Search Publications
An ultraviolet spectral study of fullerene-rich planetary nebulae
García-Hernández, D. A.; Gómez-Muñoz, M. A.; Manchado, A. +2 more
Several planetary nebulae (PNe) have been found to contain both polycyclic aromatic hydrocarbon (PAH-like) species and fullerenes (C60) distinguished by their mid-infrared emission. Previous laboratory and astronomical studies suggest that the formation of both species could be related to the decomposition, by photochemical processing, …
Discovery of the Remarkably Red L/T Transition Object VHS J183135.58-551355.9
Meisner, Aaron M.; Kirkpatrick, J. Davy; Burgasser, Adam J. +13 more
We present the discovery of VHS J183135.58‑551355.9 (hereafter VHS J1831‑5513), an L/T transition dwarf identified as a result of its unusually red near-infrared colors (J ‑ K S = 3.633 ± 0.277 mag; J ‑ W2 = 6.249 ± 0.245 mag) from the VISTA Hemisphere Survey and CatWISE2020 surveys. We obtain low-resolution near-infrared spectroscopy o…
Spectroastrometric Survey of Protoplanetary Disks with Inner Dust Cavities
Banzatti, Andrea; Najita, Joan R.; Brittain, Sean D. +6 more
We present high-resolution spectra and spectroastrometric (SA) measurements of fundamental rovibrational CO emission from nine nearby (≲300 pc) protoplanetary disks where large inner dust cavities have been observed. The emission-line profiles and SA signals are fit with a slab disk model that allows the eccentricity of the disk and intensity of t…
The Detection of Possible Quasiperiodic Oscillations in the BL Lac 4FGL J2139.4‑4235
Gong, Yunlu; Gao, Quangui; Li, Xiaopan +9 more
We present periodicity search analyses on the long-term γ-ray light curve of the BL Lacertae object 4FGL J2139.4‑4235 observed by the Fermi Large Area Telescope, over a period of more than 15 yr, from 2008 August 4 to 2023 December 10. To determine the quasiperiodic oscillation (QPO) behavior of 4FGL J2139.4‑4235 in the 0.3–300 GeV energy range, w…
Role of ionizing background and galactic feedback in the redshift space clustering of O VI absorbers in hydrodynamical simulations
Srianand, Raghunathan; Maitra, Soumak; Mallik, Sukanya
We explore the effect of ionizing ultraviolet background (UVB) on the redshift space clustering of low-z (z ≤ 0.5) O VI absorbers using the Sherwood simulations incorporating 'WIND' (i.e. outflows driven by stellar feedback)-only and 'WIND + AGN (active galactic nucleus)' feedback. These simulations show positive clustering signals up to a scale o…
Variable white dwarfs in TMTS: asteroseismological analysis of a ZZ Ceti star, TMTS J17184064+2524314
Shi, Jianrong; Filippenko, Alexei V.; Esamdin, Ali +24 more
The Tsinghua University-Ma Huateng Telescope for Survey (TMTS) has been constantly monitoring the northern sky since 2020 in search of rapidly variable stars. To find variable white dwarfs (WDs), the TMTS catalogue is cross-matched with the WD catalogue of Gaia EDR3, resulting in over 3000 light curves of WD candidates. The WD TMTS J17184064+25243…
On the Response of the Transition Region and the Corona to Rapid Excursions in the Chromosphere
Pereira, T. M. D.; Mathew, S. K.; Louis, R. E. +2 more
Spicules are the thin hair/grass-like structures that are prominently observed at the chromospheric solar limb. It is believed that fibrils and rapid blueshifted and redshifted excursions (RBEs and RREs; collectively referred to as REs) correspond to on-disk counterparts of type I spicules and type II spicules, respectively. Our investigation focu…
High-mass star formation across the Large Magellanic Cloud. I. Chemical properties and hot molecular cores observed with ALMA at 1.2 mm
Fuller, Gary A.; Sánchez-Monge, Álvaro; Schilke, Peter +4 more
Context. The formation of massive stars passes through a so-called hot molecular core phase, where the temperature of molecular gas and dust rises to above 100 K within a size scale of approximately 0.1 pc. The hot molecular cores are rich in chemical compounds found in the gas phase, which are a great probe of ongoing star formation.
Aims: T…
Astrometry as a Tool for Discovering and Weighing Faint Companions to Nearby Stars
Brandt, Timothy D.
This tutorial covers the use of absolute astrometry, in particular from the combination of the Hipparcos and Gaia missions, to identify faint companions to nearby stars and to measure the masses and orbits of those companions. Absolute astrometry has been used with increasing success to discover new planets and brown dwarfs and to measure masses a…
HybPSF: Hybrid Point-spread Function Reconstruction for the Observed JWST NIRCam Image
Cheng, Cheng; Cui, Qifan; Nie, Lin +7 more
The James Webb Space Telescope (JWST) marks a new era of astronomical observation and discovery, providing unrivaled precision in various measurements, including photometry, morphology, and shear measurement. Accurate point-spread function (PSF) models are essential for many of these measurements. In this paper, we introduce HybPSF, a hybrid PSF c…