Yet another UFO in the X-ray spectrum of a high-z lensed QSO
M. Dadina, C. Vignali, M. Cappi, G. Lanzuisi, G. Ponti, E. Torresi, B. De Marco, G. Chartas, M. Giustini
aa r X i v : . [ a s t r o - ph . H E ] J a n Astronomy&Astrophysicsmanuscript no. dad © ESO 2018June 25, 2018 L etter to the E ditor Yet another UFO in the X-ray spectrum of a high-z lensed QSO
M. Dadina , C. Vignali , , M. Cappi , G. Lanzuisi , , G. Ponti , E. Torresi , , B. De Marco , G. Chartas , M. Giustini INAF / OAS, Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, via Gobetti 93 /
3, 40129, Bologna, Italy e-mail: [email protected] Dipartimento di Fisica e Astronomia dell’Universit´a degli Studi di Bologna, via P. Gobetti 93 /
2, 40129, Bologna, Italy Max-Planck-Institut f¨ur Extraterrestrische Physik, Giessenbachstrasse 1, D-85748, Garching, Germany Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Bartycka 18, PL-00-716 Warsaw, Poland Department of Physics and Astronomy of the College of Charleston, Charleston, SC 29424, USA SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, the NetherlandsReceived ; Accepted
ABSTRACT
Aims.
Ultra-fast outflows (UFO) appear to be common in local active galactic nuclei (AGN) and may be powerful enough ( ˙ E kin ≥ bol ) to e ff ectively quench the star formation in their host galaxies. To test feedback models based on AGN outflows, it is mandatoryto investigate UFOs near the peak of AGN activity, that is, at high-z where only a few studies are available to date. Methods.
UFOs produce Fe resonant absorption lines measured above ≈ ffi culty in obtaining X-ray data with su ffi cient signal-to-noise. We therefore selected a distant QSO thatgravitational lensing made bright enough for these purposes, the z = + ≈
78 ks.
Results.
The X-ray spectrum of MG J0414 + H ≈ × cm − ) and of thepresence of an iron emission line (E ≈ = ±
53 eV) consistent with it originating in the cold absorber. Our main result,however, is the robust detection (more than 5 σ ) of an absorption line at E int ≈ obs ≈ v out ≈ ≥ E kin ≈ L bol with ˙ p out / ˙ p rad ≈
17 indicating that it is capable of installingsignificant feedback between the super-massive black hole (SMBH) and the bulge of the host galaxy. We argue that this also suggestsa magnetic driving origin of the UFO.
Key words. galaxies: high-redshift – quasar: individual: MG J0414 + +
1. Introduction
Since the discovery of the relation between the mass of a super-massive black hole (SMBH) and the bulges of their host galax-ies ( i.e., the “M • − σ relation”, Kormendy & Richstone 1995,Magorrian et al. 1998), we know that SMBHs likely play arole in the formation and growth of the galaxies (Fabian 2012).Active galactic nuclei (AGN)-driven ultra-fast outflows (UFOs)(Tombesi et al 2010a) have been recently proposed as a majorfeedback process whereby sweeping out and / or compressing theinterstellar gas may influence the formation and growth of thegalaxies (Fabian 2012, King & Pounds 2015).Resonant absorption lines detected in the ∼ ff ordet al. 2013). While the average properties of UFOs are knownat low z, we have only a few UFO detections at z ≥ • − σ relation seentoday (Hasinger et al. 2002; Chartas et al. 2002a, 2003, 2007,2016; Lanzuisi et al. 2012; Vignali et al. 2015).Here we present the XMM-Newton spectrum of MGJ0414 + µ ∼ = / heat the cold gas inthe hosting galaxy (Georgakakis et al. 2009; Urrutia et al. 2009)thus enabling feedback processes between the SMBH and thegalaxy bulges (Fabian 2012, King & Pounds 2015). In X-ray,the source was previously pointed by Chandra and the spec-trum was described by an absorbed power-law ( Γ = ± H = ± × cm − , errors are at 90% confidence levelfor one parameter of interest here and throughout the paper,Avni 1976) plus an iron line in emission (E FeK α = ± FeK α = ±
100 eV; Chartas et al. 2002).
2. Data reduction and analysis
XMM-Newton pointed to MG J0414 + ≈
78 and ≈
76 ks for EPIC-pn and EPIC-MOS instru-ments, respectively. Since it was a ff ected by soft-p + flares, high-background intervals were removed through an iterative sigma-clipping procedure applied to the 10-15 keV band data; we wereleft with cleaned exposure times of 48.5, 66.5, and 69.1 ks ofexposure for pn, MOS1, and MOS2, respectively.The images of MG J0414 + ≈
3” (Chartas etal. 2002), thus they form a single “point-like” source in XMM- = + − ( d a t a − m od e l ) / e rr o r Energy (keV)
Fek α ? ↑ UFO? ↑ Fig. 1.
Data-to-model ratio expressed in terms of standard de-viations with respect to a power-law absorbed by Galactic col-umn density (1.02 × cm − , Kalberla et al. 2005). A deep andnarrow drop of counts at E ≈ . . . . Γ N H (10 cm −2 ) + × − × − × − × − N o r m ( ph . s − c m − k e V − ) E (keV) + Fig. 2.
Confidence contours of the photon index vs. the absorb-ing column (upper panel) and of the Gaussian emission linenormalization vs. its energy centroid (lower panel) (rest frame)adopting model ≈ ≈ ≈ + . − keV ≈ × − erg s − cm − (see model . − keV ≈ × − erg s − cm − , Chartas et al. 2002;Pooley et al. 2012). Following Chartas et al. (2002) we mod-eled the XMM-Newton spectrum with an absorbed power lawplus an iron line in emission finding consistent results, that is, Γ= ± H = ± × cm − , E FeK α = ± FeK α = ±
53 eV. − × − − × − − × − s − c m − k e V − E (keV) + Fig. 3.
Confidence contours plot of the Gaussian absorption linenormalization vs. its rest-frame energy centroid (see model ≈ ≈ ∆ χ ≈
27 for twoparameters of interest corresponding, using the F-test, to a 5 σ detection; model ≈ ± ∆ χ ≈ σ ≤
250 eV, rest frame). This makes an edge ori-gin implausible for at least part of the feature as proposed forAPM 08279 + ∆ χ ≈ σ =
0) were free to vary. The result is plotted in Fig.4. The absorption line is detected at more than 99% confidencelevel in both MOS1 ( ∆ χ = ∆ χ = ∆ χ = ∼ ∆ χ of at least 10 for two instruments and 3for the other. Thus, considering the conservative approach thatwe used, we can assess that the probability of measuring an ab-sorption feature as seen in MG J0414 + ≈ ≈ ≈ = ≤ = ±
70 eV today).The detection of the FeK α emission line may indicate thepresence of a reflection component. This feature is commonlyobserved in nearby Seyfert galaxies (e.g., Perola et al. 2002), andrecently it has been detected also in some high-z QSO (Dadina etal. 2016, Lanzuisi et al. 2016). To test this hypothesis and to fur-ther probe the robustness of the detection of the absorption fea-ture against a more complex underlying continuum, we tried thePexmon reflection model (Nandra et al. 2007) fixing the incli- = + Table 1.
Spectral models.
Upper table
Column 1: Model number; Column 2: absorbing column in excess to the Galactic value;Column 3: photon index; Column 4: energy of the emission line; Column 5: emission line rest frame EW; Column 6: energy of theabsorption line; Column 7: absorption line EW; Column 8: 0.5-8 keV flux; Column 9: 2-10 keV flux; Column 10: χ / d.o.f. Lowertable
Columns 1-5 as in upper table. Column 6: column density of the ionized absorber; Column 7: Log of the ionization parameterexpressed in erg s − cm; Column 8: observed redshift of the ionized absorber; Column 10: χ / d.o.f. Line widths are fixed to 0 eV. H Γ E FeK α EW FeK α Eabs EWabs F . − keV F − keV χ / d.o.f.10 cm − keV eV keV eV 10 − erg s − cm − − erg s − cm − + . − . + . − . + . − . + − / + . − . + . − . + . − . + − + . − . + − / H Γ E FeK α EW FeK α N H , ion Log( ξ ) z χ / d.o.f.10 cm − keV eV 10 cm − + . − . + . − . + . − . + − + , pegged − + . − . + . − . / − − − × − N o r m . ( ph s − c m − k e V − ) E (keV) + pn − − − × − + MOS 1 − − − × − + MOS 2
Fig. 4.
Confidence contours plot of the Gaussian absorption linenormalization vs. its rest-rame energy for each single EPIC in-strument. Contours confidence levels are as in Fig. 2.nation angle ( Θ= ◦ ) and the high-energy cut-o ff (E cut − o f f = ≤ warmabs model based on Xstar (Kallman &Bautista 2001). We fixed the abundances af all elements to thesolar value and the turbulence velocity to v turb = / s, inagreement with what is measured in local AGN (Tombesi et al.2012, 2014). The free parameters of the fit are the column of theionized absorbing gas, its ionization parameter, and the redshiftat which the absorber is detected. This last value allows us toinfer the outflow velocity of the absorber. As presented in Table1 (model obs ≈ ff ects along the line of sight,to an outflow velocity of v out = (0.28 ± Log ( ξ ) ≈
4) strongly indicates that the absorption line is due toFeXXVI (see also Tombesi et al. 2011). −5 −4 k e V ( P ho t on s c m − s − k e V − ) −5 −4 k e V ( P ho t on s c m − s − k e V − ) Current Theoretical Model1 2 5−4−2024 ( d a t a − m od e l ) / e rr o r Energy (keV)Square root of chi−squared for each channel
Fig. 5.
Unfolded X-ray observed frame energy spectrum of MGJ0414 + upper panel ) obtained using model middle panel . This model fits well the dataand no strong residuals are left ( lower panel ). Color-code is asin Fig. 1.
3. Discussion and results
We present the results obtained analyzing the XMM-Newtondata of the radio-loud quasar MG J0414 + = f GHz / f (R ≥
10 for radio-loud sources, Kellermann et al.1989). To obtain the rest frame value of R we used the ob-served fluxes in H band (m H ≈ = + at 1.4 GHz (f . GHz = ± ≈ Γ ≈ H ≈ × cm − . We also detected a cold iron line(E FeK α = ± FeK α = ±
53 eV.According to the present analysis, the iron emission line maybe due to the same matter responsible for the cold absorptionassuming an almost spherical distribution of such a component(e.g., Leahy & Creighton 1993).The observed luminosity of MG J0414 + − keV ≈ × erg s − adopting astandard Λ CDM cosmology with H =
70 km s − Mpc − and Ω λ = µ =
45 betweenthe estimated values of 30 and 60 (Trotter, Winn, & Hewitt 2000;Minezaki et al. 2009), we can infer an intrinsic X-ray luminos-ity L − keV ≈ × erg s − that corresponds to an intrinsicL bol ≈ × erg s − assuming the bolometric correction fac-tor ( k bol ≈
30) by Lusso et al. (2012). Based on the H β broaden-ing, the SMBH mass has been estimated to be M • ≈ × M ⊙ (Peng et al. 2006) and this implies that the source is emitting at ≈
5% of its Eddington limit (L
Edd ≈ × erg s − ).The main result of our analysis is the first detection, toour knowledge, of an UFO in a radio-loud object at z ≥ ξ ) ≈ H ≈ × cm − ) with a velocity of v out = (0.28 ± + out ∼ H ≥ cm − , Log( ξ ) ∼ = • , µ andk bol , we can try to infer a very rough and purely indicative esti-mate of the outflow mechanical output. Following Tombesi et al.(2016), we assume that the outflowing gas has been detected at aradius at which the observed velocity corresponds to the escapevelocity, that is, r = GM • v out . Using M • and v out reported above, weobtain that r ≈ × cm, that is, r ≈ g . Following Crenshawet al. (2003), we can estimate the mass-ouflow rate as:˙ M out = π m p µ N H v out rC , (1)where m p is the proton mass, µ the mean atomic mass perproton (1.4 for solar abundances), N H the column of the ionizedgas, v out the line of sight outflow velocity, r the absorbers ra-dial location, and C the global covering factor (C ≈ ≈ ⊙ year − that corresponds to ˙ E kin ≈ × erg s − , that is, ≈ L bol , andto an outflow momentum rate of ˙ p out ≈ × g cm s − , thatis approximately 17 times the radiation force ˙ p rad = L bol / c . The˙ E / L bol ≈ E kin / L bol ≈ ff ord et al.2015) and well above the limit to switch-on / o ff feedback mech-anisms by AGN-driven winds ( ˙ E kin / L bol ≥ + E kin ≈ L bol , Chartaset al. 2016). Moreover, together with the large ratio between thewind and radiation forces ( ˙ p out / ˙ p rad ≈ + ≥ + + + + + + − ff ects which must beaccounted for if we want to understand how the feedback mech-anism worked along cosmic time to shape the observed M • − σ relation. Acknowledgements.
We thank the referee, James Reeves, for his helpful com-ments. This work is based on observations obtained with XMM-Newton, anESA science mission with instruments and contributions directly funded by ESAMember States and the USA (NASA). MD acknowledges financial under con-tract ASI - INAF grant I / / /
0. GP acknowledges the Bundesministeriumf¨ur Wirtschaft und Technologie / Deutsches Zentrum f¨ur Luft- und Raumfahrt(BMWI / DLR, FKZ 50 OR 1408) and the Max Planck Society. BDM acknowl-edges support from the European Union’s Horizon 2020 research and innovationprogramme under the Marie Skłodowska-Curie grant agreement No. 665778 viathe Polish National Science Center grant Polonez UMO-2016 / / P / ST9 / References