CO Lines as H2 Mass Estimators, Energy Source and SF Mode Indicators----中国科学院紫金山天文台

Seminar Title	CO Lines as H2 Mass Estimators, Energy Source and SF Mode Indicators
Speaker:	Prof. Padelis P. Papadopoulos
Affiliation:	（Max-Planck-Institut fur Radioastronomie）

When:	Friday morning, Aug. 31st，10:00 a.m
Where:	Room 619, Office Block, 2 West Beijing Road (PMO, CAS)

	Welcome to Attend

	( PMO Academic Committee & Academic Circulating committee)

Abstract　　
I will present results from a large extragalactic CO, 13CO and HCN multi-J line survey of Luminous Infrared Galaxies conducted with the James Clerk Maxwell Telescope (JCMT) in Hawaii (USA), the IRAM 30-m telescope in Granada (Spain), and expanded in Space using the Herschel Space Observatory (HSO). Analysis of complete CO Spectral Line Energy Distributions J=1--0 up to J=13--12 and the rest of the molecular lines strongly points to two major paradigm shifts: 1) Photon-dominated Regions (PDRs) are not the main power source of high-J CO line emission in (U)LIRGs (Ultra-luminous LIRGs with L_IR>10^{11} Lsol) nor they are the main repository of their molecular gas mass 2) The low-J CO lines are inappropriate to obtain the total molecular gas or to discern the star formation mode of LIRGs (merger versus disk). A serious implication is the underestimate of the H2 mass in LIRGs by up to factors of 5.