Interpreting millimeter emission from IMEGIN galaxies NGC 2146 and NGC 2976
2 IAP - Institut d'Astrophysique de Paris
3 LAGRANGE - Joseph Louis LAGRANGE
4 Cardiff University
5 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
6 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
7 UGENT - Universiteit Gent = Ghent University = Université de Gand
8 LAM - Laboratoire d'Astrophysique de Marseille
9 NEEL - HELFA - Hélium : du fondamental aux applications
10 IRAM - Institut de RadioAstronomie Millimétrique
11 NEEL - Cryo - Cryogénie
12 UNIROMA - Università degli Studi di Roma "La Sapienza" = Sapienza University [Rome]
13 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble
14 CAB - Centro de Astrobiologia [Madrid]
15 IAS - Institut d'astrophysique spatiale
16 IRAP - Institut de recherche en astrophysique et planétologie
17 NOA - National Observatory of Athens
18 ANL - Argonne National Laboratory [Lemont]
19 IRAM - Instituto de RadioAstronomía Milimétrica
20 LERMA - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres
21 Université de Liège
22 University of Leeds
23 Astrophysique
24 University of Pennsylvania
25 IPNL - Institut de Physique Nucléaire de Lyon
- Fonction : Auteur
- PersonId : 739002
- IdHAL : anthony-jones
- ORCID : 0000-0003-0577-6425
- IdRef : 066974550
- Fonction : Auteur
- PersonId : 175352
- IdHAL : nathalie-ysard
- ORCID : 0000-0003-1037-4121
- IdRef : 134281020
Résumé
The millimeter continuum emission from galaxies provides important information about cold dust, its distribution, its heating, and its role in the 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 at angular resolutions of < 18″ 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 the Spitzer, Herschel, Planck, WSRT, and the 100 m Effelsberg telescopes, we modeled 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 the 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 (β = 1.3 ± 0.1) compared to the starburst galaxy (β = 1.7 ± 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 ± 0.001 in the dwarf galaxy. In addition, there is no global balance 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.
Domaines
Astrophysique [astro-ph]Origine | Fichiers éditeurs autorisés sur une archive ouverte |
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