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Date and Time of the Query: 2019-06-16 T20:27:51 PDT
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For refcode 2003ApJ...588..771Y:
Retrieve 60 NED objects in this reference.
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2003ApJ...588..771Y CO Molecular Gas in Infrared-luminous Galaxies Lihong Yao, E. R. Seaquist, Nario Kuno, and Loretta Dunne Abstract. We present the first statistical survey of the properties of the^12^CO(1-0) and^12^CO(3-2) line emission from the nuclei of a nearly complete subsample of 60 infrared (IR) luminous galaxies selected from SCUBA Local Universe Galaxy Survey (SLUGS). This subsample is flux limited at S_60{mu}m_ >= 5.24 Jy with far-IR (FIR) luminosities mostly at L_FIR_>10^10^ L_sun_. We compare the emission line strengths of^12^CO(1-0) and (3-2) transitions at a common resolution of ~15". The measured^12^CO(3-2) to (1-0) line intensity ratios r_31_ vary from 0.22 to 1.72, with a mean value of 0.66 for the sources observed, indicating a large spread of the degree of excitation of CO in the sample. These CO data, together with a wide range of data at different wavelengths obtained from the literature, allow us to study the relationship between the CO excitation conditions and the physical properties of gas/dust and star formation in the central regions of galaxies. Our analysis shows that there is a nonlinear relation between CO and FIR luminosities, such that their ratio L_CO_/L_FIR_ decreases linearly with increasing L_FIR_. This behavior was found to be consistent with the Schmidt law relating star formation rate to molecular gas content, with an index N=1.4+/-0.3. We also find a possible dependence of the degree of CO gas excitation on the efficiency of star-forming activity. Using the large velocity gradient (LVG) approximation to model the observed data, we investigate the CO-to-H_2_ conversion factor X for the SLUGS sample. The results show that the mean value of X for the SLUGS sample is lower by a factor of 10 compared to the conventional value derived for the Galaxy, if we assume the abundance of CO relative to H_2_, Z_CO_=10^-4^. For a subset of 12 galaxies with H I maps, we derive a mean total face-on surface density of H_2_+HI of about 42 M_sun_ pc^-2^ within about 2 kpc of the nucleus. This value is intermediate between that in galaxies like our own and those with strong star formation. ########################################################################### 2003ApJ...597.1271Y Erratum: ``CO Molecular Gas in Infrared Luminous Galaxies'' (ApJ, 588, 771 [2003]) Yao, Lihong; Seaquist, E. R.; Kuno, Nario; Dunne, Loretta Abstract In the original paper, the sentence in the first paragraph of section 3.2 ``For conversion to absolute luminosities, the value of ?b=1.1x10-3 sr'' should read ``For conversion to absolute luminosities, the value of ?b=5.6x10-9 sr.'' In the original paper (item 3 of the list in the conclusion), the phrase ``are modeled using the LVG method to estimate that the CO-to-H2 conversion factor lies between 2.7x1019 and 6.6x1019 cm-2 (K km s-1)-1 for SLUGS galaxies'' should be ``are modeled using the LVG method to estimate that the CO-to-H2 conversion factor lies between 1.3x1019 and 6.7x1019 cm-2 (K km s-1)-1 for SLUGS galaxies, which is about 4-20 times lower than the conventional X derived from the Galaxy.'' Keywords: Errata, Addenda ###########################################################################
Retrieve 60 NED objects in this reference.
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