ALMA Maps of Dust and Warm Dense Gas Emission in the Starburst Galaxy IC 5179${}^{\star }$

Abstract

We present our high-resolution ($0^{\prime \prime }.15\times 0^{\prime \prime }.13$, $\sim$34 pc) observations of the CO(6-5) line emission, which probes the warm and dense molecular gas, and the 434 $\mu$m dust continuum emission in the nuclear region of the starburst galaxy IC 5179, conducted with the Atacama Large Millimeter Array (ALMA). The CO(6-5) emission is spatially distributed in filamentary structures with many dense cores and shows a velocity field that is characteristic of a circum-nuclear rotating gas disk, with 90% of the rotation speed arising within a radius of $\lesssim 150$ pc. At the scale of our spatial resolution, the CO(6-5) and dust emission peaks do not always coincide, with their surface brightness ratio varying by a factor of $\sim$10. This result suggests that their excitation mechanisms are likely different, as further evidenced by the Southwest to Northeast spatial gradient of both CO-to-dust continuum ratio and Pa-$\alpha$ equivalent width. Within the nuclear region (radius$\sim$300 pc) and with a resolution of $\sim$34 pc, the CO line flux (dust flux density) detected in our ALMA observations is $180\pm 18$ Jy km/s ($71\pm 7$ mJy), which account for 22% (2.4%) of the total value measured by Herschel.

Accepted for publication in ApJ

References in corpus (13)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, and Basic Results
• Molecular line emission in NGC1068 imaged with ALMA. I An AGN-driven outflow in the dense molecular gas
• The 0.4 < z < 1.3 star formation history of the Universe as viewed in the far-infrared
• Near-Infrared and Star-forming properties of Local Luminous Infrared Galaxies
• The Herschel Comprehensive (U)LIRG Emission Survey (HerCULES): CO Ladders, fine structure lines, and neutral gas cooling
• SMA Imaging of CO(3-2) Line and 860 micron Continuum of Arp 220 : Tracing the Spatial Distribution of Luminosity
• Understanding the 8 micron vs. Pa-alpha relationship on sub-arcsecond scales in Luminous Infrared Galaxies
• Warm Molecular Gas in Luminous Infrared Galaxies
• ALMA Observations of Warm Molecular Gas and Cold Dust in NGC 34
• Spatially resolved CO SLED of the Luminous Merger Remnant NGC 1614 with ALMA
• Around the Ring We Go: The Cold, Dense Ring of Molecular Gas in NGC 1614
• Morphology and Kinematics of Warm Molecular Gas in the Nuclear Region of Arp 220 as Revealed by ALMA
• The FUV to Near-IR Morphologies of Luminous Infrared Galaxies in the GOALS Sample

Cited by in corpus (1)

• Resolving the Interstellar Medium in Ultraluminous Infrared QSO Hosts with ALMA