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The Echellette Spectrograph and Imager (ESI) is a multipurpose instrument which has been delivered by the Instrument Development Laboratory of Lick Observatory for use at the Cassegrain focus of the Keck II telescope. ESI saw first light on August 29, 1999. ESI is a multi-mode instrument that enables the observer to seamlessly switch between three modes during an observation. The three modes of ESI are: An R=13,000-echellette mode; Low-dispersion prismatic mode; Direct imaging mode. ESI contains a unique flexure compensation system which reduces the small instrument flexure to negligible proportions. Long-exposure images on the sky show FWHM spot diameters of 34 microns (0. ′′ 34) averaged over the entire field of view. These are the best non-AO images taken in the visible at Keck Observatory to date. Maximum efficiencies are measured to be 28% for the echellette mode and greater than 41% for low-dispersion prismatic mode including atmospheric, telescope and detector losses. In this paper we describe the instrument and its development. We also discuss the performance-testing and some observational results.

The Inamori-Magellan Areal Camera and Spectrograph (IMACS) is a wide-field, multipurpose imaging spectrograph on the Magellan-Baade telescope at Las Campanas Observatory. IMACS has two channelsf/2 and f/4, each with an 8K × 8K pixel mosaic of CCD detectors, that service the widest range of capabilities of any major spectrograph. These include wide-field imaging at two scales, 0:20″ pixel À1 and 0:11″ pixel À1 , singleobject and multislit spectroscopy, integral-field spectroscopy with two 5″ × 7″ areas sampled at 0:20″ pixel À1 (Durham IFU), a multiobject echelle (MOE) capable of N ∼ 10 simultaneous full-wavelength R ≈ 20; 000 spectra, the Maryland-Magellan Tunable Filter (MMTF), and an image-slicing reformatter for dense-pack multislit work (GISMO). Spectral resolutions of 8 < R < 5000 are available through a combination of prisms, grisms, and gratings, and most modes are instantly available in any given IMACS configuration. IMACS has a spectroscopic efficiency over 50% in f/2 multislit mode (instrument only) and, by the AΩ figure of merit (telescope primary surface area times instrument field of view ), IMACS scores 5:7 m 2 deg 2 , compared with 3.1 for VIMOS on VLT3 and with 2.0 for DEIMOS on Keck2. IMACS is the most versatile, and-for wide-field optical spectroscopy-the most powerful spectrograph on the planet.

IR and radio-band observations of heavily extinguished regions in starburst galaxies suggest a high supernova (SN) rate associated with such regions. Optically measured SN rates may therefore underestimate the total SN rate by factors of up to 10, as a result of the very high extinction mag) (A B D 10È20 to core-collapse SNe in starburst regions. The IR/radio SN rates come from a variety of indirect means, however, which su †er from model dependence and other problems. We describe a direct measurement of the SN rate from a regular patrol of starburst galaxies done with K@-band imaging to minimize the e †ects of extinction. A collection of K@-band measurements of core-collapse SNe near maximum light is presented. Such measurements (excluding 1987A) are not well reported in the literature. Results of a preliminary K@-band search, using the MIRC camera at the Wyoming Infrared Observatory and an improved search strategy using the new ORCA optics, are described. A monthly patrol of a sample of IRAS bright (mostly starburst) galaxies within 25 Mpc should yield 1È6 SNe yr~1, corresponding to the range of estimated SN rates. Our initial MIRC search with low resolution pixels) failed to Ðnd (2A .2 extinguished SNe in the IRAS galaxies, limiting the SN rate outside the nucleus (at greater than 15A radius) to less than 3.8 far-IR SN rate units (SNe per century per 1010 measured at 60 and 100 km, L _ or FIRSRU) at 90% conÐdence. The MIRC camera had insufficient resolution to search nuclear starburst regions, where starburst and SN activity is concentrated ; therefore, we were unable to rigorously test the hypothesis of high SN rates in heavily obscured star-forming regions. We conclude that highresolution nuclear SN searches in starburst galaxies with small Ðelds are more productive than lowresolution, large-Ðeld searches, even for our sample of large (often several arcminutes) galaxies. With our ORCA high-resolution optics, we could limit the total SN rate to less than 1.3 FIRSRU at 90% conÐdence in 3 years of observations, lower than most estimates.

The Probe of Inflation and Cosmic Origins (PICO) is a NASA-funded study of a Probe-class mission concept. The toplevel science objectives are to probe the physics of the Big Bang by measuring or constraining the energy scale of inflation, probe fundamental physics by measuring the number of light particles in the Universe and the sum of neutrino masses, to measure the reionization history of the Universe, and to understand the mechanisms driving the cosmic star formation history, and the physics of the galactic magnetic field. PICO would have multiple frequency bands between 21 and 799 GHz, and would survey the entire sky, producing maps of the polarization of the cosmic microwave background radiation, of galactic dust, of synchrotron radiation, and of various populations of point sources. Several instrument configurations, optical systems, cooling architectures, and detector and readout technologies have been and continue to be considered in the development of the mission concept. We will present a snapshot of the baseline mission concept currently under development.