Most theoretical models invoke quasar driven outflows to quench star
formation in massive galaxies, this feedback mechanism is required to account
for the population of old and passive galaxies observed in the local universe.
The discovery of massive, old and passive galaxies at z=2, implies that such
quasar feedback onto the host galaxy must have been at work very early on,
close to the reionization epoch. We have observed the [CII]158um transition in
SDSSJ114816.64+525150.3 that, at z=6.4189, is one of the most distant quasars
known. We detect broad wings of the line tracing a quasar-driven massive
outflow. This is the most distant massive outflow ever detected and is likely
tracing the long sought quasar feedback, already at work in the early Universe.
The outflow is marginally resolved on scales of about 16 kpc, implying that the
outflow can really affect the whole galaxy, as required by quasar feedback
models. The inferred outflow rate, dM/dt > 3500 Msun/yr, is the highest ever
found. At this rate the outflow can clean the gas in the host galaxy, and
therefore quench star formation, in a few million years.Comment: 5 pages, 3 figures, accepted for publication in MNRAS Letter

A. Ferrara

Aalto

Alatalo

Alexander

Beelen

Bertoldi

Bower

C. Cicone

C. Feruglio

Cano-Díaz

Cicone

Cimatti

Croton

D. Lutz

Di Matteo

E. Piconcelli

E. Sturm

F. Fiore

F. Walter

Fabian

Farrah

Feruglio

Fischer

Glazebrook

Granato

Greene

Hailey-Dunsheath

Harrison

Hopkins

King

Komatsu

L. J. Tacconi

Lapi

Maiolino

Martin

McCarthy

Menci

Narayanan

Nesvadba

Page

R. Genzel

R. Maiolino

R. Neri

Rupke

S. Gallerani

Saracco

Savage

Silk

Springel

Sturm

Thacker

Valiante

Veilleux

Walter

Weiß

Wilson

Zubovas

English

arXiv

Most theoretical models invoke quasar driven outflows to quench star formation in massive
galaxies, and this feedback mechanism is required to account for the population of old and
passive galaxies observed in the local universe. The discovery of massive, old and passive
galaxies at z∼2, implies that such quasar feedback onto the host galaxymust have been at work
very early on, close to the reionization epoch. We have observed the [CII]158μm transition
in SDSSJ114816.64+525150.3 that, at z=6.4189, is one of the most distant quasars known.
We detect broad wings of the line tracing a quasar-driven massive outflow. This is the most
distant massive outflow ever detected and is likely tracing the long sought quasar feedback,
already at work in the early Universe. The outflow is marginally resolved on scales of ∼16 kpc,
implying that the outflow can really affect the whole galaxy, as required by quasar feedback
models. The inferred outflow rate,  ̇M &gt; 3500 M⊙ yr−1, is the highest ever found. At this rate
the outflow can clean the gas in the host galaxy, and therefore quench star formation, in a few
million years

Maiolino, R.

GALLERANI, SIMONA

Neri, R.

Cicone, C.

FERRARA, ANDREA

Genzel, R.

Lutz, D.

Sturm, E.

Tacconi, L. J.

Walter, F.

FERUGLIO, CHIARA

Fiore, F.

Piconcelli, E.

Archivio istituzionale della Ricerca - Scuola Normale Superiore

arXiv:1204.2904v2  [astro-ph.CO]  13 Jun 2012Mon. Not. R. Astron. Soc.000, 1–?? (2002) Printed 15 June 2012 (MN LATEX style file v2.2)Evidence of strong quasar feedback in the early UniverseR. Maiolino,1 S. Gallerani,2 R. Neri,3 C. Cicone,1 A. Ferrara,2 R. Genzel,4 D. Lutz,4E. Sturm,4 L. J. Tacconi,4 F. Walter,5 C. Feruglio,3 F. Fiore,6 E. Piconcelli71Cavendish Laboratory, University of Cambridge, 19 J. J. Thoms n Ave., Cambridge CB3 0HE, UK2Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy3Institute de Radioastronomie Millimetrique (IRAM), 300 Rue de la Piscine, 38406, St. Martin d’Heres, Grenoble, France4Max-Planck-Institut für Extraterrestrische Physik (MPE), Giessenbachstr. 1, 85748 Garching, Germany5Max-Planck-Institut fr Astronomie, Knigstuhl 17, 69177 Heidelberg, Germany6Osservatorio Astronomico di Roma, INAF, via di Frascati 33,00040 Monteporzio Catone, Italy7ESA-ESAC, Camino bajo del Castillo, Villanueva de la Canada, E-28692 Madrid, SpainAccepted . ReceivedABSTRACTMost theoretical models invoke quasar driven outflows to quench star formation in massivegalaxies, and this feedback mechanism is required to account f r the population of old andpassive galaxies observed in the local universe. The discovery of massive, old and passivegalaxies at z∼2, implies that such quasar feedback onto the host galaxy must have been at workvery early on, close to the reionization epoch. We have observed the [CII]158µm transitionin SDSSJ114816.64+525150.3 that, at z=6.4189, is one of the most distant quasars known.We detect broad wings of the line tracing a quasar-driven massive outflow. This is the mostdistant massive outflow ever detected and is likely tracing the long sought quasar feedback,already at work in the early Universe. The outflow is marginally resolved on scales of∼16 kpc,implying that the outflow can really affect the whole galaxy, as required by quasar feedbackmodels. The inferred outflow rate,Ṁ > 3500 M⊙ yr−1, is the highest ever found. At this ratethe outflow can clean the gas in the host galaxy, and thereforequench star formation, in a fewmillion years.Key words: galaxies: evolution - galaxies: high-redshift - quasars: general1 INTRODUCTIONThe old stellar population and low gas content characterizinglocal massive galaxies, as well as their steeply declining num-ber at high masses, have been difficult to explain in most theo-retical scenarios of galaxy formation. Indeed, in the absence of“negative feedback” on star formation (i.e. a mechanism to de-crease star formation), theoretical models expect a much largernumber of massive galaxies than observed and characterizedbyyoung stellar populations (Menci et al. 2006; Bower et al. 2006).To reconcile theory with observations, most models invoke mas-sive outflows driven by the radiation pressure generated by quasars,which are expected to clear their host galaxies of the bulk oftheir gas, therefore quenching star formation (Silk & Rees 1998;Granato et al. 2004; Di Matteo et al. 2005; Springel et al. 2005;Croton et al. 2006; Narayanan et al. 2008; Hopkins et al. 2008;Fabian et al. 2009; King 2010; King et al. 2011; Hopkins & Elvis2010; Zubovas & King 2012). Evidence for such negative feed-back has been found only recently in quasar hosts through thediscovery of massive outflows, in particular through the detectionof P-Cygni profiles of far-IR OH transitions (Fischer et al. 2010;Sturm et al. 2011), the detection high velocity wings of molecu-lar emission lines (CO, HCN, Feruglio et al. 2010; Alatalo etal.2011; Aalto et al. 2012) and the detection of high velocity neutralgas in absorption and of high velocity ionized gas (Nesvadbaet al.2010; Rupke & Veilleux 2011; Greene et al. 2011). Evidence forquasar-driven massive outflows have also been found throughthebright [CII]158µm fine structure line; indeed, Herschel spectra ofnearby quasars have revealed prominent [CII] broad wings, asso-ciated with the molecular outflow traced by the OH absorptionlines (Fischer et al. 2010, Sturm et al. in prep.). Quasar-driven out-flows have been detected also at high redshift (although exploit-ing different tracers, Alexander et al. 2010; Nesvadba et al. 2011;Harrison et al. 2012). Moreover, evidence has been found that theseoutflows are indeed quenching star formation in their host galaxies(Cano-Dı́az et al. 2012; Farrah et al. 2012; Steinhardt & Silverman2011; Page et al. 2012), as expected by models.However, the discovery of old (age> 2 Gyr), passive andmassive galaxies at z∼2 (Cimatti et al. 2004; Saracco et al. 2005;McCarthy et al. 2004; Glazebrook et al. 2004), when the Universehad an age of only∼3 Gyr, requires that the quasar feedbackquenching mechanism must have been at work already at z>6(age of the Universe less than one Gyr), i.e. close to the re-ionization epoch. Quasar driven winds have been observed uptoz∼6 (Maiolino et al. 2001, 2004), however these are associatedwith ionized gas in the vicinity of the black hole, accounting onlyc© 2002 RAS2 Maiolino et al.for a tiny fraction of the total gas in the host galaxy. So far,no ob-servational evidence was found for the massive, quasar driven out-flows at z>6 required by feedback models to explain the populationof old massive galaxies at z∼2.Here we focus on one of the most distant quasars known,SDSSJ114816.64+525150.3 (hereafter J1148+5251), at z=6.4189(Fan et al. 2003). CO observations have revealed a large reser-voir of molecular gas, MH2 ∼ 2 × 1010 M⊙, in the quasarhost galaxy (Walter et al. 2003; Bertoldi et al. 2003b). The strongfar-IR thermal emission inferred from (sub-)millimeter observa-tions reveals vigorous star formation in the host galaxy, withSFR ∼ 3000 M⊙ yr−1 (Bertoldi et al. 2003a; Beelen et al. 2006).J1148+5251 is also the first high redshift galaxy in which the the[CII]158µm line was discovered (Maiolino et al. 2005). High res-olution mapping of the same line with the IRAM PdBI revealedthat most of the emission is confined within∼ 1.5 kpc, indicatingthat most of the star formation is occurring within a very compactregion (Walter et al. 2009).Previous [CII] observations of J1148+5251 did not have abandwidth large enough to allow the investigation of broad wingstracing outflows, as in local quasars. In this letter we present n wIRAM PdBI observations of J1148+5251 that, thanks to the widebandwidth offered by the new correlator, have allowed us to dis-cover broad [CII] wings tracing a very massive and energeticout-flow in the host galaxy of this early quasar. We show that the prop-erties of this outflow are consistent with the expectations of quasarfeedback models.We assume the concordanceΛ-cosmology with H0 =70.3 km s−1 Mpc−1, ΩΛ = 0.73 andΩm = 0.27 (Komatsu et al.2011).2 OBSERVATIONS AND DATA REDUCTIONObservations with the IRAM PdBI were obtained mostly in April2011 in D configuration (mostly with 1.5 < PWV < 3.5 mm),while a few hours where also obtained in January 2011 in C+Dconfiguration (PWV< 1.5 mm). The resulting synthesized beamis 2.2′′ × 1.8′′. The receivers were tuned to 256.172 GHz, whichis the rest frame frequency of [CII] at the redshift of the quasar,z=6.4189 (Maiolino et al. 2005). The following flux calibratorswere used: 3C454.3, MWC349, 0923+ 92, 1150+497, 3C273,3C345, 1144+542, J1208+546, J1041+525, 1055+018. Uncer-tainties on the absolute flux calibration are 20%. The total on-source integration time was 17.5 hours, resulting in a sensitivityof 0.08 Jy km s−1 beam−1 in a channel with width 100 km s−1.The data were reduced by using the CLIC and MAPPINGpackages, within the GILDAS-IRAM software. Cleaning of there-sulting maps was run by selecting the clean components on an areof ∼ 3” around the peak of the emission. For each map the resultingresiduals are below the 1σ error, ensuring that sidelobes are prop-erly cleaned away. Anyhow, as discussed in the following, the sizedetermination has been investigated directly on theuv data, there-fore independently of the cleaning.3 RESULTS3.1 Detection of broad wingsThe continuum was subtracted from theuv data by estimatingits level from the channels at v< −1300 km s−1 and at v >+1300 km s−1. The inferred continuum flux is 3.7 mJy, which isa)b)Figure 1. IRAM PdBI continuum-subtracted spectrum of the [CII]158µmline, redshifted to 256.172 GHz, in the host galaxy of the quasarJ1148+5152 extracted from an aperture with a diameter of 4′′, top, and6′′, bottom. The spectrum has been resampled to a bin size of 85 kms−1.The red lines show a double Gaussian fit (FWHM=345 km s−1 andFWHM=2030 km s−1) to the line profile, while the blue line shows thesum of the two Gaussian components.fully consistent with the value expected (4 mJy) from the bolomet-ric observations (Bertoldi et al. 2003a), once the frequency rangeof the latter and the steep shape of the thermal spectrum are takeninto account.Fig. 1a shows the continuum-subtracted spectrum, extractedfrom an aperture of 4′′ (corresponding to a physical size of 11 kpc).Fig. 1b shows the spectrum extracted from a larger aperture of 6′′that, although noisier than the former spectrum, recovers rsidualflux associated with the beam wings and with any extended com-ponent.The spectrum shows a clear narrow [CII]158µm emis-sion line, which was already detected by previous observations(Maiolino et al. 2005; Walter et al. 2009). However, thanks to themuch wider bandwidth relative to previous data, our new spectrumreveals broad [CII] wings extending to about±1300 km s−1. Theseare indicative of a powerful outflow, in analogy with the broadwings that have been observed in the molecular and fine struc-c© 2002 RAS, MNRAS000, 1–??

Evidence of strong quasar feedback in the early Universe

Gallerani, S.

Ferrara, A.

Tacconi, L.

Feruglio, C.

MPG.PuRe

Evidence of strong quasar feedback in the early universe

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Monthly Notices of the Royal Astronomical Society Letters

https://ricerca.sns.it/bitstream/11384/61740/4/1204.2904v2.pdf

Evidence of strong quasar feedback in the early Universe

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