Search Publications
Hotter than Expected: Hubble Space Telescope (HST)/WFC3 Phase-resolved Spectroscopy of a Rare Irradiated Brown Dwarf with Strong Internal Heat Flux
Mayorga, L. C.; Lothringer, Joshua D.; Apai, Dániel +8 more
With infrared flux contrasts larger than typically seen in hot Jupiter, tidally locked white dwarf-brown dwarf binaries offer a superior opportunity to investigate atmospheric processes in irradiated atmospheres. NLTT5306 is such a system, with a M BD = 52 ± 3 M Jup brown dwarf, orbiting a T eff = 7756 ± 35 K white…
Early-time Ultraviolet and Optical Hubble Space Telescope Spectroscopy of the Type II Supernova 2022wsp
Filippenko, Alexei V.; Modjaz, Maryam; Matheson, Thomas +10 more
We report early-time ultraviolet (UV) and optical spectroscopy of the young, nearby Type II supernova (SN) 2022wsp obtained by the Hubble Space Telescope (HST)/STIS at about 10 and 20 days after the explosion. The SN 2022wsp UV spectra are compared to those of other well-observed Type II/IIP SNe, including the recently studied Type IIP SN 2021yja.…
The Lively Accretion Disk in NGC 2992. III. Tentative Evidence of Rapid Ultrafast Outflow Variability
Nardini, Emanuele; Bianchi, Stefano; Piconcelli, Enrico +8 more
We report on the 2019 XMM-Newton+NuSTAR monitoring campaign of the Seyfert galaxy NGC 2992, observed at one of its highest flux levels in the X-rays. The time-averaged spectra of the two XMM-Newton orbits show ultrafast outflows (UFOs) absorbing structures above 9 keV with >3σ significance. A detailed investigation of the temporal evolution on …
An Ap Star Catalog Based on LAMOST DR9
Xiang, Maosheng; Zhang, Huawei; Fu, Jianning +2 more
We present a sample of 2700 Ap stars in the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) DR9 catalog. The candidates are first selected to be in a temperature range typical of Ap stars by using the BP - RP color index from Gaia DR3. Then the 5200 Å flux depression features characteristic of Ap stars are visually checked in LA…
Arp 220: A Post-starburst Galaxy with Little Current Star Formation outside of Its Nuclear Disks
Calzetti, Daniela; Whitmore, Bradley C.; Chandar, Rupali +8 more
The ultraluminous infrared galaxy Arp 220 is a late-stage merger with several tidal structures in the outskirts and two very compact, dusty nuclei that show evidence for extreme star formation and host at least one active galactic nucleus (AGN). New and archival high-resolution images taken by the Hubble Space Telescope provide a state-of-the-art …
Influence of Solar Wind Variations on the Shapes of Venus' Plasma Boundaries Based on Venus Express Observations
André, N.; Fedorov, A.; Futaana, Y. +10 more
The interaction between the solar wind and Venus creates an induced magnetosphere. The regions of the induced magnetosphere are separated by plasma boundaries, where their shapes and sizes are influenced by variations in the surrounding environment. Investigations of the boundaries and their variability can help us understand the solar wind's effe…
MOSEL Survey: JWST Reveals Major Mergers/strong Interactions Drive the Extreme Emission Lines in the Early Universe
Harshan, Anishya; Kacprzak, Glenn G.; Nanayakkara, Themiya +7 more
Extreme emission line galaxies (EELGs), where nebular emissions contribute 30%-40% of the flux in certain photometric bands, are ubiquitous in the early Universe (z > 6). We utilize deep NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) to investigate the properties of companion galaxies (projected distance <40 kpc, ∣dv…
Uranium Abundances and Ages of r-process Enhanced Stars with Novel U II Lines
Beers, Timothy C.; Holmbeck, Erika M.; Hansen, Terese T. +7 more
The ages of the oldest stars shed light on the birth, chemical enrichment, and chemical evolution of the universe. Nucleocosmochronometry provides an avenue to determining the ages of these stars independent from stellar-evolution models. The uranium abundance, which can be determined for metal-poor r-process enhanced (RPE) stars, has been known t…
Exploring Stellar Cluster and Feedback-driven Star Formation in the Galactic Mid-infrared Bubble [HKS2019] E70
Pandey, Rakesh; Sharma, Saurabh; Dewangan, Lokesh +8 more
We present a comprehensive analysis of the Galactic mid-infrared bubble [HKS2019] E70 (E70) by adopting a multiwavelength approach to understand the physical environment and star formation scenario around it. We identified a small (radius ~1.7 pc) stellar cluster inside the E70 bubble, and its distance is estimated as 3.26 ± 0.45 kpc. This cluster…
Discovery and Timing of Millisecond Pulsars with the Arecibo 327 MHz Drift-scan Survey
Freire, Paulo C. C.; Deneva, Julia S.; McLaughlin, Maura A. +6 more
We present the discovery and timing solutions of four millisecond pulsars (MSPs) discovered in the Arecibo 327 MHz Drift-Scan Pulsar Survey. Three of these pulsars are in binary systems, consisting of a redback (PSR J2055+1545), a black widow (PSR J1630+3550), and a neutron star-white dwarf binary (PSR J2116+1345). The fourth MSP, PSR J2212+2450, …