  We present ground-based measurements of the transmission and emission spectra
of the hot-Jupiter WASP-19b in nine spectroscopic channels from 1.25 to 2.35
microns. The measurements are based on the combined analysis of time-series
spectroscopy obtained during two complete transits and two complete secondary
eclipses of the planet. The observations were performed with the MMIRS
instrument on the Magellan II telescope using the technique of multi-object
spectroscopy with wide slits. We compare the transmission and emission data to
theoretical models to constrain the composition and thermal structure of the
planet's atmosphere. Our measured transmission spectrum exhibits a scatter that
corresponds to 1.3 scale heights of the planet's atmosphere, which is
consistent with the size of spectral features predicted by theoretical models
for a clear atmosphere. We detected the secondary eclipses of the planet at
significances ranging from 2.2 to 14.4 sigma. The secondary eclipse depths, and
the significances of the detections increase towards longer wavelengths. Our
measured emission spectrum is consistent with a 2250 K effectively isothermal
1-D model for the planet's dayside atmosphere. This model also matches
previously published photometric measurements from the Spitzer Space Telescope
and ground-based telescopes. These results demonstrate the important role that
ground-based observations using multi-object spectroscopy can play in
constraining the properties of exoplanet atmospheres, and they also emphasize
the need for high-precision measurements based on observations of multiple
transits and eclipses.
