1. Accretion and Star Formation in Radio-Quiet Quasars
Sarah White
(ICRAR, Curtin University)
Matt Jarvis (Oxford),
Boris Häußler (ESO),
Natasha Maddox (ASTRON),
Eleni Kalfountzou (ESA),
Martin Hardcastle (Herts)

2. ICRAR/Curtin – Science & Engineering
I’m a new postdoc at Curtin University in Perth, using … invited talk on Friday.
Accretion and star formation in RQQs - Sarah White, July 2016

3. Active Galactic Nuclei (AGN)
However today I will be presenting …accreting material efficiently … does not mean that they are ‘radio silent’
Credit: Aurore Simonnet, Sonoma State University
Accretion and star formation in RQQs - Sarah White, July 2016

4. Does star formation (SF) dominate the radio emission?
Brightness-weighted number counts
log10[L(W Hz-1)] at <z>=0.8
AGN SF
log10[S5/2 n(S) / (Jy3/2 sr-1)]
Here we have …. radio emission enables both processes to be traced. …disentangle …probe to lower radio flux densities, where a flattening of the source …star-formation dominated regime. However, we are yet to understand the level of star formation in RQQs.
log10[ Radio flux-density / Jy ]
Condon et al. (2012)
All radio sources, < z > = 0.8
Accretion and star formation in RQQs - Sarah White, July 2016

5. Does star formation (SF) dominate the radio emission?
Brightness-weighted number counts
log10[S2 n(S) / (Jy sr-1)]
log10[ Radio flux-density / Jy ]
log10[L(W Hz-1)] at <z>=0.8
AGN SF
log10[S5/2 n(S) / (Jy3/2 sr-1)]
Now Condon … SDSS quasars…NVSS radio catalogue. Below the catalogue limit… not as radio-quiet as expected… assumption that the power-law…may not actually be true. The deviation …attributed to star formation.
log10[ Radio flux-density / Jy ]
Condon et al. (2012)
All radio sources, < z > = 0.8
Condon et al. (2013)
Optically-selected quasars, 1.8 < z < 2.5
Accretion and star formation in RQQs - Sarah White, July 2016

6. The VIDEO Survey Jarvis et al. 2013 Z, Y, J, H, Ks bands
XMM-LSS field:
~4.5 square degrees
Jarvis et al. 2013
Quasars are typically selected in the optical…luminosity function …However, with VIDEO …over 4 orders of magnitude deeper. VIDEO stands for …I use its 5 near-infrared …Canada France Hawaii Telescope Legacy Survey for selecting quasars.
UKIDSS-UDS field
VLA map (Bondi et al. 2003)
Spitzer SWIRE imaging data
CFHTLS-D1: u, g, r, I, z over 1 deg2
RA: 02h 26m 18s
Dec: -04d 44m 00s
Accretion and star formation in RQQs - Sarah White, July 2016

7. Detection of faint radio emission.
Pseudo-random positions
Gold QSOs
Quasars
Background . .
Number count . . . N
To study the radio emission…VLA-VIRMOS Deep Field… mean rms of 17.5 microJy across 1 square degree. …non-radio astronomers …AB magnitude of I extract …VIDEO positions …schematically by the blue dots)…and create a sample of random flux densities. …annulus …noise variations across the map…Kolmogorov-Smirnov test …drawn from different populations…In other words, there is excess radio emission …blue histogram. [ *log10(17.5) = to get uJy into AB mag.] E
Radio flux-density at 1.4 GHz / μJy
Bondi et al. 2003, 1 deg2
rms = 17.5 μJy = 20.8 mag (AB)
resolution = 6” at 1.4 GHz
KS test p-value = 10-12
Accretion and star formation in RQQs - Sarah White, July 2016

8. 2 star-formation rate (SFR) estimates
Rosario et al. 2013
Bennert et al. 2011: MBH -> M*
Whitaker et al. (2012) showed that SFR α M*0.6
White et al., arXiv:
MBH
= 1010 M
= 109 M
log10[SFR from stellar mass / (M yr-1)]
= 108 M
White et al. 2015, arXiv:
log10[SFR /(M yr-1)]
A route for investigating the origin …note that Rosario …consistent with galaxies belonging to the SF-mass main sequence. …To test this …two independent estimates of SFR. The first uses a scaling relation …in combination with the evolution in the SF-mass …10^8, 10^9 and 10^10 Msol. The second estimate …radio luminosity. …one-to-one correspondence between the two SFRs…probability distributions …lie on this line …1010 M¤, which is very unlikely ……either lie off the SF-mass sequence, and are starbursts, or the AGN’s contribution … Since far-infrared studies …accretion explanation must be correct. … star formation …typical black hole masses, which is in contrast … [5 mins left]
log10[SFR from radio luminosity / (M yr-1)]
The SF-mass
sequence
Yun, Reddy & Condon 2001:
SFR / (M yr-1) = 5.9 ± 1.8 x L 1.4 GHz / (W Hz-1)
log10[M*/M]
Accretion and star formation in RQQs - Sarah White, July 2016

9. Second RQQ sample ≠
The Spitzer-Herschel Active Galaxy Survey, Kalfountzou et al (in prep.)
SDSS-selected quasars
RLQs in FIRST, NVSS and WENSS removed
Factor ~100 in optical luminosity
~ 18 RQQs per Mi bin Mi N
Now moving on to …Here our aim is to …first step is …SDSS (red points) …. Next, FIRST, NVSS and …blue dots. These remaining RQQs span factor of around 100 …around 18 objects sample 4 Mi bins.
[WENSS - Westerbork Northern Sky Survey] E
Redshift
Accretion and star formation in RQQs - Sarah White, July 2016

10. Detections with the JVLA
For this sample of radio-quiet quasars, targeted observations were obtained from the JVLA. This enabled us to get down to a median rms of 30 microJansky, with 30 out of the 70 quasars detected at a 3-sigma level.
30/70 RQQs detected at 3σ - White et al (submitted)
Accretion and star formation in RQQs - Sarah White, July 2016

11. The Far-Infrared to Radio Correlation (FIRC)
log10[ Radio flux-density / mJy ]
An alternative way to …exploit the far-infrared to radio correlation. This very tight relation …arises due to …dust (giving the FIR emission) and supernova remnants (which accelerate electrons and produce radio emission).
log10[ FIR flux-density / (W m-2) ]
Far-Infrared Radio Correlation (FIRC), e.g. Helou et al. 1985
Accretion and star formation in RQQs - Sarah White, July 2016

12. The FIRC for objects at z ~ 1
White et al. 2016
(submitted)
Temperature
dependence of
the FIRC found by
Smith et al. (2014)
For 2-σ detection
in the radio:
83% have an accretion component > 0.6 Lradio
83% Σ Lradio
due to accretion
log10[ FIR luminosity / (W Hz-1) ]
Due the FIRC …dust temperature, we follow Smith …monochromatic FIR luminosity …dimensionless parameter q. This ‘q value’ …ratio …star-forming galaxies lie along this line…excess in the radio …clear evidence ..significant contribution.
log10[ Radio luminosity / (W Hz-1) ]
q125 = log10 L125 μm/ (W Hz−1) L1.4 GHz / (W Hz−1) =2.65 ± 0.25
Accretion and star formation in RQQs - Sarah White, July 2016

13. The FIRC for objects at z ~ 1
White et al. 2016
(submitted)
Temperature
dependence of
the FIRC found by
Smith et al. (2014)
For 2-σ detection
in the radio:
83% have an accretion component > 0.6 Lradio
83% Σ Lradio
due to accretion
log10[ FIR luminosity / (W Hz-1) ]
I’m able to quantify the accretion-related radio emission, …subtract off …. Considering …2 sigma, …83% …AGN dominated. …over 60% …. In addition, when summing across the objects…83% of the summed total radio luminosity. (…not a typo…coincidentally the same.) [2 mins left]
log10[ Radio luminosity / (W Hz-1) ]
q125 = log10 L125 μm/ (W Hz−1) L1.4 GHz / (W Hz−1) =2.65 ± 0.25
Accretion and star formation in RQQs - Sarah White, July 2016

14. Radio emission vs. absolute magnitude
Stronger correlation with Mi for accretion-connected Lradio than
star formation-connected Lradio
radio-luminosity /(W Hz-1)]
log10[ Star-formation
t = -0.08, p-value = 0.34
t = -0.08, p-value = 0.34 Mi
Finally, I take advantage …wide range …magnitude. Remember … quasars, …acts as a proxy for the accretion rate…star-formation connected radio emission relates to the optical magnitude, a correlation test indicates that the trend is weak and not statistically significant.
Accretion rate
Accretion and star formation in RQQs - Sarah White, July 2016

15. Radio emission vs. absolute magnitude
Stronger correlation with Mi for accretion-connected Lradio than
star formation-connected Lradio
radio-luminosity /(W Hz-1)]
log10[ Star-formation
t = -0.31, p-value = 1.2 x 10-4
t = -0.08, p-value = 0.34
t = -0.08, p-value = 0.34 Mi
log10[ Accretion radio-luminosity /(W Hz-1)]
If we instead look at the accretion-related radio luminosity …the anti-correlation is more robust. This shouldn’t be too surprising, …both to be directly associated with the accretion disc. …scatter …other factors influencing the associated radio luminosity…B fields, environmental density, and the timescale ….
Scatter due to magnetic fields
or environmental density?
White et al (submitted) Mi
Accretion and star formation in RQQs - Sarah White, July 2016

16. Summary The AGN dominates the total radio emission in RQQs
Radio observations – unbiased tracer of both accretion and star formation.
The AGN dominates the total radio emission in RQQs
Weak correlation between the accretion-connected radio emission and Mi
VIDEO sample
Optical/NIR selection, i < 27.4
74 quasars
0.5 < z < 2.7
Existing VLA map for stacking analysis
MBH -> M* -> SFR
White et al (arXiv: )
z ～ 1 sample
Optical selection, i < 21.3
70 quasars
z ～ 1
New, targeted JVLA observations
LFIR -> SFR
White et al (submitted)
So to summarise, …trace both star formation and accretion …we investigate the relative level …two samples … both of …AGN dominates ..in contrast … largely due to star formation. …taking advantage of the large span in optical luminosity for the second sample, … accretion-connected radio emission. So why is this important? …history …very high redshifts … SKA…. Thank you for listening, and I’m now happy to take questions. [13 mins currently]
Accretion and star formation in RQQs - Sarah White, July 2016

17. Accretion and star formation in RQQs - Sarah White, July 2016

18. The FIRC’s temperature dependence
Temperature dependence of the FIRC found by
Smith et al. (2014)
q250
q100
q350
q160
q500
Teff / K Teff / K
Accretion and star formation in RQQs - Sarah White, July 2016

19. Accretion vs. star formation
t = -0.05, p-value = 0.15
log10[ Radio luminosity due to accretion / (W Hz-1) ]
White et al. 2016
(submitted)
log10[ Radio luminosity due to star formation / (W Hz-1) ]
Accretion and star formation in RQQs - Sarah White, July 2016

20. BH-mass information for z~1 RQQs
Fitting to FIR
photometry
log[SFR from FIR luminosity / (M yr-1)]
log[SFR from radio luminosity / (M yr-1)]
Yun, Reddy & Condon 2001:
SFR / (M yr-1) = 5.9 ± 1.8 x L 1.4 GHz / (W Hz-1)
Accretion and star formation in RQQs - Sarah White, July 2016

21. Galaxy formation and evolution
Star formation and accretion histories: peak over 1 < z < 3
Madau & Dickinson 2014
Accretion and star formation in RQQs - Sarah White, July 2016

22. AGN radio heating K-band bJ-band Φ (h3 Mpc-3 mag-1) MK – 5log10h
MbJ – 5log10h
Croton et al. 2006
Accretion and star formation in RQQs - Sarah White, July 2016

23. Previous work Kimball et al. 2011 179 colour-selected QSOs from SDSS
Volume-limited, Mi > -23
0.2 < z < 0.3
Targeted JVLA observations at 6 GHz, rms ≈ 6-8 μJy
Correct to superpose AGN and SF luminosities?
log10[ρm / (Mpc-3 mag-1)]
log10[L6GHz / (W Hz-1)]
Accretion and star formation in RQQs - Sarah White, July 2016

24. Previous work Condon et al. 2013 2471 colour-selected QSOs from SDSS
Magnitude-limited, mr ≤ 18.5
0.8 < z < 2.5
NVSS, 1.4 GHz, catalogue limit = mJy
Stacking objects below this limit
log[S2 n(S) / (Jy sr-1)]
1.4 GHz log[S / Jy]
Accretion and star formation in RQQs - Sarah White, July 2016

25. Deeper optical data -> lower accretion rates
Previous work
Kimball et al. 2011
179 colour-selected QSOs from SDSS
Volume-limited, Mi > -23
0.2 < z < 0.3
Targeted JVLA observations at 6 GHz, rms ≈ 6-8 μJy
Correct to superpose AGN and SF luminosities?
Condon et al. 2013
2471 colour-selected QSOs from SDSS
Magnitude-limited, mr ≤ 18.5
0.8 < z < 2.5
NVSS, 1.4 GHz, catalogue limit = 2.4 mJy
Stacking objects below this limit
Why VIDEO?
Deeper optical data -> lower accretion rates
Deeper radio data
Accretion and star formation in RQQs - Sarah White, July 2016

26. The VIDEO Survey
The VISTA Deep Extragalactic Observations (VIDEO) Survey, Jarvis et al. 2013
Survey area of total 12 deg2
Trace L* galaxies out to z = 4, covering the ‘epoch of activity’
Photometric redshifts accurate to Δz/(1+z) ≤ 0.1
IR Band
λ / μm
5σ AB Z
0.88
25.7 Y
1.02
24.6 J
1.25
24.5 H
1.65
24.0 Ks
2.15
23.5
Madau & Dickinson 2014
Star formation
Black-hole accretion (scaled)
Credit: ESO
Accretion and star formation in RQQs - Sarah White, July 2016

27. Quasar selection The ‘Gold’ candidate quasar sample (75) stellar locus
z = 2
The ‘Gold’
candidate quasar sample (75)
z = 0
stellar
locus
galaxy
locus
g-J
z = 4
Track of a
model quasar with no host galaxy
J-K
Following Maddox et al Shaded region: colours of the galaxy models used by Le PHARE photometric fitting
Accretion and star formation in RQQs - Sarah White, July 2016

28. Quasar-related radio source counts
White et al. 2015, arXiv:
Power-law + Gaussian model of the number counts
log10[S2 n(S) / (Jy sr-1)]
Unobscured
RQQs (from
Wilman et
al. 2008)
log10[S2 n(S) / (Jy sr-1)]
Power-law from
Condon et al. 2013
Within the 1σ noise level
Binned data
Simulated fluxes
log10[S / Jy]
Accretion and star formation in RQQs - Sarah White, July 2016