neutral hydrogen 21 cm emission is observed in many late type spiral galaxies to extend far outside the optical disks. in addition, the rotation curves derived from the 21 cm line show in many such cases a constant rotational velocity persisting to large galactocentric radii, indicating the presence of large amounts of dark matter. besides the massive halo picture, another possible form of dark matter is the very cold gas and dust in the disk of the galaxy. we propose to search for the presence of very cold dust ( <15 k) in the outer parts of the disk of the ngc 5097 spiral galaxy. isophot has the capability to observe beyond the iras long-wave- length limit up to 240 microns and has an unprecedented sensitivi- ty in this waveband. furthermore, the combination of pht photometry in three wavebands, 180, 135, and 90 microns, enables us to eliminate the disturbing effects of warmer foreground dust (galactic cirrus) and to estimate the temperature of the very cold dust.
Instrument
PHT22
Temporal Coverage
1997-04-26T05:07:10Z/1997-04-26T10:32:46Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the world's first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
European Space Agency, 1999, Search For Very Cold Dust Outside The Optical Disks Of Galaxies, 1.0, European Space Agency, https://doi.org/10.5270/esa-bj26juz
