First Results with the ATCA 3mm Prototype System (10-Dec-2000)
Part 2: HCO+ absorption in the galaxy Centaurus A
The HCO+ spectra displayed below have been observed on December
10th, 2000, with the one baseline (CA03-CA04: 31m baseline, 1.5B array) 3mm
prototype system of the Australia
Telescope Compact Array.
- Original HCO+ absorption spectrum against the core of the
nearby radio galaxy Centaurus A.
The rest frequency of the HCO+ line is 89.188518 GHz. The
spectrum is centred on 89.030 GHz which corresponds to the systemic
velocity (approx. 550 km/s) of Cen A. The bandwidth is 32 MHz divided
into 128 channels. The integration time was two hours. No calibration
was applied.
- Here a preliminary gain and bandpass calibration of the above
HCO+ absorption spectrum has been attempted. Please note
that the velocity range covered in this narrow-band spectrum is
smaller than the total known absorption range. Consequently, only the
central absorption complex (537 - 560 km/s) is seen in detail. This
spectrum is Hanning smoothed.
- Further low and high resolution ATCA observations of Cen A will follow
soon (winter 2001). The largest bandwidth (about 180 MHz, divided into
90 channels ) will be used to study the overall spectrum, followed
by more detailed spectra. First imaging might be attempted with an
ATCA three baseline prototype system.
See also
21-03-2001 * Bärbel Koribalski