The Lyman- halo of B2 0902+34:

Evidence for infall of extended HI

Joshua Adams & Gary Hill

University of Texas, Austin

Department of Astronomy

3D2008 ESO Workshop

Garching, 6-13-08

Overview

• High Redshift Radio Galaxy (HzRG) Lyman- halo science motivation

• New integral field spectroscopy data on B2 0902+34

• New Monte Carlo resonant scattering model

• Future observations and model discrimination

Why bother with HzRG halos?“While LABs are known to exist around radio-loud quasars, they are attributable to known jets and supernova-driven outflows, and we do not attempt to model them here.”

Dijkstra et al. (2006b)“(The LSBHs) which extends across the entire object and beyond the edge of the radio lobes shows no apparent association with radio structures.”

Villar-Martin et al. (2002)

Massive galaxy and cluster formation/feedback

MRC 0052-241, Venemans et al., 2007 Rawlings and Jarvis, 2004

HzRG Lyman background

• van Ojik et al. (1997) find spatially resolved line profile structure in 11/18 HzRGs

• Villar-Martin et al. (2003) find LSBHs in 10/10 HzRGs + at least 4 more known

• Similarly, 5 quasars (Christensen et al. (2006),Weidinger et al. (2004)) show extended emission

• Unknown relation, if any, to LABs

Existing B2 0902+34 data

Reuland et al. 2007

Exciting new spectral feature

•Inclination of northern radio jet is >30˚ and <45˚ (Carilli 1995)

•21 cm HI absorption at z=3.3968 with FWHM=120 km/s and N=3x1021 cm-2 (Uson et al. 1991 and others)

•Normal line ratios for pure AGN photoionization in Ly-, CIV1549, and HeII1640 (Villar-Martín et al. 2007)

Existing B2 0902+34 data

Reuland et al., 2003

VIRUS-P instrument• Large fibers with 2.7m focal

reducer: 4.2” diameter• 105x105arcsec2 field, fill

factor 1/3, 247 fibers• 3500-5800Å, R~1000

No resampling in reductions

• Does not introduce correlated noise

• Allows sky subtraction free of any features and reaches noise limits

Liner interpolation Bspline, similar to Kelson (2003)

Our VIRUS-P data

a

b

c

Radio data from Carilli 1995

Our VIRUS-P dataPrimary emission:

5339.0 ± 2.0 Å

600 ± 90 km/s FWHM

Secondary emission:

15% as strong

5324.5 ± 1.7 Å

630 ± 270 km/s FWHM

Failing explanations for B2…• Optically Thin Infall

– No bimodal line profile allowed– Too small FWHMs

MRC 1558-003, Villar-Martin et al., 2007

Q1205-30, Weidinger et al., 2004

Failing explanations for B2…

• Outflow (Reuland et al. 2007)– Where is the 21cm HI population in Ly-?– Why is there no line profile bimodality in the

NE? Wilman et al., 2005

Our model: resonant scattering

• Monte Carlo Resonant Scattering code with 7x105 photons per simulation

• Biconal emission geometry per the Alignment Effect (McCarthy 1993)

• Isothermal NFW profile, baseline simulation uses 6x1012 Ms halo with rv=134 kpc and ri=97 kpc

Model Geometry

Tunable parameters: 1) total halo mass 2) ionization radius 3)velocity strength 4)velocity power law with radius

Monte Carlo radiative transfer• Pick a random optical depth from exponential

deviate in random direction• Transform to scattering particle’s rest frame• Obtain scatterer’s parallel velocity from the following

pdf:

• Obtain scatterer’s Maxwellian perpendicular velocity• Obtain scattering direction from dipole distribution• Transform back to observer’s frame• Repeat

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Resonant scatter trends

Blue Red

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Resonant scatter trends

Blue Red

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cosh124

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x

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axJ

Far

Cone

Near

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Resonant scatter trends

Blue Red

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cosh124

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x

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Our VIRUS-P data + model

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Radio data from Carilli 1995

Our VIRUS-P data + model

Surface brightness

Conclusions• A resonant scatter model explains

– The spatial distributions of the bimodal profile– The relative intensities of the bimodal profile– The relative wavelengths of the bimodal profile– The surface brightness profile– The 21cm data

• We predict a very large HI mass, 1011-1012Ms

• VLBI radio spectral imaging can falsify our model• Are B2 0902+34 and other HzRGs displaying

– Strong AGN feedback (outflow) or– Large (cluster?) galaxy formation (infall)

Extras

The 21cm Data,mk picObservation Our Model

N (cm-2) 3x1021 7x1021

FWHM (km/s) 120 273

V (km/s) - 121

A trial system: B2 0902+34

• Carilli (1995) derives a low inclination angle for the radio jets– Hot spot A is bright and

polarized– High projection explains

steep spectral index in north

– High projection explains lack of alignment effect

Systemic redshift estimates

Litmus Test on Infall: Skew

Infall or Outflow

Dijkstra et al. (2006b)Wilman et al. (2005)

General Resonant Scatter Results

Dijkstra et al. (2006a)

• “Dip” Due To Doppler To Line Center Against A Velocity In Neutral Hydrogen

• Velocity Magnitude May Come From Red Bump Position/Relative Magnitude

• Velocity Shape May Come From Wavelength Dependent Surface Brightness Profile

Existing B2 0902+34 data

• Undetected in CO(4-3) and CO(5-4), along with 13 other HzRGs (van Ojik et al., 1997) and in CO(4-3), CO(5-4), and CO(8-7) in Evans et al., 1996

• Spitzer data

(Seymour et al., 2007)

gives fstel=0.28 and

Mstel=1010.81Ms

Code Tests

Emergent Spectra From Static Sphere

Redistribution Function with Dipole Phase Function