Integral-field spectra of SuWt 2 were obtained during two observing runs in 2009 May and 2012 August with
the Wide Field Spectrograph (WiFeS; Dopita et al., 2007).
WiFeS is an image-slicing Integral Field Unit (IFU) developed and built for the ANU 2.3-m telescope at the Siding Spring Observatory, feeding a double-beam spectrograph. WiFeS samples 0.5 arcsec along each of twenty five arcsec
arcsec slits, which
provides a field-of-view of
arcsec
arcsec and a spatial resolution element of
arcsec
arcsec (or
for y-binning=2).
The spectrograph uses volume phase holographic gratings to provide a spectral resolution of
(100 kms
full width at half-maximum, FWHM),
and
(45 kms
FWHM) for the red and blue arms, respectively.
Each grating has a different wavelength coverage.
It can operate two data accumulation modes: classical and nod-and-shuffle (N&S).
The N&S accumulates both object and nearby sky-background data in either equal exposures or unequal exposures.
The complete performance of the WiFeS has been fully described by
Dopita et al. (2007); Dopita et al. (2010).
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Our observations were carried out with the B3000/R3000 grating combination and the RT560 dichroic using N&S mode in 2012 August; and
the B7000/R7000 grating combination and the RT560 dichroic using the classical mode in 2009 May. This covers
3300-5900 Å
in the blue channel and
5500-9300 Å
in the red channel.
As summarized in Table 1, we took two different WiFeS exposures from different positions of SuWt 2; see Fig. 1 (top).
The sky field was collected about 1 arcmin away from the object.
To reduce and calibrate the data, it is necessary to take the usual bias frames, dome flat-field frames, twilight sky flats, `wire' frames and arc calibration lamp frames.
Although wire, arc, bias and dome flat-field frames were collected during the afternoon prior to observing, arc and bias frames were also taken through the night. Twilight sky flats were taken in the evening.
For flux calibration, we also observed some spectrophotometric standard stars.
Field | 1 | 2 |
Instrument | WiFeS | WiFeS |
Wavelength Resolution | ![]() |
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Wavelength Range (Å) | 4415-5589, | 3292-5906, |
Wavelength Range (Å) | 5222-7070 | 5468-9329 |
Mode | Classical | N&S |
Y-Binning | 1 | 2 |
Object Exposure (s) | ![]() |
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Sky Exposure (s) | - | ![]() |
Standard Star | LTT3218 | LTT9491, |
HD26169 | ||
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Airmass | ![]() |
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Position (see Fig.1) | 13:55:46.2 | 13:55:45.5 |
Position (see Fig.1) | ![]() |
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Date (UTC) | 16/05/09 | 20/08/12 |