Search Publications
Spectroscopic Survey of Faint Planetary-nebula Nuclei. V. The EGB 6-type Central Star of Abell 57
Bond, Howard E.; Ciardullo, Robin; Zeimann, Gregory R. +3 more
During our spectroscopic survey of central stars of faint planetary nebulae (PNe), we found that the nucleus of Abell 57 exhibits strong nebular emission lines. Using synthetic narrowband images, we show that the emission arises from an unresolved compact emission knot (CEK) coinciding with the hot (90,000 K) central star. Thus Abell 57 belongs to…
The HST Nondetection of SN Ia 2011fe 11.5 yr after Explosion Further Restricts Single-degenerate Progenitor Systems
Shappee, B. J.; Tucker, M. A.
We present deep Hubble Space Telescope imaging of the nearby Type Ia supernova (SN Ia) 2011fe obtained 11.5 yr after explosion. No emission is detected at the SN location to a 1σ (3σ) limit of F555W > 30.2 (29.0) mag, or equivalently M V > 1.2 (‑0.1) mag, neglecting the distance uncertainty to M101. We constrain the presence of …
Front-row Seat of the Recent R Aqr Periastron Passage: X-Ray Multiepoch Spectral and Spatial Analysis
Raymond, John; Sacchi, Andrea; Karovska, Margarita +7 more
We report on the X-ray spectral and spatial evolution of the symbiotic star R Aqr. Through a multiepoch observational campaign performed with Chandra between 2017 and 2022, we study the X-ray emission of this binary system, composed of an evolved red giant star and a white dwarf (WD). This analysis is particularly timely as the WD approached the p…
Implementation of Aerosol Mie Scattering in POSEIDON with Application to the Hot Jupiter HD 189733 b's Transmission, Emission, and Reflected Light Spectrum
MacDonald, Ryan J.; Lewis, Nikole K.; Mullens, Elijah
Aerosols are a ubiquitous feature of planetary atmospheres and leave clear spectral imprints in exoplanet spectra. Pre-JWST, exoplanet retrieval frameworks mostly adopted simple parametric approximations. With JWST, we now have access to mid-infrared wavelengths where aerosols have detectable composition-specific resonance features. Here, we imple…
A VLITE Search for Millisecond Pulsars in Globular Clusters: Discovery of a Pulsar in GLIMPSE-C01
Freire, Paulo C. C.; Ransom, Scott M.; Maccarone, Thomas J. +8 more
We present results from a search for pulsars in globular clusters, including the discovery of a new millisecond pulsar in the stellar cluster GLIMPSE-C01. We searched for low-frequency radio sources within 97 globular clusters using images from the VLA Low-band Ionosphere and Transient Experiment (VLITE) and epochs 1 and 2 of the VLITE Commensal S…
Low-amplitude Solar-like Oscillations in the K5 V Star ϵ Indi A
Butler, R. Paul; Li, Yaguang; Bedding, Timothy R. +17 more
We have detected solar-like oscillations in the mid-K-dwarf ϵ Indi A, making it the coolest dwarf to have measured oscillations. The star is noteworthy for harboring a pair of brown dwarf companions and a Jupiter-type planet. We observed ϵ Indi A during two radial velocity campaigns, using the high-resolution spectrographs HARPS (2011) and UVES (2…
Size Growth on Short Timescales of Star-forming Galaxies: Insights from Size Variation with Rest-frame Wavelength with JADES
Zhang, Hongxin; Kong, Xu; Li, Hui +11 more
We investigate size variation with rest-frame wavelength for star-forming galaxies based on the second James Webb Space Telescope Advanced Deep Extragalactic Survey data release. Star-forming galaxies are typically smaller at longer wavelengths from the UV to the near-IR at z < 3.5, especially for more massive galaxies, indicating the inside-ou…
The Present-day Mass Function of Star Clusters in the Solar Neighborhood
Tang, Shih-Yun; Li, Jiadong; Pang, Xiaoying +5 more
This work analyzes the present-day mass function (PDMF) of 93 star clusters utilizing Gaia Data Release 3 data, with membership determined by the StarGo machine-learning algorithm. The impact of unresolved binary systems on mass estimation is rigorously assessed, adopting three mass ratio profiles for correction. The PDMF is characterized by the p…
The White-light Emissions in Two X-class Flares Observed by ASO-S and CHASE
Feng, Li; Gan, Weiqun; Ding, M. D. +9 more
The white-light continuum emissions in solar flares (i.e., white-light flares) are usually observed on the solar disk but, in a few cases, off the limb. Here we present on-disk as well as off-limb continuum emissions at 3600 Å (in the Balmer continuum) in an X2.1 flare (SOL2023-03-03T17:52) and an X1.5 flare (SOL2023-08-07T20:46), respectively, ob…
Exploring X-Ray Properties of Low-metallicity Dwarf Galaxies
Satyapal, Shobita; Pfeifle, Ryan W.; Secrest, Nathan J. +3 more
One of the primary outstanding questions in extragalactic astronomy is the formation and early evolution of the supermassive black holes that are seen in nearly every massive galaxy. Low-metallicity dwarf galaxies may offer the most representative local analogs to pristine early galaxies, making them a vital tool in probing black hole seed models …