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Discovery of an Inner Disk Component around HD 141569 A
Stark, Christopher C.; Weinberger, Alycia J.; Nesvold, Erika R. +20 more
We report the discovery of a scattering component around the HD 141569 A circumstellar debris system, interior to the previously known inner ring. The discovered inner disk component, obtained in broadband optical light with Hubble Space Telescope/Space Telescope Imaging Spectrograph coronagraphy, was imaged with an inner working angle of 0.″25, a…
A statistical study of plasmaspheric plumes and ionospheric outflows observed at the dayside magnetopause
Zhang, H.; Zong, Q. -G.; Rème, H. +3 more
We present a statistical study of plasmaspheric plumes and ionospheric outflows observed by the Cluster spacecraft near the dayside magnetopause. Plasmaspheric plumes are identified when the low-energy ions (<1 keV) with ∼90° pitch angle distributions are observed by the Cluster Ion Spectrometer/Hot Ion Analyzer instrument. The ionospheric outf…
The mass of the black hole in RE J1034+396
Hryniewicz, K.; Życki, P. T.; Czerny, B. +7 more
Context. The black hole mass measurement in active galaxies is a challenge, particularly in sources where the reverberation method cannot be applied.
Aims: We aim to determine the black hole mass in a very special object, RE J1034+396, one of the two active galactic nuclei (AGN) with quasi-periodic oscillations detected in X-rays, and a singl…
The Mysterious Case of the Solar Argon Abundance near Sunspots in Flares
Doschek, G. A.; Warren, H. P.
Recently we discussed an enhancement of the abundance of Ar xiv relative to Ca xiv near a sunspot during a flare, observed in spectra recorded by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. The observed Ar xiv/Ca xiv ratio yields an argon/calcium abundance ratio seven times greater than expected from the photospher…
A closer look at a coronal loop rooted in a sunspot umbra
Peter, H.; Chitta, L. P.; Young, P. R.
Context. Extreme UV (EUV) and X-ray loops in the solar corona connect regions of enhanced magnetic activity, but they are not usually rooted in the dark umbrae of sunspots because the strong magnetic field found there suppresses convection. This means that the Poynting flux of magnetic energy into the upper atmosphere is not significant within the…
A Study of Heliospheric Modulation and Periodicities of Galactic Cosmic Rays During Cycle 24
Moon, Y. -J.; Chowdhury, Partha; Kudela, K.
Galactic cosmic rays (GCRs) are energetic, charged particles coming from outside the solar system. These particles encounter an outward-moving turbulent solar wind with cyclic magnetic-field fluctuations when entering the heliosphere. This causes convection and diffusion in the heliosphere. The GCR counts detected by the ground-based neutron-monit…
Structure and Stability of Magnetic Fields in Solar Active Region 12192 Based on the Nonlinear Force-free Field Modeling
Kusano, K.; Inoue, S.; Hayashi, K.
We analyze a three-dimensional (3D) magnetic structure and its stability in large solar active region (AR) 12192, using the 3D coronal magnetic field constructed under a nonlinear force-free field (NLFFF) approximation. In particular, we focus on the magnetic structure that produced an X3.1-class flare, which is one of the X-class flares observed …
Interactions of the Infrared Bubble N4 with Its Surroundings
Liu, Hong-Li; Liu, Tie; Yuan, Jing-Hua +11 more
The physical mechanisms that induce the transformation of a certain mass of gas in new stars are far from being well understood. Infrared bubbles associated with H II regions have been considered to be good samples for investigating triggered star formation. In this paper we report on the investigation of the dust properties of the infrared bubble…
Dual Stellar Halos in the Standard Elliptical Galaxy M105 and Formation of Massive Early-type Galaxies
Lee, Myung Gyoon; Jang, In Sung
M105 is a standard elliptical galaxy, located in the Leo I Group. We present photometry of the resolved stars in its inner region at R ≈ 4‧ ≈ 4R eff, obtained from F606W and F814W images in the Hubble Space Telescope archive. We combine this with photometry of the outer region at R ≈ 12‧ ≈ 12R eff from archival imaging data. …
Iron Kα line of boson stars
Cao, Zheng; Bambi, Cosimo; Zhou, Menglei +3 more
The present paper is a sequel to our previous work [1] in which we studied the iron Kα line expected in the reflection spectrum of Kerr black holes with scalar hair. These metrics are solutions of Einstein's gravity minimally coupled to a massive, complex scalar field. They form a continuous bridge between a subset of Kerr black holes and a family…