T. Bitsakis

Light curves of the neutron star merger GW170817/SSS17a: Implications for r-process nucleosynthesis

Photons from a gravitational wave event Two neutron stars merging together generate a gravitational wave signal and have also been predicted to emit electromagnetic radiation. When the gravitational wave event GW170817 was detected, astronomers rushed to search for the source using conventional telescopes (see the Introduction by Smith). Coulter et al. describe how the One-Meter Two-Hemispheres (1M2H) collaboration was the first to locate the electromagnetic source. Drout et al. present the 1M2H measurements of its optical and infrared brightness, and Shappee et al. report their spectroscopy of the event, which is unlike previously detected astronomical transient sources. Kilpatrick et al. show how these observations can be explained by an explosion known as a kilonova, which produces large quantities of heavy elements in nuclear reactions. Science, this issue p. 1556, p. 1570, p. 1574, p. 1583; see also p. 1554 Photometric observations of a neutron star merger show that it produced heavy elements through r-process nucleosynthesis. On 17 August 2017, gravitational waves (GWs) were detected from a binary neutron star merger, GW170817, along with a coincident short gamma-ray burst, GRB 170817A. An optical transient source, Swope Supernova Survey 17a (SSS17a), was subsequently identified as the counterpart of this event. We present ultraviolet, optical, and infrared light curves of SSS17a extending from 10.9 hours to 18 days postmerger. We constrain the radioactively powered transient resulting from the ejection of neutron-rich material. The fast rise of the light curves, subsequent decay, and rapid color evolution are consistent with multiple ejecta components of differing lanthanide abundance. The late-time light curve indicates that SSS17a produced at least ~0.05 solar masses of heavy elements, demonstrating that neutron star mergers play a role in rapid neutron capture (r-process) nucleosynthesis in the universe.

Suppression of Star Formation in NGC 1266

NGC1266 is a nearby lenticular galaxy that harbors a massive outflow of molecular gas powered by the mechanical energy of an active galactic nucleus (AGN). It has been speculated that such outflows hinder star formation (SF) in their host galaxies, providing a form of feedback to the process of galaxy formation. Previous studies, however, indicated that only jets from extremely rare, high power quasars or radio galaxies could impart significant feedback on their hosts. Here we present detailed observations of the gas and dust continuum of NGC1266 at millimeter wavelengths. Our observations show that molecular gas is being driven out of the nuclear region at

Early spectra of the gravitational wave source GW170817: Evolution of a neutron star merger

dot{M}_{rm out} approx 110 M_odot

Star Formation Suppression in Compact Group Galaxies: A New Path to Quenching?

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STRONG FAR-INFRARED COOLING LINES, PECULIAR CO KINEMATICS, AND POSSIBLE STAR-FORMATION SUPPRESSION IN HICKSON COMPACT GROUP 57

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Accretion-inhibited star formation in the warm molecular disk of the green-valley elliptical galaxy NGC 3226?

, of which the vast majority cannot escape the nucleus. Only 2

Studying the evolution of galaxies in compact groups over the past 3 Gyr – I. Nuclear activity

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Studying the evolution of galaxies in compact groups over the past 3 Gyr – II. The importance of environment in the suppression of star formation

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Welcome to the Twilight Zone: The Mid-infrared Properties of Post-starburst Galaxies

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A Novel Method to Automatically Detect and Measure the Ages of Star Clusters in Nearby Galaxies: Application to the Large Magellanic Cloud

is actually capable of escaping the galaxy. Most of the molecular gas that remains is very inefficient at forming stars. The far-infrared emission is dominated by an ultra-compact (