Search Publications

The high energy X-ray probe (HEX-P): probing the physics of the X-ray corona in active galactic nuclei

Nardini, Emanuele; Ricci, Claudio; Walton, Dominic J. +27 more

The hard X-ray emission in active galactic nuclei (AGN) and black hole X-ray binaries is thought to be produced by a hot cloud of electrons referred to as the corona. This emission, commonly described by a power law with a high-energy cutoff, is suggestive of Comptonization by thermal electrons. While several hypotheses have been proposed to expla…

Kepler main-sequence solar-like stars: surface rotation and magnetic-activity evolution

García, Rafael A.; Breton, Sylvain N.; Mathur, Savita +4 more

While the mission's primary goal was focused on exoplanet detection and characterization, Kepler made and continues to make extraordinary advances in stellar physics. Stellar rotation and magnetic activity are no exceptions. Kepler allowed for these properties to be determined for tens of thousands of stars from the main sequence up to the red gia…

A study on the metallicity gradients in the galactic disk using open clusters

Deepak; Malhotra, Sagar; Joshi, Yogesh Chandra

We study the metallicity distribution and evolution in the galactic disk based on the largest sample of open star clusters in the galaxy. From the catalog of 1,879 open clusters in the range of galactocentric distance (RGC) from 4 to 20 kpc, we investigate the variation in metallicity in the galactic disk as functions of RGC, vertical distance (Z)…

The role of magnetar transient activity in time-domain and multimessenger astronomy

Younes, George; Negro, Michela; Burns, Eric +3 more

Time-domain and multimessenger astronomy (TDAMM) involves the study of transient and time-variable phenomena across various wavelengths and messengers. The Astro2020 Decadal Survey has identified TDAMM as the top priority for NASA in this decade, emphasizing its crucial role in advancing our understanding of the universe and driving new discoverie…

Crucial future observations and directions for unveiling magnetopause dynamics and their geospace impacts

Nykyri, Katariina; Shi, Xueling; Hartinger, Michael D. +5 more

The dynamics of Earth's magnetopause, driven by several different external/internal physical processes, plays a major role in the geospace energy budget. Given magnetopause motion couples across many space plasma regions, numerous forms of observations may provide valuable information in understanding these dynamics and their impacts. In-situ mult…

The toroidal curvatures of interplanetary coronal mass ejection flux ropes from multi-point observations

Luhmann, J. G.; Lai, H. R.; Russell, C. T. +5 more

Interplanetary coronal mass ejections (ICMEs), characterized by their magnetic flux ropes, could potentially trigger geomagnetic disturbances. They have been attracting extensive investigations for decades. Despite numerous ICME models proposed in the past, few account for the curvature of the flux rope axis. In this study, we use conjunction obse…

Magnetic fields and electric currents around the dayside magnetopause as inferred from data-constrained modeling

Semenov, V. S.; Erkaev, N. V.; Tsyganenko, N. A. +1 more

Based on a new mathematical framework and large multi-year multi-mission data sets, we reconstruct electric currents and magnetic fields around the dayside magnetopause and their dependence on the incoming solar wind, IMF, and geodipole tilt. The model architecture builds on previously developed mathematical frameworks and includes two separate bl…

Acceleration of an interplanetary shock through the magnetosheath: a global hybrid simulation

Modolo, R.; Fontaine, D.; Savoini, P. +1 more

According to most observations and simulations, interplanetary shocks slow down when they propagate through the magnetosheath. In this article, we present results from a self-consistent global hybrid PIC simulation of an interplanetary shock which, by contrast, accelerates as it propagates through the magnetosheath. In this simulation, the solar w…

Evaluation of the astrometric capability of Multi-Channel Imager and simulated calculation of proper motion of M31

Peng, Xiyan; Liao, Shilong; Qi, Zhaoxiang +8 more

Introduction: The Multi-Channel Imager (MCI), one of the back-end modules of the future China Space Station Telescope (CSST), is designed for high-precision spacebased astronomical observations. This paper evaluates the astrometric capability of the MCI based on simulated observational images and Gaia data: the M31 galaxy is selected as a represen…

Cluster: List of plasma jets in the subsolar magnetosheath

Temmer, Manuela; Plaschke, Ferdinand; Simon Wedlund, Cyril +6 more