Highly-excited CO emission in APM 08279+5255 at z = 3.9

By A. Weiss, D. Downes, R. Neri, F. Walter, Christian Henkel, D. Wilner, J. Wagg, T. Wiklind. 2007

202 citations recorded by the source corpus.

We report the detection of the CO 4–3, 6–5, 9–8, 10–9, and 11–10 lines in the Broad Absorption Line quasar APM 08279+5255 at $z=3.9$ using the IRAM 30 m telescope. We also present IRAM PdBI high spatial resolution observations of the CO 4–3 and 9–8 lines, and of the 1.4 mm dust radiation as well as an improved spectrum of the HCN(5–4) line. Unlike CO in other QSO host galaxies, the CO line SED of APM 08279+5255 rises up to the CO(10–9) transition. The line fluxes in the CO ladder and the dust continuum fluxes are best fit by a two component model, a “cold” component at ~$ 65$ K with a high density of n (H 2 ) = 1$\times$10 5 cm -3 , and a “warm”, ~$ 220$ K component with a density of 1$\times$10 4 cm -3 . We show that IR pumping via the 14 $\mu{\rm m}$ bending mode of HCN is the most likely channel for the HCN excitation. From our models we find, that the CO(1–0) emission is dominated by the dense gas component which implies that the CO conversion factor is higher than usually assumed for high- z galaxies with $\alpha \approx$ 5$ M_{\odot}$ (K km s -1 pc 2 ) -1 . Using brightness temperature arguments, the results from our high-resolution mapping, and lens models from the literature, we argue that the molecular lines and the dust continuum emission arise from a very compact ( r ≈ 100-300 pc), highly gravitationally magnified ($ m = 60{-}110$) region surrounding the central AGN. Part of the difference relative to other high- z QSOs may therefore be due to the configuration of the gravitational lens, which gives us a high-magnification zoom right into the central 200-pc radius of APM 08279+5255 where IR pumping plays a significant role for the excitation of the molecular lines.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/b0647ac6861c8c4bee967bb00d0a9b198948a4e1

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Citations in the corpus

THE SCUBA-2 COSMOLOGY LEGACY SURVEY: ALMA RESOLVES THE REST-FRAME FAR-INFRARED EMISSION OF SUB-MILLIMETER GALAXIES (2014, background): “…from 12CO emission lines across a range of rotational transitions, from J = 2–1 to 7–6, and we note that there is ongoing debate over whether emission from different transitions traces the same molecular gas (Weiß et al. 2007; Panuzzo et al. 2010; Bothwell et al. 2013; Narayanan & Krumholz 2014).”
ALMA REDSHIFTS OF MILLIMETER-SELECTED GALAXIES FROM THE SPT SURVEY: THE REDSHIFT DISTRIBUTION OF DUSTY STAR-FORMING GALAXIES (2013, methodology): “The dust temperature is better derived using the source structural information that will be available with lens models based on high spatial resolution ALMA observations (Hezaveh et al. 2013), which will help constrain the dust opacity (e.g., Weiß et al. 2007).”
Cool Gas in High-Redshift Galaxies (2013, background): “For APM0827+5255, strong emission from very high order transitions is seen (Weiß et al. 2007a; Riechers et al. 2010c).”
OBSERVATIONS OF Arp 220 USING HERSCHEL-SPIRE: AN UNPRECEDENTED VIEW OF THE MOLECULAR GAS IN AN EXTREME STAR FORMATION ENVIRONMENT (2011, background): “There is also evidence for IR pumping of higher-J HCN lines in the host galaxy of the z = 3.91 quasar APM 08279+5255 (Riechers et al. 2010; Weiß et al. 2007).”
A MASSIVE MOLECULAR GAS RESERVOIR IN THE z = 5.3 SUBMILLIMETER GALAXY AzTEC-3 (2010, methodology): “We adopted a CO abundance per velocity gradient of [CO]/(dv/dr) = 1 × 10−5 pc ( km s−1)−1 (e.g., Weiß et al. 2005, 2007; Riechers et al. 2006).”
Star-formation laws in luminous infrared galaxies. New observational constraints on models (2011, background): “In addition, non-collisional excitation could also be responsible for the surprising strength of HCN lines in some IR luminous systems (e.g.; Aalto et al. 1995; Garcı́a-Burillo et al. 2006; Guélin et al. 2007; Weiß et al.2007).”
MOLECULAR GAS IN z ∼ 6 QUASAR HOST GALAXIES (2010, background): “The high-order CO transitions (J ≥ 5) detected in SMGs and high-redshift quasars are usually not thermalized (e.g., Weiß et al. 2005a, 2007; Riechers et al. 2009).”
ALMA IMAGING OF GAS AND DUST IN A GALAXY PROTOCLUSTER AT REDSHIFT 5.3: [C ii] EMISSION IN “TYPICAL” GALAXIES AND DUSTY STARBURSTS ≈1 BILLION YEARS AFTER THE BIG BANG (2014, background): “The gas excitation in AzTEC-3, however, is lower than in quasar host galaxies, where the active galactic nucleus (AGN) may contribute to the excitation of high-level CO lines (e.g., Riechers et al. 2006, 2009, 2011c; Weiß et al. 2007).”
The Relationship between Molecular Gas Tracers and Kennicutt-Schmidt Laws (2007, background): “…et al. (2007) note, however, that in the three systems for which the contribution from the AGN has been estimated (F10214+4724, D. Downes & P. Solomon 2007, in preparation; Cloverleaf, Weiß et al. 2003; APM 08279+5255, Weiß et al. 2005, 2007) the corrections are only significant for APM 08279+5255.”
Dusty Star Forming Galaxies at High Redshift (2014, result): “This is in contrast with high-z quasar host galaxies, which can typically bemodeled as dominated by a single high-excitation gas component (e.g. Riechers et al., 2011a; Weiß et al., 2007).”
GAS AND DUST IN A SUBMILLIMETER GALAXY AT z = 4.24 FROM THE HERSCHEL ATLAS (2011, methodology): “As in Weiß et al. (2007), we adopt a CO abundance per velocity gradient of [CO]/(dv/dr) = 10−5 pc (km s−1)−1 that best fits the high-J lines and implies low enough opacities to reproduce the fluxes of the two lower CO transitions.”
A Multi-Transition HCN and HCO+ Study of 12 Nearby Active Galaxies: Active Galactic Nucleus versus Starburst Environments (2007, background): “…stage of the activity, particularly important for starburst, f) additional non-collisional excitation of the gas through IR pumping by UV/X-ray heated dust (e.g. Garćıa-Burillo et al. 2006; Weiß et al. 2007), and g) supernova explosions (SNe), especially important for the HCO+ excitation.”