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A Semi-analytical Line Transfer Model to Interpret the Spectra of Galaxy Outflows
Panagia, N.; Scarlata, C.
We present a semi-analytical line transfer model, (SALT), to study the absorption and re-emission line profiles from expanding galactic envelopes. The envelopes are described as a superposition of shells with density and velocity varying with the distance from the center. We adopt the Sobolev approximation to describe the interaction between the p…
Revisiting cosmological bounds on sterile neutrinos
Mena, Olga; Vincent, Aaron C.; Lattanzi, Massimiliano +2 more
We employ state-of-the art cosmological observables including supernova surveys and BAO information to provide constraints on the mass and mixing angle of a non-resonantly produced sterile neutrino species, showing that cosmology can effectively rule out sterile neutrinos which decay between BBN and the present day. The decoupling of an additional…
ALMA Resolves the Spiraling Accretion Flow in the Luminous OB Cluster-forming Region G33.92+0.11
Zhang, Qizhou; Liu, Hauyu Baobab; Galván-Madrid, Roberto +4 more
How rapidly collapsing parsec-scale massive molecular clumps feed high-mass stars and how they fragment to form OB clusters have been outstanding questions in the field of star formation. In this work, we report the resolved structures and kinematics of the approximately face-on, rotating massive molecular clump, G33.92+0.11. Our high-resolution A…
Measuring the speed of cosmological gravitational waves
Raveri, Marco; Silvestri, Alessandra; Baccigalupi, Carlo +1 more
In general relativity gravitational waves propagate at the speed of light; however, in alternative theories of gravity that might not be the case. We investigate the effects of a modified speed of gravity, cT2, on the B modes of the cosmic microwave background (CMB) anisotropy in polarization. We find that a departure from th…
Measurements of the near-nucleus coma of comet 67P/Churyumov-Gerasimenko with the Alice far-ultraviolet spectrograph on Rosetta
Parker, Joel Wm.; Bertaux, Jean-Loup; Weaver, Harold A. +8 more
Aims. The Alice far-ultraviolet spectrograph onboard Rosetta is designed to observe emissions from various atomic and molecular species from within the coma of comet 67P/ Churyumov-Gerasimenko and to determine their spatial distribution and evolution with time and heliocentric distance. Methods. Following orbit insertion in August 2014, Alice made…
Evolution of the lower hybrid drift instability at reconnection jet front
André, M.; Vaivads, A.; Khotyaintsev, Yu. V. +3 more
We investigate current-driven modes developing at jet fronts during collisionless reconnection. Initial evolution of the reconnection is simulated using conventional 2-D setup starting from the Harris equilibrium. Three-dimensional PIC calculations are implemented at later stages, when fronts are fully formed. Intense currents and enhanced wave ac…
New observations and models of circumstellar CO line emission of AGB stars in the Herschel SUCCESS programme
Olofsson, H.; Teyssier, D.; García-Lario, P. +8 more
Context. Asymptotic giant branch (AGB) stars are in one of the latest evolutionary stages of low to intermediate-mass stars. Their vigorous mass loss has a significant effect on the stellar evolution, and is a significant source of heavy elements and dust grains for the interstellar medium. The mass-loss rate can be well traced by carbon monoxide …
Helium Atmospheres on Warm Neptune- and Sub-Neptune-sized Exoplanets and Applications to GJ 436b
Seager, Sara; Hu, Renyu; Yung, Yuk L.
Warm Neptune- and sub-Neptune-sized exoplanets in orbits smaller than Mercury’s are thought to have experienced extensive atmospheric evolution. Here we propose that a potential outcome of this atmospheric evolution is the formation of helium-dominated atmospheres. The hydrodynamic escape rates of Neptune- and sub-Neptune-sized exoplanets are comp…
The Morphologies of Massive Galaxies from z ~ 3—Witnessing the Two Channels of Bulge Growth
Daddi, E.; Huertas-Company, M.; Mei, S. +8 more
We quantify the morphological evolution of z∼ 0 massive galaxies ({M}*/{M}⊙ ∼ {10}11.2+/- 0.3) from z∼ 3 in the 5 CANDELS fields. The progenitors are selected using abundance matching techniques to account for the mass growth. At z\lt 1, the population matches the massive end of the Hubble sequence, with 30% of pur…
B fields in OB stars (BOB): on the detection of weak magnetic fields in the two early B-type stars β CMa and ɛ CMa. Possible lack of a "magnetic desert" in massive stars
Ilyin, I.; Carroll, T. A.; Fossati, L. +14 more
Only a small fraction of massive stars seem to host a measurable structured magnetic field, whose origin is still unknown and whose implications for stellar evolution still need to be assessed. Within the context of the "B fields in OB stars (BOB)" collaboration, we used the HARPSpol spectropolarimeter to observe the early B-type stars β CMa (HD 4…