From the very beginning of the

we can learn how complex is the interaction between dust and stars..

only the panchromatic view on the galaxy can give full information about the physical properties of galaxies.

The main components

(but not all of them):

• old and young star,
• stellar remnants,
• interstellar medium,
• metallicity,
• dust emission/geometry,
• supermassive black holes ....

only the panchromatic view on the galaxy can give full information about the physical properties of galaxies.

CIGALE, Boquien+19

But how to deal with the photometric measurements?

Spectral Energy Distribution fitting

i.e. A. Nanni,  V. Buat, L. Barrufet, M. Hamed,  J.Alvarez-Marquez, D. Donevski, G. Riccio talks

the link between

stellar (complex)

&

dust (complex)

λ [μm]

Attenuation laws

V. Buat talk

Calzetti 2000

Chalrot&Fall 2000

Lo Faro+2017

Credit: M. Hamed

Are all attenuation laws interchangeable?

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

HELP (Oliver et al., in prep)

aims to collate and homogenize photometric observations from many astronomical observatories

XID+ deblending tool for Herschel maps (Hurley+17)

HELP

aims to collate and homogenize photometric observations from many astronomical observatories, 

ELAIS N1

CDFS SWIRE

Charlot&Fall 2000

Lo Faro 2017

Calzetti 2000

Małek et al., 2018

But why?  

see also V. Buat & M. Hamed talks based on the ALMA selected galaxies

M_star (basic physical parameter) changes with dust attenuation

~45 000 galaxies

For sure not due to the attenuation in the FUV regime ...

... but because of the changes in the NIR wavelenghts.

Att. NIR

Att. FUV

Małek et al., 2020

Lo Faro+2017

Charlot&Fall 2000

Calzetti 2000

Małek et al., 2018

... and taking into account changes with SFR (i.e. M. Figueira, poster):

we can change for example Main Sequance (not that "Main" anymore?)

Figueira et al., in prep.

GALEX-SDSS-WISE (z < 0.3)

VIPERS (z ~ 0.7)

Hamed, KM et al., in preparation

 Mahmoud HAMED talk ("Dust attenuation in ALMA-detected dusty star-forming galaxies in the COSMOS field "

The difference in specific dust mass over redshifts with different attenuation laws.

redshift

Calzetti 2000

Charlot&Fall 2000

Lo Faro+2017

Riccio, KM et al., in preparation

 Gabriele RICCIO talk (Friday, "How reliable are galaxies physical parameters estimations for LSST main sequence sample?"

Overestimation of the FUV attenuation for the LSST-like data (ugrizy).

Summary

• a universal attenuation law doesn't exist (yet),
• a flatter attenuation curve at longer λ results in the larger estimation of M_star,
• the geometry of the galaxy plays an important role in the selection of proper attenuation law (Buat+19, M.Hamed talk), but what else?
• the set of photometric data  (G.Riccio talk) and metallicity is also important.

we have a unique photometric data set:

the Herschel Extragalactic Legacy Project  

(~ 1300 deg²  of the Herschel Space Observatory)

Our main conclusion is that we need to work on the possible new dust attenuation law or we should find a  boundary condition for the application of different laws.

and we are working on that 

ASTROdust team

Mahmoud (Misha) Hamed

Gabriele Riccio

Kasia Małek

Ambra Nanni

Krzysztof Lisiecki

Thank you for your attention