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A Numerical Study of the Effects of a Corotating Interaction Region on Cosmic-Ray Transport. II. Features of Cosmic-Ray Composition and Rigidity
Luo, Xi; Shen, Fang; Zhang, Ming +1 more
We continue the numerical modeling of a corotating interaction region (CIR) and the effects it has on solar-rotational recurrent variations of galactic cosmic rays (GCRs). A magnetohydrodynamic model is adapted to simulate the background solar wind plasma with a CIR structure in the inner heliosphere, which is incorporated into a comprehensive Par…
CHAOS. VIII. Far-ultraviolet Spectra of M101 and the Impact of Wolf–Rayet Stars
Skillman, Evan D.; Chisholm, John; Erb, Dawn K. +8 more
We investigate the stellar and nebular properties of nine H II regions in the spiral galaxy M101 with far-ultraviolet (FUV; ∼900–2000 Å) and optical (∼3200–10,000 Å) spectra. We detect significant C III] λλ1907,1909 nebular emission in seven regions, but O III] λ1666 only in the lowest-metallicity region. We produce new analytic functions of the c…
The High-mass X-Ray Binary Luminosity Functions of Dwarf Galaxies
Greene, Jenny E.; Goulding, Andy D.; Lehmer, Bret D. +2 more
Drawing from the Chandra archive and using a carefully selected set of nearby dwarf galaxies, we present a calibrated high-mass X-ray binary (HMXB) luminosity function in the low-mass galaxy regime and search for an already hinted at dependence on metallicity. Our study introduces a new sample of local dwarf galaxies (D < 12.5 Mpc and M *<…
Short-period Variables in TESS Full-frame Image Light Curves Identified via Convolutional Neural Networks
Powell, Brian P.; Barclay, Thomas; Kruse, Ethan +9 more
The Transiting Exoplanet Survey Satellite (TESS) mission measured light from stars in ∼85% of the sky throughout its 2 yr primary mission, resulting in millions of TESS 30-minute-cadence light curves to analyze in the search for transiting exoplanets. To search this vast data set, we aim to provide an approach that is computationally efficient, pr…
Atmospheric parameters and chemical abundances within 100 pc: a sample of G, K, and M main-sequence stars
Stassun, Keivan G.; Kounkel, Marina; Lane, Richard R. +9 more
To date, we have access to enormous inventories of stellar spectra that allow the extraction of atmospheric parameters and chemical abundances essential in stellar studies. However, characterizing such a large amount of data is complex and requires a good understanding of the studied object to ensure reliable and homogeneous results. In this study…
Predicting the Arrival Time of an Interplanetary Shock Based on DSRT Spectrum Observations for the Corresponding Type II Radio Burst and a Blast Wave Theory
Feng, Shiwei; Ruan, Mengsi; Li, Ran +7 more
Since fast head-on coronal mass ejections and their associated shocks represent potential hazards to the space environment of the Earth and even other planets, forecasting the arrival time of the corresponding interplanetary shock is a priority in space weather research and prediction. Based on the radio spectrum observations of the 16-element arr…
The Empirical and Radiative Transfer Hybrid (EaRTH) Disk Model: Merging Analyses of Protoplanetary Dust Disk Mineralogy and Structure
Stassun, Keivan G.; Pinte, Christophe; Principe, David A. +7 more
Our understanding of how exoplanets form and evolve relies on analyses of both the mineralogy of protoplanetary disks and their detailed structures; however, these key complementary aspects of disks are usually studied separately. We present initial results from a hybrid model that combines the empirical characterization of the mineralogy of a dis…
Crimson Behemoth: A massive clumpy structure hosting a dusty AGN at z=4.91
Casey, Caitlin M.; Kartaltepe, Jeyhan S.; Koekemoer, Anton M. +40 more
The current paradigm for the co-evolution of galaxies and their supermassive black holes postulates that dust-obscured active galactic nuclei (AGNs) represent a transitional phase towards a more luminous and unobscured state. However, our understanding of dusty AGNs and their host galaxies at early cosmic times is inadequate due to observational l…
The Age Distribution of Stellar Orbit Space Clumps
Rix, Hans-Walter; Fürnkranz, Verena; Coronado, Johanna +1 more
The orbit distribution of young stars in the Galactic disk is highly structured, from well-defined clusters to streams of stars that may be widely dispersed across the sky, but are compact in orbital action-angle space. The age distribution of such groups can constrain the timescales over which conatal groups of stars disperse into the "field." Ga…
Study of star formation in dual nuclei galaxies using UVIT observations
Kharb, P.; Das, M.; Rahna, P. T. +3 more
We have used the Ultraviolet Imaging Telescope (UVIT) aboard AstroSat to study star formation in a sample of nine dual nuclei galaxies with separations ⪅ 11 kpc, which is an expected outcome of galaxy mergers. To minimize the contribution of active galactic nuclei (AGN) emission, we have used mid-IR colour cut-offs and masked the AGN-dominated nuc…