Search Publications
Observation of bi-directional jets in a prominence
Polito, V.; Hillier, A.
Quiescent prominences host a large range of flows, many driven by buoyancy, which lead to velocity shear. The presence of these shear flows could bend and stretch the magnetic field resulting in the formation of current sheets which can lead to magnetic reconnection. Though this has been hypothesised to occur in prominences, with some observations…
Spectroscopic Monitoring of the Candidate Tidal Disruption Event in F01004-2237
Jonker, Peter G.; Cannizzaro, Giacomo; Mata-Sánchez, D.
We present results of spectroscopic monitoring observations of the ultraluminous infrared galaxy F01004-2237. This galaxy was observed to undergo changes in its optical spectrum, detected by comparing a spectrum from 2015 with one from 2000. These changes were coincident with photometric brightening. The main changes detected in the optical spectr…
The Fundamental Plane of Massive Quiescent Galaxies at z ∼ 2
Conselice, Christopher J.; Gallazzi, Anna; Zibetti, Stefano +11 more
We examine the Fundamental Plane (FP) and mass-to-light ratio (M/L) scaling relations using the largest sample of massive quiescent galaxies at 1.5 < z < 2.5 to date. The FP (re, σe, Ie) is established using 19 UVJ quiescent galaxies from COSMOS with Hubble Space Telescope HF160W rest-frame optical…
Are we observing an NSC in course of formation in the NGC 4654 galaxy?
Mastrobuono-Battisti, A.; Georgiev, I. Y.; Capuzzo-Dolcetta, R. +2 more
We use direct N-body simulations to explore some possible scenarios for the future evolution of two massive clusters observed towards the centre of NGC 4654, a spiral galaxy with mass similar to that of the Milky Way. Using archival HST data, we obtain the photometric masses of the two clusters, M = 3 × 105 M⊙ and M = 1.7 × 1…
Low-frequency Waves due to Newborn Interstellar Pickup He+ Observed by the Ulysses Spacecraft
Isenberg, Philip A.; Schwadron, Nathan A.; Murphy, Neil +8 more
We have surveyed magnetic field data from the Ulysses spacecraft and found examples of magnetic waves with the expected characteristics that point to excitation by newborn pickup He+. With interstellar neutrals as the likely source for the pickup ions, we have modeled the ion production rates and used them to produce wave excitation rat…
Seeking Echoes of Circumstellar Disks in Kepler Light Curves
Kenyon, Scott J.; Bromley, Benjamin C.; Leonard, Austin +3 more
Light echoes of flares on active stars offer the opportunity for direct detection of circumstellar dust. We revisit the problem of identifying faint echoes in postflare light curves, focusing on debris disks from ongoing planet formation. Starting with simulations, we develop an algorithm for estimating the radial extent and total mass from disk e…
Low surface brightness galaxies in z > 1 galaxy clusters: HST approaching the progenitors of local ultra diffuse galaxies
Muzzin, Adam; Brammer, Gabriel; van der Burg, Remco F. J. +2 more
Ultra diffuse galaxies (UDGs) are a type of large low surface brightness (LSB) galaxies with particularly large effective radii (reff > 1.5 kpc) that are now routinely studied in the Local (z < 0.1) Universe. While they are found to be abundant in clusters, groups, and in the field, their formation mechanisms remain elusive and co…
Photospheric downflows observed with SDO/HMI, HINODE, and an MHD simulation
Malherbe, J. M.; Roudier, T.; Ballot, J. +3 more
Downflows on the solar surface are suspected to play a major role in the dynamics of the convection zone, at least in its outer part. We investigate the existence of the long-lasting downflows whose effects influence the interior of the Sun but also the outer layers. We study the sets of Dopplergrams and magnetograms observed with Solar Dynamics O…
Stellar, Gas, and Dust Emission of Star-forming Galaxies out to z ∼ 2
Gronwall, Caryl; Ciardullo, Robin; Bowman, William P. +1 more
While dust is a major player in galaxy evolution, its relationship with gas and stellar radiation in the early universe is still not well understood. We combine 3D-Hubble Space Telescope emission-line fluxes with far-UV through far-IR photometry in a sample of 669 emission-line galaxies (ELGs) between 1.2 < z < 1.9 and use the MCSED spectral…
Multi-Point Observation of Hiss Emerging From Lightning Whistlers
Gurnett, Donald A.; Pickett, Jolene S.; Santolík, Ondřej +1 more
We analyze continuous multi-point measurements of electromagnetic field waveforms onboard the Cluster spacecraft in order to contribute to the discussion on sources of plasmaspheric hiss, known as a shaping agent for the Earth radiation belts. In our case study we aim at finding sources of hiss observed close to the geomagnetic equator in the oute…