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The Relativistic Jet-accretion Flow-Wind Connection in Mrk 231
O'Dea, Christopher P.; Miniutti, Giovanni; Punsly, Brian +2 more
Long-term radio monitoring of the broad absorption line (BAL) quasar Mrk 231 at 17.6 GHz detected a strong flare in 2015. This triggered four epochs of Very Long Baseline Array (VLBA) observations from 8.4 to 43 GHz as well as three epochs of X-ray observations with NuSTAR and two with XMM over a 15 week period. Two ejected components were detecte…
Exploring the progenitors of brightest cluster galaxies at z ∼ 2
Conselice, Christopher J.; Zhao, Dongyao; Aragón-Salamanca, Alfonso +5 more
We present a new method for tracing the evolution of brightest cluster galaxies (BCGs) from z ∼ 2 to z ∼ 0. We conclude on the basis of semi-analytical models that the best method to select BCG progenitors at z ∼ 2 is a hybrid environmental density and stellar mass ranking approach. Ultimately, we are able to retrieve 45 per cent of BCG progenitor…
Resolving the X-ray emission from the Lyman-continuum emitting galaxy Tol 1247-232
Kaaret, P.; Prestwich, A. H.; Brorby, M. +1 more
Chandra observations of the nearby, Lyman-continuum (LyC) emitting galaxy Tol 1247-232 resolve the X-ray emission and show that it is dominated by a point-like source with a hard spectrum (Γ = 1.6 ± 0.5) and a high luminosity [(9 ± 2) × 1040 erg s- 1]. Comparison with an earlier XMM-Newton observation shows flux variation of …
Calculating travel times and arrival speeds of CMEs to Earth: An analytic tool for space weather forecasting
Aguilar-Rodriguez, E.; Corona-Romero, P.; Gonzalez-Esparza, J. A. +3 more
Coronal mass ejections (CME) are one of the most important phenomena derived from solar activity that potentially perturb space weather of Earth. In this work we present a semiempirical arrival forecasting tool for Earth-directed halo CMEs. This tool combines the piston shock model and an empirical relationship to estimate in situ arrivals of halo…
Cold Ion Outflow Modulated by the Solar Wind Energy Input and Tilt of the Geomagnetic Dipole
Wei, Y.; Nilsson, H.; André, M. +7 more
The solar wind energy input into the Earth's magnetosphere-ionosphere system drives ionospheric outflow, which plays an important role in both the magnetospheric dynamics and evolution of the atmosphere. However, little is known about the cold ion outflow with energies lower than a few tens of eV, as the direct measurement of cold ions is difficul…
The Stickney Crater ejecta secondary impact crater spike on Phobos: Implications for the age of Stickney and the surface of Phobos
Head, James W.; Ramsley, Kenneth R.
A global and uniformly distributed spike of secondary impact craters on Phobos with diameters (D) <0.6 km and a portion of craters up to D 2 km were produced by Stickney Crater ejecta, including secondary craters within the surface area of Stickney Crater. The global exposure of Phobos to Stickney secondary impacts was facilitated by the desync…
The nova-like nebular optical spectrum of V404 Cygni at the beginning of the 2015 outburst decay
Gandhi, P.; Tomsick, J. A.; Rossi, A. +7 more
We report on FORS2 optical spectroscopy of the black hole X-ray binary V404 Cygni, performed at the very beginning of its 2015 outburst decay, complemented by quasi-simultaneous Swift X-ray and ultraviolet as well as Rapid Eye Mountain near-infrared observations. Its peculiar spectrum is dominated by a wealth of emission signatures of H I, He I, a…
Automated detection of coronal mass ejections in three-dimensions using multi-viewpoint observations
Morgan, H.; Hutton, J.
A new, automated method of detecting coronal mass ejections (CMEs) in three dimensions for the LASCO C2 and STEREO COR2 coronagraphs is presented. By triangulating isolated CME signal from the three coronagraphs over a sliding window of five hours, the most likely region through which CMEs pass at 5 R⊙ is identified. The centre and size…
Insights from Synthetic Star-forming Regions. I. Reliable Mock Observations from SPH Simulations
Dale, James E.; Robitaille, Thomas P.; Koepferl, Christine M. +1 more
Through synthetic observations of a hydrodynamical simulation of an evolving star-forming region, we assess how the choice of observational techniques affects the measurements of properties that trace star formation. Testing and calibrating observational measurements requires synthetic observations that are as realistic as possible. In this part o…
Influence of the crustal magnetic field on the Mars aurora electron flux and UV brightness
Gérard, J. -C.; Hubert, B.; Shematovich, V. I. +1 more
Observations with the SPICAM instrument on board Mars Express have shown the occasional presence of localized ultraviolet nightside emissions associated with enhanced energetic electron fluxes. These features generally occur in regions with significant radial crustal magnetic field. We use a Monte-Carlo electron transport model to investigate the …