Search Publications
Mapping the Longitudinal Magnetic Field in the Atmosphere of an Active Region Plage from the Inversion of the Near-ultraviolet CLASP2.1 Spectropolarimetric Data
Song, Donguk; Rachmeler, Laurel A.; Kobayashi, Ken +10 more
We apply the HanleRT Tenerife Inversion Code to the spectropolarimetric observations obtained by the Chromospheric Layer Spectropolarimeter. This suborbital space experiment measured the variation with wavelength of the four Stokes parameters in the near-ultraviolet spectral region of the Mg II h and k lines over a solar disk area containing part …
Inversion for Inferring Solar Meridional Circulation: The Case with Constraints on Angular Momentum Transport inside the Sun
Sekii, Takashi; Hotta, Hideyuki; Hatta, Yoshiki
We have carried out inversions of travel times as measured by Gizon et al. to infer the internal profile of the solar meridional circulation (MC). A linear inverse problem has been solved by the regularized least-squares method with a constraint that the angular momentum (AM) transport by MC should be equatorward (HK21-type constraint). Our motiva…
The AH Pictoris Syndrome: Continuous Trains of Stunted Outbursts in Novalike Variables
Bruch, Albert
Novalike variables are a subgroup of cataclysmic variables (CVs) that—unlike dwarf novae—do not exhibit strong brightenings in their long-term light curves. Variations over timescales of weeks, months, or years are mostly restricted to irregular low-amplitude modulations. However, some of them occasionally suffer from so-called stunted outbursts, …
Molecular Gas Tracers in Young and Old Protoplanetary Disks
Zhang, Ke; Cleeves, L. Ilsedore; Bergin, Edwin A. +6 more
Molecular emission is used to investigate both the physical and chemical properties of protoplanetary disks. Therefore, to derive disk properties accurately, we need a thorough understanding of the behavior of the molecular probes upon which we rely. Here we investigate how the molecular line emission of N2H+, HCO+…
Detection of the Actinide Th in an r-process-enhanced Star with Accretion Origin
Zhao, Gang; Li, Haining; Matsuno, Tadafumi +4 more
The thorium and six second-peak r-process element (56 ≤ Z ≤ 72) abundances are determined for the α-poor star LAMOST J1124+4535 based on a high-resolution spectrum obtained with the High Dispersion Spectrograph on the Subaru Telescope. The age of J1124+4535 is 11.3 ± 4.4 Gyr using thorium and other r-process element abundances. J1124+4535 is confi…
Circumgalactic Environments Around Distant Quasars 3C 9 and 4C 05.84
Kriek, Mariska; Armus, Lee; Wright, Shelley A. +6 more
We present results from the Quasar hosts Unveiled by high Angular Resolution Techniques survey studying the circumgalactic medium (CGM) by observing rest-frame UV emission lines Lyα, C IV, and He II around two radio-loud quasars, 3C 9 (z = 2.02) and 4C 05.84 (z = 2.32), using the Keck Cosmic Web Imager. We detect large-scale Lyα nebulae around bot…
Subkiloparsec Scaling Relations between Hot Gas, Dense Gas, and Star Formation Rate in Five Nearby Star-forming Galaxies
Gao, Yu; Tan, Qing-Hua; Wang, Junfeng +3 more
Based on the newly acquired dense gas observations from the JCMT MALATANG survey and X-ray data from Chandra, we explore the correlation between hot gas and HCN J = 4 → 3 and HCO+ J = 4 → 3 emission for the first time at subkiloparsec scale of five nearby star-forming galaxies, namely M82, M83, IC 342, NGC 253, and NGC 6946. We find tha…
Detecting the Effect of Nonthermal Sources on the Warm-hot Galactic Halo
Das, Sanskriti
We report the first detection of nonthermal broadening of O VII lines in the warm-hot ≈106 K circumgalactic medium of the Milky Way. We use z = 0 absorption of O VII Kα, O VII Kβ, and O VIII Kα lines in archival grating data of b > 15° quasar sightlines from Chandra and XMM-Newton. Nonthermal line broadening is evident in two-thirds …
Mapping Multiphase Metals in Star-forming Galaxies: A Spatially Resolved UV+Optical Study of NGC 5253
Kumari, Nimisha; Hernandez, Svea; Aloisi, Alessandra +4 more
We present a pioneering, spatially resolved, multiphase gas abundance study on the blue compact dwarf galaxy NGC 5253, targeting 10 star-forming (SF) clusters inside six far-UV (FUV) Hubble Space Telescope/Cosmic Origins Spectrograph (COS) pointings with cospatial optical Very Large Telescope/MUSE observations throughout the galaxy. The SF regions…
Revisiting the Activity–Rotation Relation for Evolved Stars
Liu, Jifeng; Wang, Song; Li, Xue +2 more
The magnetic dynamo mechanism of giant stars remains an open question, which can be explored by investigating their activity–rotation relations with multiple proxies. By using the data from the LAMOST and Galaxy Evolution Explorer surveys, we carried out a comprehensive study of activity–rotation relations of evolved stars based on Ca II H and K l…