Extremly long introduction

part 1: what do we know about galaxies?

What do we know about galaxies?

• galaxies are extremely complex objects composed of  billions of stars, gas and dust (and dark matter)

• they are the basic building blocks in the Large-Scale Structure of the Universe.

Credit: ESO; VIMOS facility, the "first light" on February 26, 2002. The famous "Antennae Galaxies" (NGC 4038/9), the result of a recent collision between two galaxies.

Credit: ESO; VIPERS

What do we know about galaxies?

• galaxies are extremely complex objects composed of  billions of stars, gas and dust (and dark matter)

• they are the basic building blocks in the Large-Scale Structure of the Universe.

Credits:

F. Summers, Z. Levay, L. Frattare, B. Mobasher, A. Koekemoer and the HUDF Team (STScI)

Copyright: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University), K. Noll (STScI), and J. Westphal (Caltech)

No matter if we are observing the Milky Way, its nearby neighbors, or very distant galaxies, we know that they are similar objects at different stages of evolution.

Extremly long introduction

part 2: galaxy's  classification

classification of galaxies into groups of objects with similar physical properties

galaxy evolution

Credit: NASA, ESA, R. Ellis (Caltech), and the HUDF 2012 The Hubble Ultra Deep Field 2012

Morphology

nearby Universe (special observations)

Credit: Galaxy zoo

Morphology

high-z Universe

Credit: Canada-France-Hawaii Telescope Legacy Survey.

Morphology

high-z Universe

Credit: Canada-France-Hawaii Telescope Legacy Survey.

z=0.56 (the light travel time ~6 Gyr)

Credit: CFHTLS, VIPERS, K.Lisiecki

stellar mass (M✸) is the mass of all stars (young and old)  in the galaxy

Star Formation Rate (SFR) is the total mass of stars formed per year.

This portrait view panorama shows our colourful Milky Way stretch above the Atacama Desert. Taken during the ESO Ultra HD Expedition.

Credit: SO/B. Tafreshi (twanight.org)

The lightest galaxies are around a billion solar masses, while the heaviest are 30 trillion, or 30,000 times more massive. The Milky Way's mass of 1.5 trillion solar masses is fairly normal for a galaxy of its brightness

M✸ & SFR can be roughly counted by counting individual stars (every year).

This portrait view panorama shows our colourful Milky Way stretch above the Atacama Desert. Taken during the ESO Ultra HD Expedition.

Credit: SO/B. Tafreshi (twanight.org)

The whole procedure seems quite easy

The entire arc of the Milky Way can be seen in the southern sky in this view from the European Southern Observatory's Very Large Telescope at the Paranal Observatory in Chile's Atacama Desert. (Image: © Miguel Claro).

but obviously it's not doable

but nonetheless there are studies on the star-forming activity of galaxies

Credit: CANDELS collaboration

Credit: https://www.almaobservatory.org/

Centaurus A (NGC 5128)

Credit: https://www.almaobservatory.org/

Centaurus A (NGC 5128)

Credit: https://www.almaobservatory.org/

Centaurus A (NGC 5128)

Credit: https://www.almaobservatory.org/

Centaurus A (NGC 5128)

Credit: https://www.almaobservatory.org/

Centaurus A (NGC 5128)

Credit: https://www.almaobservatory.org/

Centaurus A (NGC 5128)

?

Credit: https://www.almaobservatory.org/

Centaurus A (NGC 5128)

Colour composite image, revealing the lobes and jets originates from the active galaxy’s central black hole. This image was obtained with three instruments: 

• submm (870micron) LABOCA/APEXPEX (Chile)
• X ray data from Chandra X-ray Observatory
• optical observations (2.2-m WFI, MPG/ESO, Chile)  show the background stars and the galaxy’s characteristic dust lane in close to "true colour".

Centaurus A (NGC 5128)

Credit: ESO Centaurus A LABOCA

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)

Credit: Mahmoud Hamed

Credit: Mahmoud Hamed

Dust absorbs part of the  UV (0,1- 0,4μm) radiation from young, massive stars and then re-emits the energy in the ​IR rage (IR, 8-1000μm ).

The energy distribution of a galaxy as a function of wavelength is called the galaxy energy spectrum (SED)

Multiwavelength imagery of DustPedia galaxy NGC 368 and Six of the enigmatic blue and dusty gas rich galaxies revealed in Clark et al., 2015

Credit: Mahmoud Hamed

modelling of spectral energy distribution

In fact, it should be very simple - we have satellites, large telescopes, networks of radio observatories ...

... but we have also dust in galaxies (and on the way between a galaxy and Earth...)

Credits: NASA

a key component of the interstellar medium (ISM)

• dust particles are formed as a product of stellar evolution, 
• they are formed in the environment of evolved stars and  then they are ejected into the interstellar medium,
• their sizes range from a few nm to a few μm,
• the main building block is carbon, including graphite + silicate,
• its presence in galaxies is "noticeable" as
  • emission in the IR wavelenghts,
  • modification of the stellar continuum (UV - NIR) 

Dust absorbs part of the  UV (0,1- 0,4μm) radiation from young, massive stars and then re-emits the energy in the ​IR rage

(IR, 8-1000μm ).

Without dust, we don't have new stars!

Credit: M. Hamed

Credit: M. Hamed

Credit: D. Donevski

dust attenuation

we have different dust attenuation models to use..

all of them are extremly simple ...

Are all attenuation laws interchangeable?

To reply to that question in static way, we need a statistically important, sample of galaxies with reach photometrical measurements, with farIR data, spread out in a wide redshift range.

+

FIR

submm

Małek+2018

Astarte & Adonis (z~2, the age of the Universe at that time~3.316 Gyr.).

Hammed+2021

Hammed+in prep

Slowly we are opening new windows of  modelling galaxy by using ...

Toba et al., 2021

Guang, KM et al., submitted

Radio LOFAR

KM preliminary results

Radio LOFAR

X-ray Chandra

Infrared observations are crucial to understand it 

Madau and Dickinson 2014

 discovery of a giant black hole hidden in a galaxy that existed 1,4 Gyr after the Bing Bang!

Efstathiou, Małek+2021

What is the influence of dust attenuation on the main physical parameters of galaxies?

What are the properties of dusty, giant galaxies formed just a few billion years after the Big Bang?

redshift

Riccio, Małek+ 2021

LSST optical data (ugriz)

Legacy Survey of Space and Time

starting 2022 - 10 years of observations, ~60 petabytes of pictures and  15-petabytes of data, 20 terabytes of data/night

Text

LSST + auxiliary IR data

The growth of dust in young but already metal-rich galaxies (z~3-4) is dominated by the growth of particles due to their collisions with gas

Donevski, Lappi, Małek+2021

What is the influence of dust attenuation on the main physical parameters of galaxies?

What are the properties of dusty, giant galaxies formed just a few billion years after the Big Bang?

+

FIR

submm

+

radio

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.

Kondapally+2021

Best,..KM+2021

LOFAR Deep Fields

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

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

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

We know that galaxies evolve...

How?

1. stars evolve (they are are born, grow up, die exploding or not),
2. the structure of the Universe evolve

It means that the dust also evolves and the attenuation law is not constant