Search Publications
Fermi-GBM Observations of GRB 210812A: Signatures of a Million Solar Mass Gravitational Lens
Veres, P.; Fraija, N.; Bhat, N. +1 more
Observing gravitationally lensed objects in the time domain is difficult, and well-observed time-varying sources are rare. Lensed gamma-ray bursts (GRBs) offer improved timing precision for this class of objects, complementing observations of quasars and supernovae. The rate of lensed GRBs is highly uncertain, approximately one in 1000. The Gamma-…
Testing the Limits of Precise Subgiant Characterization with APOGEE and Gaia: Opening a Window to Unprecedented Astrophysical Studies
Stassun, Keivan G.; van Saders, Jennifer L.; Beaton, Rachael L. +6 more
Given their location on the Hertzsprung-Russell (H-R) diagram, thoroughly characterized subgiant stars can place stringent constraints on a wide range of astrophysical problems. Accordingly, they are prime asteroseismic targets for the Transiting Exoplanet Survey Satellite (TESS) mission. In this work, we infer stellar properties for a sample of 3…
On the Use of Field RR Lyrae as Galactic Probes. V. Optical and Radial Velocity Curve Templates
Lemasle, B.; Latour, M.; Zoccali, M. +29 more
We collected the largest spectroscopic catalog of RR Lyrae (RRLs) including ≈20,000 high-, medium-, and low-resolution spectra for ≈10,000 RRLs. We provide the analytical forms of radial velocity curve (RVC) templates. These were built using 36 RRLs (31 fundamental-split into three period bins-and five first-overtone pulsators) with well-sampled R…
The Lithium Abundances from the Large Sky Area Multi-object Fiber Spectroscopic Telescope Medium-resolution Survey. I. The Method
Zhang, Yong; Gao, Qi; Yan, Hong-Liang +9 more
One of the purposes of taking spectra for millions of stars through the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) medium-resolution survey (MRS) is to obtain the elemental abundances, so that one can trace the origin and evolution for the element of interests. Lithium is one of such elements of great importance, which exhi…
Oscillations and Mass Draining that Lead to a Sympathetic Eruption of a Quiescent Filament
Xu, Zhe; Zhang, Qingmin; Zhang, Yanjie +3 more
In this paper, we present a multiwavelength analysis to mass draining and oscillations in a large quiescent filament prior to its successful eruption on 2015 April 28. The eruption of a smaller filament that was parallel and in close, ~350″ proximity was observed to induce longitudinal oscillations and enhance mass draining within the filament of …
Binary Fractions of G and K Dwarf Stars Based on Gaia EDR3 and LAMOST DR5: Impacts of the Chemical Abundances
Niu, Zexi; Liu, Jifeng; Wang, Song +1 more
Based on the large volume Gaia Early Data Release 3 and LAMOST Data Release 5 data, we estimate the bias-corrected binary fractions of the field late G and early K dwarfs. A stellar locus outlier method is used in this work, which works well for binaries of various periods and inclination angles with single-epoch data. With a well-selected, distan…
Regulating Star Formation in Nearby Dusty Galaxies: Low Photoelectric Efficiencies in the Most Compact Systems
Inami, H.; Pope, A.; Armus, L. +5 more
Star formation in galaxies is regulated by heating and cooling in the interstellar medium (ISM). In particular, the processing of molecular gas into stars will depend strongly on the ratio of gas heating to gas cooling in the neutral gas around sites of recent star formation. In this work, we combine mid-infrared (mid-IR) observations of polycycli…
Predictions of Astrometric Jitter for Sun-like Stars. II. Dependence on Inclination, Metallicity, and Active-region Nesting
Solanki, S. K.; Shapiro, A. I.; Mints, A. +5 more
Ultra-precise astrometry from the Gaia mission is expected to lead to astrometric detections of more than 20,000 exoplanets in our Galaxy. One of the factors that could hamper such detections is the astrometric jitter caused by the magnetic activity of the planet host stars. In our previous study, we modeled astrometric jitter for the Sun observed…
LOFAR Observations of a Jet-driven Piston Shock in the Low Solar Corona
Gallagher, Peter T.; Zucca, Pietro; Carley, Eoin P. +2 more
The Sun produces highly dynamic and eruptive events that can drive shocks through the corona. These shocks can accelerate electrons, which result in plasma emission in the form of a type II radio burst. Despite the large number of type II radio burst observations, the precise origin of coronal shocks is still subject to investigation. Here, we pre…
Observations of the Quiet Sun during the Deepest Solar Minimum of the Past Century with Chandrayaan-2 XSM: Elemental Abundances in the Quiescent Corona
Joshi, Bhuwan; Janardhan, P.; Bhardwaj, Anil +12 more
Elements with low first ionization potential (FIP) are known to be 3-4 times more abundant in active region loops of the solar corona than in the photosphere. There have been observations suggesting that this observed "FIP bias" may be different in other parts of the solar corona and such observations are thus important in understanding the underl…