Search Publications
Mid-infrared Fine Structure Lines from the Galactic Warm Ionized Medium
Kulkarni, S. R.; Beichman, Charles; Ressler, Michael E.
The Warm Ionized Medium (WIM) hosts most of the ionized gas in the Galaxy and occupies perhaps a quarter of the volume of the Galactic disk. Decoding the spectrum of the Galactic diffuse ionizing field is of fundamental interest. This can be done via direct measurements of ionization fractions of various elements. Based on current physical models …
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…
Multi-wavelength spectroscopic analysis of the ULX Holmberg II X-1 and its nebula suggests the presence of a heavy black hole accreting from a B-type donor
Hamann, W. -R.; Bozzo, E.; Soria, R. +11 more
Context. Ultra-luminous X-ray sources (ULXs) are high-mass X-ray binaries with an X-ray luminosity above 1039 erg s‑1. These ULXs can be powered by black holes that are more massive than 20 M⊙, accreting in a standard regime, or lighter compact objects accreting supercritically. There are only a few ULXs with known…
Accretion versus core-filament collision: Implications for streamer formation in Per-emb-2
Nakamura, Fumitaka; Nguyen-Luong, Quang; Ishihara, Kousuke +1 more
Context. Recent millimetre and sub-millimetre observations have unveiled elongated and asymmetric structures around protostars. These structures, referred to as streamers, often exhibit coherent velocity gradients, seemingly indicating a directed gas flow towards the protostars. However, their origin and role in star formation remain uncertain. Ai…
Characterization of the Blue Straggler Star Populations, through Statistical, Photometric, and Spectral Energy Distribution Analysis, in the Old Open Cluster: NGC 2243
Medhi, Biman J.; Sheikh, A. H.
We present a statistical, photometric, and spectral energy distribution (SED) analysis of the poorly studied old open cluster: NGC 2243, to characterize its blue straggler star (BSS) population. We applied ensemble-based unsupervised machine learning methods to estimate the membership probabilities using Gaia Data Release 3 (DR3) astrometric data.…
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…
Diverse volcanism and crustal recycling on early Mars
Xiao, Long; Edwards, Christopher S.; Michalski, Joseph R. +2 more
The relatively well-preserved ancient crust of Mars provides a natural window into early planetary evolution not available on Earth due to sustained tectonic recycling and erosion on this planet. Mars has generally been considered a one-plate basaltic planet, though recent evidence suggests magmatic evolution resulting in felsic crust might have o…
Probing solar wind velocity from simultaneous superior solar conjunction radio science experiments of BepiColombo and Akatsuki missions
Imamura, T.; Shiota, D.; Iess, L. +5 more
A radio link directly probing the inner solar corona offers the possibility to characterize solar wind properties, including velocity, density, turbulence, and even the axial ratio. In this study, we leveraged radiometric data obtained during a joint superior solar conjunction of the ESA/JAXA BepiColombo mission and the JAXA Akatsuki mission. Our …
Periodic Bedrock Ridges at Oxia Planum and Chryse Planitia, Mars: Evidence for widespread aeolian erosion of an ancient surface by regional paleowinds
Fawdon, Peter; Grindrod, Peter M.; Balme, Matthew R. +4 more
Periodic Bedrock Ridges (PBRs) are repeating, symmetrical, wind-transverse, bedrock-abraded linear ridges that occur on Mars as parallel sets. Here, we extend our previous survey of PBRs at Oxia Planum - the landing site of ESA's ExoMars Rosalind Franklin rover - to include three additional sites along the margins of the circum-Chryse basin to und…
Under the magnifying glass: A combined 3D model applied to cloudy warm Saturn-type exoplanets around M dwarfs
Decin, L.; Helling, Ch.; Jørgensen, U. G. +8 more
Context. Warm Saturn-type exoplanets orbiting M dwarfs are particularly suitable for an in-depth cloud characterisation through transmission spectroscopy because the contrast of their stellar to planetary radius is favourable. The global temperatures of warm Saturns suggest efficient cloud formation in their atmospheres which in return affects the…