Search Publications
Extrapolation of Three-dimensional Magnetic Field Structure in Flare-productive Active Regions with Different Initial Conditions
Shimizu, T.; Inoue, S.; Kawabata, Y.
Nonlinear force-free field (NLFFF) modeling has been extensively used as a tool to infer three-dimensional (3D) magnetic field structure. In this study, the dependency of the NLFFF calculation with respect to the initial guess of the 3D magnetic field is investigated. While major parts of the previous studies used the potential field as the initia…
Magnetohydrodynamic Modeling of the Solar Wind Key Parameters and Current Sheets in the Heliosphere: Radial and Solar Cycle Evolution
Malova, H. V.; Popov, V. Yu.; Petrukovich, A. A. +4 more
We develop an axisymmetric numerical MHD model that allows us to investigate the spatial characteristics of the interplanetary magnetic field (IMF) and key solar wind plasma parameters from 20 to 400 solar radii over all heliolatitudes. The study is aimed at an analysis of the evolution of the spatial structure of the heliosphere through the solar…
A Retrograde Spin of the Black Hole in MAXI J1659-152
Méndez, Mariano; Vadawale, Santosh; Rout, Sandeep K.
We present the results of spectral analysis of the galactic black hole binary MAXI J1659-152 in the rising phase of the outburst that lasted for about 65 days starting on 2010 September 25. The presence of a broad Fe line, verified by Monte Carlo simulations, and coverage of a wide energy band by utilizing the combined spectral capabilities of XMM…
On Measuring Divergence for Magnetic Field Modeling
Leka, K. D.; Barnes, G.; Wheatland, M. S. +2 more
A physical magnetic field has a divergence of zero. Numerical error in constructing a model field and computing the divergence, however, introduces a finite divergence into these calculations. A popular metric for measuring divergence is the average fractional flux $\left\langle | {f}_{i}| \right\rangle $ . We show that $\left\langle | {f}_{i}| \r…
Ultraviolet Line Identifications and Spectral Formation Near Max Light in Type Ia Supernova 2011fe
Baron, E.; Wang, Lifan; Branch, David +4 more
We present ultraviolet line identifications of near maximum-light Hubble Space Telescope observations of SN 2011fe using synthetic spectra generated from both SYNOW and PHOENIX. We find the spectrum to be dominated by blends of iron group elements Fe, Co, and Ni (as expected due to heavy line blanketing by these elements in the UV) and for the fir…
Multiwavelength Photometry and Progenitor Analysis of the Nova V906 Car
Law, Nicholas M.; Blagorodnova, Nadejda; Kupfer, Thomas +12 more
We present optical and infrared photometry of the classical nova V906 Car, also known as Nova Car 2018 and ASASSN-18fv, which was discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) on 2018 March 16.32 UT (MJD 58193.0). The nova reached its maximum on MJD 58222.56 at Vmax = 5.84 ± 0.09 mag, and had decline times of ${t}_…
HST Survey of the Orion Nebula Cluster in the H2O 1.4 µm Absorption Band. III. The Population of Substellar Binary Companions
Gennaro, Mario; Pueyo, Laurent; Ubeda, Leonardo +4 more
We present new results concerning the substellar binary population in the Orion Nebula Cluster (ONC). Using the Karhunen-Loève Image Projection algorithm, we have reprocessed images taken with the IR channel of the Wide Field Camera 3 mounted on the Hubble Space Telescope to unveil faint, close companions in the wings of the stellar point-spread f…
NuSTAR Non-detection of a Faint Active Galactic Nucleus in an Ultraluminous Infrared Galaxy with Kpc-scale Fast Wind
Kawamuro, Taiki; Toba, Yoshiki; Noda, Hirofumi +4 more
Large-scale outflows are generally considered to be possible evidence that active galactic nuclei (AGNs) can severely affect their host galaxies. Recently, an ultraluminous infrared galaxy (ULIRG) at z = 0.49, AKARI J0916248+073034, was found to have a galaxy-scale [O III] λ5007 outflow with one of the highest energy-ejection rates at z < 1.6. …
Discovery of a Rare Late-type, Low-mass Wolf-Rayet Star in the LMC
Prochaska, J. Xavier; Morrell, Nidia; Bond, Howard E. +4 more
We report the serendipitous discovery of an object, UVQS J060819.93-715737.4, with a spectrum dominated by extremely intense, narrow C II emission lines. The spectrum is similar to those of the very rare, late-type [WC11] low-mass Wolf-Rayet stars. Despite the recognition of these stars as a distinct class decades ago, there remains barely a handf…
Sequential Lid Removal in a Triple-decker Chain of CME-producing Solar Eruptions
Joshi, Bhuwan; Joshi, Navin Chandra; Moore, Ronald L. +1 more
We investigate the onsets of three consecutive coronal mass ejection (CME) eruptions in 12 hr from a large bipolar active region (AR) observed by the Solar Dynamics Observatory (SDO), the Solar Terrestrial Relations Observatory (STEREO), the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), and the Geostationary Operational Environmen…