an unobscured probe of obscured agn - dartmouth collegehiddenmonsters/talks/zaw.pdf · an...

Unique location 0.1-1.0 pc from SMBH

104 - 106 Rg

Zier & Biermann (2002)

H2O masers live here.

2

• Microwave Amplification by Stimulated Emission of Radiation (MASER)

• Power Source

• Column density along line of sight => type 2 AGN

• Velocity cohesion (~1 km/s)

• J = 616 → J = 523: 22.235 GHz (λ = 1.35 cm)

• Traces warm (~400-1000 K), dense (~107 - 1011 cm-3) gas

H2O Maser Emission

3

No. 1, 2008 HIGH OBSCURATION IN H2O MASER AGNs L15

Fig. 1.—XMM EPIC PN spectra of 8 AGNs that host H2O masers. Each source was fitted with thermal emission model and a Compton reflection component(Table 2). All except VV 340A and ESO 013–G012 exhibit Fe Ka emission at 6.4 keV (rest). Mrk 34, NGC 1320, and NGC 1194 also show Fe Kb at 7.05 keV(rest). NGC 1194 exhibits evidence as well for (1) direct transmission of the central engine power law spectrum, obscured below ∼5 keV by a 1.06!0.36 24#10"0.24

cm column, and (2) Ka emission from Si, S, and Ca."2

TABLE 3Column Measurements among Known Maser AGNs

Sample 11023 cm"2 11024 cm"2 Number

Disk masersa 100% 76% 21All AGN masers 95% 60% 42Megamasersb 87% 58% 31

a In addition to five sources in Table 2, we recognize 16other reported disk-maser AGNs with accompanying es-timates of N or limits: NGC 591, NGC 1068, NGC 1386,H

NGC 2273, NGC 3079, NGC 3393, NGC 4051, NGC 4258,NGC 4388, NGC 4945, NGC 5728, IC 2560, Mrk 1, Mrk1210, Circinus, and 3C 403.

b We include 26 megamasers with estimates of N or limitsH

as listed by Zhang et al. (2006), four objects in Table 2 (NGC1194, NGC 6926, Mrk 34, Mrk 1419), and Mrk 1.

Fig. 2.—Left: Distribution of N in AGNs that host masers and where X-H

ray data are available. Shaded bars indicate lower limits. Middle: Distributionfor disk masers. Based on geometry, disk-maser hosts are plausibly anticipatedto constitute a more homogeneous sample with respect to N . Right: Distri-H

bution for maser AGNs that are not identifiable as disk masers at this time.

al. 2006), (2) two AGNs listed by Zhang et al. (2006) butwithout known columns (NGC 591, Mrk 1), (3) five AGNstreated here (Table 2), and (4) four nuclei in which maseremission has been recently discovered (NGC 17 [Kondratko2007], and NGC 3081, NGC 4253, and NGC 3783 [J. A. Braatzet al. 2008, in preparation]). Columns are taken from Zhanget al. (2006) (31 objects, except NGC 5256 [see Guainazzi etal. 2005]), this work (5 objects), Guainazzi et al. (2005) (Mrk1, NGC 17, and NGC 591), Reeves et al. (2004) (NGC 3783),Maiolino et al. (1998) (NGC 3081), and Pounds et al. (2003)(NGC 4253). In order of precedence, we adopt results fromBeppoSAX, XMM, Chandra, and ASCA, except for NGC 3079,where we judged the XMM lower limit (Cappi et al. 2006) tobe more consistent with BeppoSAX data than larger limits basedon BeppoSAX data alone (Iyomoto et al. 2001).

Of the 42 AGNs, 60% (25) are Compton thick (Table 3; Fig.2). This fraction is consistent with that obtained for the smallersample of Zhang et al. (2006), 58% (18 of 31). Within thecurrent sample of 42, a greater fraction of recognized disk-maser galaxies are Compton thick, 76% (16 of 21). The dis-tribution of columns for disk masers is significantly skewedand non-Gaussian (Fig. 2). Substitution (over time) of N es-H

timates for lower limits will exaggerate this. In contrast, thedistribution for AGN masers without evidence of origins inedge-on disks includes a larger proportion of Compton-thinsources. A Kolmogorov-Smirnov (K-S) test indicates a !3.2%probability that the two distributions are drawn from a singleparent. To account for lower limits in our test, we constructeda Monte Carlo simulation of 1000 trials, sampled a uniformlydistributed random variable of and cm for each24 26 "210 10galaxy with a limit, and compiled a distribution of K-S statis-tics. Boundaries of and yielded probabilities of !3%25.5 2810 10as well.

Distinctions between N distributions for AGNs that hostH

acknowledged disk masers and those that do not may be stillgreater than estimated. Maser classifications depend on iden-tification of spectroscopic markers: highly red and blueshifted

10

Table 6. X-ray properties of confirmed disk-masers.

Name Distance NH Ref. Log(LI2−10) Ref. log(MBH) Disk size Ref. Log(LH2O)

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)

NGC1068 16 !100 Mat97 43.4 Til08 7.3 0.65–1.1 Til08 1.7NGC1194 53 10.6+3.6

−2.4 Gre08 42.6 Gre08 7.8 0.54–1.33 Kuo11 2.0

NGC1386 12 20+5−3 Fuk11 43.0 Til08 6.1 0.44–0.94 Til08 2.1

NGC2273 26 15±4 Awa09 42.2 Awa09 6.9 0.028–0.084 Ku011 0.9UGC3789 46 >10 this work 42.3 this work 7.0 0.084–0.30 Kuo11 2.6NGC2960 72 !10 Gre08 42.3 Gre08 7.1 0.13–0.37 Kuo11 2.7NGC3079 15 54.0+6.1

−6.5 Bur11 42.8 Til08 6.3 ∼0.4 Til08 2.6IC 2560 40 !10 Til08 41.8 Til08 6.5 0.08–0.27 Gre09 2.1NGC3393 51 45.0+6.2

−3.6 Bur11 41.6 Til08 7.5 0.17 Til08 2.5NGC4258 7.2 0.87±0.03 Cap06 41.2 Til08 7.6 0.12–0.28 Til08 1.9NGC4388 19 3.5±0.1 Fuk11 41.9 Cap06 6.9 0.24–0.29 Kuo11 0.6NGC4945 8 42.5±2.5 Don03 42.5 Til08 6.1 ∼0.3 Til08 1.7Circinus 6 43+4

−7 Mat99 42.1 Til08 6.2 0.11–0.4 Til08 1.2NGC6264 139 >10 this work 42.6 this work 7.5 0.24–0.80 Kuo11 2.5

Note: (1): Galaxy name. Thick disks with flattened rotation curves are in boldface. (2): Distance in Mpc. We adopted the distancesused in the determination of the maser disk radii. (3): Intrinsic column density in units of 1023 cm−2. (4): References for NH; Awa09:Awaki et al. (2009); Bur11: Burlon et al. (2011); Cap06: Cappi et al. (2006); Don03: Done et al. (2003); Fuk11: Fukuzawa et al. (2011);Gre08: Greenhill et al. (2008); Mat97: Matt et al. (1997); Mat99: Matt et al. (1999); Til08: Tilak et al. (2008). (5): Logarithm of the

intrinsic luminosity in the 2-10 keV band (in erg s−1cm−2). For NGC2273, UGC3789, NGC2690, and NGC6264 we used the observedfluxes or the apparent luminosities multiplied by a factor of 60 (see Sect.5.3) to estimate the intrinsic luminosities (6): References forLog(LI

2−10). Awa09: Awaki et al. (2009); Cap06: Cappi et al. (2006); Gre08: Greenhill et al. (2008); Til08: Tilak et al. (2008, andreferences therein). (7) Logarithm of the black hole mass (in M⊙). (8) Disk size in pc. (9) References for columns 8-9. Kuo11:

Kuo et al. (2011); Gre09: Greenhill et al. (2009); Til08: Tilak et al. (2008, and references therein). (10): Logarithm of the maserisotropic luminosity (in L⊙). The H2O luminosities are taken from Kondratko et al. (2006a, and references therein) for all the galaxies,with exception of NGC1194 (whose luminosity was derived directly from the spectrum), UGC3789, NGC2690, and NGC6264 (whose

data are reported in Tarchi et al. (2011a)).

Figure 5. Intrinsic (corrected for intrinsic absorption) X-ray lu-minosity in the 2–10 keV band against total isotropic water maserluminosity for the sources in Table 6.

(iv) when considering only disk maser galaxies, 86%(18/21) of them host Compton-thick AGN

Globally, this work clearly indicates and confirms thetrend of water maser sources associated with AGN to showhigh column densities and, in particular, the strong connec-tion between H2O masers in accretion disks and Compton-thick AGN.

In addition, our analysis, benefiting from a databasenearly twice as large as that of previous publications, con-firms the correlation between the bolometric luminosity andaccretion disk radius reported by Tilak et al. (2008) with ahigher degree of confidence. Furthermore, we found that theanomalous position of NGC2273 in the RH2O − LBol planemight indicate the presence of clumpy material at the innerradius of the masing disk.

ACKNOWLEDGMENTS

F. P. acknowledges support by INTEGRAL ASI I/033/10/0and ASI/INAF I/009/10/0. P. C. would like to thank Lin-coln Greenhill and Avanti Tilak for helpful suggestions inthe early stages of this project and Annika Kreikenbohmand Eugenia Litzinger for critically reading the manuscript.

REFERENCES

Antonucci R. 1993, ARA&A, 31, 473Awaki H., Terashima Y., Higaki Y., Fukazawa Y. 2009,PASJ, 61, 317

Bassani L., Dadina M., Maiolino R., Salvati M., Risaliti G.,della Ceca R., Matt G., Zamorani G. 1999, ApJSS, 121,473

Baumgartner W. H., Tueller J., Markwardt C., Skinner G.K., Barthelmy S., Mushotzky R. F., Evans P. A., GehrelsN. 2013, ApJS, 207, 19

x1023

Hα/HβZhu, IZ, Blanton, & Greenhill (2011)

Greenhill et al. (2008)

Castangia et al. (2013)

Highly Obscured

Resolved in position (~millarcsec)and velocity (~km/s)

Maps (VLBI)Spectra (Single Dish)

4

Miyoshi et al. (1995) Herrnstein et al. (1999)

Greenhill et al. (2003)

Claussen et al., 1998 (map), http://www.gb.nrao.edu/~jbraatz/masergifs/ngc1052.gif (spectrum)

Circinus

NGC 4258, disk

NGC 1052, jet

Circinus, disk+outflow

Zier & Biermann (2002)

H2O masers live here.

Distances and Massesfrom “clean” disk systems

5

36 GREENE ET AL. Vol. 721

Figure 8. Relation between BH mass and bulge velocity dispersion for the maser galaxies presented here (open circles) and those from the literature (gray stars).IC 2560 is indicated with a cross and the BH mass error bar is heuristic only. For reference, we show the MBH–σ∗ relation of elliptical galaxies from Gultekin et al.(2009, red dashed line). The maser galaxies trace a population of low-mass systems whose BHs lie below the MBH–σ∗ relation defined by elliptical galaxies. Thelargest outlier galaxies are (from highest to lowest MBH) NGC 2960, NGC 6323, and NGC 2273.

Sersic index, see Section 5.1). These authors also show that theaverage B/T of pseudobulges (0.16) is lower than that of clas-sical bulges (0.4) with a large spread. Gadotti (2009), on theother hand, advocates use of the Kormendy (1977) relation as adiscriminator, since pseudobulges tend to have lower central sur-face brightnesses at a fixed radius (see also Carollo 1999; Fisher& Drory 2008). Finally, while classical bulges are typified byold stellar populations, pseudobulges tend to have ongoing starformation (e.g., Kormendy & Kennicutt 2004; Drory & Fisher2007; Fisher et al. 2009; Gadotti 2009). Since deriving robustvelocity measurements is beyond the scope of this paper, andin the absence of more robust structural information, we relyon morphology and stellar population properties at the presenttime.

The nearest, well-studied targets in our sample (NGC 4388,and NGC 2273) probably contain pseudobulges. In the case ofNGC 2273, this classification is based on both the young stellarpopulations and the rings and nuclear disk. NGC 4388 is lesscertain, but there is clear evidence for recent star formation anddust. We suspect that NGC 6264 contains a pseudobulge, givenits morphological similarities with NGC 2273 (namely the outerring and inner bar) and the evidence for young stars. The samegoes for NGC 3393 and IC 2560, which each contain an outerring, a bar, and an inner ring. On the other hand, NGC 1194,with both evolved stellar populations and a large bulge, probablycontains a classical bulge. NGC 2960 has some of the clearestevidence for ongoing star formation, and so we tentatively putit into the pseudobulge category. Finally, we remain agnostic

about NGC 6323, which is one of the most distant targets. Thus,of the nine targets we consider, at least seven likely containpseudobulges.

6. SCALING BETWEEN MBH AND σ∗

In Figure 8, we present the location of the megamaser galaxiesin the MBH–σ∗ plane. The maser galaxies do not follow theextrapolation of the MBH–σ∗ relation defined by the ellipticalgalaxies. Instead, they scatter towards smaller BH masses ata given velocity dispersion. Quantitatively, taking ∆MBH ≡log(MBH) − log[M(σ∗)], where log[M(σ∗)] is the expected MBHgiven σ∗, we find ⟨∆MBH⟩ = 0.24 ± 0.10 dex. There are manyhints in the literature that the MBH–σ∗ relation does not extendto low-mass and late-type galaxies in a straightforward manner(e.g., Hu 2008; Greene et al. 2008; Gadotti & Kauffmann2009). However, the precision BH masses afforded by the masergalaxies make a much stronger case. The MBH–σ∗ relation isnot universal. Neither the shape nor the scatter of the ellipticalgalaxy MBH–σ∗ relation provides a good description of themaser galaxies in this plane.

We now add the maser galaxies to the larger sample of localgalaxies with dynamical BH masses to show that indeed a single,low-scatter power-law does not provide an adequate descriptionof all galaxies in the MBH–σ∗ plane. For convenience and tofacilitate comparison with previous work, we assume a powerlaw for all fits, although that form may not provide the bestdescription of the sample as a whole.

Greene et al. (2010)

Ade et al. 2013

NGC 6264: H0 = 68 ± 9 km/s/Mpc, Kuo et al. (2013)

Reid et al. (2008)

-60

-40

-20

0

20

Nor

th-S

outh

Offs

et (m

as)

-60-40-200East-West Offset (mas)

CO MajorAxis

730680630580530Heliocentric Radio Velocity (km s -1)

6420

Flux

(Jy)

750700650600550500Velocity (km/s)

Systemic

NGC4945(H2O)(Parkes-Tidbinbilla-Hobart-Mopra 6-97)

-4

-2

0

2

2 0 -2

6

Accretion and Outflow Physicsfrom “messy” systems

-60

-40

-20

0

20

Nor

th-S

outh

Offs

et (m

as)


CO MajorAxis


6420

Flux

(Jy)

750700650600550500Velocity (km/s)

Systemic


-4

-2

0

2

2 0 -2

7


-60

-40

-20

0

20

Nor

th-S

outh

Offs

et (m

as)


CO MajorAxis


6420

Flux

(Jy)

750700650600550500Velocity (km/s)

Systemic


-4

-2

0

2

2 0 -2

X-ray Wind

IR Wind

Done et al. (2003)

Moorewood et al. (1996)

Greenhill, IZ, & Zhang, in prep8


Traces warm, dense gasTest temperature gradient

9

Sources of error : - Uncertainty in vsys- Maser variability- Assumed symmetry of disk- Lower end of temp range- Temp and density overlap- Assumed mid-plane

Temperature required: ~400-1000 K

0

2

4

6

8R

ou

t / R

in

VLBI

Spectrum

Cir

cinu

s

NG

C 1

386

UG

C 3

789

NG

C 4

258

NG

C 1

194

NG

C 2

273

CG

211

NG

C 6

323

MR

K 3

4

VV

340

a

NG

C 3

393

NG

C 6

264

MR

K 1

419

IC 2

560

J043

7+24

56

ESO

558

-G00

9

UG

C 6

093

NG

C 5

495

T = 8.6⇥ 107��1/5m3/10m�1/5r�3/4(1� z�1/2)3/10 Shakura & Sunyaev (1973)

IZ, Greenhill, & Gruzinov, in prep

T Rout/Rin = (400/1000)-4/3 = 3.39

10

Preliminary maps from Megamaser Cosmology Grouphttps://safe.nrao.edu/wiki/bin/view/Main/MegamaserCosmologyProject

• NuSTAR spectroscopic fitting of AGN which host disk masers

• Model torus as extension of maser disk, exploit maser density condition to predict torus dimensions

• Torus dimensions agree roughly with available IR interferometry (NGC 1068 and Circinus)

11LBol

Rin

,mas

erR

out,m

aser

Rou

t,tor

us

Density required: ~107 - 1011 cm-3

Traces warm, dense gasTest obscuration

Masini et al. (2016)

Maser Host AGN

12

•Systems (~150 currently known):•Mostly local (z < ~0.067)

•Most distant known maser at z = 2.64•Rare, only ~few % of Sy2’s host masers

Zhu, IZ, Blanton, & Greenhill (2011)

What is special about maser hosts?

Maser Host AGN

• Maser detections and non-detections cross-matched with SDSS

• Overall detection rate ~3%, ~4.5% in Sy 2’s

• Detection rates higher at higher L[OIII]5007 and velocity dispersion, σ13

L[OIII]5007σt


Is Maser Luminosity an unobscured proxy for AGN activity and SMBH mass?

14

Rcr � L0.38AGNM0.62

BH

Assuming α, ηx, µ similar to NGC 4258

z• Maser emission beamed and variable

• Data from different surveys with different sensitivities

• SDSS data supplemented with values from literatureZhu, IZ, Blanton, & Greenhill (2011)

Neufeld & Maloney (1995)


• Large scatter but appears to be correlated, defying expectations

• Fit (dashed line), large errors:

• Dotted line assuming LH2O proportional to L[OIII] and MBH (σ4)

15

L[OIII]5007 σt MB


LH2O / L0.3[OIII] LH2O / �2.7

ObservedExtinction Corrected

Disk

Jet

Other

https://safe.nrao.edu/wiki/bin/view/Main/PrivateWaterMaserList

Maser Types

IZ, Mei, & Greenhill, in prep

Eddington Ratios

17


L[OIII]σ4t

LH2O

ModelBest Fit

All

Disks+Jets

“Others”

IZ, Mei, & Greenhill, in prep

LH2O / L0.20±0.12AGN M0.75±0.19

BH

LH2O / L0.06±0.08AGN M0.59±0.14

BH

Rcr � L0.38AGNM0.62

BH

LH2O / L0.01±0.11AGN M0.18±0.24

BH

LH2O

L[OIII]σ4t

σ4t L[OIII]

LH2O

Search for New Masers• Northern Sky: Megamaser Cosmology Project

(MCP)• ~3000 Type 2 AGN from SDSS surveyed with the Green Bank

Telescope, completed in 2015 (Braatz et al. 2016)

• Follow-up systems suitable for distance measurements

• Southern Sky: Tidbinbilla AGN Maser Survey (TAMS)• Co-PIs: Ingyin Zaw, Lincoln Greenhill (CfA),

Team: Shinji Horiuchi (CDSCC), Tom Kuiper (JPL), Frank Briggs (ANU)

• ~900 Type 2 AGN identified from 6dF spectra, δ < -30°

• 1200 hrs at the 70 m Tidbinbilla telescope (NASA DSN, near Canberra, Australia)

• Expect ~38 new masers, ~16 disks

• Combine with multi-wavelength data to understand AGN physics18

Summary• Masers offer a direct view of region ~0.1-1.0 pc from the

SMBH in highly obscured systems, combine with multi-wavelength data

• Single systems: detailed study of disk and outflow geometry

• Population studies:

• Masers are probes of disk temperature and density which can be used to test models of accretion and obscuration

• Maser luminosity could be a proxy for SMBH mass and AGN activity

• Conducting a large survey in the Southern hemisphere

19

an unobscured probe of obscured agn - dartmouth collegehiddenmonsters/talks/zaw.pdf · an...

Documents