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New bright optical spectrophotometric standards: A-type stars from the STIS Next Generation Spectral Library
del Burgo, C.; Allende Prieto, C.
Exoplanets have sparked interest in extremely high signal-to-noise ratio spectroscopic observations of very bright stars, in a regime where flux calibrators, in particular DA white dwarfs, are not available. We argue that A-type stars offer a useful alternative and reliable space-based spectrophotometry is now available for a number of bright ones…
Active Region Emergence and Remote Flares
Welsch, Brian T.; Fu, Yixing
We study the effect of new emerging solar active regions on the large-scale magnetic environment of existing regions. We first present a theoretical approach to quantify the "interaction energy" between new and pre-existing regions as the difference between i) the summed magnetic energies of their individual potential fields and ii) the energy of …
The Agilkia boulders/pebbles size-frequency distributions: OSIRIS and ROLIS joint observations of 67P surface
Jorda, L.; Lamy, P. L.; Jaumann, R. +57 more
By using the images acquired by the OSIRIS (Optical, Spectroscopic and Infrared Remote Imaging System) and ROLIS (ROsetta Lander Imaging System) cameras, we derive the size-frequency distribution (SFD) of cometary pebbles and boulders covering the size range 0.05-30.0 m on the Agilkia landing site. The global SFD measured on OSIRIS images, reflect…
The gaseous debris disk of the white dwarf SDSS J1228+1040. HST/COS search for far-ultraviolet signatures
Rauch, T.; Werner, K.; Nagel, T. +1 more
Context. Gaseous and dust debris disks around white dwarfs (WDs) are formed from tidally disrupted planetary bodies. This offers an opportunity to determine the composition of exoplanetary material by measuring element abundances in the accreting WD's atmosphere. A more direct way to do this is through spectral analysis of the disks themselves.
Constraining the Solar Coronal Magnetic Field Strength using Split-band Type II Radio Burst Observations
Ramesh, R.; Kathiravan, C.; Hariharan, K. +2 more
We report on low-frequency radio (85-35 MHz) spectral observations of four different type II radio bursts, which exhibited fundamental-harmonic emission and split-band structure. Each of the bursts was found to be closely associated with a whitelight coronal mass ejection (CME) close to the Sun. We estimated the coronal magnetic field strength fro…
Dust and Polycyclic Aromatic Hydrocarbon in the Pre-transitional Disk around HD 169142
Seok, Ji Yeon; Li, Aigen
The pre-transitional disk around the Herbig Ae star HD 169142 shows a complex structure of possible ongoing planet formation in dust thermal emission from the near-infrared (IR) to millimeter wavelength range. Also, a distinct set of broad emission features at 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 µ {{m}}, commonly attributed to polycyclic arom…
Transport and electrodynamical coupling of nano-grains ejected from the Saturnian rings and their possible ionospheric signatures
Ip, W. -H.; Liu, C. -M.; Pan, K. -C.
Besides oxygen-bearing neutral gas and ions, the Saturnian rings could be a source of small dust particles of nano-meter size range. Electrostatic charging effect by photoemission and/or electron impact could lead to ejection of the nano-grains out of the ring plane by electromagnetic force. The orbital motion of low-velocity charged dust generate…
MUSE three-dimensional spectroscopy and kinematics of the gigahertz peaked spectrum radio galaxy PKS 1934-63: interaction, recently triggered active galactic nucleus and star formation
Roche, Nathan; Humphrey, Andrew; Lagos, Patricio +4 more
We observe the radio galaxy PKS 1934-63 (at z = 0.1825) using the Multi-Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope (VLT). The radio source is a gigahertz peaked spectrum source and is compact (0.13 kpc), implying an early stage of evolution (≤104 yr). Our data show an interacting pair of galaxies, with projected sepa…
Delineation of alluvial fans from Digital Elevation Models with a GIS algorithm for the geomorphological mapping of the Earth and Mars
Norini, Gianluca; Zuluaga, Maria Clara; Ortiz, Iris Jill +2 more
Alluvial fans are prominent depositional geomorphic features present in nearly all global climates on Earth, and also found on Mars. In this study, we present a Geographic Information System (GIS) algorithm designed for the semi-automated detection of alluvial fans that are connected to their contributing upstream drainage network, from the analys…
The Off-centered Seyfert-like Compact Emission in the Nuclear Region of NGC 3621
Steiner, J. E.; Menezes, R. B.; da Silva, Patrícia
We analyze an optical data cube of the nuclear region of NGC 3621, taken with the integral field unit of the Gemini Multi-object Spectrograph. We found that the previously detected central line emission in this galaxy actually comes from a blob, located at a projected distance of 2.″14 ± 0.″08 (70.1 ± 2.6 pc) from the stellar nucleus. Only diffuse…