Conditions in a black hole outburst The binary system V404 Cygni consists of a red giant star orbiting a black hole. In 2015, a surge of accretion by the black hole caused the surrounding plasma to brighten suddenly for the first time since 1989, briefly becoming the brightest x-ray source in the sky. Dallilar et al. combined observations from radio, infrared, optical, and x-ray telescopes taken during the outburst. They compared how fast the flux decayed at each wavelength, which allowed them to constrain the size of the emitting region, determine that the plasma within it cooled through synchrotron radiation, and measure the magnetic field around the black hole. Science , this issue p. 1299

URIS is a near-infrared (1 -2.5 microns) intermediate resolution spectrograph (R=1000-3000) with added capabilities for multi-slit, imaging, coronography, and polarimetry, built by the TAC to be a common in strument for the WHT (La Palma). Here we report the results of the two commissioning periods. The image quality was checked, obtaining a FWHM ofO".5 in the Ks band over the whole field ofview (4'.2 x 4'.2). Zero points and sky brightness were measured, and very low values were found in the latter. The long slit spectra obtained matched the expected spectral resolution ( 2.6 pixels for a O".65 -wide slit) Flexure tests were carried out with good results. Several science targets were observed, the most note-worthy result being the detection ofthe CIV 154.9 nm line in the most distant qso at z=6.41. ENTRODUCTIONThe study of the spectra of astronomical objects in the Near Infrared (NIR) has enormous scientific potential: by using NIR, the composition of the dust can be established, molecular hydrogen can be studied, and high redshift (z=1) galaxies whose main emission lines ofActive Galatic Nuclei (AGN) (for example, Ha) lie in the NIR region can also be observed. This kind of instrument can therefore be useful in a wide variety of fields1, from studies of the solar system, stellar physics or extragalactic astronomy to cosmology. However, working in this spectral region (1 -2.5 microns) is quite a challenge, posing several problems for the astronomer.Key points to consider when designing a NIR spectrograph include target acquisition and sky subtraction. Target acquisition is difficult due to the impossibility of using an optical slit view with a CCD, since on the one hand differential sky refraction causes the optical and infrared (IR) image to be shifted by several arcseconds (depending on the airmass), and on the other hand some sources are very red and therefore very weak in the optical image. Another factor to take into account is the strong sky emission in the NIR: for example, the sky emission in the Ks band is 13 magnitude per square arcseconds. The other key point is sky subtraction, as this spectral range is dominated by strong atmospheric OH emissin lines. In order to allow for proper sky subtraction, the design should minimize flexures which will shift the spectral lines. As an example, the user requirement of URIS allows maximum flexure of a few microns between the focal plane and the detector in the course of one hour of integration time. Regarding spectral resolution, in order to avoid the atmospheric OH lines, the optimal resolution is between 1000 and 3000.In February 1998 the IAC started the construction of URIS, a near infrared (NIR) spectrograph for the 4.2 m WHT on La Palma. The main goal of the design was to make it as simple as possible to ensure that the project could be completed within a fixed budget and schedule (which was actually achieved in the end), and at the same time achieve

Received (to be inserted by publisher); Revised (to be inserted by publisher); Accepted (to be inserted by publisher);The Canarias InfraRed Camera Experiment (CIRCE) is a near-infrared (1-2.5 micron) imager, polarimeter and low-resolution spectrograph operating as a visitor instrument for the Gran Telescopio Canarias 10.4-meter telescope. It was designed and built largely by graduate students and postdocs, with help from the UF astronomy engineering group, and is funded by the University of Florida and the U.S. National Science Foundation. CIRCE is intended to help fill the gap in near-infrared capabilities prior to the arrival of EMIR to the GTC, and will also provide the following scientific capabilities to compliment EMIR after its arrival: high-resolution imaging, narrowband imaging, high-time-resolution photometry, imaging polarimetry, low resolution spectroscopy. In this paper, we review the design, fabrication, integration, lab testing, and on-sky performance results for CIRCE. These include a novel approach to the opto-mechanical design, fabrication, and alignment.

We report on the design and status of the FLAMINGOS-2 instrument -a fully-cryogenic facility near-infrared imager and multi-object spectrograph for the Gemini 8-meter telescopes. FLAMINGOS-2 has a refractive all-spherical optical system providing 0.18-arcsecond pixels and a 6.2-arcminute circular field-of-view on a 2048x2048-pixel HAWAII-2 0.9-2.4 µm detector array. A slit/decker wheel mechanism allows the selection of up to 9 multi-object laser-machined plates or 3 long slits for spectroscopy over a 6x2-arcminute field of view, and selectable grisms provide resolutions from ~1300 to ~3000 over the entire spectrograph bandpass. FLAMINGOS-2 is also compatible with the Gemini Multi-Conjugate Adaptive Optics system, providing multi-object spectroscopic capabilities over a 3x1-arcminute field with high spatial resolution (0.09-arcsec/pixel). We review the designs of optical, mechanical, electronics, software, and On-Instrument WaveFront Sensor subsystems. We also present the current status of the project, currently in final testing in mid-2006.

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