Search Publications
A Diagnostic of Coronal Elemental Behavior during the Inverse FIP Effect in Solar Flares
Brooks, David H.
The solar corona shows a distinctive pattern of elemental abundances that is different from that of the photosphere. Low first ionization potential (FIP) elements are enhanced by factors of several. A similar effect is seen in the atmospheres of some solar-like stars, while late-type M stars show an inverse FIP effect. This inverse effect was rece…
Light propagation in 2PN approximation in the field of one moving monopole I. Initial value problem
Zschocke, Sven
In this investigation the light propagation in the gravitational field of one arbitrarily moving body with monopole structure is considered in the second post-Newtonian approximation. It is found that the light trajectory depends on the acceleration of the body. Some of these acceleration terms are important in order to get well-defined logarithmi…
A Likely Supermassive Black Hole Revealed by Its Einstein Radius in Hubble Frontier Fields Images
Broadhurst, Tom; Ohyama, Youichi; Ford, Holland +4 more
At cosmological distances, gravitational lensing can in principle provide direct mass measurements of supermassive black holes (SMBHs). Here, we directly estimate the mass of a SMBH in the brightest cluster galaxy (BCG) of MACS J1149.5+2223 at z = 0.54 using one of the multiply lensed images of a background spiral galaxy at z = 1.49 projected clos…
In-flight performance of the soft x-ray spectrometer detector system on Astro-H
Tsujimoto, Masahiro; Eckart, Megan E.; Leutenegger, Maurice A. +17 more
The soft x-ray spectrometer (SXS) instrument was launched aboard the Astro-H (Hitomi) observatory on February 17, 2016. The SXS is based on a high-sensitivity x-ray calorimeter detector system that has been successfully deployed in many ground and suborbital spectrometers. The instrument was to provide essential diagnostics for nearly every class …
Characterization of a candidate dual AGN
Torres, M. A. P.; Heida, M.; Jonker, P. G. +2 more
We present Chandra and optical observations of a candidate dual active galactic nucleus (AGN) discovered serendipitously while searching for recoiling black holes via a cross-correlation between the serendipitous XMM source catalogue (2XMMi) and SDSS-DR7 galaxies with a separation no larger than 10 times the sum of their Petrosian radii. The syste…
The UV Spectrum of the Ultracool Dwarf LSR J1835+3259 Observed with the Hubble Space Telescope
Saur, Joachim; Roth, Lorenz; Feldman, Paul D. +4 more
An interesting question about ultracool dwarfs recently raised in the literature is whether their emission is purely internally driven or partially powered by external processes similar to planetary aurora known from the solar system. In this work, we present Hubble Space Telescope observations of the energy fluxes of the M8.5 ultracool dwarf LSR …
Scaling of X-ray spectral properties of a black hole in the Seyfert 1 galaxy NGC7469
Titarchuk, Lev; Seifina, Elena; Ugolkova, Lyubov
We present our analysis of X-ray spectral properties observed from the Seyfert 1 galactic nucleus NGC 7469 using the Rossi X-ray Timing Explorer (RXTE) and Advanced Satellite for Cosmology and Astrophysics mission (ASCA) observations. We demonstrate strong observational evidence that NGC 7469 undergoes spectral transitions from the low hard state …
Extreme star formation in the Milky Way: luminosity distributions of young stellar objects in W49A and W51
König, C.; Moore, T. J. T.; Elia, D. +8 more
We have compared the star-formation properties of the W49A and W51 regions by using far-infrared data from the Herschel infrared Galactic Plane Survey (Hi-GAL) and 850-µm observations from the James Clerk Maxwell Telescope (JCMT) to obtain luminosities and masses, respectively, of associated compact sources. The former are infrared luminosit…
Untwisting Jets Related to Magnetic Flux Cancellation
Wang, Yuming; Liu, Rui; Liu, Jiajia +1 more
The rotational motion of solar jets is believed to be a signature of the untwisting process resulting from magnetic reconnection, which takes place between twisted closed magnetic loops (i.e., magnetic flux ropes) and open magnetic field lines. The identification of the pre-existing flux rope, and the relationship between the twist contained in th…
The Influence of IMF By on the Bow Shock: Observation Result
Li, G.; Wang, M.; Zhao, J. S. +4 more
In this study we use the bow shock crossings contained in the Space Physics Data Facility database, collected by four spacecraft (IMP 8, Geotail, Magion-4, and Cluster1) to analyze the effect of the interplanetary magnetic field (IMF) By component on the bow shock position and shape. Although the IMF Bz component is usually c…