Ryde, Felix Iyyani, Shabnam Ahlgren, Björn Pe’er, Asaf Sharma, Vidushi Lundman, Christoffer Axelsson, Magnus
Published in
The Astrophysical Journal Letters
The physical processes of gamma-ray emission and particle acceleration during the prompt phase in gamma-ray bursts (GRBs) are still unsettled. In order to perform unambiguous physical modeling of observations, a clear identification of the emission mechanism is needed. An instance of a clear identification is the synchrotron emission during the ver...
Banik, Prabir Ghosh, Sanjay K.
Published in
The Astrophysical Journal Letters
Recent ultrahigh-energy gamma-ray observations by the High Altitude Water Cherenkov Observatory up to 100 TeV and LHAASO observatories up to 1.4 PeV energies from the direction of Fermi Large Area Telescope 4FGL source 4FGL J2028.6 + 4110e (Cygnus Cocoon) are indicative of a hadronic origin over a leptonic process for their creation. The IceCube Ne...
Hasheminia, Maryam Mosleh, Moein Tacchella, Sandro Hosseini-ShahiSavandi, S. Zahra Park, Minjung Naidu, Rohan P.
Published in
The Astrophysical Journal Letters
The Milky Way (MW) galaxy is in focus, thanks to new observational data. Here we shed new light on the MW’s past by studying the structural evolution of MW progenitors, which we identify from extragalactic surveys. Specifically, we constrain the stellar-mass growth history (SMGH) of the MW with two methods: (i) direct measurement of the MW’s star f...
Murchikova, Lena White, Christopher J. Ressler, Sean M.
Published in
The Astrophysical Journal Letters
We compare the 230 GHz near-horizon emission from Sagittarius A* to simulations representing three classes of accretion flows. Using the structure function to capture the variability statistics of the light curve, we find a noticeable discrepancy between the observations and models based on torus-fed accretion disks, whether those disks bring in a ...
Cuesta, Manuel Enrique Chhiber, Rohit Roy, Sohom Goodwill, Joshua Pecora, Francesco Jarosik, Jake Matthaeus, William H. Parashar, Tulasi N. Bandyopadhyay, Riddhi
Published in
The Astrophysical Journal Letters
We examine the radial evolution of correlation lengths perpendicular ( λC⊥ ) and parallel ( λC∥ ) to the magnetic-field direction, computed from solar wind magnetic-field data measured by Parker Solar Probe (PSP) during its first eight orbits, Helios 1, Advanced Composition Explorer (ACE), WIND, and Voyager 1 spacecraft. Correlation lengths are gro...
Biscoveanu, Sylvia Callister, Thomas A. Haster, Carl-Johan Ng, Ken K. Y. Vitale, Salvatore Farr, Will M.
Published in
The Astrophysical Journal Letters
The population-level distributions of the masses, spins, and redshifts of binary black holes (BBHs) observed using gravitational waves can shed light on how these systems form and evolve. Because of the complex astrophysical processes shaping the inferred BBH population, models allowing for correlations among these parameters will be necessary to f...
Gais, Joseph Ng, Ken K. Y. Seo, Eungwang Wong, Kaze W. K. Li, Tjonnie G. F.
Published in
The Astrophysical Journal Letters
The population properties of intermediate-mass black holes remain largely unknown, and understanding their distribution could provide a missing link in the formation of supermassive black holes and galaxies. Gravitational-wave observations can help fill in the gap from stellar mass black holes to supermassive black holes with masses between ∼100–10...
Cyganowski, C. J. Ilee, J. D. Brogan, C. L. Hunter, T. R. 张, 遂楠 Harries, T. J. Haworth, T. J.
Published in
The Astrophysical Journal Letters
We present high-resolution (≲160 au) Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm observations of the high-mass prestellar core candidate G11.92−0.61 MM2, which reveal that this source is in fact a protobinary system with a projected separation of 505 au. The binary components, MM2E and MM2W, are compact (radii 24.7 L ⊙ for MM2E and ...
Zhang, Yingjie Sun, Tianran Wang, Chi Ji, Li Carter, Jennifer. A. Sembay, Steve Koutroumpa, Dimitra Liu, Ying D. Liang, Guiyun Liu, Wenhao
...
Published in
The Astrophysical Journal Letters
Soft X-ray emissions from solar wind charge exchange (SWCX) are applied in a recently developed approach to study the magnetosphere using panoramic soft X-ray imaging. This study represents the first attempt to distinguish magnetospheric SWCX emissions observed by XMM-Newton during the impact of an interplanetary coronal mass ejection (ICME) and it...
Donlon II, Thomas Newberg, Heidi Jo Kim, Bokyoung Lépine, Sebastien
Published in
The Astrophysical Journal Letters
We use halo dwarf stars with photometrically determined metallicities that are located within 2 kpc of the Sun to identify local halo substructure. The kinematic properties of these stars do not indicate a single, dominant radial merger event (RME). The retrograde Virgo Radial Merger (VRM) component has [Fe/H] = −1.7. A second, nonrotating RME comp...
