FLAMINGOS-2 uses a Teledyne HAWAII-2 array with 2048x2048 pixels. Unlike more recent versions such as the HAWAII-2RG, the detector in FLAMINGOS-2 does not offer on-detector arithmetics such as image coadds before readout.
FLAMINGOS-2 currently contains three grisms (located in the grism wheel; see the FLAMINGOS-2 optomechanical diagrams). When used with a 2-pixel slit (0.36"), the two moderate-resolution grisms, JH and HK, have a 2-pixel slit maximum resolving power R = λ/dλ ~1250, at the center of each spectral range.
FLAMINGOS-2 covers a circular 6.1 arcmin field with an average plate scale of about 0.179 arcsec / pixel. We present here:
Two types of spectroscopy are possible with FLAMINGOS-2 and its selection of gratings:
The values in these tables are based on results from the FLAMINGOS-2 Integration Time Calculator and from the early commissioning runs. They assume 70-percentile (IQ70, ~average) image quality for all categories, photometric conditions (CC50), and an airmass of less than 1.2 for the sensitivites presented here.
Two guiding options are available, the F2 On-Instrument Wavefront Sensor (OIWFS) and the telescope's Peripheral Wavefront Sensors (PWFSs). In a nutshell, the PWFS covers a larger range and has a higher probability of finding a suitably bright guide star. However, it also causes severe vignetting of the field, which can impact imaging observations. The OIWFS has a smaller patrol field, but offers minimal vignetting. The OIWFS has experienced several mechanical faults in the past and may be unavailable.
Nifty4Gemini is a Python based data reduction pipeline for the Gemini North Near-Infrared Integral Field Spectrometer (NIFS) that uses the Gemini IRAF Package. The detailed information can be find here: Nifty4Gemini's documentation.
In the four sections of this form, select the appropriate astronomical source, telescope and instrument configuration, observing conditions, and observation parameters.
This section contains instructions for configuring NIFS at phase II. It is organized as follows:
This page brings together information that might affect decisions on observing strategy in various NIFS observing modes, and provides guidelines/tips to maximize observing efficiency and avoid some common errors. The other NIFS web pages also give information about what to expect from the instrument. For information about actually setting up observations in the Observing Tool, please see the Observation Preparation section of these pages.
R~5000 infrared IFU spectroscopy at AO resolutions using the 0."2 or 0."5 occulting disks for coronagraphic measurements is available. The best performance is achieved in the H and K bands. Coronagraphy can be carried out with or without ALTAIR's field lens, and with or without a NIFS OIWFS guide star. However, for best results, use of the field lens and OIWFS is recommended (OIWFS is currently not available).
Current estimates are that the overheads associated with each new science target (for target acquisition, telescope, WFS and instrument re-configuration etc) depend upon the guide configuration chosen for the observation.
Setup times for various observation types are:
Like all Gemini facility instruments, NIFS is operated through the Gemini observing tool (OT). This page guides you through the main steps and considerations for configuring NIFS observations in the OT.
To speed up acceptance of your phase II file so that your program can be scheduled, observed, you may wish to consider the following checklist. When setting up your program in the OT, please also consult the NIFS observing strategies section and download and look at the example observations in the OT libraries.
Near-IR calibrations are discussed in detail on the general Near-IR Resources page, as they are generally similar for NIFS and Gemini's other NIR instruments.
Note that when selecting telluric standard stars, an accurate airmass match is often critical.
The table below summarises the NIFS detector properties. Additional important information on the detector array is given below.
Below is a table of central wavelengths and spectral coverage of the four filters available for NIFS. The Gemini filter IDs are given in the table and transmission curves (and electronic transmission data) can be displayed or downloaded. In practice the wavelength coverage of NIFS data also depends on the grating efficiency and the wavelength cut-off of the detector.
NIFS has four gratings physically mounted in the dewar which are briefly described in the tables below, the first table gives the standard grating properties. It also states the defaultconfigurations of grating choice which is used in conjunction with a dual blocking filter, one ofZ-J, J-H, or H-K for Z and J, H, and K gratings, respectively.
NIFS offsers ZJHK coronagraphy with 0".2 and 0".5 occulting masks. While an 0".1 occulting mask is available it is not currently offered.
R~5000 infrared IFU spectroscopy at AO resolutions using the 0."2 or 0."5 occulting disks for coronagraphic measurements is available. The best performance is achieved in the H and K bands. Coronagraphy can be carried out with or without ALTAIR's field lens, and with or without a NIFS OIWFS guide star.
The following sensitivity table provides signal-to-noise ratios (S/N) of 5 per spectral pixel in one hour (6 x 600 seconds) on-source integration. They were estimated using the NIFS Integration Time Calculator (ITC) and the obtained S/N of 5 is the averaged S/N in the wavelength intervals. These values are for silver coatings on the telescope optics and NIFS on the up-looking port, and the lowest-read noise mode was assumed (~6 e- at 77 K).
NIFS has a number of different guiding options, which can be summarized as follows:
This section describes the format of and some features associated with NIRI data. More detailed information on reduction of NIRI data accompanies the NIRI IRAF package.
This page describes NIRI data and its reduction:
The GNAAC detector controller in NIRI and GNIRS sometimes superimposes vertical striping, horizontal banding, and quadrant offsets on the data. The "cleanir" python routine can remove many of these artifacts. Run the script with no arguments to see the full help.
NIRLIN should be used to linearize all science data. This version uses three coefficients to correct for non-linearity in the NIRI detector: an exposure time correction, a counts squared term, and a counts cubed term. These coefficients are dependent on the read mode and detector ROI. We have currently derived coefficients for the following configurations:
The NIRI Integration Time Calculator (ITC) can be used to determine limiting magnitudes, exposure times, S/N ratios, background levels, etc. for a wide range of source properties, observing conditions, and NIRI configurations. at present in imaging mode only, either using a natural guide star or the laser guide star).
The following five tables provide various exposure time limits. Constraints are due to a number of factors, more than one of which may need to be considered for a given NIRI configuration:
Table 1: Minimum Recommended Exposure Times (sec)