CO(J = 1→0) IN z > 2 QUASAR HOST GALAXIES: NO EVIDENCE FOR EXTENDED MOLECULAR GAS RESERVOIRS

By D. Riechers, C. Carilli, R. Maddalena, J. Hodge, A. Harris, A. Baker, F. Walter, J. Wagg, P. V. Vanden Bout, A. Weiss and 1 more. 2006

168 citations recorded by the source corpus.

We report the detection of CO(J = 1→0) emission in the strongly lensed high-redshift quasars IRAS F10214+4724 (z = 2.286), the Cloverleaf (z = 2.558), RX J0911+0551 (z = 2.796), SMM J04135+10277 (z = 2.846), and MG 0751+2716 (z = 3.200), using the Expanded Very Large Array and the Green Bank Telescope. We report lensing-corrected CO(J = 1→0) line luminosities of L′CO = (0.34–18.4) × 1010 K km s−1 pc2 and total molecular gas masses of M(H2) = (0.27–14.7) × 1010 M☉ for the sources in our sample. Based on CO line ratios relative to previously reported observations in J ⩾ 3 rotational transitions and line excitation modeling, we find that the CO(J = 1→0) line strengths in our targets are consistent with single, highly excited gas components with constant brightness temperature up to mid-J levels. We thus do not find any evidence for luminous-extended, low-excitation, low surface brightness molecular gas components. These properties are comparable to those found in z > 4 quasars with existing CO(J = 1→0) observations. These findings stand in contrast to recent CO(J = 1→0) observations of z ≃ 2–4 submillimeter galaxies (SMGs), which have lower CO excitation and show evidence for multiple excitation components, including some low-excitation gas. These findings are consistent with the picture that gas-rich quasars and SMGs represent different stages in the early evolution of massive galaxies.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/c8a830a7524dbb0b45820da1de4120b70428ca8b

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In Astronomy and Astrophysics

1. F. Walter
2. D. Narayanan
3. C. Carilli
4. C. Casey
5. P. Hopkins
6. L. Hernquist
7. A. Cooray
8. R. Somerville

Citations in the corpus

• Dusty Star Forming Galaxies at High Redshift (2014, background): “Similarly, Riechers et al. (2011c) find source radii of∼3–15 kpc in a sample of 3 SMGs detected in CO (J = 1–0), and note again that these sizes are notably more extended than the CO (J = 4–3) and (J = 6–5) sizes measured by Engel et al. (2010) for the same galaxies.”
• OBSERVATIONS OF Arp 220 USING HERSCHEL-SPIRE: AN UNPRECEDENTED VIEW OF THE MOLECULAR GAS IN AN EXTREME STAR FORMATION ENVIRONMENT (2011, background): “More recently, EVLA observations of five high-z quasar host galaxies (Riechers et al. 2011; Ivison et al. 2011) indicate that SMGs with AGN show no cold gas component; i.e., the CO J = 1-0 line strengths in these five systems are consistent with warm, highly excited gas that is also seen in the…”
• The CO-to-H2 Conversion Factor (2013, background): “At the brightest end of the galaxy distribution Riechers et al. (2011) report r31 ∼ 0.96− 1.06 for four high-redshift SMGs hosting quasars, suggesting that the excitation in these sources is such that the emission is thermalized to higher rotational transitions (see also Weiss et al. 2007, for a CO…”
• 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).”
• An ALMA [C ii] Survey of 27 Quasars at z > 5.94 (2018, background): “High CO excitation is observed in some of these quasars, as would be expected in compact violent starbursts (e.g., Barvainis et al. 1997; Bertoldi et al. 2003a; Walter et al. 2003; Weiß, 2007; Riechers et al. 2009, 2011).”
• Cool Gas in High-Redshift Galaxies (2013, background): “These galaxies have also been shown to harbor massive reservoirs of gas (Cox et al. 2011, Combes et al. 2012a, Riechers et al. 2011a, Harris et al. 2012).”
• REGULARITY UNDERLYING COMPLEXITY: A REDSHIFT-INDEPENDENT DESCRIPTION OF THE CONTINUOUS VARIATION OF GALAXY-SCALE MOLECULAR GAS PROPERTIES IN THE MASS-STAR FORMATION RATE PLANE (2013, unknown): “1+573027; see Swinbank et al. 2010 and Riechers et al. 2011, resp.).”