Search Publications
Properties of the Closest Young Binaries. I. DF Tau’s Unequal Circumstellar Disk Evolution
Prato, L.; Schaefer, G.; Simon, M. +6 more
We present high-resolution, spatially resolved, near-infrared spectroscopy and imaging of the two components of DF Tau, a young, low-mass, visual binary in the Taurus star-forming region. With these data, we provide a more precise orbital solution for the system, determine component spectral types, radial velocity, veiling and v\sin i values, and …
Sudden Penumbral Reappearance and Umbral Motion Induced by an M7.9 Solar Flare
Yang, Jiayan; Hong, Junchao; Xu, Zhe +2 more
The sudden flare-related changes of sunspot structures have been recognized as the photospheric responses to the solar eruptions in the corona. In this study, we report two distinctive sunspots variations associated with the flare SOL2015-06-25T08:16 (M7.9). Along the flaring polarity inversion line (PIL), the originally decayed penumbra showed a …
Observations of Reconnection Flows in a Flare on the Solar Disk
Fletcher, L.; Hannah, I. G.; Jeffrey, N. L. S. +3 more
Magnetic reconnection is a well-accepted part of the theory of solar eruptive events, though the evidence is still circumstantial. Intrinsic to the reconnection picture of a solar eruptive event, particularly in the standard model for two-ribbon flares (CSHKP model), are an advective flow of magnetized plasma into the reconnection region, expansio…
H2 Fluorescence in M Dwarf Systems: A Stellar Origin
Loyd, R. O. Parke; Roberge, Aki; Kruczek, Nicholas +7 more
Observations of molecular hydrogen (H2) fluorescence are a potentially useful tool for measuring the H2 abundance in exoplanet atmospheres. This emission was previously observed in {{M}} dwarfs with planetary systems. However, low signal-to-noise prevented a conclusive determination of its origin. Possible sources include exo…
SOFIA-EXES Mid-IR Observations of [Fe II] Emission from the Extended Atmosphere of Betelgeuse
Ryde, N.; Greathouse, T. K.; Guinan, E. F. +5 more
We present a NASA-DLR SOFIA-Echelon Cross Echelle Spectrograph (EXES) and NASA Infrared Telescope Facility-Texas Echelon Cross Echelle Spectrograph (TEXES) mid-IR R≃ {{50,000}} spectral study of forbidden Fe II transitions in the early-type M supergiants, Betelgeuse (α Ori: M2 Iab) and Antares (α Sco: M1 Iab + B3 V). With EXES, we spectrally resol…
Constraints on the Progenitor of SN 2010jl and Pre-existing Hot Dust in its Surrounding Medium
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Kelly, Patrick L. +6 more
A search for the progenitor of SN 2010jl, an unusually luminous core-collapse supernova of Type IIn, using pre-explosion Hubble/WFPC2 and Spitzer/IRAC images of the region, yielded upper limits on the UV and near-infrared (IR) fluxes from any candidate star. These upper limits constrain the luminosity and effective temperature of the progenitor, t…
NuSTAR Hard X-Ray Observation of the Gamma-Ray Binary Candidate HESS J1832-093
Hailey, Charles J.; Mori, Kaya; Gotthelf, E. V. +13 more
We present a hard X-ray observation of the TeV gamma-ray binary candidate HESS J1832-093, which is coincident with the supernova remnant G22.7-0.2, using the Nuclear Spectroscopic Telescope Array. Non-thermal X-ray emission from XMMU J183245-0921539, the X-ray source associated with HESS J1832-093, is detected up to ∼30 keV and is well-described b…
Turbulent Density Fluctuations and Proton Heating Rate in the Solar Wind from 9-20 R ⊙
Vourlidas, Angelos; Ramesh, R.; Subramanian, Prasad +2 more
We obtain scatter-broadened images of the Crab Nebula at 80 MHz as it transits through the inner solar wind in 2017 and 2016 June. These images are anisotropic, with the major axis oriented perpendicular to the radially outward coronal magnetic field. Using these data, we deduce that the density modulation index (δ {N}e/{N}e)…
A Radio Relic and a Search for the Central Black Hole in the Abell 2261 Brightest Cluster Galaxy
Lauer, Tod R.; Postman, Marc; Lazio, T. Joseph W. +4 more
We present VLA images and HST/STIS spectra of sources within the center of the brightest cluster galaxy (BCG) in Abell 2261. These observations were obtained to test the hypothesis that its extremely large, flat core reflects the ejection of its supermassive black hole. Spectra of three of the four most luminous “knots” embedded in the core were t…
Outflow and Metallicity in the Broad-Line Region of Low-Redshift Active Galactic Nuclei
Nagao, Tohru; Woo, Jong-Hak; Shin, Jaejin
Outflows in active galactic nuclei (AGNs) are crucial to understand in investigating the co-evolution of supermassive black holes (SMBHs) and their host galaxies since outflows may play an important role as an AGN feedback mechanism. Based on archival UV spectra obtained with the Hubble Space Telescope and IUE, we investigate outflows in the broad…