Search Publications
Fermi-bubble Bulk and Edge Analysis Reveals Dust, Cooling Breaks, and Cosmic-Ray Diffusion, Facilitating a Self-consistent Model
Keshet, Uri; Gurwich, Ilya; Lavi, Assaf +2 more
The full, radio to γ-ray spectrum of the Fermi bubbles is shown to be consistent with standard strong-shock electron acceleration at the bubble edge, without the unnatural energy cutoffs and unrealistic electron cooling of previous studies, if the ambient interstellar radiation is strong; the γ-ray cooling break should then have a microwave counte…
Determining the Origin of Very-high-energy Gamma Rays from Galactic Sources by Future Neutrino Observations
Wang, Kai; Song, Bo-Heng; Huang, Tian-Qi
Recently, the Large High Altitude Air Shower Observatory (LHAASO) identified 12 gamma-ray sources emitting gamma rays with energies above 100 TeV, making them potential PeV cosmic-ray accelerators (PeVatrons). Neutrino observations are crucial in determining whether the gamma-ray radiation process is of hadronic or leptonic origin. In this paper, …
Detection of the Temperature Dependence of the White Dwarf Mass–Radius Relation with Gravitational Redshifts
Hermes, J. J.; Zakamska, Nadia L.; Gänsicke, Boris T. +8 more
Models predict that the well-studied mass–radius relation of white dwarf stars depends on the temperature of the star, with hotter white dwarfs having larger masses at a given radius than cooler stars. In this paper, we use a catalog of 26,041 DA white dwarfs observed in Sloan Digital Sky Survey Data Releases 1–19. We measure the radial velocity, …
Investigation of [KSF2015] 1381-19L, a WC9-type Star in the High-extinction Galactic Region
Baug, Tapas; Das, Ramkrishna; Kar, Subhajit
We report on a multiwavelength study of the Wolf–Rayet star [KSF2015] 1381-19L, which is located in the solar metallicity region (Z = 0.014) of the Milky Way, strongly obscured by interstellar dust. We perform a detailed characterization of the stellar atmosphere by fitting the spectral emission lines observed in the optical and near-infrared (NIR…
The AstroSat UV Deep Field North: The IRX–β Relation for the UV-selected Galaxies at z ∼ 0.5‑0.7
Saha, Kanak; Mondal, Chayan
The relation between the observed UV continuum slope (β) and the infrared excess (IRX) is used as a powerful probe to understand the nature of dust attenuation law in high-redshift galaxies. We present a study of 83 UV-selected galaxies between a redshift of 0.5 and 0.7 from the AstroSat UV Deep Field north that encloses the GOODS-North field. Usi…
The Spatial Correlation between CN-line- and Dust-continuum-emitting Regions in High-mass Star-forming Clouds
Hwang, Jihye; Chung, Eun Jung; Kim, Jongsoo +2 more
Measuring the strength of a three-dimensional (3D) magnetic field vector is challenging as it is not easy to recognize whether its line-of-sight (LOS) and plane-of-sky (POS) components are obtained from the same region. CN (N = 1–0) emission has been used to get the LOS component of a magnetic field (B LOS) from its Zeeman splitting lin…
A Multiwavelength Machine-learning Approach to Classifying X-Ray Sources in the Fields of Unidentified 4FGL-DR4 Sources
Kargaltsev, Oleg; Yang, Hui; Hare, Jeremy
A large fraction of Fermi-Large Area Telescope (LAT) sources in the fourth Fermi-LAT 14 yr catalog (4FGL) still remain unidentified (unIDed). We continued to improve our machine-learning pipeline and used it to classify 1206 X-ray sources with signal-to-noise ratios >3 located within the extent of 73 unIDed 4FGL sources with Chandra X-ray Obser…
Embedded Young Stellar Objects near H72.97-69.39: A Forming Super Star Cluster in N79
Hirschauer, Alec S.; Lenkić, Laura; Meixner, Margaret +10 more
We present 102 embedded young stellar object (YSO) candidates associated with the H72.97-69.39 super star cluster (SSC) in the Large Magellanic Cloud (LMC). With the use of the James Webb Space Telescope Mid-Infrared Instrument (MIRI) imaging mode, we utilize an F770W – F1000W versus F1000W color–magnitude diagram to select 70 YSO candidates. An a…
Local Transition of Electron Pitch Angle Distribution within Flux Pileup Region behind Dipolarization Front
Cao, J. B.; Liu, Y. Y.; Liu, C. M. +2 more
Dipolarization fronts (DFs), earthward-propagating magnetic transients with a strong magnetic field, are important regions favorable for energetic electron acceleration in the magnetotail. The DF-driven electron acceleration usually generates coherent pitch angle distributions (PADs) inside flux pileup regions (FPRs), i.e., strong magnetic field r…
On the Nature of Nonthermal Broadening of Spectral Lines Observed by IRIS
Testa, Paola; De Pontieu, Bart; Cho, Kyuhyoun
The origin of nonthermal broadening in solar spectra is one of the long-standing questions in solar physics. Various processes have been invoked—including unresolved flows, waves, and turbulent processes—but definitive answers are lacking. To investigate the physical processes responsible for nonthermal broadening, we examine its relation with the…