Search Publications
N2H+(1-0) as a tracer of dense gas in and between spiral arms
Moore, T. J. T.; Clark, P. C.; Ragan, S. E. +2 more
Recent advances in identifying giant molecular filaments in Galactic surveys allow us to study the interstellar material and its dense, potentially star forming phase on scales comparable to resolved extragalactic clouds. Two large filaments detected in the 13CO/C18O(J = 3-2) Heterodyne Inner Milky Way Plane Survey (CHIMPS) s…
Low-Frequency Solar Radio Type II Bursts And Their Association With Space Weather Events During The Ascending Phase Of Solar Cycle 25
Ndacyayisenga, Theogene; Uwamahoro, Jean; Uwamahoro, Jean Claude +5 more
Type II solar radio bursts are signatures of the coronal shocks and, therefore, particle acceleration events in the solar atmosphere and interplanetary space. Type II bursts can serve as a proxy to provide early warnings of incoming solar storm disturbances, such as geomagnetic storms and radiation storms, which may further lead to ionospheric eff…
Magnetic Field in the Earth's Magnetosheath: Models Versus Observations
Vandas, M.; Romashets, E.
Magnetic field measurements in the Earth's magnetosheath are compared with four analytical models, namely Kobel and Flückiger (1994), (https://doi.org/10.1029/94ja01778), Romashets and Vandas (2019), (https://doi.org/10.1029/2018ja026006), Vandas and…
Singular Spectrum Analysis of Exoplanetary Transits
Sajadian, Sedighe; Fatheddin, Hossein
Transit photometry is currently the most efficient and sensitive method for detecting extrasolar planets (exoplanets) and a large majority of confirmed exoplanets have been detected with this method. The substantial success of space-based missions such as NASA's Kepler/K2 and Transiting Exoplanet Survey Satellite has generated a large and diverse …
The first high-redshift cavity power measurements of cool-core galaxy clusters with the International LOFAR Telescope
Botteon, A.; van Weeren, R. J.; Röttgering, H. J. A. +3 more
Radio-mode feedback associated with the active galactic nuclei (AGNs) at the cores of galaxy clusters injects a large amount of energy into the intracluster medium (ICM), offsetting radiative losses through X-ray emission. This mechanism prevents the ICM from rapidly cooling down and fueling extreme starburst activity as it accretes onto the centr…
Visual Orbits of Wolf–Rayet Stars. I. The Orbit of the Dust-producing Wolf–Rayet Binary WR 137 Measured with the CHARA Array
Moffat, Anthony F. J.; Monnier, John D.; Schaefer, Gail H. +19 more
Classical Wolf–Rayet (W-R) stars are the descendants of massive OB stars that have lost their hydrogen envelopes and are burning helium in their cores prior to exploding as Type Ib/c supernovae. The mechanisms for losing their hydrogen envelopes are either through binary interactions or through strong stellar winds potentially coupled with episodi…
Classification of circular polarization Stokes profiles in a sunspot using k-means clustering
Mathew, Shibu K.; Raja Bayanna, A.; Louis, Rohan Eugene
The magnetic and velocity fields in sunspots are highly structured on small spatial scales which are encoded in the Stokes profiles. The Stokes profiles are in turn, derived from a sequence of polarization modulations on the incoming light that are imaged using an analyser-detector combination. Our aim is to identify Stokes profiles in a sunspot w…
Imaging and spectroscopic observations of a confined solar filament eruption with two-stage evolution
Xu, Zhe; Xue, Zhike; Yan, Xiaoli +3 more
Solar filament eruptions are often characterized by stepwise evolution due to the involvement of multiple mechanisms, such as magnetohydrodynamic instabilities and magnetic reconnection. In this article, we investigated a confined filament eruption with a distinct two-stage evolution by using the imaging and spectroscopic observations from the Int…
Identification of A-type supergiants from LAMOST DR5
Liu, Chao; Liu, Zhicun; Cui, Wenyuan +7 more
We present a new method for selecting A-type supergiants (A-SGs hereafter) in the LAMOST DR5 data set using the line indices, and identify 40 spectra of 30 A-SG candidates. Based on the analysis of the absolute magnitude of Gaia DR3, SIMBAD data base, ZTF light variation data, and spectral characteristics of A-SGs, we classified the 30 A-SG candid…
SRG/eROSITA 3D mapping of the interstellar medium using X-ray absorption spectroscopy
Czesla, S.; Kallman, T. R.; Wilms, J. +6 more
We present a detailed study of the hydrogen density distribution in the local interstellar medium (ISM) using the X-ray absorption technique. Hydrogen column densities were precisely measured by fitting X-ray spectra from coronal sources observed during the initial eROSITA all-sky survey (eRASS1). Accurate distance measurements were obtained throu…