Search Publications
Revisiting Ulysses Observations of Interstellar Helium
Wood, Brian E.; Müller, Hans-Reinhard; Witte, Manfred
We report the results of a comprehensive reanalysis of Ulysses observations of interstellar He atoms flowing through the solar system, the goal being to reassess the interstellar He flow vector and to search for evidence of variability in this vector. We find no evidence that the He beam seen by Ulysses changes at all from 1994-2007. The direction…
Heating Signatures in the Disk Counterparts of Solar Spicules in Interface Region Imaging Spectrograph Observations
De Pontieu, B.; Rouppe van der Voort, L.; Carlsson, M. +2 more
We use coordinated observations with the Interface Region Imaging Spectrograph (IRIS) and the Swedish 1 m Solar Telescope to identify the disk counterpart of type II spicules in upper-chromospheric and transition region (TR) diagnostics. These disk counterparts were earlier identified through short-lived asymmetries in chromospheric spectral lines…
The Influence of Spatial resolution on Nonlinear Force-free Modeling
Sun, X.; Schrijver, C. J.; Canou, A. +11 more
The nonlinear force-free field (NLFFF) model is often used to describe the solar coronal magnetic field, however a series of earlier studies revealed difficulties in the numerical solution of the model in application to photospheric boundary data. We investigate the sensitivity of the modeling to the spatial resolution of the boundary data, by app…
Supernova 1987A: a Template to Link Supernovae to Their Remnants
Miceli, M.; Bocchino, F.; Orlando, S. +1 more
The emission of supernova remnants (SNRs) reflects the properties of both the progenitor supernovae (SNe) and the surrounding environment. The complex morphology of the remnants, however, hampers the disentanglement of the two contributions. Here, we aim at identifying the imprint of SN 1987A on the X-ray emission of its remnant and at constrainin…
IRIS Si IV Line Profiles: An Indication for the Plasmoid Instability during Small-scale Magnetic Reconnection on the Sun
Innes, D. E.; Huang, Y. -M.; Guo, L. -J. +1 more
Our understanding of the process of fast reconnection has undergone a dramatic change in the last 10 years driven, in part, by the availability of high-resolution numerical simulations that have consistently demonstrated the break-up of current sheets into magnetic islands, with reconnection rates that become independent of Lundquist number, chall…
A Multiwavelength Study of the Relativistic Tidal Disruption Candidate Swift J2058.4+0516 at Late Times
Fruchter, Andrew S.; Filippenko, Alexei V.; Cenko, S. Bradley +12 more
We report a multiwavelength (X-ray, ultraviolet/optical/infrared (UVOIR), radio) analysis of the relativistic tidal disruption event (TDE) candidate Sw J2058+05 from 3 months to 3 yr post-discovery in order to study its properties and compare its behavior with that of Sw J1644+57. Our main results are as follows: (1) The long-term X-ray light curv…
The Metagalactic Ionizing Background: A Crisis in UV Photon Production or Incorrect Galaxy Escape Fractions?
Shull, J. Michael; Danforth, Charles W.; Tilton, Evan M. +1 more
Recent suggestions of a “photon underproduction crisis” have generated concern over the intensity and spectrum of ionizing photons in the metagalactic ultraviolet background (UVB). The balance of hydrogen photoionization and recombination determines the opacity of the low-redshift intergalactic medium (IGM). We calibrate the hydrogen photoionizati…
Storm in a "Teacup": A Radio-quiet Quasar with ≈10 kpc Radio-emitting Bubbles and Extreme Gas Kinematics
Thomson, A. P.; Alexander, D. M.; Bauer, F. E. +5 more
We present multi-frequency (1-8 GHz) Very Large Array data, combined with VIsible MultiObject Spectrograph integral field unit data and Hubble Space Telescope imaging, of a z = 0.085 radio-quiet type 2 quasar (with L 1.4 GHz ≈ 5 × 1023 W Hz-1 and L AGN ≈ 2 × 1045 erg s-1). Due to th…
An Extreme Metallicity, Large-scale Outflow from a Star-forming Galaxy at z ~ 0.4
Charlton, Jane C.; Kacprzak, Glenn G.; Churchill, Christopher W. +4 more
We present a detailed analysis of a large-scale galactic outflow in the circumgalactic medium of a massive ({M}{{h}}∼ {10}12.5 {M}⊙ ), star-forming (∼ 6.9 {M}⊙ yr-1), sub-L* (∼ 0.5{L}B*) galaxy at z = 0.39853 that exhibits a wealth of metal-line absorption in …
Cross-correlation between the CMB Lensing Potential Measured by Planck and High-z Submillimeter Galaxies Detected by the Herschel-Atlas Survey
Baccigalupi, C.; Bielewicz, P.; Danese, L. +15 more
We present the first measurement of the correlation between the map of the cosmic microwave background (CMB) lensing potential derived from the Planck nominal mission data and z≳ 1.5 galaxies detected by the Herschel-ATLAS (H-ATLAS) survey covering about 600 {{deg }2}, i.e., about 1.4% of the sky. We reject the hypothesis that there is …