Testing the evolutionary link between submillimetre galaxies and quasars: CO observations of QSOs at z∼ 2

By K. Coppin, M. Swinbank, R. Neri, P. Cox, D. M. Alexander, I. Smail, M. Page, J. Stevens, K. Knudsen, R. Ivison and 19 more. 2008

135 citations recorded by the source corpus.

We have used the IRAM Plateau de Bure millimeter interferometer and the UKIRT 1– 5µm Imager Spectrometer (UIST) to test the connection between the major phases of spheroid growth and nuclear accretion by mapping CO emission in nine submillimetredetected QSOs at z = 1.7–2.6 with black hole (BH) masses derived from near-infrared spectroscopy. When combined with one QSO obtained from the literature, we present sensitive CO(3–2) or CO(2–1) observations of 10 submillimetre-detected QSOs selected at the epoch of peak activity in both QSOs and submillimetre (submm) galaxies (SMGs). CO is detected in 5/6 very optically luminous (MB ∼ −28) submm-detected QSOs with BH masses MBH ≃ 10 9 –10 10 M⊙, confirming the presence of large gas reservoirs of Mgas ≃ 3.4 × 10 10 M⊙. Our BH masses and dynamical mass constraints on the host spheroids suggest, at face value, that these optically luminous QSOs at z = 2 lie about an order of magnitude above the local BH-spheroid relation, MBH/Msph, although this result is dependent on the size and inclination of the CO-emitting region. However, we find that their BH masses are ∼ 30 times too large and their surface density is ∼ 300 times too small to be related to typical SMGs in an evolutionary sequence. Conversely, we measure weaker CO emission in four fainter (MB ∼ −25) submm-detected QSOs with properties, BH masses (MBH ≃ 5 ×10 8 M⊙), and surface densities similar to SMGs. These QSOs appear to lie near the local MBH/Msph relation, making them plausible ‘transition objects’ in the proposed evolutionary sequence linking QSOs to the formation of massive young galaxies and BHs at high-redshift. We show that SMGs have a higher incidence of bimodal CO line profiles than seen in our QSO sample, which we interpret as an effect of their relative inclinations, with the QSOs seen more face-on. Finally, we find that the gas masses of the four fainter submm-detected QSOs imply that their star formation episodes could be sustained for ∼ 10Myr, and are consistent with representing a phase in the formation of massive galaxies which overlaps a preceding SMG starburst phase, before subsequently evolving into a population of present-day massive ellipticals.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/7d0dd383d5270822a9865ec4f6918fb74bcfc681

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In Astronomy and Astrophysics

1. D. M. Alexander
2. L. Hernquist
3. P. Hopkins
4. D. Narayanan
5. F. Walter
6. E. Daddi
7. C. Casey
8. R. Ivison

In Instrumentation

1. D. M. Alexander
2. P. Hopkins
3. D. Narayanan
4. E. Daddi
5. L. Hernquist
6. C. Casey
7. P. Capak
8. R. Ivison

Citations in the corpus

• Dusty Star Forming Galaxies at High Redshift (2014, methodology): “At higher redshifts, the best measurements of DSFG timescales come from 850 µm-selected SMGs with CO measurements (Neri et al., 2003; Greve et al., 2005; Tacconi et al., 2006, 2008; Coppin et al., 2008b; Bothwell et al., 2010; Casey et al., 2011a; Bothwell et al., 2013a).”
• The Dramatic Size Evolution of Elliptical Galaxies and the Quasar Feedback (2008, background): “…onset of the massive outflows determining the transition from the active star-forming phase to the unobscured QSO phase, indicate very large gas masses in the central regions of their host galaxies (Lutz et al. 2008, and references therein), comparable to the stellar masses (Coppin et al. 2008).”
• AN ALMA SURVEY OF SUBMILLIMETER GALAXIES IN THE EXTENDED CHANDRA DEEP FIELD SOUTH: THE REDSHIFT DISTRIBUTION AND EVOLUTION OF SUBMILLIMETER GALAXIES (2013, background): “It has been speculated that this growth may come in the form of a QSO phase (e.g. Sanders et al. 1988; Coppin et al. 2008; Simpson et al. 2012), during which the SMBH would grow at approximately the Eddington limit.”
• An ALMA survey of sub-millimetre Galaxies in the Extended Chandra Deep Field South: the far-infrared properties of SMGs (2013, background): “…detected subset of the population gave a median redshift of z ∼ 2.5 (Chapman et al. 2005), confirming their ULIRG-like luminosities (Kovács et al. 2006; Coppin et al. 2008a; Magnelli et al. 2012a) and demonstrated that ULIRGs undergo a 1000-fold increase in space density from z=0 to z ∼ 2.5.”
• Cool Gas in High-Redshift Galaxies (2013, background): “This suggests the presence of a coeval starburst with the SMBH growth (Walter et al. 2004, Wang et al. 2010, Coppin et al. 2008).”
• MID-INFRARED SPECTROSCOPY OF SUBMILLIMETER GALAXIES: EXTENDED STAR FORMATION IN MASSIVE HIGH-REDSHIFT GALAXIES (2009, background): “Hence it is possible that a small fraction of luminous, but Compton thick, AGN lurk within the SMG population (see Coppin et al. 2008).”
• Enhanced star formation rates in AGN hosts with respect to inactive galaxies from PEP-Herschel observations (2012, background): “Moreover, there is good evidence for a close connection between AGN activity and SF in SMGs (e.g. Chapman et al. 2005; Alexander et al. 2008; Coppin et al. 2008).”
• STAR FORMATION AND GAS KINEMATICS OF QUASAR HOST GALAXIES AT z ∼ 6: NEW INSIGHTS FROM ALMA (2013, background): “…found with other high-z FIR and CO luminous quasars that the SMBH–bulge mass ratios are 10–30 times higher than the average value of 0.0014 found in local normal galaxies (Marconi et al. 2003; Walter et al. 2004; Riechers et al. 2008; Wang et al. 2010; Coppin et al. 2008; Venemans et al. 2012).”
• The mean star formation rate of X-ray selected active galaxies and its evolution from z~2.5: results from PEP-Herschel (2012, background): “…signatures in a sizable fraction of bright QSOs (as much as 80%, depending on selection), with some reaching infrared (IR) luminosities placing them in the ultra-luminous IR galaxy (ULIRG) regime (e.g., Page et al. 2004; Stevens et al. 2005; Alexander et al. 2008; Coppin et al. 2008).”
• MOLECULAR GAS IN z ∼ 6 QUASAR HOST GALAXIES (2010, methodology): “The derived molecular gas masses are on the order of ∼ 1010M⊙, which are also comparable to the typical values found in SMGs (Greve et al. 2005; Carilli & Wang 2006; Coppin et al. 2008a) and the z∼1.5 massive star forming disk galaxies (Daddi et al. 2008).”
• CANDELS: THE COSMIC ASSEMBLY NEAR-INFRARED DEEP EXTRAGALACTIC LEGACY SURVEY (2011, unknown): “…combined with CANDELS HST imaging will also allow us to connect and compare this active BH accretion phase of galaxy formation to active star-formation phases that produce ultra-luminous IR and sub-mm galaxies (e.g., Donley et al. 2010; Pope et al. 2008; Alexander et al. 2008; Coppin et al. 2008).”
• A survey of molecular gas in luminous sub-millimetre galaxies (2012, result): “This behaviour is the reverse of that seen in studies of the SMBHs in QSOs (Peng et al. 2006), including those using 12CO dynamics (Walter et al. 2004; Coppin et al. 2008; Simpson et al. 2012), suggesting that SMGs must grow their SMBHs to lie on the present-day relation.”
• The LABOCA survey of the Extended Chandra Deep Field-South: clustering of submillimetre galaxies (2011, background): “…to the potential nonisotropic orientation of the QSO hosts on the sky and the lack of high-resolution velocity fields necessary to solve for this (Coppin et al. 2008), as well as the general difficulties in modelling CO kinematics (e.g. Tacconi et al. 2006; Bothwell et al. 2010; Engel et al.…”
• A MASSIVE MOLECULAR GAS RESERVOIR IN THE z = 5.3 SUBMILLIMETER GALAXY AzTEC-3 (2010, background): “Second, of the >20 SMGs detected in CO emission to date, none has a FWHM linewidth of >1200 km s−1 (median: 530 km s−1; Coppin et al. 2008).”
• SUBMILLIMETER GALAXIES AS PROGENITORS OF COMPACT QUIESCENT GALAXIES (2014, background): “…scenario (e.g. Blain et al. 2004; Chapman et al. 2005; Tacconi et al. 2006; Toft et al. 2007; Cimatti et al. 2008; Capak et al. 2008; Tacconi et al. 2008; Schinnerer et al. 2008; Coppin et al. 2008; Micha lowski et al. 2010a; Smolčić et al. 2011), but see Riechers (2013) for a counter example.”
• Characterization of Scuba-2 450 μm and 850 μm selected galaxies in the COSMOS field (2013, background): “…to derive dust temperature despite the fact that they are not directly comparable (e.g. Blain et al. 2003; Kovács et al. 2010; Casey et al. 2009a; Coppin et al. 2008; Hwang et al. 2010); see Casey (2012), Figure 2, for more details on the impact of model assumption on measured dust temperature.”