Search Publications
Filament Eruption Driving EUV Loop Contraction and Then Expansion above a Stable Filament
Schmieder, Brigitte; Joshi, Reetika; Chandra, Ramesh +2 more
We analyze the observations of EUV loop evolution associated with the filament eruption located at the border of an active region (AR). The event SOL2013-03-16T14:00 was observed with a large difference in view point by the Solar Dynamics Observatory and Solar Terrestrial Relations Observatory. The filament height is fitted with the sum of a linea…
DIISC-I: The Discovery of Kinematically Anomalous H I Clouds in M 100
Heckman, Timothy M.; Nelson, Dylan; Thilker, David +10 more
We report the discovery of two kinematically anomalous atomic hydrogen (H I) clouds in M 100 (NGC 4321), which was observed as part of the Deciphering the Interplay between the Interstellar medium, Stars, and the Circumgalactic medium (DIISC) survey in H I 21 cm at 3.3 km s-1 spectroscopic and 44″ × 30″ spatial resolution using the Karl…
The Effect of the Morphological Quenching Mechanism on Star Formation Activity at 0.5 < z < 1.5 in 3D-HST/CANDELS
Fang, Guanwen; Kong, Xu; Gu, Yizhou +3 more
Several mechanisms for the transformation of blue star-forming to red quiescent galaxies have been proposed, and the green valley (GV) galaxies amid them are widely accepted in a transitional phase. Thus, comparing the morphological and environmental differences of the GV galaxies with early-type disks (ETDs; bulge dominated and having a disk) and…
Possible Evidence of Hydrogen Emission in the First-overtone and Multimode RR Lyrae Variables
Deng, Li-Cai; Liu, Chao; Zhang, Hua-Wei +4 more
The nature of shock waves in nonfundamental mode RR Lyrae stars remains a mystery because of limited spectroscopic observations. We apply a pattern recognition algorithm on spectroscopic data from SDSS and LAMOST and report the first evidence of hydrogen emission in first-overtone (RRc) and multimode (RRd) RR Lyrae stars showing the "first apparit…
The Missing Link? Discovery of Pulsations in the Nitrogen-rich PG 1159 Star PG 1144+005
Jones, David; Handler, Gerald; Sowicka, Paulina +1 more
Up to 98% of all single stars will eventually become white dwarfs-stars that link the history and future evolution of the Galaxy, and whose previous evolution is engraved in their interiors. Those interiors can be studied using asteroseismology, utilizing stellar pulsations as seismic waves. The pulsational instability strips of DA and DB white dw…
X-Ray Constraints on the Hot Gas Content of Early-type Galaxies in Virgo
Jones, Christine; Li, Zhiyuan; Hou, Meicun +2 more
We present a systematic study of the diffuse hot gas around early-type galaxies (ETGs) residing in the Virgo cluster, based on archival Chandra observations. Our representative sample consists of 79 galaxies with low-to-intermediate stellar masses (M* ≈ 109-11 M⊙), a mass range that has not been extensively explore…
Tracing the Ionization Structure of the Shocked Filaments of NGC 6240
Kewley, Lisa J.; Heckman, Timothy M.; Calzetti, Daniela +14 more
We study the ionization and excitation structure of the interstellar medium in the late-stage gas-rich galaxy merger NGC 6240 using a suite of emission-line maps at ~25 pc resolution from the Hubble Space Telescope, Keck/NIRC2 with Adaptive Optics, and the Atacama Large Millimeter/submillimeter Array (ALMA). NGC 6240 hosts a superwind driven by in…
Surveying the Giant H II Regions of the Milky Way with SOFIA. III. W49A
Lim, Wanggi; Karnath, Nicole; De Buizer, James M. +2 more
We present our third set of results from our mid-infrared imaging survey of Milky Way Giant H II regions with our detailed analysis of W49A, one of the most distant, yet most luminous, GH II regions in the Galaxy. We used the FORCAST instrument on the Stratospheric Observatory For Infrared Astronomy (SOFIA) to obtain 20 and 37 µm images of t…
Forward Modeling Helioseismic Signatures of One- and Two-cell Meridional Circulation
Kosovichev, Alexander G.; Pipin, Valery V.; Stejko, Andrey M.
Using a 3D global solver of the linearized Euler equations, we model acoustic oscillations over background velocity flow fields of single-cell meridional circulation with deep and shallow return flows as well as double-cell meridional circulation with strong and weak reversals. The velocities are generated using a mean-field hydrodynamic and dynam…
Influence of Heliolatitudinal Anisotropy of Solar FUV/EUV Emissions on Lyα Helioglow: SOHO/SWAN Observations and WawHelioGlow Modeling
Bzowski, M.; Kubiak, M. A.; Strumik, M.
Observations of the Sun's surface suggest a nonuniform radiated flux as related to the presence of bright active regions and darker coronal holes. The variations of the FUV/EUV source radiation can be expected to affect the Lyα backscatter glow measured by spaceborne instruments. In particular, inferring the heliolatitudinal structure of the solar…