Search Publications
The Kinematic Evolution of Erupting Structures in Confined Solar Flares
Cheng, X.; Ding, M. D.; Huang, Z. W.
In this Letter, we study the kinematic properties of ascending hot blobs associated with confined flares. Taking advantage of high-cadence extreme-ultraviolet images provided by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory, we find that for the 26 events selected here, the hot blobs are first impulsively accelerated out…
X-Ray Constraints on the Spectral Energy Distribution of the z = 5.18 Blazar SDSS J013127.34-032100.1
An, Hongjun; Romani, Roger W.
We report on X-ray measurements constraining the spectral energy distribution (SED) of the high-redshift z = 5.18 blazar SDSS J013127.34-032100.1 with new XMM-Newton and NuSTAR exposures. The blazar's X-ray spectrum is well fit by a power law with Γ = 1.9 and ${N}_{{\rm{H}}}=1.1\times {10}^{21}\,{\mathrm{cm}}^{-2}$ , or a broken power law with ${{…
Infrared Color Separation between Thin-shelled Oxygen-rich and Carbon-rich AGB Stars
Sjouwerman, Loránt O.; Pihlström, Ylva M.; Lewis, Megan O. +1 more
We present 43 GHz VLA spectra for 51 AGB sources with the goal of verifying an infrared (IR) color cut intended to separate carbon-rich (C) and oxygen-rich (O) AGB sources throughout the Galaxy. The color cut is a simple line in the [Ks] - [A] versus [A] - [E] color-color diagram based on 2MASS and MSX photometry, and was originally der…
Distinct Accretion Modes of Cygnus X-1 Revealed from Hard X-Rays
Zdziarski, Andrzej A.; Lubiński, Piotr; Pooley, Guy +1 more
Thanks to recurrent observations of the black hole binary Cyg X-1 carried out over 15 years the INTEGRAL satellite has collected the largest data set in the hard X-ray band for this source. We have analyzed these data, complemented by data collected by other X-ray satellites and radio flux at 15 GHz. To characterize the spectral and variability pr…
An Extremely Bright QSO at z = 2.89
Stern, Daniel; Gonzalez, Anthony; Ackley, Kendall +4 more
We report the discovery and confirmation of a bright quasi-stellar object (QSO), 2MASS J13260399 + 7023462, at $z=2.889$ . This QSO is the first spectroscopically confirmed candidate from an ongoing search using the combination of Gaia and Wide-field Infrared Survey Explorer photometry to identify bright QSOs at z > 2, the redshift regime for w…
Anomalous Extinction toward NGC 1938
Milone, Antonino P.; Panagia, Nino; De Marchi, Guido
Intrigued by the extended red giant clump (RC) stretching across the color-magnitude diagram of the stars in a 50 × 50 pc2 region of the Large Magellanic Cloud (LMC) containing the clusters NGC 1938 and NGC 1939, we have studied the stellar populations to learn about the properties of the interstellar medium (ISM) in this area. The exte…
Prediction of the Sun's Coronal Magnetic Field and Forward-modeled Polarization Characteristics for the 2019 July 2 Total Solar Eclipse
Nandy, Dibyendu; Dash, Soumyaranjan; Bhowmik, Prantika +2 more
On 2019 July 2 a total solar eclipse—visible across parts of the Southern Pacific Ocean, Chile, and Argentina—enabled observations of the Sun's corona. The structure and emission characteristics of the corona are determined by underlying magnetic fields, which also govern coronal heating and solar eruptive events. However, coronal magnetic field m…
ASASSN-16oh: A Nova Outburst with No Mass Ejection—A New Type of Supersoft X-Ray Source in Old Populations
Kato, Mariko; Hachisu, Izumi; Saio, Hideyuki
ASASSN-16oh is a peculiar transient supersoft X-ray source without a mass-ejection signature in the field of the Small Magellanic Cloud. Maccarone et al. concluded that ASASSN-16oh is the first dwarf nova with supersoft X-ray that originated from an equatorial accretion belt on a white dwarf (WD). Hillman et al. proposed a thermonuclear runaway mo…
Ages of Dwarfs in the Solar Neighborhood: Considering C and O Enhancements
Wu, Yaqian; Chen, Yuqin; Bi, Shaolan +7 more
Precise stellar ages of stars are necessary to study the evolution of the Milky Way. The age determination is significantly affected by C and O abundances of stars due to their contribution to the overall metallicity and opacity. On the basis of C and O abundances derived from high-resolution observations, we determine the ages of 148 FGK-type dwa…
Ultradiffuse Galaxies in the Coma Cluster: Probing Their Origin and AGN Occupation Fraction
Bogdán, Ákos; Canning, Rebecca E. A.; Kovács, Orsolya E.
Ultradiffuse galaxies (UDGs) exhibit low surface brightness, but their optical extent is comparable to that of Milky Way-type galaxies. In this work, we utilize Chandra X-ray observations of 404 UDGs in the Coma cluster and address two crucial goals. First, we constrain the formation scenario of UDGs by probing the X-ray emission originating from …