IRAS Galaxy Atlas

Background Information

The High Resolution IRAS Galaxy Atlas (IGA) is an atlas of the far infrared emission (60 and 100 micron) from Galactic Plane (-4.7 to +4.7 degrees galactic latitude) plus the molecular clouds in Orion, Rho Oph and Taurus-Auriga produced using data from the Infrared Astronomical Satellite (IRAS). The IGA maps have 1'-2' resolution and provide a ten-fold improvement in areal information relative to the IRAS Sky Survey Atlas (ISSA). However, unlike the ISSA, the IGA does not contain any 12 or 25 micron data. These wavelengths were not processed as part of the generation of the IGA.

The IGA incorporates several important improvements from standard HIRES processing at IPAC. Foremost is improved destriping and zodiacal emission subtraction, which lead to reduced artifacts, better ability to discern low-surface-brightness features and the ability to mosaic images without edge discontinuities. The IGA is well suited to high-resolution studies of extended structure, and will be valuable for a wide range of scientific studies, including: the structure and dynamics of the interstellar medium (ISM); cloud core surveys within giant molecular clouds; detailed studies of HII regions and star-forming regions; determination of initial mass functions (IMFs) of massive stars; and study of supernova remnants (SNRs). The IGA will be especially useful for multi-wavelength studies using the many Galactic plane surveys that have similar (1') resolution.

The IGA images consist of maps made with 1 or 20 iterations of the HIRES algorithm, corresponding to no either non-linear processing (1 iteration), or to the maximum amount (20 iterations) of non-linear processing deemed to be reasonably free of artifacts. We emphasize that the spatial resolution within the maps varies with the details of the scan coverage for a particular area of the sky. The beam maps provided with each field are essential for assessing the angular resolution at various positions in the maps.

The IGA is arranged as a series of 1.4x1.4 deg FITS images (plates) with 15 arcsec resolution on 1 deg centers. Maps of molecular clouds are 2.5 deg in size on 2 deg centers.

Please refer to file IGA.ps for a full explanation of the atlas. TECHNICAL.ps deals with the technical aspects. Refer to software/besthires/README for instructions on running besthires. File 'field_centers' is an ASCII table file that contains the TYPE catalog, IRAS plate number and LON LAT center positions for all fields.