Large-Scale Winds in Starbursts and AGN
David S. Rupke University of Maryland
Collaborators:Sylvain VeilleuxD. B. Sanders
v = -1550 km s-1
Rupke, Veilleux, & Sanders 2005a,b,c, submitted
Density Temperature
Cooper, Bicknell, & Sutherland 2005, in prep., and . . .Veilleux, Cecil, & Bland-Hawthorn 2005, ARAA, in press
Sample
• 78 starbursts– 50% luminous infrared galaxies (LIR > 1011 L)
– 50% ultraluminous infrared galaxies (LIR > 1012 L)
• 26 AGN– mostly Seyfert 2 ULIRGs– a few Seyfert 1s
• 104 total galaxies!
the largest superwind survey to date at z < 3
Method
• Spectroscopy of the Na I D doublet– Moderate resolution 65-85 km s-1
– Data from Keck II (10m), MMT (6.5m), KPNO (4m)
• Fit absorption lines– multiple velocity components– Gaussians in optical depth– yields velocity, Doppler parameter, optical depth, covering
fraction
• Compute– Mass, Momentum, Energy, and their outflow rates– *Simple model of constant-velocity, mass-conserving wind
11221f yr M
s km 200
Δv
cm 10
(H)
kpc 5
rC
0.4
4π / Ω 5
t
M
N
d
d
(* Model assumes thin shell, time-averaged outflow rates)
Detection rates• Comparison of different subsamples
– starburst LIRGs 45% (± 10%)
– Seyfert 2 ULIRGs 45% (± 10%)
– starburst ULIRGs 70 – 80% (± 10%)
• Differences in detection rate appear to reflect GEOMETRY– wind opening angle for moderate starbursts and Seyfert
2s in local universe is CΏ ~ 0.4-0.5
there are winds in all starburst LIRGs and Seyfert 2 ULIRGs!
• Same conclusion applies to ULIRGs
Velocities
V(LIRG) < V(SB ULIRG) < V(Sy2 ULIRG) 100 km/s < 170 km/s < 220 km/s
V(H II) < V(LINER) < V(Sy2)120 km/s < 230 km/s < 310 km/s
Spectral Type
Star Formation rate / Nuclear Activity
} significant
AGN- vs. Starburst-driven winds?
• Can we demonstrate that AGNs help drive winds in Seyfert ULIRGs?– No! The statistics don’t convincingly indicate it.
– But there are hints . . .
• Seyfert 2 ULIRGs are statistically indistinguishable from SB ULIRGs– however, the SFRs and outflow detection rates are
lower in Seyfert 2 ULIRGs than in SB ULIRGs
– So differences between Sy2 ULIRGs and LIRGs may imply an AGN contribution.
Circular velocity Star formation rate
Ou
tflo
w v
eloc
ity
isothermal escape speed
= Starbursts = Seyfert 2s
Outflow properties vs.Galaxy properties
dwarf galaxies from Schwartz & Martin 2004
Murray et al. 2004, Martin 2005
Circular velocity Infrared luminosity
Mas
s ou
tflo
w r
ate
Starburst99 prediction(tSB > 40 Myr, Z = Z)
= Starbursts = Seyfert 2s
Circular velocity Infrared luminosityMom
entu
m o
utf
low
rat
e SB99
= Starbursts = Seyfert 2s
Radiation pressure
Slopes of Correlations
• Strong dependence on galactic mass– velocity, mass, momentum, and energy all increase
sharply with circular velocity
– Power-law slopes of 3-5 !• Linear dependence of mass, momentum on SFR
– but energy increases more sharply as SFR increases increase in thermalization efficiency with SFR?– v SFR0.2
• Metallicity effects– incorporating the K-band L–Z relationship (Salzer et al.
2005) does not change these conclusions significantly– I.e. metallicity is not driving these trends! (preliminary)
Correlations at SFR 100 M yr-1
• We observe a statistically significant flattening in dependence of outflow properties on galaxy properties.
• Possible explanations:– depletion of gas reservoirs– decrease in thermalization efficiency– velocity ceiling (Murray et al. 2004, Martin 2005)
– saturation in star formation surface density (Strickland et al. 2004a,b)
Neutral/Ionized CorrelationsF
WH
M [
O I
II] 5
007
Na I D velocity Na I D velocity
All galaxies Galaxies with BELA
Mrk 231 – AGN + Starburst winds?
• A Seyfert 1 ULIRG• Small-scale AGN outflow observed in Na I D
– broad, high-velocity (v = 4000 – 8000 km s-1) absorption (e.g., Boksenberg et al. 1977)
– highest velocity component is variable
• A large-scale outflow observed– blueshifted emission lines (Hamilton & Keel 1987)
– blueshifted absorption lines (v 2000 km s-1)
• Jet or wide-angle outflow?– disk geometry and measured velocities favor wide-angle outflow– however, jet could still inject energy . . .
Summary/Outlook• Winds occur in ~ all LIRGs and ULIRGs• Can’t yet convincingly demonstrate influence of AGNs on
large-scale outflow– need more data on Seyfert 2s– there are hints
• Outflow and galaxy properties are strongly correlated– flattening at high SFR, galaxy mass
• Ionized and neutral gas is correlated– Vmax(ionized) Vmax(neutral)
• Mrk 231 is a good example of a galaxy with both a small- and a (spatially-resolved!) large-scale wind.
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