[Previous] | [Session 40] | [Next]
R. J. Allen (STScI), B.W. Holwerda (Kapteyn/STScI), R.A. Gonzalez (UNAM), P.C. van der Kruit (Kapteyn)
The opacity of spiral disks can in principle be determined from the numbers of field galaxies seen through it. To calibrate the numbers found, Gonzalez (1998) and Holwerda (2004) used the "Synthetic Field Method", where the relation between extinction and the numbers of field galaxies is found from a series of simulated fields, essentially dimmed Hubble Deep Fields added to the original data. This calibrates the crowding and confusion unique to each disk field.
From earlier studies using occulting galaxies, it is suspected that the spiral arms are a much more opaque region of the spiral disk. We have applied the "Synthetic Field Method" on a sample of 30 deep HST/WFPc2 archival fields. Here we present our results for the average opacities of arm and inter-arm regions derived from the calibrated numbers of field galaxies seen in these regions.
[Previous] | [Session 40] | [Next]
Bulletin of the American Astronomical Society, 36 #2
© YEAR. The American Astronomical Soceity.