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The 500 ks Chandra observation of the z = 6.31 QSO SDSS J1030 + 0524
Prandoni, I.; Cappi, M.; Vignali, C. +23 more
We present the results from a 500 ks Chandra observation of the z = 6.31 QSO SDSS J1030 + 0524. This is the deepest X-ray observation to date of a z 6 QSO. The QSO is detected with a total of 125 net counts in the full (0.500A0-7 keV) band and its spectrum can be modeled by a single power-law model with photon index of Γ = 1.81 ± 0.18 and full ban…
Dust grains fall from Saturn's D-ring into its equatorial upper atmosphere
Persoon, A. M.; Kurth, W. S.; Mitchell, D. G. +12 more
The sizes of Saturn's ring particles range from meters (boulders) to nanometers (dust). Determination of the rings' ages depends on loss processes, including the transport of dust into Saturn's atmosphere. During the Grand Finale orbits of the Cassini spacecraft, its instruments measured tiny dust grains that compose the innermost D-ring of Saturn…
Formation of Dawn-Dusk Asymmetry in Earth's Magnetotail Thin Current Sheet: A Three-Dimensional Particle-In-Cell Simulation
Artemyev, A. V.; Pritchett, P. L.; Angelopoulos, V. +1 more
Using a three-dimensional particle-in-cell simulation, we investigate the formation of dawn-dusk asymmetry in Earth's magnetotail. The magnetotail current sheet is compressed by an external driving electric field down to a thickness on the order of ion kinetic scales. In the resultant thin current sheet (TCS) where the magnetic field line curvatur…
The double population of Chamaeleon I detected by Gaia DR2
Franciosini, E.; Randich, S.; Roccatagliata, V. +1 more
Context. Chamaeleon I represents an ideal laboratory to study the cluster formation in a low-mass environment. Recently, two sub-clusters spatially located in the northern and southern parts of Chamaeleon I were found with different ages and radial velocities.
Aims: In this Letter we report new insights into the structural properties, age, an…
PAHs and star formation in the H II regions of nearby galaxies M83 and M33
Tielens, A. G. G. M.; Peeters, E.; Stock, D. J. +3 more
We present mid-infrared (MIR) spectra of H II regions within star-forming galaxies M83 and M33. Their emission features are compared with Galactic and extragalactic H II regions, H II-type galaxies, starburst galaxies, and Seyfert/LINER type galaxies. Our main results are as follows: (i) the M33 and M83 H II regions lie in between Seyfert/LINER ga…
Metallicity Variations in the Type II Globular Cluster NGC 6934
Milone, A. P.; Marino, A. F.; Bedin, L. R. +7 more
The Hubble Space Telescope photometric survey of Galactic globular clusters (GCs) has revealed a peculiar “chromosome map” for NGC 6934. In addition to a typical sequence, similar to that observed in Type I GCs, NGC 6934 displays additional stars on the red side, analogous to the anomalous Type II GCs, as defined in our previous work. We present a…
The Properties of Lion Roars and Electron Dynamics in Mirror Mode Waves Observed by the Magnetospheric MultiScale Mission
Russell, C. T.; Lavraud, B.; Anderson, B. J. +47 more
Mirror mode waves are ubiquitous in the Earth's magnetosheath, in particular behind the quasi-perpendicular shock. Embedded in these nonlinear structures, intense lion roars are often observed. Lion roars are characterized by whistler wave packets at a frequency ∼100 Hz, which are thought to be generated in the magnetic field minima. In this study…
Planetary nebula distances in Gaia DR2
Kimeswenger, S.; Barría, D.
Context. Planetary nebula distance scales often suffer from model-dependent solutions. Model-independent trigonometric parallaxes have been rare. Space-based trigonometric parallaxes are now available for a larger sample using the second Data Release of Gaia.
Aims: We aim to derive a high-quality approach for selection criteria of trigonometr…
Storm in a Teacup: X-Ray View of an Obscured Quasar and Superbubble
Mullaney, James R.; Edge, Alastair C.; Alexander, David M. +5 more
We present the X-ray properties of the “Teacup AGN” (SDSS J1430+1339), a z = 0.085 type 2 quasar that is interacting dramatically with its host galaxy. Spectral modeling of the central quasar reveals a powerful, highly obscured active galactic nucleus (AGN) with a column density of N H = (4.2-6.5) × 1023 cm-2 and a…
Wide binaries in Tycho-Gaia II: metallicities, abundances and prospects for chemical tagging
Agüeros, Marcel A.; Andrews, Jeff J.; Chanamé, Julio
From our recent catalogue based on the first Gaia data release (TGAS), we select wide binaries in which both stars have been observed by the Radial Velocity Experiment (RAVE) or the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). Using RAVE and LAMOST metallicities and RAVE Mg, Al, Si, Ti and Fe abundances, we find that the dif…