Infrared Space Observatory Mapping of 60 Micron Dust Emission around Vega-Type Systems: Erratum

Abstract

In the Letter ``Infrared Space Observatory Mapping of 60 Micron Dust Emission around Vega-type Systems'' by S. B. Fajardo-Acosta, R. E. Stencel, and D. E. Backman (ApJ, 487, L151 [1997]), there is an error in the equatorial coordinates that we assigned to our maps. Using preliminary versions of the PHOT Interactive Analysis (PIA) program, we incorrectly labeled the PHOT C-100 array axes as if they were aligned with equatorial coordinates. We rereduced our PHOT maps with a more recent version of PIA, version 6.3. The orientation of the C-100 array relative to equatorial coordinates, unique to each mapping observation, is now properly taken into account. This orientation is indicated by the scan direction vector plotted in Figures 2a (α PsA) and 2b (α Boo) of our Letter.

The scan direction of the map of γ Oph, in which we found hints of extended emission (Figs. 1c and 1d of our Letter), is along P.A. 184°, very close to the scan direction of the map of α Boo (P.A. 186°). Therefore, the one-dimensional profile cuts in these maps should be reinterpreted as hinting at extended emission being present north and south of γ Oph.

Below we show a corrected version of Figure 2 of our Letter. The maps of α PsA (Fig. 2a) and α Boo (Fig. 2b) are now properly rotated relative to equatorial coordinates. The morphology of these maps is slightly different from that of our Letter. The reason is that the point-spread function model from α Boo is now rotated relative to the map of α PsA by the difference in the scan directions of these two maps (29° clockwise).

Corrected Figure 2a shows that the inferred disk around α PsA is aligned nearly north-south, or 12^deg+/-13^deg west of north. This orientation is consistent with previous inferences from 60 μm IRAS scans by F. C. Gillett (in Light on Dark Matter, ed. F. P. Israel [Dordrecht: Reidel], 61 [1986]), which suggested that extended emission was present along 29° west of north. A recent 850 μm image of α PsA by W. S. Holland et al. (Nature, 392, 788 [1998]) shows extended emission along 18^deg+/-4^deg west of north, thus also consistent with our corrected measurement.