Search Publications
NuSTAR Reveals Relativistic Reflection But No Ultra-Fast Outflow in the Quasar Pg∼1211+143
Harrison, F. A.; Craig, W.; Stern, D. +9 more
We report on four epochs of observations of the quasar PG 1211+143 using NuSTAR. The net exposure time is 300 ks. Prior work on this source found suggestive evidence of an ultra-fast outflow (UFO) in the Fe K band with a velocity of approximately 0.1c. The putative flow would carry away a high-mass flux and kinetic power, with broad implications f…
A Solar Coronal Jet Event Triggers a Coronal Mass Ejection
Wang, Yuming; Shen, Chenglong; Wang, S. +3 more
In this paper, we present multi-point, multi-wavelength observations and analysis of a solar coronal jet and coronal mass ejection (CME) event. Employing the GCS model, we obtained the real (three-dimensional) heliocentric distance and direction of the CME and found it to propagate at a high speed of over 1000 km s-1. The jet erupted be…
Evidence for a Transition Region Response to Penumbral Microjets in Sunspots
Carlsson, M.; Rouppe van der Voort, L. H. M.; Vissers, G. J. M.
Penumbral microjets (PMJs) are short-lived, fine-structured, and bright jets that are generally observed in chromospheric imaging of the penumbra of sunspots. Here we investigate their potential transition region signature by combining observations with the Swedish 1-m Solar Telescope in the Ca ii H and Ca ii 8542 Å lines with ultraviolet imaging …
High-resolution Imaging of NGC 2346 with GSAOI/GeMS: Disentangling the Planetary Nebula Molecular Structure to Understand Its Origin and Evolution
Villaver, Eva; Shaw, Richard A.; García-Hernández, D. A. +3 more
We present high spatial resolution (≈ 60-90 mas) images of the molecular hydrogen emission in the planetary nebula (PN) NGC 2346. The data were acquired during the system verification of the Gemini Multi-conjugate Adaptive Optics System + Gemini South Adaptive Optics Imager. At the distance of NGC 2346, 700 pc, the physical resolution corresponds …
Energy Dissipation in Magnetic Null Points at Kinetic Scales
Lapenta, Giovanni; Eriksson, Elin; Divin, Andrey +2 more
We use kinetic particle-in-cell and MHD simulations supported by an observational data set to investigate magnetic reconnection in clusters of null points in space plasma. The magnetic configuration under investigation is driven by fast adiabatic flux rope compression that dissipates almost half of the initial magnetic field energy. In this phase …
The Stellar Initial Mass Function at 0.9 < z < 1.5
Barro, Guillermo; Pérez-González, Pablo G.; Koekemoer, Anton M. +12 more
We explore the stellar initial mass function (IMF) of a sample of 49 massive quiescent galaxies (MQGs) at 0.9 < z < 1.5. We base our analysis on intermediate resolution spectro-photometric data in the GOODS-N field taken in the near-infrared and optical with the Hubble Space Telescope Wide Field Camera 3 G141 grism and the Survey for High-z …
Origin of Interplanetary Dust through Optical Properties of Zodiacal Light
Ishiguro, Masateru; Yang, Hongu
This study investigates the origin of interplanetary dust particles (IDPs) through the optical properties, albedo and spectral gradient, of zodiacal light. The optical properties were compared with those of potential parent bodies in the solar system, which include D-type (as analogs of cometary nuclei), C-type, S-type, X-type, and B-type asteroid…
Tracing the Magnetic Field Morphology of the Lupus I Molecular Cloud
Franco, G. A. P.; Alves, F. O.
Deep R-band CCD linear polarimetry collected for fields with lines of sight toward the Lupus I molecular cloud is used to investigate the properties of the magnetic field within this molecular cloud. The observed sample contains about 7000 stars, almost 2000 of them with a polarization signal-to-noise ratio larger than 5. These data cover almost t…
Multi-spacecraft Measurement of Turbulence within a Magnetic Reconnection Jet
Khotyaintsev, Yu. V.; Matthaeus, W. H.; Chapman, S. C. +3 more
The relationship between magnetic reconnection and plasma turbulence is investigated using multipoint in situ measurements from the Cluster spacecraft within a high-speed reconnection jet in the terrestrial magnetotail. We show explicitly that work done by electromagnetic fields on the particles, {\boldsymbol{J}}\cdot {\boldsymbol{E}}, has a non-G…
Evidence for High-frequency QPOs with a 3:2 Frequency Ratio from a 5000 Solar Mass Black Hole
Cenko, S. Bradley; Zoghbi, Abderahmen; Tombesi, Francesco +3 more
Following the discovery of 3:2 resonance quasi-periodic oscillations (QPOs) in M82X-1, we have constructed power density spectra (PDS) of all 15 (sufficiently long) XMM-Newton observations of the ultraluminous X-ray source NGC 1313 X-1 (LX ≈ 2 × 1040 erg s-1). We detect a strong QPO at a frequency of 0.29 ± 0.01 Hz…