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The dense gas in the largest molecular complexes of the Antennae: HCN and HCO+ observations of NGC 4038/39 using ALMA
- Publication Year :
- 2016
-
Abstract
- We present observations of the dense molecular gas tracers HCN, HNC, and HCO+ in the J=1-0 transition using ALMA. We supplement our datasets with previous observations of CO J=1-0, which traces the total molecular gas content. We separate the Antennae into 7 bright regions in which we detect emission from all three molecules, including the nuclei of NGC 4038 and NGC 4039, 5 super giant molecular complexes in the overlap region and 2 additional bright clouds. We find that the ratio of L(HCN)/L(CO), which traces the dense molecular gas fraction, is greater in the two nuclei (L(HCN)/L(CO) ~ 0.07 - 0.08) than in the overlap region (L(HCN)/L(CO) = 5% - 10% of the PDR surface heating to the total heating budget. Finally, the ratio of L(HCN)/L(HCO+) varies from ~1 in the nucleus of NGC 4038 down to ~0.5 in the overlap region. The lower ratio in the overlap region may be due to an increase in the cosmic ray rate from the increased supernova rate within this region.<br />Accepted to ApJ; 12 pages
- Subjects :
- 010504 meteorology & atmospheric sciences
0306 Physical Chemistry (Incl. Structural)
Milky Way
FOS: Physical sciences
Cosmic ray
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
Astronomy & Astrophysics
MASS
DIAGNOSTICS
01 natural sciences
STAR-FORMATION EFFICIENCY
0305 Organic Chemistry
Ion
PHOTON-DOMINATED REGIONS
0103 physical sciences
medicine
galaxies: interactions
Astrophysics::Solar and Stellar Astrophysics
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
0105 earth and related environmental sciences
Luminous infrared galaxy
Physics
Science & Technology
ORIGIN
galaxies: individual (NGC 4038, NGC 4039)
Astronomy and Astrophysics
NGC-4038/4039
LUMINOUS INFRARED GALAXIES
Astrophysics - Astrophysics of Galaxies
Galaxy
Charged particle
ISM: molecules
CO
Supernova
STARBURSTS
0201 Astronomical And Space Sciences
medicine.anatomical_structure
Space and Planetary Science
Astrophysics of Galaxies (astro-ph.GA)
Physical Sciences
Astrophysics::Earth and Planetary Astrophysics
Nucleus
galaxies: ISM
PROTOTYPICAL MERGER
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....03bace73df965afda61557ad70826d52