TY - JOUR AU - Greve, T.R. AU - Leonidaki, I. AU - Xilouris, E.M. AU - Weiß, A. AU - Zhang, Z.-Y. AU - Van Der Werf, P. AU - Aalto, S. AU - Armus, L. AU - Díaz-Santos, T. AU - Evans, A.S. AU - Fischer, J. AU - Gao, Y. AU - González-Alfonso, E. AU - Harris, A. AU - Henkel, C. AU - Meijerink, R. AU - Naylor, D.A. AU - Smith, H.A. AU - Spaans, M. AU - Stacey, G.J. AU - Veilleux, S. AU - Walter, F. T1 - Star formation relations and co spectral line energy distributions across the j-ladder and redshift LA - eng PY - 2014/10/20/ T2 - Astrophysical Journal SN - 1538-4357 VL - 794 IS - 2 PB - Institute of Physics Publishing AB - We present FIR [50-300μ m]-CO luminosity relations (i.e., logLFIR = a logL' CO + ß) for the full CO rotational ladder from J = 1-0up toJ = 13-12 for a sample of 62 local (z ≤ 0.1) (Ultra) Luminous InfraredGalaxies (LIRGs; LIR[8-1000μ m] > 1011 L?) using data from Herschel SPIRE-FTS and ground-based telescopes.We extend our sample to high redshifts (z > 1) by including 35 submillimeter selected dusty star forming galaxies from the literature with robust CO observations, and sufficiently well-sampled FIR/submillimeter spectral energy distributions (SEDs), so that accurate FIR luminosities can be determined. The addition of luminous starbursts at high redshifts enlarge the range of the FIR-CO luminosity relations toward the high-IR-luminosity end, while also significantly increasing the small amount of mid-J/high-J CO line data (J = 5-4 and higher) that was available prior to Herschel. This new data set (both in terms of IR luminosity and J-ladder) reveals linear FIR-CO luminosity relations (i.e., a ? 1) for J = 1-0 up to J = 5-4, with a nearly constant normalization (ß ~ 2). In the simplest physical scenario, this is expected from the (also) linear FIR-(molecular line) relations recently found for the dense gas tracer lines (HCN and CS), as long as the dense gas mass fraction does not vary strongly within our (merger/starburst)-dominated sample. However, from J = 6-5 and up to the J = 13-12 transition, we find an increasingly sublinear slope and higher normalization constant with increasing J. We argue that these are caused by a warm (~100 K) and dense (>104 cm-3) gas component whose thermal state is unlikely to be maintained by star-formation-powered far-UV radiation fields (and thus is no longer directly tied to the star formation rate). We suggest that mechanical heating (e.g., supernova-driven turbulence and shocks), and not cosmic rays, is the more likely source of energy for this component. The global CO spectral line energy distributions, which remain highly excited from J = 6-5 up to J = 13-12, are found to be a generic feature of the (U)LIRGs in our sample, and further support the presence of this gas component. DO - 10.1088/0004-637X/794/2/142 UR - https://portalcientifico.uah.es/documentos/61578fe3d3e35f5001a23c6a DP - Dialnet - Portal de la Investigación ER -