Giant clouds of molecules in space provide the gain material for astrophysical masers, emitting microwave radiation by stimulated emission. These bright sources can be used to determine extragalactic distances and black hole masses. This paper reports on a search for new extragalactic water masers with the Very Long Baseline Array, and reports on the discovery of four sources in 37 objects searched.
In this paper the authors present simulations of a model to explain rapidly-fading supernovae, a class of transients whose lightcurves decline quickly without substantial radioactive tails. They posits a standard core-collapse explosion of a standard Type Ib/Ic supernova progenitor, but one that produces very little radioactivity and instead exhibits a light curve governed by oxygen recombination.
In 2010 the Fermi-LAT reported a surprising discovery: detection of a gamma ray transient that appeared to come from a nova, V407 Cyg. Since V407 Cyg is a special type of nova, however, it was considered a one-off event. Now two other classical novae have also been found in gamma rays.
When the supernova impostor SN2009ip brightened to a V-band absolute magnitude of -17.7 near the end of 2012, the outburst was classified as a Type IIn supernova and many observers thought the star had finally exploded for good. In this paper, however, the authors present several months of multiband imaging of transient 2012b and argue that the low limit on the nickel mass and lack of most heavy elements in the ejecta suggest the progenitor is still around, and that transient 2012b was produced instead by the collision of two massive shells, possibly ejected by the pulsational pair instability.
The federal budget sequester is symptomatic of a larger dysfunction.
The authors discuss the possibility that the strangely-shaped supernova remnant W49B was created by a core-collapse supernova that formed strong bipolar jets instead of a spherical shockwave.
TITLE: A Search for Vulcanoids with the STEREO Heliospheric Imager AUTHORS: A. J. Steffl, N. J. Cunningham, A. B. Shinn, D. D. Durda, S. A. Stern FIRST AUTHOR’S INSTITUTION: Southwest Research Institute, Boulder The recent evidence for an asteroid belt in the Vega system highlights how well we’re getting to know the solar systems around other […]
Let’s be serious for a moment: nothing dire is going to happen on December 21st. Rest easy. But in celebration I’ve decided to count down my top five favorite astronomical doomsday scenarios, ordered from most to least plausible.
The neutrino reheating mechanism works out in theory to trigger core-collapse supernovae, but we’ve had a lot of trouble getting it to work in 3-dimensional simulations. Because of the prohibitive computational expense, really accurate neutrino physics have thus far only been implemented in 2D. This paper seeks to investigate whether there are systematic differences in fluid behavior between 2D and 3D models in order to figure out whether a 2D model can really stand in for a 3D one.