TY - JOUR TI - Herschel-SPIRE Fourier Transform Spectrometer observations of excited CO and [C I] in the Antennae (NGC 4038/39): warm and cold molecular gas IS - 2 ID - discovery10093776 N1 - This version is the version of record. For information on re-use, please refer to the publisher?s terms and conditions. Y1 - 2014/02/01/ JF - The Astrophysical Journal N2 - We present Herschel Spectral and Photometric Imaging Receiver (SPIRE) Fourier Transform Spectrometer (FTS) observations of the Antennae (NGC 4038/39), a well-studied, nearby (22 Mpc), ongoing merger between two gas-rich spiral galaxies. The SPIRE-FTS is a low spatial ( FWHM ~ 19''-43'') and spectral (~1.2 GHz) resolution mapping spectrometer covering a large spectral range (194-671 ?m, 450-1545 GHz). We detect five CO transitions (J = 4-3 to J = 8-7), both [C I] transitions, and the [N II] 205 ?m transition across the entire system, which we supplement with ground-based observations of the CO J = 1-0, J = 2-1, and J = 3-2 transitions and Herschel Photodetecting Array Camera and Spectrometer (PACS) observations of [C II] and [O I] 63 ?m. Using the CO and [C I] transitions, we perform both a local thermodynamic equilibrium (LTE) analysis of [C I] and a non-LTE radiative transfer analysis of CO and [C I] using the radiative transfer code RADEX along with a Bayesian likelihood analysis. We find that there are two components to the molecular gas: a cold (T kin ~ 10-30 K) and a warm (T kin gsim 100 K) component. By comparing the warm gas mass to previously observed values, we determine a CO abundance in the warm gas of x CO ~ 5 × 10?5. If the CO abundance is the same in the warm and cold gas phases, this abundance corresponds to a CO J = 1-0 luminosity-to-mass conversion factor of ?CO ~ 7 M ? pc?2 (K km s?1)?1 in the cold component, similar to the value for normal spiral galaxies. We estimate the cooling from H2, [C II], CO, and [O I] 63 ?m to be ~0.01 L ?/M ?. We compare photon-dominated region models to the ratio of the flux of various CO transitions, along with the ratio of the CO flux to the far-infrared flux in NGC 4038, NGC 4039, and the overlap region. We find that the densities recovered from our non-LTE analysis are consistent with a background far-ultraviolet field of strength G 0 ~ 1000. Finally, we find that a combination of turbulent heating, due to the ongoing merger, and supernova and stellar winds are sufficient to heat the molecular gas. KW - galaxies: individual (NGC 4038 KW - NGC 4039) KW - galaxies: interactions KW - infrared: galaxies KW - ISM: molecules KW - submillimeter: galaxies VL - 781 UR - https://doi.org/10.1088/0004-637X/781/2/101 A1 - Schirm, MRP A1 - Wilson, CD A1 - Parkin, TJ A1 - Kamenetzky, J A1 - Glenn, J A1 - Rangwala, N A1 - Spinoglio, L A1 - Pereira-Santaella, M A1 - Baes, M A1 - Barlow, MJ A1 - Clements, DL A1 - Cooray, A A1 - De Looze, I A1 - Karczewski, OL A1 - Madden, SC A1 - Rémy-Ruyer, A A1 - Wu, R AV - public ER -