A dataset provided by the European Space Agency

Name HI_Q_GAL
Title EXCEPTIONS TO THE RADIO-INFRARED CORRELATION: RADIO-DEFICIENT GALAXIES
URL

http://nida.esac.esa.int/nida-sl-tap/data?RETRIEVAL_TYPE=OBSERVATION&PRODUCT_LEVEL=ALL&obsno=819016070

DOI https://doi.org/10.5270/esa-w3q3ior
Author Helou, G.
Description the ratio q of infrared to radio luminosity of galaxies dominated by star formation is a well-defined and universal quantity (helou et al. 1985; de jong et al. 1985). out of 550 galaxies brighter than 5 jy at 60um, only two objects, ngc 1377 and ic 1953, are characterized by a ratio q more than a factor of 10 and more than 6 sigma greater than the average value (condon et al. 1990). we propose to obtain photometry and spectroscopy with iso on these two objects to help determine why they are different, and thereby gain more insight into the physics of the basic radio-ir correlation. using iso data in combination with ground-based data we hope to discriminate between two hypotheses that might explain this singularly high ratio: (1) an abnormally weak interstellar magnetic field, or (2) that we happen to observe the galaxies at a privileged, very early epoch in a star-formation burst. hypothesis (1) predicts an interstellar medium dominated by low-density ionized and photo-dissociated regions (pdr), with little mass in the cold, dense molecular phase; hypothesis (2) predicts the reverse. the atomic fine-structure lines accessible to lws will yield physical parameters (density, pressure, t) for pdrs, while the ionic lines will probe the hii regions. long-wavelength pht photometry will yield the dust temperature distribution. these diagnostics will allow us to test the hypotheses above, both directly and by comparison with normal star forming galaxies observed under the guaranteed time programme.
Instrument CAM01 , LWS02
Temporal Coverage 1998-02-05T00:46:47Z/1998-02-12T01:07:19Z
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.
Creator Contact https://support.cosmos.esa.int/iso/
Date Published 1999-02-27T00:00:00Z
Publisher And Registrant European Space Agency
Credit Guidelines European Space Agency, Helou, G., 1999, HI_Q_GAL, 1.0, European Space Agency, https://doi.org/10.5270/esa-w3q3ior