Search Publications
Circumnuclear Dust in AP Librae and the Source of Its VHE Emission
Georganopoulos, Markos; Breiding, Peter; Meyer, Eileen T. +2 more
The broad high-energy spectral component in blazars is usually attributed to various inverse Compton scattering processes in the relativistic jet, but has not been clearly identified in most cases due to degeneracies in physical models. AP Librae, a low-synchrotron-peaking BL Lac object (LBL) detected in 2015 by H.E.S.S. at very high energies (VHE…
The Role of Filamentary Structures in the Formation of Two Dense Cores, L1544 and L694-2
Caselli, Paola; Chung, Eun Jung; Kim, Shinyoung +5 more
We present mapping results of two prestellar cores, L1544 and L694-2, embedded in filamentary clouds in C18O (3-2), 13CO (3-2), 12CO (3-2), HCO+ (4-3), and H13CO+ (4-3) lines with the James Clerk Maxwell Telescope to examine the role of the filamentary structures in the formation of…
Luminous Optical and X-Ray Flaring of the Putative Redback Millisecond Pulsar 1FGL J0523.5-2529
Perez, Karen I.; Bogdanov, Slavko; Halpern, Jules P.
Several redback and black widow millisecond pulsar binaries have episodes of flaring in X-rays and optical. We initially detected such behavior from the Fermi selected redback candidate 1FGL J0523.5-2529 during optical time-series monitoring. Triggered observations with the Neil Gehrels Swift Observatory over the next ≈100 days showed episodic fla…
The Fast Evolving, Tremendous Blue Superoutburst in ASASSN-21au Reveals a Dichotomy in the Outbursts of Long-period AM CVns
Heinke, C. O.; Cavecchi, Y.; Vanmunster, T. +4 more
ASASSN-21au is an ultracompact accreting white dwarf binary (AM CVn type) with a period of ~58 minutes. Using multiwavelength observations of the system, we discovered a dichotomy in the behavior of outbursts in AM CVns. The binary showed an initial increase in brightness that lasted for at least 82 days, followed by an additional increase that la…
The Properties of Fast Yellow Pulsating Supergiants: FYPS Point the Way to Missing Red Supergiants
Davenport, James R. A.; Dorn-Wallenstein, Trevor Z.; Levesque, Emily M. +3 more
Fast yellow pulsating supergiants (FYPS) are a recently discovered class of evolved massive pulsators. As candidate supergiant objects, and one of the few classes of pulsating evolved massive stars, these objects have incredible potential to change our understanding of the structure and evolution of massive stars. Here we examine the lightcurves o…
Optical and Near-infrared Excesses are Correlated in T Tauri Stars
Kraus, Adam L.; Sullivan, Kendall
Accretion is one of the defining characteristics of classical T Tauri stars, fueled by the presence of a circumstellar disk comprised of dust and gas. Accretion produces a UV and optical excess, while re-radiated emission at the inner edge of the dust component of the disk produces a near-infrared (NIR) excess. The interplay between stars and thei…
Characterizing the 3D Kinematics of Young Stars in the Radcliffe Wave
Alves, João; Speagle, Joshua S.; Zucker, Catherine +5 more
We present an analysis of the kinematics of the Radcliffe Wave, a 2.7 kpc long sinusoidal band of molecular clouds in the solar neighborhood recently detected via 3D dust mapping. With Gaia DR2 astrometry and spectroscopy, we analyze the 3D space velocities of ~1500 young stars along the Radcliffe Wave in action-angle space, using the motion of th…
A Comparative L-dwarf Sample Exploring the Interplay between Atmospheric Assumptions and Data Properties
Gonzales, Eileen C.; Marley, Mark; Faherty, Jacqueline K. +3 more
Comparisons of atmospheric retrievals can reveal powerful insights on the strengths and limitations of our data and modeling tools. In this paper, we examine a sample of five L dwarfs of similar effective temperature (T eff) or spectral type to compare their pressure-temperature (P-T) profiles. Additionally, we explore the impact of an …
Coevolution of Broad Emission Lines and X-Ray Spectrum in Changing-look AGNs
Liu, Hao; Wu, Qingwen; Lyu, Bing
Changing-look active galactic nuclei (CLAGNs) show the disappearance and reappearance of broad emission lines in a few years, which challenges the orientation-based AGN unification model. We reduce the X-ray data for five well-studied CLAGNs that show a strong change in broad emission lines in the past several decades. We find that the X-ray photo…
Suzaku Observations of the Cluster Outskirts and Intercluster Filament in the Triple Merger Cluster A98
Sarazin, Craig L.; Walker, Stephen; Randall, Scott W. +5 more
We present Suzaku observations of the Abell 98 (A98) triple galaxy cluster system and the purported intercluster filament. The three subclusters are expected to lie along a large-scale cosmic filament. With partial azimuthal coverage of the northernmost cluster, we find that the inferred entropy profile of this relatively low-mass cluster (kT ≈ 2.…