Search Publications
Modeling the Observed Distortion of Multiple (Ghost) CME Fronts in STEREO Heliospheric Imagers
Wang, Yuming; Shen, Chenglong; Lockwood, Mike +10 more
In this work we have, for the first time, applied the interpretation of multiple "ghost-fronts" to two synthetic coronal mass ejections (CMEs) propagating within a structured solar wind using the Heliospheric Upwind eXtrapolation time (HUXt) solar wind model. The two CMEs occurred on 2012 June 13-14 showing multiple fronts in images from Solar Ter…
The Kiloparsec-scale Fe Ka Emission in the Compton-thin Seyfert 2 Galaxy NGC 4388 Resolved by Chandra
Fabbiano, Giuseppina; Shu, Xinwen; Wang, Junfeng +4 more
We present imaging and spectral analysis of the combined ∼48 ks Chandra observations of Seyfert 2 galaxy NGC 4388. Compared with previous studies, three prominent extended X-ray structures around the nucleus on a kiloparsec-scale are well imaged, allowing an in-depth spatially resolved study. Both the extended hard continuum (4-6 keV) and the Fe K…
Two-component Magnetic Field along the Line of Sight to the Perseus Molecular Cloud: Contribution of the Foreground Taurus Molecular Cloud
Bastien, Pierre; Coudé, Simon; Hasegawa, Tetsuo +13 more
Optical stellar polarimetry in the Perseus molecular cloud direction is known to show a fully mixed bimodal distribution of position angles across the cloud. We study the Gaia trigonometric distances to each of these stars and reveal that the two components in position angles trace two different dust clouds along the line of sight. One component, …
Observations of Forbush Decreases of Cosmic-Ray Electrons and Positrons with the Dark Matter Particle Explorer
Alemanno, Francesca; An, Qi; Azzarello, Philipp +147 more
The Forbush decrease (FD) represents the rapid decrease of the intensities of charged particles accompanied with the coronal mass ejections or high-speed streams from coronal holes. It has been mainly explored with the ground-based neutron monitor network, which indirectly measures the integrated intensities of all species of cosmic rays by counti…
Properties of the Obscuring Torus in NGC 1052 from Multiepoch Broadband X-Ray Spectroscopy
Brenneman, L.; Urry, C. M.; Baloković, M. +1 more
Obscuration of the innermost parts of active galactic nuclei (AGN) is observed in the majority of the population both in the nearby universe and at high redshift. However, the nature of the structures causing obscuration, especially in low-luminosity AGN, is poorly understood at present. We present a novel approach to multiepoch broadband X-ray sp…
On the Impact of Inclination-dependent Attenuation on Derived Star Formation Histories: Results from Disk Galaxies in the Great Observatories Origins Deep Survey Fields
Basu-Zych, Antara; Garofali, Kristen; Lehmer, Bret D. +4 more
We develop and implement an inclination-dependent attenuation prescription for spectral energy distribution (SED) fitting and study its impact on derived star formation histories. We apply our prescription within the SED fitting code Lightning to a clean sample of 82, z = 0.21-1.35 disk-dominated galaxies in the Great Observatories Origins Deep Su…
Census of R Coronae Borealis Stars. I. Infrared Light Curves from Palomar Gattini IR
Soria, Roberto; Tinyanont, Samaporn; De, Kishalay +16 more
We are undertaking the first systematic infrared (IR) census of R Coronae Borealis (RCB) stars in the Milky Way, beginning with IR light curves from the Palomar Gattini IR (PGIR) survey. The PGIR is a 30 cm J-band telescope with a 25 deg2 camera that is surveying 18,000 deg2 of the northern sky (δ > -28°) at a cadence of 2…
XMM-Newton Observes the Intrabinary Shock of PSR J1959+2048
An, Hongjun; Romani, Roger W.; Kandel, D.
In a multi-orbit (100 ks) XMM-Newton exposure of the original black widow pulsar, PSR J1959+2048, we measure the strong orbital modulation caused by intrabinary shock (IBS) emission. The IBS light curve peak appears asymmetric, which we attribute to sweep-back effects in the companion wind. We also see evidence for an X-ray eclipse by the companio…
Discovery of an Edge-on Circumstellar Debris Disk around BD+45° 598: A Newly Identified Member of the β Pictoris Moving Group
Mamajek, Eric; Hinkley, Sasha; Matthews, Brenda +25 more
We report the discovery of a circumstellar debris disk viewed nearly edge-on and associated with the young, K1 star BD+45° 598 using high-contrast imaging at 2.2 µm obtained at the W.M. Keck Observatory. We detect the disk in scattered light with a peak significance of ∼5σ over three epochs, and our best-fit model of the disk is an almost ed…
Multiple Sources of Solar High-energy Protons
Yu, Sijie; Vainio, Rami; Gary, Dale E. +6 more
During the 24th solar cycle, the Fermi Large Area Telescope (LAT) has observed a total of 27 solar flares possessing delayed γ-ray emission, including the exceptionally well-observed flare and coronal mass ejection (CME) on 2017 September 10. Based on the Fermi/LAT data, we plot, for the first time, maps of possible sources of the delayed >100 …