A Multi-wavelength View of the Archetypal CSS Radio Galaxy 3C303.1: Evidence for Shocks and Induced Star Formation Chris O Dea (Rochester Institute of Technology) HST Spectroscopy: Alvaro Labiano, Wim de Vries, Anton Koekemoer, Stefi Baum, Raffaella Morganti, Roberto Fanti, Alessandro Capetti, Clive Tadhunter, Peter Barthel, David Axon, Richard Gelderman HST UV: Alvaro Labiano, Peter Barthel, Wim de Vries, Stefi Baum XMM: Bo Mu, Diana Worrall, Joel Kastner, Stefi Baum, Wim de Vries
Radio Source Feedback (see talk by Best) Radio Source heating has been invoked to explain the luminosity function of galaxies (e.g., Benson et al 2003; Binney 2004, Croston et al 2005) the lack of intermediate temperature gas in X-ray spectra of the ICM of cool core clusters (e.g., Peterson & Fabian 2006, McNamara & Nulsen 2007). the entropy of the ICM (e.g., Voit and Bryan 2001) CSS sources are well matched to the scale of the host galaxy (Top) Unsharp masked image from Chandra Image. (Bottom) Radio image in blue superimposed on pressure difference map in red (Fabian et al 2006)
The CSS Radio Source Asymmetric double Z =0.267 No radio core detected Power at 5 GHz P ~ few x 1026 W/Hz Total projected size 6.2 kpc VLA 8.4 GHz image, 0.25 arcsec resolution (Akujor & Garrington 1995, A&AS, 112, 235).
The Alignment Effect in CSS Sources Broad and narrow band HST imaging of CSS radio sources (De Vries etal. 1997, 1999; Axon etal 2000, Privon et al. 2008) have revealed: CSS radio sources at all redshifts show emission line gas strongly aligned with the radio source Alignment is stronger than seen in low z large scale radio sources In most cases the emission line gas lies interior to the radio hot spots Where gas is seen beyond the radio source it is fainter than the gas interior See talks by Holt, Labiano (Top) HST/WFPC2 F702W imaging. (De Vries et al. 1997). (Bottom) 3C303.1 z=0.270. HST/WFPC2 F702W and LRF imaging. (De Vries etal 1999).
The Alignment Effect in CSS Sources CSS radio sources at all redshifts show emission line gas strongly aligned with the radio source (De Vries etal. 1997, 1999; Axon etal 2000, Privon et al. 2008). The [OIII] emitting clouds have densities in the range 100-1000 cm-3. Path lengths of 1 pc imply column densities of N(H) ~ 1020 1021 cm-2. There is a population of dense clouds throughout the ISM which accounts for both the emission line nebulae and the atomic hydrogen. These clouds probably originate in the merger/interaction which also feeds the nucleus. If the distribution of clouds is not uniform, jet/cloud interactions might produce the observed asymmetries in the radio structure. The bow shock compresses and heats the clouds, initially to sufficiently high temperatures that they need to cool before they emit [OIII]. R(gap) ~ vhs tcool See talks by Holt, Labiano (Top) HST/WFPC2 F702W imaging. (De Vries et al. 1997). (Bottom) 3C303.1 z=0.270. HST/WFPC2 F702W and LRF imaging. (De Vries etal 1999).
HST/STIS Long Slit Spectroscopy Goals: kinematics and ionization diagnostics of aligned gas in 3C303.1 STIS long slit spectra (width 0.1 ) One orbit each slit position (2500-3000sec) For kinematics: G750M slit parallel to source axis and two perpendicular For ionization diagnostics G430L and G750L slit along source axis. Slit orientation optimized for emission line gas HST/STIS slit positions overlayed on radio/emission line image of 3C303.1 (O Dea et al. 2002, 123, 2333)
3C303.1 N & S Lobes show similar kinematics FWHM ~ 200-500 km/s Complex velocity field with several components (split lines?) Side-to-side velocity offset ~500 km/s (S lobe) and ~250 km/s (N lobe) 3C303.1. (Above) 2-D spectrum of slit aligned with the radio axis. (Right Top) [OIII]5007 Line properties as a function of distance from the nucleus. At some locations, multiple Gaussians are needed to fit the lines. Positive offset is North.. (Right Middle South Lobe; Bottom North Lobe) Plot of [OIII]λ5007 emission line properties across the lobes. Slit is approx parallel to the radio source axis. At some locations, multiple Gaussians are needed to fit the lines. Positive offset is East. (O Dea et al 2002, AJ, 123, 2333).
Comparison with Large Low z RGs CSS sources tend to have larger organized gas motions for a given value of random motions. Squares are low redshift radio galaxies from Baum, Heckman & van Breugel 1990,1992 ε is the mean of the rms velocity variations on either side of the nucleus. It is a measure of the random motions. Δ is ½ the difference in average velocities on both sides of the source. It is a measure of the organized gas motions. Sources on the right of the line are dominated by organized gas motions while those on left by random motions (O Dea et al. 2002, AJ, 123, 2333).
BPT Diagrams: Shock Ionization of the Nebula The extended emission has lower ionization than the nucleus. The observed ratios are consistent with a mixture of shocks and photoionization. De-redenned diagnostic emission line ratios. Predictions from the Mappings (Kewley etal 2003) shock models and Cloudy (Ferland 1998) AGN photoionization models are shown. The Mappings models illustrate the effect of different combinations of pure shock and precursor emission, while the Cloudy models illustrate the effect of varying ionization parameter. High ionization is the the lower right and low ionization is to the upper left. (Labiano et al. 2005, A&A, 436, 493).
Optical Emission Line Summary 3C303.1 sources shows complex kinematics Evidence for multiple velocity components (split lines?) Asymmetric side-to-side offsets in velocity ~300-700 km/s Emission Line Diagnostics (BPT) indicate a significant contribution from shocks to the ionization of the gas. Suggests expanding radio source shocks gas clouds, giving them a kick, and exciting line emission.
Spitzer IRS Spectrum of 3C303.1 is Consistent with hidden quasar + torus + Star Formation High ionization lines [NeV] (97 ev), [OIV] (55 ev) produced by nuclear photoionization from hidden quasar Mid-far IR continuum from torus and/or extended warm dust Low ionization lines [NeII] (21 ev) and PAH features (7.7 and 11.3 µm) which are excited by star formation. Spitzer IRS low resolution spectrum of 3C303.1 (Haas et al. 2005, A&A, 442, L39). Long slit aperture width is 3.7 and 10.6 respectively at the short and long wavelengths.
UV Observations of Jet-Induced Star Formation? We find UV emission aligned with the radio source in 3C303.1. We suggest the emission is due to recent star formation which has been triggered by the expanding radio lobes. Probably not a lot of star formation. The lack of alignment in GPS sources suggests the UV Overlay of HST/ACS/HRC/F330W image on the radio source emission is not scattered (green contours). The relative registration is uncertain, but the alignment between the radio and the UV is clear. (Labiano etal. nuclear light. 2008, A&A, 477, 491). Note image is rotated.
XMM Detection of 3C303.1 We observed 3C303.1 for 40 ks with XMM. We detect an unresolved source (< 6 ). So cluster scale emission is ruled out. But the radio source and host galaxy are possible contributors. Lx (0.4-8keV) ~ few x 1042 ergs/s 3C 303.1. Left: XMM-Newton pn image showing detection of 3C 303.1. A circle of 15 arcse radius is shown around the source. Right: Optical image from the STScI digitized sky survey. A circle of 10 arcsec radius is shown around the source (O Dea et al. 2006, ApJ, 653, 1115)
Host Galaxy + Something Else We find a good fit to a 0.8 kev Raymond-Smith model plus an additional component which is not well constrained. The 0.8 kev component is likely to be produced by the ISM of the host galaxy. 3C 303.1. XMM-Newton spectrum showing the pn (darker) and MOS (lighter) data and the model consisting of a 0.8 kev thermal model plus a power-law. Residuals are plotted in units of 1 sigma error. (O Dea et al. 2006, ApJ, 653, 1115)
The Second Component is probably not the Nucleus A high absorbing column is not required to fit the XMM spectrum of the second component. The radio core is faint. A Chandra snapshot (Harris et al) does not detect the nucleus, but finds faint emission distributed on the scale of the radio source. (But some hard photons from the nucleus are not ruled out.) Based on the XMM spectrum, we consider SSC from the S radio lobe A very hot (shocked?) gas. 3C 303.1. Chandra snapshot (8 ks) showing faint emission on the scale of the radio source (Harris et al in preparation). Note that the relative astrometry is uncertain to 1, and the image is sub-pixelized.
The Second Component is probably not the Nucleus A high absorbing column is not required to fit the XMM spectrum of the second component. The radio core is faint. A Chandra snapshot (Harris et al) does not detect the nucleus, but finds faint emission distributed on the scale of the radio source. (But some hard photons from the nucleus are not ruled out.) Based on the XMM spectrum, we consider SSC from the S radio lobe A very hot (shocked?) gas. (Top)3C 303.1. Chandra snapshot (8 ks) showing faint emission on the scale of the radio source (Harris et al in preparation). Note that the relative astrometry is uncertain to 1, and the image is sub-pixelized. (Bottom) Same data, but in two energy bands, and with actual Chandra pixel sizes (Worrall).
Synchrotron Self Compton? N lobe is too faint. Could be SSC from S lobe if B field is ~3.5 below equipartition value. 3C 303.1. Table of SSC parameters from O Dea et al. 2006.
Hot Shocked Gas? Cooling time arguments suggest lobe expansion speed is ~6000 km/s (De Vries et al. 1999). Sound speed in 0.8 kev ISM is cs ~ 460 km/s Implies M ~ 13, Strong shock Rankine-Hugoniot conditions imply T ~ 43 kev. Numerical simulations suggest volume of shocked gas is ~ 3 times radio luminous cocoon, so Vsh ~ 14 kpc3, consistent with XMM spectra 3C 303.1. (Top) Spectral fits to two temperature model (O Dea et al., 2006, ApJ, 653, 1115). (Bottom) Cartoon of evolution of outline of jet, cocoon and bow shock (based on Carvalho and O Dea 2002, ApJS, 141, 337)
Summary Optical emission line kinematics are consistent with clouds run over and shocked by radio source bow shock Ionization diagnostics consistent with shocks + hidden quasar Spitzer IRS spectrum consistent with hidden quasar + torus + star formation UV light aligned with radio axis consistent with radio-source triggered star formation XMM spectrum consistent with component due to hot shocked gas (M~13, T ~ 43 kev). This suggests the expanding radio source provides energy to both the hot and warm/cool components of the ISM of the host galaxy.
Postdoctoral Position Chris and Stefi and looking for a postdoc to work on multi-wavelength observations of clusters of galaxies. odea@cis.rit.edu
The End