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An Ultraviolet Survey of Low-redshift Partial Lyman-limit Systems with the HST Cosmic Origins Spectrograph
Stevans, Matthew L.; Shull, J. Michael; Danforth, Charles W. +2 more
We present an ultraviolet spectroscopic survey of strong H I absorbers in the intergalactic medium, probing their evolution over the last 6-7 Gyr at redshifts 0.24 ≤ z ≤ 0.84. We measure column densities N H I (cm-2) from the pattern of Lyman-series absorption lines and flux decrement at the Lyman limit (LL) when available. …
Investigating short-time-scale variations in cometary ions around comet 67P
Karlsson, Tomas; Simon Wedlund, Cyril; Nilsson, Hans +10 more
The highly varying plasma environment around comet 67P/Churyumov-Gerasimenko inspired an upgrade of the ion mass spectrometer (Rosetta Plasma Consortium Ion Composition Analyzer) with new operation modes, to enable high time resolution measurements of cometary ions. Two modes were implemented, one having a 4 s time resolution in the energy range 0…
Migration and kinematics in growing disc galaxies with thin and thick discs
Binney, James; Schönrich, Ralph; Aumer, Michael
We analyse disc heating and radial migration in N-body models of growing disc galaxies with thick and thin discs. Similar to thin-disc-only models, galaxies with appropriate non-axisymmetric structures reproduce observational constraints on radial disc heating in and migration to the Solar Neighbourhood (Snhd). The presence of thick discs can supp…
Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power
Page, M. J.; Hardcastle, M. J.; Elvis, M. +6 more
Several studies support the existence of a link between the active galactic nucleus (AGN) and star formation activity. Radio jets have been argued to be an ideal mechanism for direct interaction between the AGN and the host galaxy. A drawback of previous surveys of AGN is that they are fundamentally limited by the degeneracy between redshift and l…
OMEGA - OSIRIS Mapping of Emission-line Galaxies in A901/2 - II. Environmental influence on integrated star formation properties and AGN activity
Chies-Santos, Ana L.; Wolf, Christian; Aragón-Salamanca, Alfonso +6 more
We present a study of the star formation and AGN activity for galaxies in CP 15051 the Abell 901/2 multicluster system at z ∼ 0.167 as part of the OSIRIS Mapping of Emission-line Galaxies in A901/2 (OMEGA) survey. Using Tuneable Filter data obtained with the OSIRIS instrument at the Gran Telescopio Canarias, we produce spectra covering the Hα and …
Real-time prediction of the occurrence of GLE events
Núñez, Marlon; Reyes-Santiago, Pedro J.; Malandraki, Olga E.
A tool for predicting the occurrence of Ground Level Enhancement (GLE) events using the UMASEP scheme is presented. This real-time tool, called HESPERIA UMASEP-500, is based on the detection of the magnetic connection, along which protons arrive in the near-Earth environment, by estimating the lag correlation between the time derivatives of 1 min …
Potential cooling of an accretion-heated neutron star crust in the low-mass X-ray binary 1RXS J180408.9-342058
Altamirano, D.; Degenaar, N.; Wijnands, R. +11 more
We have monitored the transient neutron star low-mass X-ray binary 1RXS J180408.9-342058 in quiescence after its ∼4.5 month outburst in 2015. The source has been observed using Swift and XMM-Newton. Its X-ray spectra were dominated by a thermal component. The thermal evolution showed a gradual X-ray luminosity decay from ∼18 × 1032 to ∼…
North-south asymmetries in cold plasma density in the magnetotail lobes: Cluster observations
Snekvik, K.; Østgaard, N.; Tenfjord, P. +7 more
In this paper, we present observations of cold (0-70 eV) plasma density in the magnetotail lobes. The observations and results are based on 16 years of Cluster observation of spacecraft potential measurements converted into local plasma densities. Measurements from all four Cluster spacecraft have been used, and the survey indicates a persistent a…
SED-dependent galactic extinction prescription for Euclid and future cosmological surveys
Paltani, Stéphane; Galametz, Audrey; Saglia, Roberto +2 more
The outcome of upcoming cosmological surveys will depend on the accurate estimates of photometric redshifts. In the framework of the implementation of the photometric redshift algorithm for the ESA Euclid mission, we are exploring new avenues to improve current template-fitting methods. This paper focusses in particular on the prescription of the …
Galaxy Populations in Massive z = 0.2-0.9 Clusters. I. Analysis of Spectroscopy
Jørgensen, Inger; Chiboucas, Kristin; Takamiya, Marianne +3 more
We present an analysis of stellar populations in passive galaxies in seven massive X-ray clusters at z = 0.19-0.89. Based on absorption-line strengths measured from our high signal-to-noise spectra, the data support primarily passive evolution of the galaxies. We use the scaling relations between velocity dispersions and the absorption-line streng…