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Chandra X-Ray Observations of PSR J1849-0001, Its Pulsar Wind Nebula, and the TeV Source HESS J1849-000
Kargaltsev, Oleg; Klingler, Noel; Yang, Hui +4 more
We obtained a 108 ks Chandra X-ray Observatory (CXO) observation of PSR J1849-0001 and its pulsar wind nebula (PWN) coincident with the TeV source HESS J1849-000. By analyzing the new and old (archival) CXO data, we resolved the pulsar from the PWN, explored the PWN morphology on arcsecond and arcminute scales, and measured the spectra of differen…
Atmospheric Abundances and Bulk Properties of the Binary Brown Dwarf Gliese 229Bab from JWST/MIRI Spectroscopy
Zhang, Yapeng; Perrin, Marshall D.; Knutson, Heather A. +8 more
We present JWST/Mid Infrared Instrument (MIRI) low-resolution spectroscopy (4.75–14 µm) of the first known substellar companion, Gliese 229Bab, which was recently resolved into a tight binary brown dwarf. Previous atmospheric retrieval studies modeling Gliese 229B as a single brown dwarf have reported anomalously high carbon-to-oxygen ratios…
Determining the Nanoflare Heating Frequency of an X-Ray Bright Point Observed by MaGIXS
Reeves, Katharine K.; Del Zanna, Giulio; Golub, Leon +18 more
Nanoflares are thought to be one of the prime candidates that can heat the solar corona to its multimillion kelvin temperature. Individual nanoflares are difficult to detect with the present generation of instruments, but their presence can be inferred by comparing simulated nanoflare-heated plasma emissions with the observed emission. Using HYDRA…
Stellar Characterization and a Chromospheric Activity Analysis of a K2 Sample of Planet-hosting Stars
Cunha, Katia; Smith, Verne V.; Quispe-Huaynasi, F. +4 more
Effective temperatures, surface gravities, and iron abundances were derived for 109 stars observed by the K2 mission using equivalent width measurements of Fe I and Fe II lines. Calculations were carried out in local thermodynamic equilibrium using Kurucz model atmospheres. Stellar masses and radii were derived by combining the stellar parameters …
UVIT Survey of the Host Galaxies of Active Galactic Nuclei. I. Star Formation Scenarios
Stalin, C. S.; Nandi, Payel; Saikia, D. J. +1 more
Circumnuclear star formation (SF) is generally seen in galaxies hosting active galactic nuclei (AGN); however, the connection between the AGN activity and SF in them is less well understood. To explore this connection on scales of a few tens of parsecs to a few tens of kiloparsecs and larger, we carried out an investigation of SF in seven Seyfert-…
A New Rarity Assessment of the "Disk of Satellites": The Milky Way System Is the Exception Rather Than the Rule in the ΛCDM Cosmology
Yoon, Suk-Jin; Paudel, Sanjaya; Moon, Jun-Sung +2 more
The majority of satellite galaxies around the Milky Way (MW) show disk-like distributions (the disk of satellites; DoS), which is a small-scale problem of the lambda cold dark matter cosmology. The conventional definition of the MW-like DoS is a satellite system with a minor-to-major axis ratio (c/a) lower than the MW's c/a value of 0.181. Here, w…
The Dark Energy Camera Magellanic Clouds Emission-line Survey
White, Richard L.; Rest, Armin; Blair, William P. +7 more
We have used the Dark Energy Camera (DECam) on the CTIO Blanco 4 m telescope to perform a new emission-line survey of the Large Magellanic Cloud (LMC) using narrowband Hα and [S II] filters in addition to a continuum band to create pure emission-line images. We refer to this new survey as DeMCELS, to distinguish it from the earlier Magellanic Clou…
Boron Abundances in Early B Dwarfs of the Galactic Open Cluster NGC 3293
Cunha, Katia; Langer, Norbert; Proffitt, Charles R. +4 more
New boron abundances or upper limits have been determined for eight early B stars in the young Galactic open cluster NGC 3293, using UV spectra obtained by the Hubble Space Telescope Cosmic Origins Spectrograph. With previous observations, there are now 18 early B stars in this cluster with boron measurements. Six of the newly observed stars have …
Asteroseismology of One of the Most Rapidly Rotating DBV Stars: EPIC 248705247
Su, Jie; Cang, Tianqi; Fu, Jianning +4 more
We present a comprehensive analysis of oscillations of the helium-rich white dwarf DBV star EPIC 248705247 (SDSS J102106.69+082724.8). We extract the light curves from 79.7 days of K2 Campaign 14 data and identify 21 independent frequencies, including three complete and three incomplete dipole modes, with an average frequency splitting of 20.37 ± …
Direct Observations of a Shock Traversing Preceding Two Coronal Mass Ejections: Insights from Solar Orbiter, Wind, and STEREO Observations
Zhang, Zhiyong; Wang, Yuming; Shen, Chenglong +8 more
The three successive coronal mass ejections (CMEs) that erupted from 2023 November 27–28, provide the first opportunity to shed light on the entire process of a shock propagating through, sequentially compressing, and modifying two preceding CMEs using in situ data from Solar Orbiter, Wind, and STEREO-A. We describe the interaction of the three CM…