Search Publications
Jitter Radiation as an Alternative Mechanism for the Nonthermal X-Ray Emission of Cassiopeia A
Greco, Emanuele; Vink, Jacco; Ferrigno, Carlo +1 more
Synchrotron radiation from relativistic electrons is usually invoked as responsible for the nonthermal emission observed in supernova remnants. Diffusive shock acceleration is the most popular mechanism to explain the process of particles acceleration and within its framework a crucial role is played by the turbulent magnetic field. However, the s…
Exploring the Origin of Solar Energetic Electrons. I. Constraining the Properties of the Acceleration Region Plasma Environment
Jeffrey, Natasha L. S.; Pallister, Ross
Solar flare electron acceleration is an efficient process, but its properties (mechanism, location) are not well constrained. Via hard X-ray (HXR) emission, we routinely observe energetic electrons at the Sun, and sometimes we detect energetic electrons in interplanetary space. We examine if the plasma properties of an acceleration region (size, t…
NGC 6302: The Tempestuous Life of a Butterfly
Frank, Adam; Balick, Bruce; Kastner, Joel H. +4 more
NGC 6302 (The Butterfly Nebula) is an extremely energetic and rapidly expanding bipolar planetary nebula (PN). If the central source is a single star, then its apparent location in an H-R diagram places it among the most massive, hottest, and presumably rapidly evolving of all central stars of PNe. Our proper motion study of NGC 6302, based on Hub…
Testing Physical Scenarios for the Reflection Features of Type-1 AGNs using XMM-Newton and NuSTAR Simultaneous Observations
González-Martín, Omaira; Masegosa, Josefa; Victoria-Ceballos, César Ivan +3 more
Above ~3 keV, the X-ray spectrum of active galactic nuclei (AGNs) is characterized by the intrinsic continuum and Compton reflection features. For type-1 AGNs, several regions may contribute to the reflection. To investigate the nature of the reflecting medium, we perform a systematic analysis of the reflector using XMM-Newton and Nuclear Spectros…
Speed and Acceleration of Coronal Mass Ejections Associated with Sustained Gamma-Ray Emission Events Observed by Fermi/LAT
Gopalswamy, Nat; Akiyama, Sachiko; Yashiro, Seiji +2 more
The sustained gamma-ray emission (SGRE) from the Sun is a prolonged enhancement of >100 MeV gamma-ray emission that extends beyond the flare impulsive phase. The origin of the >300 MeV protons resulting in SGRE is debated, with both flares and shocks driven by coronal mass ejections (CMEs) being the suggested sites of proton acceleration. We…
Structure of the W3A Low-density Foreground Region
Seo, Youngmin; Goldsmith, Paul. F.; Stutzki, Jürgen +5 more
We present analysis of [O I] 63 µm and CO J = 5 - 4 and 8 - 7 multiposition data in the W3A region and use it to develop a model for the extended low-density foreground gas that produces absorption features in the [O I] and J = 5 - 4 CO lines. We employ the extinction to the exciting stars of the background H II region to constrain the total…
The Low-temperature Corona in ESO 511-G030 Revealed by NuSTAR and XMM-Newton
Fabian, Andrew C.; Reynolds, Christopher S.; Yu, Zhibo +9 more
We present the results from a coordinated XMM-Newton + NuSTAR observation of the Seyfert 1 galaxy ESO 511-G030. With this joint monitoring program, we conduct a detailed variability and spectral analysis. The source remained in a low flux and very stable state throughout the observation period, although there are slight fluctuations of flux over l…
New Resonance Scattering Model in AtomDB: Application to Line Suppression in Galaxy Clusters and Elliptical Galaxies
Raymond, John; Smith, Randall; Chakraborty, Priyanka +2 more
In this paper, we present the simple, one-step, self-consistent, and fast resonance scattering model rsapec based on the AtomDB database. This model can be used as an alternative to the commonly used APEC model for fitting X-ray spectra with optically thick lines. The current model is intended, in general, for verifying the presence of the effect …
The Photodissociation and Ionization Fronts in M17-SW Localized with FIFI-LS on Board SOFIA
Fadda, Dario; Looney, Leslie W.; Tielens, Alexander G. G. M. +5 more
To understand star formation rates, studying feedback mechanisms that regulate star formation is necessary. The radiation emitted by nascent massive stars play a significant role in feedback by photodissociating and ionizing their parental molecular clouds. To gain a detailed picture of the physical processes, we mapped the photodissociation regio…
Disk Dissipation, Giant Planet Formation, and Star Formation Rate Fluctuations in the 3 Myr History of Gould's Belt
Liu, Tie; He, Jinhua; Ge, Jixing +3 more
Although episodic star formation (SF) has been suggested for nearby SF regions, a panoramic view of the recent episodic SF history in the solar neighborhood is still missing. By uniformly constraining the slope α of infrared spectral energy distributions (SEDs) of young stellar objects (YSOs) in the 13 largest Gould's Belt (GB) protoclusters surve…