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Simultaneous-color Wide-field Infrared Multi-object Spectrograph, or SWIMS, is an imager and multi-object spectrograph in the NIR wavelength of 0.9--2.5 $&u;m. The major feature is simultaneous two-color observing capability using two optical arms (blue=0.9--1.40 μm and red=1.45--2.5 μm). It provides us
both with a single exposure.
| SWIMS | Component Assembly |
 |  |
The field of view (FoV) of the telescope is covered with two HAWAII-2RG focal plane arrays . Gaps between arrays are ∼ 2.3 mm or ∼ 130 pixels.
| Imag. FoV | 6.6' × 3.3' |
| Spec. FoV | 2.8' × 3.3' |
| # of arrays per arm | 2 (4096 × 2048 pixels) |
| Pixel scale (arcsec/pix) | 0.095 |
| Array configuration |   |
Light-shaded regions show the FoV for the imaging mode while dark-shaded regions for the spectroscopy mode (for full range of spectra).
Black dots represent positions of source in the imaging mode which are also equivalent to the spectral positions of undeviated wavelength (λ ∼ 1.027 μm for blue, ∼ 1.734 μm for red).
Each stripe indicates the full range of the spectrum obtained (from shorter on the left to longer wavelength on the right). Note that any optical aberrations are not considered which would make the spectrum slightly broaden.
| Blue (0.9-1.4 μm) | Red (1.4-2.5 μm) | |
| Broad-band | Y (λc=1.03, Δλ=0.09), J (1.25, 0.16) | H (1.64, 0.30), Ks (2.14, 0.32) |
| Medium-band | J1 (1.17, 0.13), J2 (1.29, 0.12) | H1 (1.50, 0.12), H2 (1.61, 0.11), H3 (1.73, 0.12), K1 (2.02, 0.14), K2 (2.17, 0.14), K3 (2.31, 0.13) |
| Narrow-band | NB1244# (1.244, 0.012), NB1261# (1.261, 0.012), Paβ (1.292, 0.040), Paβ-off (1.326, 0.034) | NB1630# (1.630, 0.016), NB1653# (1.653, 0.016), Paα (1.875, 0.020), Paα-off (1.945, 0.040), NB2137# (2.137, 0.021), NB2167# (2.167, 0.021) |
| Grism | zJ (2.40 Å/pix, R ∼ 700-1200 w/ 0.5" slit) | HKs (4.57 Å/pix, R ∼ 600-1000 w/ 0.5" slit) |
Filters followed by "#" are those for SWIMS-18 survey.
Requests for use for any other purpose will be also welcomed.
| Transmission curves |
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ASCII data for each filter transmittance will be available soon. Please contact us for urgent use.
The cryogenic storage called the carousel have 23 slots for night observations. Of them, several kinds of engineering-use masks and long-slit masks (one slot each), and one IFU module (occupying two slots) will be exclusively assigned. Other (∼ 15) slots can be used for users' MOS masks.
The time required to exchange from one mask to another is about 2.5 minutes (and additional 5 seconds/slot to rotate the carousel). The time for target acquisition will be measured on the telescope during engineering nights.
Note that the Integral Field Spectroscopy Unit (IFU) is not available in S21A.
We utilize an ASIC, called SIDECAR, and its interface board, JADE-2, which control all of readout functions, to efficiently operate Teledyne HAWAII-2RG 2048 × 2048 HgCdTe infrared array.
Under cryogenic condition (∼ 77K), the detector performance has been assessed, as listed below.
| Minimum Exposure Time | 1.48 sec |
| Dark Current | < 0.05 e-/sec/pix |
| Readout Noise | ∼ 20--25 e- (CDS) ∼ 3--5 e- (32 Fowler) |
Integrated performance (e.g., simulateneous control of multiple arrays, influences of other peripherals on readout noise, etc.) is currently being investigated.
Total throughput including the telescope is estimated to be ∼ 0.4 for imaging and ∼ 0.3 for spectroscopy.
Expected sensitivities (AB mag) on the Subaru telescope are calculated with assumptions of seeing size=0.5 arcsec (photometry aperture radius=0.5 arcsec for point source or spatial extent=5.0 arcsec for extended source), exposure time=1 hr, and S/N=5.
| Point source (mag) | Y=24.9, J=24.8, H=24.6, Ks=24.5 |
| Extended source (mag/arcsec2) | TBW |
| Point source (mag) | J=20.9, H=20.5, Ks=20.6 |
| Extended source (mag/arcsec2) | TBW |
