Search Publications
The EUV spectrum of the Sun: Quiet- and active-Sun irradiances and chemical composition
Del Zanna, G.
We benchmark new atomic data against a selection of irradiances obtained from medium-resolution quiet-Sun spectra in the extreme ultraviolet (EUV), from 60 to 1040 Å. We used as a baseline the irradiances measured during solar minimum on 2008 April 14 by the prototype (PEVE) of the Solar Dynamics Observatory Extreme ultraviolet Variability Experim…
EVR-CB-001: An Evolving, Progenitor, White Dwarf Compact Binary Discovered with the Evryscope
Law, Nicholas M.; Kupfer, Thomas; Glazier, Amy +7 more
We present EVR-CB-001, the discovery of a compact binary with an extremely low-mass (0.21 ± 0.05M ⊙) helium core white dwarf progenitor (pre-He WD) and an unseen low-mass (0.32 ± 0.06M ⊙) helium white dwarf (He WD) companion. He WDs are thought to evolve from the remnant helium-rich core of a main-sequence star stripped durin…
HST/COS observations of the newly discovered obscuring outflow in NGC 3783
Kaastra, J. S.; Kriss, G. A.; Arav, N. +24 more
Aims: To understand the nature of transient obscuring outflows in active galactic nuclei, we use simultaneous multiwavelength observations with XMM-Newton, NuSTAR, the Hubble Space Telescope (HST), and the Max Planck Gesellschaft/European Southern Observatory (ESO) 2.2 m telescope triggered by soft X-ray absorption detected by Swift.
Met…
A deep XMM-Newton look on the thermally emitting isolated neutron star RX J1605.3+3249
Haberl, F.; Motch, C.; Zane, S. +3 more
Previous XMM-Newton observations of the thermally emitting isolated neutron star RX J1605.3+3249 provided a candidate for a shallow periodic signal and evidence of a fast spin down, which suggested a high dipolar magnetic field and an evolution from a magnetar. We obtained a large programme with XMM-Newton to confirm its candidate timing solution,…
Near-Earth asteroid 2012 TC4 observing campaign: Results from a global planetary defense exercise
Masiero, Joseph R.; Kareta, Theodore; Springmann, Alessondra +66 more
Impacts due to near-Earth objects (NEOs) are responsible for causing some of the great mass extinctions on Earth. While nearly all NEOs of diameter > 1 km, capable of causing a global climatic disaster, have been discovered and have negligible chance of impacting in the near future, we are far from completion in our effort to detect and charact…
Variable Stars in Terzan 5: Additional Evidence of Multi-age and Multi-iron Stellar Populations
Dalessandro, E.; Massari, D.; Contreras Ramos, R. +7 more
Terzan 5 is a complex stellar system in the Galactic bulge, harboring stellar populations (SPs) with very different iron content (Δ[Fe/H] ∼ 1 dex) and with ages differing by several gigayears. Here we present an investigation of its variable stars. We report on the discovery and characterization of three RR Lyrae stars. For these newly discovered …
Characterizing circumgalactic gas around massive ellipticals at z ≈ 0.4 - III. The galactic environment of a chemically pristine Lyman limit absorber
Bouché, Nicolas; Johnson, Sean D.; Marino, Raffaella Anna +7 more
This paper presents a study of the galactic environment of a chemically pristine (<0.6 per cent solar metallicity) Lyman Limit system (LLS) discovered along the sightline towards QSO SDSSJ 135726.27+043541.4 (zQSO = 1.233) at projected distance d = 126 physical kpc (pkpc) from a luminous red galaxy (LRG) at z = 0.33. Combining deep H…
Investigations of a supra-arcade fan and termination shock above the top of the flare-loop system of the 2017 September 10 event
Lin, Jun; Raymond, John C.; Roussev, Ilia I. +4 more
On 2017 September 10, a major eruption on the west solar limb produced a class X-8.2 flare and a superfast coronal mass ejection (CME). During the eruptive process, the geometric topology of the erupting magnetic configuration presented a clear flare-current sheet (CS)-CME structure. Analysing the images and spectral data from the Solar Dynamics O…
The Population of Pulsating Variable Stars in the Sextans Dwarf Spheroidal Galaxy
Mateo, Mario; Vivas, A. Katherina; Alonso-García, Javier +2 more
A large extension of the Sextans dwarf spheroidal galaxy, 7 deg2, has been surveyed for variable stars using the Dark Energy Camera at the Blanco Telescope at Cerro Tololo Inter-American Observatory, Chile. We report seven anomalous Cepheids, 199 RR Lyrae stars, and 16 dwarf Cepheids in the field. This is only the fifth extragalactic sy…
Measuring the filamentary structure of interstellar clouds through wavelets
Ossenkopf-Okada, V.; Stepanov, R.
Context. The ubiquitous presence of filamentary structures in the interstellar medium asks for an unbiased characterization of their properties including a stability analysis.
Aims: We propose a novel technique to measure the spectrum of filaments in any two-dimensional data set. By comparing the power in isotropic and anisotropic structures …