NOTcam WFC spectroscopy: first lightFor the first-light observations we chose an easy object, meaning lots of photons and clearly identifiable spectral features. On the evening of August 7, 2003, we observed the bright Be star 66 Ophiuchi (B2Ve, V=4.6). Be stars are rapidly rotating main-sequence B stars with strong recombination emission lines arising from a quasi-keplerian circumstellar disk. The origin of the disk is under great debate, but it is clear from abundant observations that the star feeds the disk, i.e. these disks are the opposite of accretion disks. Proposed mechanisms to feed the disk are non-radial pulsations, magnetic fields and stellar wind, all in combination with rapid stellar rotation.We used baffle-lamp flats for flatfielding and for the creation of a bad-pix map. In H and Ks bands we used the OH sky lines for wavelength calibration. The star was observed in an ABBA nodding pattern for J, H, K', Ks, and K with 20 second exposure time at each telescope position. For correction of telluric lines and fringes we used the F4V star HIP87860 (V=7.6, two offset exposures of 100s each). The spectra were optimally extracted.
J band Dispersed flat field obtained using the baffle lamp. The 5th order runs from the J cut-off around 1330 nm towards shorter wavelength at the top of the image. The 6th order runs from the bottom of the image to the J cut-on at around 1160 nm. The two orders overlap by about 100 pixels.
H band 100 sec H band exposure of HIP87860. Note that the sky lines are bent due to optical distortion. The straight horizontal lines are hot rows.
Ks band Ks band spectrum of HIP87860. Flat fielded, bad-pix corrected, and optimally extracted. The wavelength solution was obtained from OH skylines.
Last updated Aug 2003 John Telting |
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