tip of the red giant branch. However, the number of known active giants is much lower than active stars on the main sequence (MS) since the stars spend only about 10% of their MS lifetime on the giant branch. Due to their rapid evolution it is di…
Non-synchronous rotations in massive binary systems. HD 93343 revisited
Simón-Díaz, S.; Gamen, R.; Barbá, R. H. +5 more
Context. Most massive stars are in binary or multiple systems. Several massive stars have been detected as double-lined spectroscopic binaries and among these, the OWN Survey has detected a non-negligible number whose components show very different spectral line broadening (i.e., projected rotational velocities). This fact raises a discussion abou…
A contaminant-free catalogue of Gaia DR2-WISE Galactic plane matches: including the effects of crowding in the cross-matching of photometric catalogues
Wilson, Tom J.; Naylor, Tim
Faint, hidden contaminants in the point spread functions (PSFs) of stars cause shifts to their measured positions. Wilson & Naylor showed failing to account for these shifts can lead to a drastic decrease in the number of returned catalogue matches in crowded fields. Here, we highlight the effect these perturbations have on cross-matching, for…