Search Publications
Time-dependent Ionization in a Steady Flow in an MHD Model of the Solar Corona and Wind
Reeves, Katharine K.; Raymond, John C.; Linker, Jon A. +3 more
Time-dependent ionization is important for diagnostics of coronal streamers and pseudostreamers. We describe time-dependent ionization calculations for a three-dimensional magnetohydrodynamic (MHD) model of the solar corona and inner heliosphere. We analyze how non-equilibrium ionization (NEI) influences emission from a pseudostreamer during the W…
Comparing Coronal and Heliospheric Magnetic Fields over Several Solar Cycles
Mursula, K.; Koskela, J. S.; Virtanen, I. I.
Here we use the PFSS model and photospheric data from Wilcox Solar Observatory, SOHO/MDI, SDO/HMI, and SOLIS to compare the coronal field with heliospheric magnetic field measured at 1 au, compiled in the NASA/NSSDC OMNI 2 data set. We calculate their mutual polarity match and the power of the radial decay, p, of the radial field using different s…
Spatially Resolved Patchy Lyα Emission within the Central Kiloparsec of a Strongly Lensed Quasar Host Galaxy at z = 2.8
Acharyya, Ayan; Rigby, Jane R.; Bian, Fuyan +10 more
We report the detection of extended Lyα emission from the host galaxy of SDSS J2222+2745, a strongly lensed quasar at z = 2.8. Spectroscopic follow-up clearly reveals extended Lyα in emission between two images of the central active galactic nucleus (AGN). We reconstruct the lensed quasar host galaxy in the source plane by applying a strong lens m…
A Complete Census of Hα Emitters in NGC 6397
Pallanca, Cristina; Mucciarelli, Alessio; Ferraro, Francesco R. +3 more
We used a data set of archival Hubble Space Telescope images obtained through the F555W, F814W, and F656N filters to perform a complete search for objects showing {{H}}α emission in the globular cluster NGC 6397. As a photometric diagnostic, we used the {(V-{{H}}α )}0 color excess in the {(V-{{H}}α )}0-{(V-I)}0 col…
SHARDS Frontier Fields: Physical Properties of a Low-mass Lyα Emitter at z = 5.75
Pérez-González, Pablo G.; Richard, Johan; Conselice, Christopher J. +20 more
We analyze the properties of a multiply imaged Lyα (Lyα) emitter at z = 5.75 identified through SHARDS Frontier Fields intermediate-band imaging of the Hubble Frontier Fields (HFF) cluster Abell 370. The source, A370-L57, has low intrinsic luminosity (M UV ∼ -16.5), steep UV spectral index (β = -2.4 ± 0.1), and extreme rest-frame equiva…
Calibrating the Planck Cluster Mass Scale with Cluster Velocity Dispersions
Chary, Ranga-Ram; Stern, Daniel; Shim, Hyunjin +7 more
We measure the Planck cluster mass bias using dynamical mass measurements based on velocity dispersions of a subsample of 17 Planck-detected clusters. The velocity dispersions were calculated using redshifts determined from spectra that were obtained at the Gemini observatory with the GMOS multi-object spectrograph. We correct our estimates for ef…
The Deflection of the Cartwheel CME: ForeCAT Results
Landi, Enrico; Kay, Christina; Capannolo, Luisa +1 more
We analyze the Cartwheel coronal mass ejection's (CME; 2008 April 9) trajectory in the low corona with the ForeCAT model. This complex event presented a significant rotation in the low corona and a reversal in its original latitude direction. We successfully reproduce the observed CME’s trajectory (latitude and longitude deflection) and speed. Thr…
A Multi-band Study of the Remarkable Jet in Quasar 4C+19.44
Cheung, C. C.; Uchiyama, Y.; Siemiginowska, A. +14 more
We present arcsecond-resolution data in the radio, IR, optical, and X-ray for 4C+19.44 (=PKS 1354+195), the longest and straightest quasar jet with deep X-ray observations. We report results from radio images with half to one arcsecond angular resolution at three frequencies, plus Hubble Space Telescope and Spitzer data. The Chandra data allow us …
The 2013 February 17 Sunquake in the Context of the Active Region's Magnetic Field Configuration
Guglielmino, S. L.; Green, L. M.; Valori, G. +3 more
Sunquakes are created by the hydrodynamic response of the lower atmosphere to a sudden deposition of energy and momentum. In this study, we investigate a sunquake that occurred in NOAA active region 11675 on 2013 February 17. Observations of the corona, chromosphere, and photosphere are brought together for the first time with a nonlinear force-fr…
No Evidence for Feedback: Unexceptional Low-ionization Winds in Host Galaxies of Low Luminosity Active Galactic Nuclei at Redshift z ∼ 1
Prochaska, J. Xavier; Faber, S. M.; Coil, Alison L. +6 more
We study winds in 12 X-ray AGN host galaxies at z∼ 1. We find, using the low-ionization Fe II λ2586 absorption in the stacked spectra, that the probability distribution function (PDF) of the centroid-velocity shift in AGNs has 50th (median), 16th, and 84th percentiles of (-87, -251, +86) km s-1 respectively. The PDF of the velocity disp…