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07Sep2004     NEWS: We've got LOTS OF galaxies!

ALFA detects galaxies beyond 10000 km/s in 1 sec!   Observations from the afternoon of 04 Sep 2004 showing the detection of UGC 9234 (cz~10900 km/s; an old friend of Wolfram) near record 425. It was detected by Beam 2, in mid-afternoon. The image displays 4096 frequency channels across the x-axis, with a channel separation of 25 kHz (about 5 km/s). Along the y-axis runs time, in seconds, along a 900 sec drift strip. The white vertical lines are, from left to right, respectively RFI, RFI and galactic HI. The fading of the map towards the edges is due to dropping sensitivity of the bandpass filter. The line profile on the right corresponds to the continuum emission seen by the beam (in this case Beam 5), along the declination strip.

The map was smoothed with a Gaussian 7 sec wide (FWHM) along the time direction and [0.25,0.5,0.25] Hanning along the spectral direction.

The line profile of UGC 9234 was averaged over one full beam in the time direction (15 sec). The flux units are of brightness temperature, in K. The abscissa is the spectrometer channel number.

Image Spectrum
ALFA detects lots of galaxies!   The map to the left shows the detection of NGC 672 (cz~500 km/s) near record 545 and of CGCG 482-017 (cz~10900), near record 565. The image displays 4096 frequency channels across the x-axis, with a channel separation of 25 kHz (about 5 km/s). Along the y-axis runs time, in seconds, along a 900 sec drift strip. The white vertical lines are, from left to right, respectively RFI, RFI, RFI and galactic HI. The fading of the map towards the edges is due to dropping sensitivity of the bandpass filter. The line profile on the right corresponds to the continuum emission as seen by the beam (in this case Beam 3), along the declination strip.

The similarly-constructed map to the right shows the detection of NGC 684 (cz~3500 km/s) near record 675. It was detected by Beam 5, during the same drift that also detected CGCG 482-017 (cz~10900) and NGC 672 (cz~400).

Both maps were smoothed with a Gaussian 7 sec wide (FWHM) along the time direction and [0.25,0.5,0.25] Hanning along the spectral direction.

Image image
First results!   Drift map across UGC 228 (cz=5600 km/s), obtained 22 Aug 2004, by members of the A1946 team at Arecibo: Riccardo Giovanelli, Lyle Hoffman, Martha Haynes, Barbara Catinella, Emmanuel Momjian and Erik Muller (with considerable help from our Cornell EGG friends in Ithaca, especially Brian Kent.)

(Left) Channel number-record number (frequency versus position) map. The galaxy is the feature at 400,550; it is easily visible in 1 second integration. The narrow arching feature is rfi. (Right) Spectrum of the galaxy (channel number versus normalized intensity in units of Tsys). The map and spectrum were produced before the end of the observing session (at 5am).

Image Spectrum


This page created and maintained by Martha Haynes.

Last modified: Fri Oct 29 18:26:57 EDT 2004