"We have argued that 6% +/-  1% of the baryons are in stars and stellar remnants"

(M. Fukugita & P. J. E. Peebles 2004).

Which process regulates the galaxy growth (acceleration and quenching of star formation )

• 'social': e.g, galaxy mergers 
• 'private':  AGN feedback - large radiative energies emitted in the process of black hole (BH) accretion

Aird+2015

positive feedback: AGN's outflows enhance SF by compressing molecular clouds and/or the interstellar medium (e.g, Schaye+2015,Ishibashi & Fabian2012)

negative feedback:

• winds, outflows, or jets heat the surrounding ISM and prevents molecular gas from radiatively cooling
•  outflows expells gas from the host galaxy (e.g, Yuan & Narayan 2014; Heckman & Best 2014)

tied relation between SF & BH  

We have some ideas ...

however, studies investigating the relation between AGN activity and SF activity sometimes give mixed results (sample selection, observational bias, etc.)

Finding a way to understand the coevolution of galaxies and AGN is thus a crucial element to characterize the build-up of matter in the Universe.

But how we can  do it

analyse a single feature that could constrain a single parameter (Hα line to derive the SF rate, Pashen and Brecket line series (IR) to calculate the mass of the black hole, Fe Kalpha to analyse the accretion disc structure, radio flux to calculate  synchrotron emission etc ).

take into account all possible information taken from different instruments to look at the galaxy in a holistic way  - it can allow for statistical analysis and to reduce the selection bias

"Integrated spectral energy distributions (SEDs) are our primary source of information about the properties of unresolved galaxies. Indeed, the different physical processes occurring in galaxies all leave their imprint on the global and detailed shape of the spectrum, each dominating at different wavelengths."

Walcher 2011

multiwavelengths astrophysics

GALEX (UV)

(Credit: NASA)

Herschel( Credit: NASA)

GEMINI (opt)

CFHT (Credit: cfht)

astrophysics full of colours!

GALEX (UV)

(Credit: NASA)

Herschel( Credit: NASA)

GEMINI (opt)

CFHT (Credit: cfht)

Credit: ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray)

composite image of Centaurus A (z=0.0008)

 870-micron submm  LABOCA on APEX

X-ray:  Chandra X-ray Observatory

visible: Wide Field Imager 9WFI)  on the MPG/ESO 2.2 m telescope (dust lane and stars)

Credit: ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray)

composite image of Centaurus A (z=0.0008)

 870-micron submm  LABOCA on APEX

X-ray:  Chandra X-ray Observatory

visible: Wide Field Imager 9WFI)  on the MPG/ESO 2.2 m telescope (dust lane and stars)

A hyperluminous obscured quasar at a redshift of z ~ 4.3

daCunha+2008

unattenuated stellar spectrum

attenuated stellar spectrum

UV-NIR

measurements

daCunha+2008

unattenuated stellar spectrum

attenuated stellar spectrum

measurements

UV-NIR

MIR

the emission by dust in the ambient ISM

the emission by dust in stellar birth clouds

daCunha+2008

unattenuated stellar spectrum

attenuated stellar spectrum

measurements

UV-NIR

MIR

the emission by dust in the ambient ISM

the emission by dust in stellar birth clouds

FIR

simple model without AGN component

the ratio between optical and IR energy changes as starburst activity increases

We can also add informaion about AGNs

Gao, Wang, KM+ submitted

We can also add informaion about AGNs

+ ratio slope between 2500A (UV) &  2keV (X-ray)

But we are still missing something ...

something which can probe very cold  areas in the galaxy  - radio emisson

Credit: Mahmoud Hamed

What we can observe in radio wavelengths

SF galaxies & AGN 

As both of those processes are closely related to the overall mass growth of galaxies we can use them to properly investigate the mass growth in the Universe.

SF galaxies:  the synchrotron emission is powered by high-energy electrons and positrons, accelerated in supernova remnants when interacting with the diffuse magnetic field of the galaxy. The synchrotron emission in SF galaxies is closely related to recent star formation. In radio, we can also see cold areas in the birth clouds

origin of the radio emission:

AGNs: the synchrotron emission is powered by the central accreting black hole. However, the observed emission is believed to be emitted from regions  which differ depending on the nature of the AGN  (Smolic+2008)

from radio continuum

Synchrotron emission from AGN activity

obscuration free measure of star-formation

from spectral lines

Atomic gas (HI) - gas mass/fraction

from polarisation

magnetic fields in the cosmic web/LSS, 

magnetic fields in galaxies/AGN

needed for SED modelling

!

Credits: Cyril Tasse and the LOFAR surveys team

LOw Frequency ARray

LOFAR is the world’s leading telescope of its type. It is operated by ASTRON, the Netherlands Institute for Radio Astronomy, and coordinated by a partnership of 9 European countries: France, Germany, Ireland, Italy, Latvia, the Netherlands, Poland, Sweden and the UK.

 Exloo, Netherlands

Low-band antenna
(10-90 MHz)

POLFARO: Polish station of LOFAR in Bałdy, Łazy and Borówiec.

In its ‘high-band’ configuration, LOFAR observes at frequencies of around 150 MHz.

 Nearby galaxies

Cosmology and large-scale structure

Strong gravitational lenses

Galactic radio sources

Serendipitous discovery

High redshift radio galaxies

Galaxy clusters

Cosmic star formation history

Detailed studies of AGN physics and feedback

AGN evolution and black hole accretion history

LOFAR Deep Fields

Kondapally+2021

Best,..KM+2021

80 - 164 hrs of LOFAR observations

Real radio galaxies from Morabito et al. (2021). The gif fades from the standard resolution to the high resolution, showing the detail we can see by using the new techniques. Credit: L.K. Morabito; LOFAR Surveys KSP

z=4.3

Sy 1 z=0.86

Sy 1 z=0.16

Sy 2 z=0.46

quasar z=1.43

Sy 1 z=0.69

radio z=0.58

z=2.43

quasar z = 4.30

APR 229 (interactive galaxies) z=0.0010

Hercules A  Brightest galaxy in a Cluster, z=0.15

z = 3.2 quasar lensed by a galaxy at z= 0.35

Sy 1 z=0.86

Sy 1 z=0.16

Sy 2 z=0.46

quasar z=1.43

Sy 1 z=0.69

radio z=0.58

z=2.43

quasar z = 4.30

APR 229 (interactive galaxies) z=0.0010

Sy 1 z=0.86

Sy 1 z=0.16

Sy 2 z=0.46

quasar z=1.43

Sy 1 z=0.69

radio z=0.58

z=2.43

quasar z = 4.30

APR 229 (interactive galaxies) z=0.0010

Hercules A  Brightest galaxy in a Cluster, z=0.15

z = 3.2 quasar lensed by a galaxy at z= 0.35

Sy 1 z=0.86

Sy 1 z=0.16

Sy 2 z=0.46

quasar z=1.43

Sy 1 z=0.69

radio z=0.58

z=2.43

quasar z = 4.30

APR 229 (interactive galaxies) z=0.0010

Hercules A  Brightest galaxy in a Cluster, z=0.15

Sy 1 z=0.86

Sy 1 z=0.16

Sy 2 z=0.46

quasar z=1.43

Sy 1 z=0.69

radio z=0.58

z=2.43

quasar z = 4.30

APR 229 (interactive galaxies) z=0.0010

Hercules A  Brightest galaxy in a Cluster, z=0.15

z = 3.2 quasar lensed by a galaxy at z= 0.35

Sy 1 z=0.86

Sy 1 z=0.16

Sy 2 z=0.46

quasar z=1.43

Sy 1 z=0.69

radio z=0.58

z=2.43

quasar z = 4.30

APR 229 (interactive galaxies) z=0.0010

Hercules A  Brightest galaxy in a Cluster, z=0.15

z = 3.2 quasar lensed by a galaxy at z= 0.35

Sy 1 z=0.86

Sy 1 z=0.16

Sy 2 z=0.46

quasar z=1.43

Sy 1 z=0.69

radio z=0.58

z=2.43

quasar z = 4.30

APR 229 (interactive galaxies) z=0.0010

Hercules A  Brightest galaxy in a Cluster, z=0.15

z = 3.2 quasar lensed by a galaxy at z= 0.35

Using radio data to uncover properties of star-forming galaxies in young Universe

Calistro-Rivera et al., 2017

modeling the SED of galaxies

Guang, KM et al., submitted

modeling the SED of galaxies

new CIGALE will be public soon

Hyper Luminous Infrared Galaxies

Hyper Luminous Infrared Galaxies

LOFAR data allows us to identify highly complete (~92%) samples of bright Herschel sources with a simple selection based on the 250 µm flux density (45, 40, and 35 mJy in Boötes, Lockman Hole, and ELAIS-N1, respectively).

Wang, Gao,... KM+ 2020

We found  that the population of HLIRGs has surface densities of ~5 to ~18 /deg2

Hyper Luminous Infrared Galaxies

Contribution of LoTSS HLIRGs to cosmic star-formation density.

Gao, Wang, Efstathiou, KM+ in prep

The BH growth rate to SFR ratio as a function of stellar mass.The sizes indicate the AGN fractions.

Source classification

Source classifications

Magphys (da Cunha et al., 2008)
BAGPIPES (Carnall et al., 2019)

CIGALE (Boquien et al., 2019) x2
AGNfitter (Calistro-Rivera et al. , 2016)

Best et al., in prep

four classes: star-forming galaxies, radio-quiet AGN, and radio-loud high-excitation and low-excitation AGN.

~80, 000 radio sources from the

LoTSS Deep Fields

ELAIS N1, Boötes
Lockman Hole

Source classifications

(Best et al., in prep)

four classes: SF galaxies (SFG), radio-quiet AGN (RQQ), and radio-loud high-excitation (HERG) and low-excitation AGN (LERG).

Star-forming galaxies dominate the LoTSS Deep fields at all redshifts

Source classifications

(Best et al., in prep)

LoTSS Deep Fields summary:

~80,000 radio sources with IDs over 25 sq.deg

Consistent redshifts, stellar masses, SFR estimates and source classifications

Star formation rate estimation

Calistro-Rivera et al., 2017

Calistro-Rivera et al., 2017

total IR luminosity / radio luminosity

evolution??

relation between 150MHz and SFR for a NIR selected sample  18,517 z < 1 galaxies (ELAIS N1).

No evolution with redshift

Strong evolution with mass

Smith et al., 2020

Strong evolution with mass

In the absence of AGN, 150MHz observations can be used to measure accurate galaxy SFRs out to z = 1 at least, but it is necessary to account for stellar mass in the estimation in order to obtain 150MHz-derived SFRs accurate to better than 0.5dex.

Mulcahey, KM et al., submitted

SF and AGN Feedback  at z<0.15
 LOFAR + MaNGA integral field spectroscopy

radio detected AGN have broad SFR distributions, typically lie below the SF main sequence  -> they occupy galaxies with suppressed SF

AGNs selected based on their current activity are not responsible for suppressing their host galaxies’ star formation.

we also have a lot of sources at high z ...

Best et al., in prep

SUMMARY

Thank you for your attention