Search Publications
Extremely Broad Lyα Line Emission from the Molecular Intragroup Medium in Stephan's Quintet: Evidence for a Turbulent Cascade in a Highly Clumpy Multiphase Medium?
Shull, J. M.; Boulanger, F.; Falgarone, E. +8 more
We present Hubble Space Telescope Cosmic Origin Spectrograph (COS) UV line spectroscopy and integral-field unit (IFU) observations of the intragroup medium in Stephan's Quintet (SQ). SQ hosts a 30 kpc long shocked ridge triggered by a galaxy collision at a relative velocity of 1000 km s-1, where large amounts of molecular gas coexist wi…
Multiwavelength Observations by XSM, Hinode, and SDO of an Active Region. Chemical Abundances and Temperatures
Mason, H. E.; Del Zanna, G.; Janardhan, P. +7 more
We have reviewed the first year of observations of the Solar X-ray Monitor (XSM) on board Chandrayaan-2 and the available multiwavelength observations to complement the XSM data, focusing on the Solar Dynamics Observatory AIA and Hinode XRT and EIS observations. XSM has provided disk-integrated solar spectra in the 1-15 keV energy range, observing…
A Generative Model for Quasar Spectra
Hogg, David W.; Foreman-Mackey, Daniel; Schindler, Jan-Torge +3 more
We build a multi-output generative model for quasar spectra and the properties of their black hole engines, based on a Gaussian process latent-variable model. This model treats every quasar as a vector of latent properties such that the spectrum and all physical properties of the quasar are associated with non-linear functions of those latent para…
Astrophysical Distance Scale. IV. Preliminary Zero-point Calibration of the JAGB Method in the HST/WFC3-IR Broad J-band (F110W) Filter
Madore, Barry F.; Freedman, Wendy L.; Lee, Abigail J.
We present an absolute calibration of the J-region Asymptotic Giant Branch (JAGB) method using published photometry of resolved stars in 20 nearby galaxies observed with the Hubble Space Telescope using the WFC3-IR camera and the F110W (broad J-band) filter. True distance moduli for each of the galaxies are based on the Tip of the Red Giant Branch…
Changes in the Near-surface Shear Layer of the Sun
Basu, Sarbani; Antia, H. M.
We use helioseismic data obtained over two solar cycles to determine whether there are changes in the near-surface shear layer (NSSL). We examine this by determining the radial gradient of the solar rotation rate. The radial gradient itself shows a solar-cycle dependence, and the changes are more pronounced in the active latitudes than at adjoinin…
Evidence for Corotation Origin of Super-metal-rich Stars in LAMOST-Gaia: Multiple Ridges with a Similar Slope in the ϕ versus L z Plane
Zhao, Gang; Chen, Yuqin; Zhang, Haopeng
Super-metal-rich (SMR) stars in the solar neighborhood are thought to be born in the inner disk and come to their present location by radial migration, which is most intense at the corotation resonance (CR) of the Galactic bar. In this work, we show evidence for the CR origin of SMR stars in the Large Sky Area Multi-Object Fiber Spectroscopic Tele…
The Pulsating Helium-atmosphere White Dwarfs. I. New DBVs from the Sloan Digital Sky Survey
Kepler, S. O.; Hermes, J. J.; Bell, Keaton J. +4 more
We present a dedicated search for new pulsating helium-atmosphere (DBV) white dwarfs from the Sloan Digital Sky Survey using the McDonald 2.1 m Otto Struve Telescope. In total we observed 55 DB and DBA white dwarfs with spectroscopic temperatures between 19,000 and 35,000 K. We find 19 new DBVs and place upper limits on variability for the remaini…
Intrinsic Shapes of Brightest Cluster Galaxies
Bender, Ralf; Thomas, Jens; Saglia, Roberto P. +5 more
We discuss the statistical distribution of galaxy shapes and viewing angles under the assumption of triaxiality by deprojecting observed surface brightness profiles of 56 brightest cluster galaxies (BCGs) coming from a recently published large deep-photometry sample. For the first time, we address this issue by directly measuring axis ratio profil…
Central Black Hole Mass in the Distant Tidal Disruption Event Candidate of Swift J2058.4+0516
Zhang, XueGuang
In this article, the central black hole (BH) mass in the distant tidal disruption event (TDE) of Swift J2058.4+0516, the second candidate of relativistic jet birth related to a TDE, is estimated. Swift J2058.4+0516 has quite different BH masses estimated through different indirect methods in the literature. Therefore, it is necessary and interesti…
Large Impact of the Mg II h and k Incident Radiation Change on Results of Radiative Transfer Models and the Importance of Dynamics
Heinzel, Petr; Gunár, Stanislav; Koza, Július +1 more
We demonstrate that changes in the incident radiation in Mg II h and k lines have a significant impact on the results of radiative transfer modeling of prominence-like plasmas. To uncover the extent of this impact and allow easy comparison, here we study two cases, one representing the minimum of the solar activity and the other corresponding to t…