Search Publications
SPLUS J210428.01-004934.2: An Ultra Metal-poor Star Identified from Narrowband Photometry
Lee, Young Sun; Placco, Vinicius M.; Roederer, Ian U. +6 more
We report on the discovery of SPLUS J210428.01-004934.2, an ultra metal-poor (UMP) star first identified from the narrowband photometry of the Southern Photometric Local Universe Survey (S-PLUS) Data Release 1, in the SDSS Stripe 82 region. Follow-up medium- and high-resolution spectroscopy (with Gemini South and Magellan-Clay, respectively) confi…
Stellar Rotation of T Tauri Stars in the Orion Star-forming Complex
Stassun, Keivan G.; Kounkel, Marina; Briceño, Cesar +14 more
We present a large-scale study of stellar rotation for T Tauri stars in the Orion star-forming complex. We use the projected rotational velocity ( $v\sin (i)$ vsin(i) ) estimations reported by the APOGEE-2 collaboration as well as individual masses and ages derived from the position of the stars in the HR diagram, considering Gaia-EDR3 parallaxes …
Discovery of a Fast Iron Low-ionization Outflow in the Early Evolution of the Nearby Tidal Disruption Event AT 2019qiz
Cenko, S. B.; Veilleux, S.; Filippenko, Alexei V. +16 more
We report the results of ultraviolet (UV) and optical photometric and spectroscopic analysis of the tidal disruption event (TDE) AT 2019qiz. Our follow-up observations started <10 days after the source began to brighten in the optical and lasted for a period of six months. Our late-time host-dominated spectrum indicates that the host galaxy lik…
Magellanic Mayhem: Metallicities and Motions
Evans, N. W.; Belokurov, V.; Grady, J.
We assemble a catalog of Magellanic Cloud red giants from Data Release 2 of the Gaia mission and, utilizing machine-learning methods, obtain photometric metallicity estimates for them. In doing so, we are able to chemically map the entirety of the Magellanic System at once. Our maps reveal a plethora of substructure within our red giant sample, wi…
From Pseudostreamer Jets to Coronal Mass Ejections: Observations of the Breakout Continuum
Antiochos, Spiro K.; Lynch, Benjamin J.; Kumar, Pankaj +3 more
The magnetic breakout model, in which reconnection in the corona leads to destabilization of a filament channel, explains numerous features of eruptive solar events, from small-scale jets to global-scale coronal mass ejections (CMEs). The underlying multipolar topology, pre-eruption activities, and sequence of magnetic-reconnection onsets (first b…
Reconstructing the Extreme Ultraviolet Emission of Cool Dwarfs Using Differential Emission Measure Polynomials
Loyd, R. O. Parke; Kowalski, Adam F.; Redfield, Seth +16 more
Characterizing the atmospheres of planets orbiting M dwarfs requires understanding the spectral energy distributions of M dwarfs over planetary lifetimes. Surveys like MUSCLES, HAZMAT, and FUMES have collected multiwavelength spectra across the spectral type's range of Teff and activity, but the extreme ultraviolet (EUV, 100-912 Å) flux…
RR Lyrae Variables in Messier 53: Near-infrared Period-Luminosity Relations and the Calibration Using Gaia Early Data Release 3
Herczeg, Gregory J.; de Grijs, Richard; Marconi, Marcella +6 more
We present new near-infrared, JHKs, period-luminosity relations (PLRs) for RR Lyrae variables in the Messier 53 (M53 or NGC 5024) globular cluster. Multi-epoch JHKs observations, obtained with the WIRCam instrument on the 3.6 m Canada-France-Hawaii Telescope, are used for the first time to estimate precise mean magnitudes for…
Evidence for an MHD Disk Wind via Optical Forbidden Line Spectroastrometry
Pascucci, I.; Sterzik, M. F.; Alexander, R. D. +4 more
Spectroastrometry is used to investigate the low-velocity component (LVC) of the optical forbidden emission from the T Tauri stars RU Lupi and AS 205 N. Both stars also have high-velocity forbidden emission, which is tracing a jet. For AS 205 N, analysis reveals a complicated outflow system. For RU Lupi, the [O I] λ6300 and [S II]λλ6716,6731 LV na…
Probing Kilonova Ejecta Properties Using a Catalog of Short Gamma-Ray Burst Observations
Berger, E.; Smith, N.; Chornock, R. +11 more
The discovery of GW170817 and GRB 170817A in tandem with AT 2017gfo cemented the connection between neutron star mergers, short gamma-ray bursts (GRBs), and kilonovae. To investigate short GRB observations in the context of diverse kilonova behavior, we present a comprehensive optical and near-IR catalog of 85 bursts discovered over 2005-2020 on t…
First Simultaneous In Situ Measurements of a Coronal Mass Ejection by Parker Solar Probe and STEREO-A
Lugaz, Noé; Scolini, Camilla; Galvin, Antoinette B. +1 more
We present the first Parker Solar Probe mission (PSP)-observed coronal mass ejection (CME) that hits a second spacecraft before the end of the PSP encounter, providing an excellent opportunity to study short-term CME evolution. The CME was launched from the Sun on 2019 October 10 and was measured in situ at PSP on 2019 October 13 and at STEREO-A o…