ALMA Observations of Warm Dense Gas in NGC 1614 --- Breaking of Star Formation Law in the Central kpc

We present ALMA Cycle-0 observations of the CO (6-5) line emission and of the 435um dust continuum emission in the central kpc of NGC 1614, a local luminous infrared galaxy (LIRG) at a distance of 67.8 Mpc (1 arcsec = 329 pc). The CO emission is well resolved by the ALMA beam (0.26 x 0.20) into a circum-nuclear ring, with an integrated flux of f_{CO(6-5)} = 898 (+-153) Jy km/s, which is 63(+-12)% of the total CO(6-5) flux measured by Herschel. The molecular ring, located between 100pc < r < 350pc from the nucleus, looks clumpy and includes seven unresolved (or marginally resolved) knots with median velocity dispersion of 40 km/s. These knots are associated with strong star formation regions with Sigma_{SFR} 100 M_sun/yr/kpc^{2} and Sigma_{Gas} 1.0E4 M_sun/pc^{2}. The non-detections of the nucleus in both the CO (6-5) line emission and the 435um continuum rule out, with relatively high confidence, a Compton-thick AGN in NGC 1614. Comparisons with radio continuum emission show a strong deviation from an expected local correlation between Sigma_{Gas} and Sigma_{SFR}, indicating a breakdown of the Kennicutt-Schmidt law on the linear scale of 100 pc.

Warm Molecular Gas in Luminous Infrared Galaxies

We present our initial results on the CO rotational spectral line energy distribution (SLED) of the $J$ to $J$$-$1 transitions from $J=4$ up to $13$ from Herschel SPIRE spectroscopic observations of 65 luminous infrared galaxies (LIRGs) in the Great Observatories All-Sky LIRG Survey (GOALS). The observed SLEDs change on average from one peaking at $J le 4$ to a broad distribution peaking around $J sim,$6$-$7 as the IRAS 60-to-100 um color, $C(60/100)$, increases. However, the ratios of a CO line luminosity to the total infrared luminosity, $L_{rm IR}$, show the smallest variation for $J$ around 6 or 7. This suggests that, for most LIRGs, ongoing star formation (SF) is also responsible for a warm gas component that emits CO lines primarily in the mid-$J$ regime ($5 lesssim J lesssim 10$). As a result, the logarithmic ratios of the CO line luminosity summed over CO (5$-$4), (6$-$5), (7$-$6), (8$-$7) and (10$-$9) transitions to $L_{rm IR}$, $log R_{rm midCO}$, remain largely independent of $C(60/100)$, and show a mean value of $-4.13$ ($equiv log R^{rm SF}_{rm midCO}$) and a sample standard deviation of only 0.10 for the SF-dominated galaxies. Including additional galaxies from the literature, we show, albeit with small number of cases, the possibility that galaxies, which bear powerful interstellar shocks unrelated to the current SF, and galaxies, in which an energetic active galactic nucleus contributes significantly to the bolometric luminosity, have their $R_{rm midCO}$ higher and lower than $R^{rm SF}_{rm midCO}$, respectively.

ALMA Observations of Warm Molecular Gas and Cold Dust in NGC 34

We present ALMA Cycle-0 observations of the CO (6-5) line emission (rest-frame frequency = 691.473 GHz) and of the 435$mu m$ dust continuum emission in the nuclear region of NGC 34, a local luminous infrared galaxy (LIRG) at a distance of 84 Mpc (1 = 407 pc) which contains a Seyfert 2 active galactic nucleus (AGN) and a nuclear starburst. The CO emission is well resolved by the ALMA beam ($rm 0.26times 0.23$), with an integrated flux of $rm f_{CO~(6-5)} = 1004; (pm 151) ; Jy; km; s^{-1}$. Both the morphology and kinematics of the CO (6-5) emission are rather regular, consistent with a compact rotating disk with a size of 200 pc. A significant emission feature is detected on the red-shifted wing of the line profile at the frequency of the $rm H^{13}CN; (8-7)$ line, with an integrated flux of $rm 17.7 pm 2.1 (random) pm 2.7 (sysmatic); Jy;km; s^{-1}$. However, it cannot be ruled out that the feature is due to an outflow of warm dense gas with a mean velocity of $rm 400; km; s^{-1}$. The continuum is resolved into an elongated configuration, and the observed flux corresponds to a dust mass of $rm M_{dust} = 10^{6.97pm 0.13}; M_{sun}$. An unresolved central core ($rm radius simeq 50; pc$) contributes $28%$ of the continuum flux and $19%$ of the CO (6-5) flux, consistent with insignificant contributions of the AGN to both emissions. Both the CO (6-5) and continuum spatial distributions suggest a very high gas column density ($rm >= 10^4; M_{sun}; pc^{-2}$) in the nuclear region at $rm radius <= 100; pc$.

Absolute Calibration and Characterization of the Multiband Imaging Photometer for Spitzer: IV. The Spectral Energy Distribution Mode

The Spectral Energy Distribution (SED) mode of the Multiband Imaging Photometer for Spitzer (MIPS) Space Telescope provides low-spectral resolution (R ~ 15-25) spectroscopy in the far infrared using the MIPS 70 um detector. A reflective grating provides a dispersion of 1.7 um per pixel, and an effective wavelength coverage of 52.8--98.7 um over detector rows 1-27. The final 5 detector rows are contaminated by second-order diffracted light and are left uncalibrated. The flux calibration is based on observations of MIPS calibration stars with 70 um flux densities of 0.5--15 Jy. The point-source flux calibration accuracy is estimated to be 10% or better down to about 0.5 Jy at the blue end of the spectrum and to 2 Jy near the red end. With additional uncertainties from the illumination and aperture corrections included, the surface brightness calibration of extended sources is accurate to ~15%. Repeatability of better than 5% is found for the SED mode through multiple measurements of several calibration stars.