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Astron. Astrophys. 364, L36-L41 (2000)

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2. Observations

Spectroscopic observations were carried out with FORS1 1 at VLT/UT1 in longslit mode on 1999 June 14-15 at a median seeing of [FORMULA]. A Tek [FORMULA] CCD with a pixel size of [FORMULA] and a spatial resolution of [FORMULA] pix-1 was used for the measurements. Grism GRIS_600B+12 was chosen for the blue and GRIS_600R+14 for the red spectral region, yielding a wavelength coverage of 3500-5900Å and 5250-7400Å, respectively. The slit length of FORS1 is [FORMULA] and the selected slit width of [FORMULA] gives an average resolution of 5.9Å for the red and 6.2Å for the blue grism, respectively. Our slit covers large filamentary structures of H[FORMULA] emission in the NE and SW halo (Fig. 1). For each grism the total integration time amounted to 3 hours, reaching a noise level of [FORMULA] ergs cm-2 s- 1 Å-1 pix-1. Data reduction was performed in the usual manner using standard IRAF software while the analysis was done within the MIDAS environment.

[FIGURE] Fig. 1. Continuum subtracted H[FORMULA] image of NGC 5775 obtained with EMMI at the NTT. H[FORMULA]-contours shown for the disk reveal that s1 covers a gap of H[FORMULA] emission in the disk, cutting also through the NE and SW filament.

Maps of total power and the linearly polarized radio-continuum emission of NGC 5775 at 1.49 GHz and 4.86 GHz have been obtained from archive data of the Very Large Array (VLA) of the National Radio Astronomy Observatory (NRAO 2). All data were recorded during 1989 - 1994. The total observation time used on source was about 10 hours at 4.86 GHz (D-array), 14 hours at 1.49 GHz with C-array, and 2.5 hours with D-array. Data reduction has been performed with the AIPS software package following standard procedures. The r.m.s. noise obtained in the final maps is 16 µJy/b.a. and 100 µJy/b.a. in total power, and 7 µJy/b.a. and 25 µJy/b.a. in polarized intensity at 4.86 GHz and 1.49 GHz, respectively.

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© European Southern Observatory (ESO) 2000

Online publication: December 15, 2000
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