Search Publications
Varstrometry for Off-nucleus and Dual Subkiloparsec Active Galactic Nuclei (VODKA): Investigating the Nature of SDSS J0823+2418 at z = 1.81, A Likely Lensed Quasar
Shen, Yue; Oguri, Masamune; Zakamska, Nadia L. +8 more
Dual quasars at small physical separations are an important precursor phase of galaxy mergers, ultimately leading to the coalescence of the two supermassive black holes. Starting from a sample of dual and/or lensed quasar candidates discovered using astrometric jitter in Gaia data, we present a pilot case study of one of the most promising yet puz…
Modeling the Multiwavelength Evolution of the V960 Mon System
Sitko, Michael; Russell, Ray W.; Hillenbrand, Lynne A. +7 more
We study the evolution of the FU Ori object V960 Mon since its outburst, using available multiwavelength photometric time series over 8 yr, complemented by several epochs of moderate-dispersion spectrophotometry. We find that the source fading can be well-described by a decrease in the temperature of the inner disk, which results from a combinatio…
Soft gamma-ray spectral and time evolution of the GRB 221009A: Prompt and afterglow emission with INTEGRAL/IBIS-PICsIT
Ubertini, Pietro; Rodi, James
Aims: The gamma-ray burst (GRB) 221009A, with its extreme brightness, has provided the opportunity to explore GRB prompt and afterglow emission behavior on short timescales with high statistics. In conjunction with detection up to very-high-energy gamma rays, studies of this event shed light on the emission processes at work in the initial ph…
The Mid-infrared Molecular Inventory toward Orion IRc2
Drozdovskaya, Maria N.; Herbst, Eric; Acharyya, Kinsuk +8 more
We present the first high spectral resolution mid-infrared survey in the Orion BN/KL region, covering 7.2–28.3 µm. With SOFIA/EXES, we target the enigmatic source Orion IRc2. While this is in the most prolifically studied massive star-forming region, longer wavelengths and molecular emission lines dominated previous spectral surveys. The mid…
Survey of Bare Active Galactic Nuclei in the Local Universe (z < 0.2). I. On the Origin of Soft Excess
Safi-Harb, Samar; Chang, Hsiang-Kuang; Naik, Sachindra +5 more
We analyze a sample of 21 "bare" Seyfert 1 active galactic nuclei, a subclass of Seyfert 1 galaxies, with intrinsic absorption N H ~ 1020 cm-2, in the local Universe (z < 0.2) using XMM-Newton and Swift/XRT observations. The luminosities of the primary continuum, the X-ray emission in the 3-10 keV energy range, …
Signatures of dynamic fibrils at the coronal base: Observations from Solar Orbiter/EUI
Teriaca, Luca; Solanki, Sami K.; Liu, Wei +20 more
The solar chromosphere hosts a wide variety of transients, including dynamic fibrils (DFs) that are characterised as elongated, jet-like features seen in active regions, often through Hα diagnostics. So far, these features have been difficult to identify in coronal images, primarily due to their small size and the lower spatial resolution of the c…
Investigating Gaia EDR3 parallax systematics using asteroseismology of Cool Giant Stars observed by Kepler, K2, and TESS. I. Asteroseismic distances to 12 500 red-giant stars
Khan, S.; Cantat-Gaudin, T.; Clementini, G. +10 more
Gaia EDR3 has provided unprecedented data that has generated a great deal of interest in the astrophysical community, even though systematics affect the reported parallaxes at the level of ∼10 µas. Independent distance measurements are available from asteroseismology of red-giant stars with measurable parallaxes, whose magnitude and colour r…
Parker Solar Probe Encounters the Leg of a Coronal Mass Ejection at 14 Solar Radii
Mitchell, D. G.; McComas, D. J.; Bale, S. D. +14 more
We use Parker Solar Probe (PSP) observations to report the first direct measurements of the particle and field environments while crossing the leg of a coronal mass ejection (CME) very close to the Sun (~14 Rs). An analysis that combines imaging from 1 au and PSP with a CME model, predicts an encounter time and duration that correspond to an unusu…
The hunt for formamide in interstellar ices. A toolkit of laboratory infrared spectra in astronomically relevant ice mixtures and comparisons to ISO, Spitzer, and JWST observations
van Dishoeck, E. F.; Rocha, W. R. M.; Slavicinska, K. +3 more
Context. Although solid-state pathways are expected to dominate the formation mechanisms of many complex organic molecules (COMs), very few COMs have been securely identified in interstellar ices, in stark contrast with the many COM detections in the gas phase. The launch of the James Webb Space Telescope (JWST) and its increase in sensitivity and…
Spectroscopic survey of faint planetary-nebula nuclei - I. Six new 'O VI' central stars
Bond, Howard E.; Zeimann, Gregory R.; Werner, Klaus +1 more
We report initial results from an ongoing spectroscopic survey of central stars of faint planetary nebulae (PNe), obtained with the Low-Resolution Spectrograph on the Hobby-Eberly Telescope. The six PN nuclei (PNNi) discussed here all have strong emission at the O VI 3811-3834 Å doublet, indicative of very high temperatures. Five of them - the nuc…