The luminosity- dependent evolution of the radio luminosity function Emma Rigby Emma Rigby University of Nottingham University of Nottingham Collaborators: P. Best, M. Brookes, J. Collaborators: P. Best, M. Brookes, J. Dunlop, J. Peacock, L. Ker, H. Dunlop, J. Peacock, L. Ker, H. Rottgering, J. Wall Rottgering, J. Wall QuickTime™ and a decompressor are needed to see this pi
19
Embed
The luminosity-dependent evolution of the radio luminosity function
The luminosity-dependent evolution of the radio luminosity function. Emma Rigby University of Nottingham Collaborators: P. Best, M. Brookes, J. Dunlop, J. Peacock, L. Ker, H. Rottgering, J. Wall. Model of a radio-loud AGN (Urry & Padovani). Why study radio galaxy evolution?. - PowerPoint PPT Presentation
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
The luminosity-dependent evolution of the radio luminosity function
The luminosity-dependent evolution of the radio luminosity function
Emma RigbyEmma RigbyUniversity of NottinghamUniversity of Nottingham
Collaborators: P. Best, M. Brookes, J. Dunlop, J. Collaborators: P. Best, M. Brookes, J. Dunlop, J. Peacock, L. Ker, H. Rottgering, J. WallPeacock, L. Ker, H. Rottgering, J. Wall
Emma RigbyEmma RigbyUniversity of NottinghamUniversity of Nottingham
Collaborators: P. Best, M. Brookes, J. Dunlop, J. Collaborators: P. Best, M. Brookes, J. Dunlop, J. Peacock, L. Ker, H. Rottgering, J. WallPeacock, L. Ker, H. Rottgering, J. Wall
QuickTime™ and a decompressor
are needed to see this picture.
Why study radio galaxy evolution?Why study radio galaxy evolution?
• Important for Important for galaxy evolution galaxy evolution models via models via feedbackfeedback
• Radio-loud AGN Radio-loud AGN powered by most powered by most massive black massive black holes so provide holes so provide information on information on upper end of black upper end of black hole mass function hole mass function
• Important for Important for galaxy evolution galaxy evolution models via models via feedbackfeedback
• Radio-loud AGN Radio-loud AGN powered by most powered by most massive black massive black holes so provide holes so provide information on information on upper end of black upper end of black hole mass function hole mass function
Model of a radio-loud AGN (Urry & Padovani)
Model of a radio-loud AGN (Urry & Padovani)
The evolving radio luminosity function (RLF)
The evolving radio luminosity function (RLF)
• Comoving space density of radio galaxies increases to z Comoving space density of radio galaxies increases to z ~2 (Dunlop & Peacock 1990), with indications of a ~2 (Dunlop & Peacock 1990), with indications of a decline at higher redshiftdecline at higher redshift
• Previous work lacked depth & volume necessary to probe Previous work lacked depth & volume necessary to probe high-z behaviorhigh-z behavior• Motivated development of Motivated development of CENSORSCENSORS - a faint radio source - a faint radio source
• Investigate using a grid-based modelling technique with Investigate using a grid-based modelling technique with no assumptions made about the RLF behaviorno assumptions made about the RLF behavior
• Comoving space density of radio galaxies increases to z Comoving space density of radio galaxies increases to z ~2 (Dunlop & Peacock 1990), with indications of a ~2 (Dunlop & Peacock 1990), with indications of a decline at higher redshiftdecline at higher redshift
• Previous work lacked depth & volume necessary to probe Previous work lacked depth & volume necessary to probe high-z behaviorhigh-z behavior• Motivated development of Motivated development of CENSORSCENSORS - a faint radio source - a faint radio source
• Investigate using a grid-based modelling technique with Investigate using a grid-based modelling technique with no assumptions made about the RLF behaviorno assumptions made about the RLF behavior
RLF Modelling: input dataRLF Modelling: input data• 5 input radio source samples5 input radio source samples
(Downes et al 1986),(Downes et al 1986),• CENSORS (Best et al. 2003)CENSORS (Best et al. 2003)• Hercules, (Waddington et al. Hercules, (Waddington et al.
2001)2001)• VLA-COSMOS, (Smolcic et al. VLA-COSMOS, (Smolcic et al.
2008)2008)
• Local radio luminosity Local radio luminosity functions covering ~20 < Log functions covering ~20 < Log PP1.4GHz1.4GHz < 27 < 27 (Best et al., 2010; Sadler et al., (Best et al., 2010; Sadler et al., 2002; Mauch et al., 2007)2002; Mauch et al., 2007)
• Integrated source counts Integrated source counts covering 0.05 mJy to 94 Jy covering 0.05 mJy to 94 Jy (Bondi et al. 2008; Seymour et al. (Bondi et al. 2008; Seymour et al. 2004; Windhorst et al. 1984; 2004; Windhorst et al. 1984; White et al. 1997; Kellermann & White et al. 1997; Kellermann & Wall 1987)Wall 1987)
(Downes et al 1986),(Downes et al 1986),• CENSORS (Best et al. 2003)CENSORS (Best et al. 2003)• Hercules, (Waddington et al. Hercules, (Waddington et al.
2001)2001)• VLA-COSMOS, (Smolcic et al. VLA-COSMOS, (Smolcic et al.
2008)2008)
• Local radio luminosity Local radio luminosity functions covering ~20 < Log functions covering ~20 < Log PP1.4GHz1.4GHz < 27 < 27 (Best et al., 2010; Sadler et al., (Best et al., 2010; Sadler et al., 2002; Mauch et al., 2007)2002; Mauch et al., 2007)
• Integrated source counts Integrated source counts covering 0.05 mJy to 94 Jy covering 0.05 mJy to 94 Jy (Bondi et al. 2008; Seymour et al. (Bondi et al. 2008; Seymour et al. 2004; Windhorst et al. 1984; 2004; Windhorst et al. 1984; White et al. 1997; Kellermann & White et al. 1997; Kellermann & Wall 1987)Wall 1987)
The radio-power - redshift plane covered by the 5 samples
The radio-power - redshift plane covered by the 5 samples
RLF Modelling: input dataRLF Modelling: input data• 5 input radio source samples5 input radio source samples
(Downes et al 1986),(Downes et al 1986),• CENSORS (Best et al. 2003)CENSORS (Best et al. 2003)• Hercules, (Waddington et al. Hercules, (Waddington et al.
2001)2001)• VLA-COSMOS, (Smolcic et al. VLA-COSMOS, (Smolcic et al.
2008)2008)
• Local radio luminosity Local radio luminosity functions covering ~20 < Log functions covering ~20 < Log PP1.4GHz1.4GHz < 27 < 27 (Best et al., 2010; Sadler et al., (Best et al., 2010; Sadler et al., 2002; Mauch et al., 2007)2002; Mauch et al., 2007)
• Integrated source counts Integrated source counts covering 0.05 mJy to 94 Jy covering 0.05 mJy to 94 Jy (Bondi et al. 2008; Seymour et al. (Bondi et al. 2008; Seymour et al. 2004; Windhorst et al. 1984; 2004; Windhorst et al. 1984; White et al. 1997; Kellermann & White et al. 1997; Kellermann & Wall 1987)Wall 1987)
(Downes et al 1986),(Downes et al 1986),• CENSORS (Best et al. 2003)CENSORS (Best et al. 2003)• Hercules, (Waddington et al. Hercules, (Waddington et al.
2001)2001)• VLA-COSMOS, (Smolcic et al. VLA-COSMOS, (Smolcic et al.
2008)2008)
• Local radio luminosity Local radio luminosity functions covering ~20 < Log functions covering ~20 < Log PP1.4GHz1.4GHz < 27 < 27 (Best et al., 2010; Sadler et al., (Best et al., 2010; Sadler et al., 2002; Mauch et al., 2007)2002; Mauch et al., 2007)
• Integrated source counts Integrated source counts covering 0.05 mJy to 94 Jy covering 0.05 mJy to 94 Jy (Bondi et al. 2008; Seymour et al. (Bondi et al. 2008; Seymour et al. 2004; Windhorst et al. 1984; 2004; Windhorst et al. 1984; White et al. 1997; Kellermann & White et al. 1997; Kellermann & Wall 1987)Wall 1987) The CENSORS redshift distributionThe CENSORS redshift distribution
QuickTime™ and a decompressor
are needed to see this picture.
QuickTime™ and a decompressor
are needed to see this picture.
Modelling TechniqueModelling Technique
RedshiftRedshift
Radio PowerRadio Power
Space densitiesSpace densities
RLFRLF Cosmic evolutionCosmic evolution
Modelling TechniqueModelling Technique3 input radio-luminosity - redshift (P,z) density grids: 21 points in
log P (19.25 < Log P < 29.25) and 8 points in z (0.1 < z < 6)3 input radio-luminosity - redshift (P,z) density grids: 21 points in
log P (19.25 < Log P < 29.25) and 8 points in z (0.1 < z < 6)
Steep Steep spectrum spectrum
gridgrid
Steep Steep spectrum spectrum
gridgrid
Flat Flat spectrum spectrum
gridgrid
Flat Flat spectrum spectrum
gridgrid
Starforming Starforming gridgrid
Starforming Starforming gridgrid
Created by evolving the local starforming
galaxy luminosity function
Created by evolving the local starforming
galaxy luminosity function
Taken as the median of the
evolutionary models of Dunlop &
Peacock 1990
Taken as the median of the
evolutionary models of Dunlop &
Peacock 1990
Starting estimate created by evolving the local AGN RLF
by (1+z)3
Starting estimate created by evolving the local AGN RLF
Dashed line: median of Dunlop & Peacock (1990) resultsDashed line: median of Dunlop & Peacock (1990) results
Results: model luminosity functions
Results: model luminosity functions
Results: model luminosity functions
Results: model luminosity functions
Blue: lack of coverage in local RLF Green: Incomplete coverage of radio power - redshift planeBlue: lack of coverage in local RLF Green: Incomplete coverage of radio power - redshift plane
Robustness testingRobustness testing
Randomly moving the redshift limits to higher valuesRandomly moving the redshift limits to higher values
Varying the spectral index used to calculate the steep source number grid
Varying the spectral index used to calculate the steep source number grid
Redshift cutoffs still presentRedshift cutoffs still present
The high redshift cutoffThe high redshift cutoff
• High redshift cutoffs seen High redshift cutoffs seen across the radio power rangeacross the radio power range
• Cutoffs still present when Cutoffs still present when model parameters are variedmodel parameters are varied
• Need ~5 extra sources in Need ~5 extra sources in CENSORS sample to reduce CENSORS sample to reduce the cutoff strength to <3the cutoff strength to <3 for 27 < log P < 28for 27 < log P < 28
• Position of cutoff appears to Position of cutoff appears to be radio luminosity -be radio luminosity -dependent dependent
• High redshift cutoffs seen High redshift cutoffs seen across the radio power rangeacross the radio power range
• Cutoffs still present when Cutoffs still present when model parameters are variedmodel parameters are varied
• Need ~5 extra sources in Need ~5 extra sources in CENSORS sample to reduce CENSORS sample to reduce the cutoff strength to <3the cutoff strength to <3 for 27 < log P < 28for 27 < log P < 28
• Position of cutoff appears to Position of cutoff appears to be radio luminosity -be radio luminosity -dependent dependent
The future…The future…
• Larger radio source samplessamples will mean RLF evolution of different populations can be studied individually
• e.g. FRI vs FRII or Low vs High excitation sources
• Larger radio source samplessamples will mean RLF evolution of different populations can be studied individually
• e.g. FRI vs FRII or Low vs High excitation sources
Predictions for the LOFAR-deep survey [dashed line - FRIs, solid line - starforming galaxies, dot-dashed line - radio quiet quasars, dotted line - FRIIs]
Predictions for the LOFAR-deep survey [dashed line - FRIs, solid line - starforming galaxies, dot-dashed line - radio quiet quasars, dotted line - FRIIs]
FRIs
FRIIs
Starforming galaxies
The future…The future…• Luminosity dependence seen for cutoff needs to be
incorporated into SKA population models• Luminosity dependence seen for cutoff needs to be
incorporated into SKA population models
Red dashed line computed from S3 SKADS simulations (Wilman et al. 2008)
ConclusionsConclusionsConclusionsConclusions
• Using our new grid-based modelling have Using our new grid-based modelling have found clear high-redshift cutoff in the RLFfound clear high-redshift cutoff in the RLF
• Cutoff appears to move to higher redshift Cutoff appears to move to higher redshift
at higher radio powerat higher radio power
• Results still limited by uncertain redshifts Results still limited by uncertain redshifts & small radio samples& small radio samples