“School of Astronomy”
Back to Papers HomeBack to Papers of School of Astronomy
| Paper IPM / Astronomy / 17945 |
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Abstract: | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
The millimeter continuum emission from galaxies provides important information about cold dust, its distribution, heating, and role in their
InterStellar Medium (ISM). This emission also carries an unknown portion of the free-free and synchrotron radiation. The IRAM 30 m Guaranteed
Time Large Project, Interpreting Millimeter Emission of Galaxies with IRAM and NIKA2 (IMEGIN) provides a unique opportunity to study
the origin of the millimeter emission on angular resolutions of < 18�???�??�?�â?�???�??�?�ò�???�??�?�â?�???�??�?�ò in a sample of nearby galaxies. As a pilot study, we present millimeter
observations of two IMEGIN galaxies, NGC 2146 (starburst) and NGC 2976 (peculiar dwarf) at 1.15 mm and 2 mm. Combined with the data taken
with Spitzer, Herschel, Plank, WSRT, and the 100 m Effelsberg telescopes, we model the infrared-to-radio Spectral Energy Distribution (SED) of
these galaxies, both globally and at resolved scales, using a Bayesian approach to 1) dissect different components of the millimeter emission, 2)
investigate the physical properties of dust, and 3) explore correlations between millimeter emission, gas, and Star Formation Rate (SFR). We find
that cold dust is responsible for most of the 1.15 mm emission in both galaxies and at 2 mm in NGC 2976. The free-free emission emits more
importantly in NGC 2146 at 2 mm. The cold dust emissivity index is flatter in the dwarf galaxy (�????�???�??�?�ò = 1.3 �????�???�??�?�ñ 0.1) compared to the starburst galaxy
(�????�???�??�?�ò = 1.7 �????�???�??�?�ñ 0.1). Mapping the dust-to-gas ratio, we find that it changes between 0.004 and 0.01 with a mean of 0.006 �????�???�??�?�ñ 0.001 in the dwarf galaxy.
In addition, no global balance holds between the formation and dissociation of H2 in this galaxy. We find tight correlations between the millimeter
emission and both the SFR and molecular gas mass in both galaxies.
Download TeX format |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| back to top | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
