Search Publications
A JWST MIRI MRS View of the η Tel Debris Disk and Its Brown Dwarf Companion
Law, David R.; Chen, Christine H.; Hines, Dean C. +12 more
We report JWST Mid-Infrared Instrument (MIRI) Medium Resolution Spectrograph (MRS) observations of the β Pic moving-group member, η Tel A, along with its brown dwarf binary companion, η Tel B. Following point-spread-function subtraction, we recover the spatially resolved flux from the debris disk around η Tel A, along with the position of the comp…
Spectropolarimetric Radio Imaging of Faint Gyrosynchrotron Emission from a CME: A Possible Indication of the Insufficiency of Homogeneous Models
Mondal, Surajit; Oberoi, Divya; Kansabanik, Devojyoti
The geo-effectiveness of coronal mass ejections (CMEs) is determined primarily by their magnetic fields. Modeling of gyrosynchrotron (GS) emission is a promising remote sensing technique to measure the CME magnetic field at coronal heights. However, faint GS emission from CME flux ropes is hard to detect in the presence of bright solar emission fr…
WawHelioIonMP: A Semiempirical Tool for the Determination of Latitudinal Variation in the Ionization Rate of Interstellar Hydrogen and the Solar Wind
Bzowski, M.; Porowski, C.
The latitudinal structure of the solar wind varies during the cycle of solar activity. Analysis of this variation is important for understanding the solar activity and interpretation of observations of heliospheric energetic neutral hydrogen atoms and interstellar neutral (ISN) atoms inside the heliosphere, which yield information on the heliosphe…
Revealing the Elusive Companion of the Red Giant Binary 2MASS J05215658+4359220 from UV HST and Astrosat/UVIT Data
Hutchings, John; Thilker, David; Bianchi, Luciana +2 more
Black hole (BH) demographics in different environments is critical in view of recent results on massive star binarity, and of the multimessenger detectability of compact object mergers. But the identification and characterization of noninteracting BHs are elusive, especially in the sparse field stellar population. A candidate noninteractive BH + r…
Resolving Red Giant Winds with the Hubble Space Telescope
Harper, Graham M.; Wood, Brian E.; Müller, Hans-Reinhard
We describe recent spectroscopic observations of red giant stars made by the Space Telescope Imaging Spectrograph (STIS) instrument on board the Hubble Space Telescope, which has provided spatially resolved observations of the warm chromospheric winds that predominate for early K to mid-M giants. The H I Lyα lines of a set of 11 red giants observe…
JWST Resolves Collision-induced Absorption Features in White Dwarfs
Blouin, Simon; Dufour, Patrick; Kilic, Mukremin +2 more
Infrared-faint white dwarfs are cool white dwarfs exhibiting significant infrared flux deficits, most often attributed to collision-induced absorption (CIA) from H2–He in mixed hydrogen–helium atmospheres. We present James Webb Space Telescope (JWST) near- and mid-infrared spectra of three such objects using Near-Infrared Spectrograph (…
Statistical Investigation of Wave Propagation in the Quiet-Sun Using IRIS Spectroscopic Observations
Srivastava, A. K.; Scullion, E.; Kayshap, P. +2 more
In this analysis, we use spectroscopic observations of the quiet Sun made by the IRIS instrument and investigate wave propagation. We analyze various spectral lines formed in different atmospheric layers, such as the photosphere, chromosphere, and transition region. We examine the Doppler velocity time series at various locations in the quiet Sun …
Filament Accretion and Fragmentation in the Perseus Molecular Cloud
Caselli, Paola; Di Francesco, James; Ginsburg, Adam +6 more
Observations suggest that filaments in molecular clouds can grow by mass accretion while forming cores via fragmentation. Here, we present one of the first large-sample studies of filament accretion using velocity gradient measurements of star-forming filaments on the ∼0.05 pc scale with NH3 observations of the Perseus Molecular Cloud, …
A Search for Soft X-Ray Emission Lines in the Afterglow Spectrum of GRB 221009A
Tiengo, Andrea; Campana, Sergio; Braito, Valentina +1 more
GRB 221009A was the brightest gamma-ray burst (GRB) of all time (BOAT), surpassing in prompt brightness all GRBs discovered in ∼50 yr and in afterglow brightness in ∼20 yr. We observed the BOAT with XMM-Newton 2.3 days after the prompt. The X-ray afterglow was still very bright and we collected the largest number of photons with the reflection gra…
The Dustiest Galactic S Stars: Mid-infrared Spectra from SOFIA/FORCAST
Sloan, G. C.; Kraemer, Kathleen E.; Ramirez, Ramses M.
We present spectra of 12 of the reddest, and hence dustiest, S stars in the Milky Way, observed with the FORCAST grisms on SOFIA. S stars are asymptotic giant branch (AGB) stars with C/O ∼ 1, so their molecular and dust chemistries are dominated by neither O nor C, often leading to atypical spectral features from their molecules and dust grains. A…