investigating galaxy evolution with deep learning

Investigating galaxy evolution with deep

learningMarc Huertas-Company

Instituto de Astrofísica de CanariasObservatoire de Paris

Université Paris DiderotInstitut Universitaire de France

AAS 233rd meeting, Machine Learning in Astronomical Data Analysis, Seattle 2019

Berta Margalef-Bentabol, Fernando Caro, Christoph Lee, Alexandre Boucaud, Avishai Dekel, Joel Primack, Tom Charnock, Annalisa Pillepich, Vicente Rodriguez (+ TNG team), Emille Ishida (+ COIN initiative), Helena Dominguez-Sanchez …

AI FEVER?GOOGLE SEARCH TRENDS

PUBLICATIONS

CONFERENCES

Source

https://www.slideshare.net/LuMa921/deep-learning-the-past-present-and-future-of-artificial-intelligence

BEFORE 2012….

CAT?

DOG?

TRIVIAL HUMAN TASKS REMAINED CHALLENGING FOR COMPUTERS

AFTER 2012

IT HAS BECOME TRIVIAL….

MHC+15b

99.8

96.3

88.5

97.1

93.7

11.5 3.0 5.6

2.9 0.2

0.5 0.8

0.8

0.8

0.4

0.4

0.4

0.3

0.3

0.3

0.0

0.0

0.0

0.2

0.2

SPHEROID DISK IRR PS UncVISUAL DOMINANT CLASS

SPHEROID

DISK

IRR

PS

Unc

AUTO

DO

MIN

ANT

CLAS

S

9799

VISUAL

AUTOMATIC

“OUR CATS AND DOGS”: GALAXY MORPHOLOGY

CNNs DEEP LEARNING SOLVES

THE PROBLEMOF GALAXY MORPHOLOGICAL

CLASSIFICATION?

TALK ON WEDNESDAY AFTERNOON -

SPECIAL SESSION ON “MODERN” GALAXY MORPHOLOGIES

1. MOST OF THE PROCESSING WE DO ON IMAGES CAN BE DONE WITH AI - POSSIBLY MORE EFFICIENTLY AND MORE ACCURATELY

2. WE CAN LEARN SOME PHYSICS BY USING AI TO LINK SIMULATIONS AND OBSERVATIONS

2 TAKE HOME MESSAGES FOR TODAY

IMAGE

DETECTED OBJECT

Boucaud+19

GALAXY 1

GALAXY 1

IMAGE

DETECTED OBJECT

Boucaud+19

GALAXY 1

GALAXY 1

IMAGE

DETECTED OBJECT

MEASUREMENTS

Photometry

Shape

…

Boucaud+19

GALAXY 1

GALAXY 1

IMAGE

DETECTED OBJECT

MEASUREMENTS

Photometry

Shape

…

Boucaud+19

ISOLATED GALAXIES IN

CANDELS ARTIFICALLY

BLENDED

U-NET(ENCODER DECODER)

IMAGE OF BLENDED OBJECTS

OUTPUT SEGMENTATION MAP (BINARY 2

CHANNELS)

VANILLA CNN

FLUX GALAXY 1

FLUX GALAXY 2

Boucaud+19

U-NET+CNN SExtractor

MAG(CENTRAL)-MAG(COMPANION) MAG(CENTRAL)-MAG(COMPANION)

DE

LTA

MA

G (C

EN

TR

AL

)

DE

LTA

MA

G (C

EN

TR

AL

)

PHOTOMETRY OF BLENDED SOURCES

Boucaud, MHC+19

MAG(CENTRAL)-MAG(COMPANION) MAG(CENTRAL)-MAG(COMPANION)

AVE

RA

GE

SC

ATT

ER

AVE

RA

GE

SC

ATT

ER

SExtractor

Deep Learning

CONSTANT <0.2 SCATTER. A FACTOR3-4 BETTER THAN SExtractor

REASONABLE BEHAVIOR FOR DIFFERENT MORPHOLOGIES

Boucaud, MHC+19

PHOTOMETRY OF BLENDED SOURCES

Lee, MHC+19

DETECTION OF CLUMPS IN HIGH REDSHIFT GALAXIES

SIMILAR APPROACHES CAN BE USED FOR…

BULGE-DISK DECOMPOSITIONS

Tuccillo, MHC+19

BULGE+DISK BULGE

DISK

THEORY / SIMULATIONS

[FULL 3D EVOLUTION HISTORY]

AI TO LINK THEORY AND OBSERVATION

IN THE DATA SPACEIllustris, EAGLE, Horizon-AGN …



PROJECT HYDRO SIMS IN

THE “OBSERVATIONAL

PLANE”



ASSUMPTIONS OF MASS TO LIGHT CONVERSION

+ DUST +PSF

+ NOISE



MOCK OBSERVATIONS



PLANE”





OBSERVATIONSMOCK OBSERVATIONS



PLANE”

MACHINE (DEEP)LEARNING








PLANE”



IN THE DATA SPACE

TRAINTEST

Illustris, EAGLE, Horizon-AGN …






PLANE”



IN THE DATA SPACE

TRAIN TEST

Illustris, EAGLE, Horizon-AGN …

SIMULATIONS OBSERVATIONS

SDSS DR7

CNN MODEL TO ESTIMATE GALAXY “VISUAL”

MORPHOLOGY

HOW REALISTIC ARE ILLUSTRIS

TNG MORPHOLOGIES?

Dominguez-Sanchez+18

TRAIN

Nair&Abraham10GZOO

ILLUTRIS TNG

MOCK SDSS

GALAXIES

CLASSIFY

MHC+19

ILLUSTRIS ELLIPTICALS ILLUSTRIS S0s

ILLUSTRIS EARLY SPIRALS ILLUSTRIS LATE SPIRALS

MHC+19

ILLUSTRIS ELLIPTICALS ILLUSTRIS S0s

ILLUSTRIS EARLY SPIRALS ILLUSTRIS LATE SPIRALS

MHC+19

ATTRIBUTION TECHNIQUES

PROVIDE SOME INFORMATION

BUT STILL RATHER LIMITED

ELL

SPIRAL

THE HIGH MASS END OF THE STELLAR MASS FUNCTION OF

ILLUSTRIS TNG IS DOMINATED BY DISKS

MHC+19

THE HIGH MASS END OF THE STELLAR MASS FUNCTION OF

ILLUSTRIS TNG IS DOMINATED BY DISKS

MHC+18

Dekel&Burkert+14, Ceverino+15, Zolotov+15,Tacchella+16a,b, Dekel+18

COSMIC TIME

MAS

S

IDENTIFYING COMPACTION IN THE VELA ZOOM-IN OF SIMULATIONS

VELA suite of hydro simulations

[Ceverino, Dekel+]

SIMULATION OBSERVATIONS

MHC+18


COSMIC TIME

MAS

S

LABELLING EXCLUSIVELY

BASED ON THE FULL HISTORY

OF THE GALAXY FROM ADVANCED

NUMERICAL SIMULATIONS

BASED ON PHYSICAL PRINCIPLES

PRE-BN BN POST-BN

IDENTIFYING COMPACTION IN THE VELA ZOOM-IN OF SIMULATIONS

MHC+18

MHC+18


COSMIC TIME

MAS

SPRE-BN BN POST-BN

IN THE OBSERVATIONS WE ONLY HAVE ONE SNAPSHOT OF A GALAXY AT A GIVEN TIME

MHC+18

MHC+18


COSMIC TIME

MAS

S

?

?

PRE-BN BN POST-BN

HOW CAN WE ESTIMATE THE PHASE FROM A UNIQUE IMAGE?

MHC+18

[COSMOLOGICALSIMULATION]

USE THE FORMATION HISTORY OF EACH GALAXYTO LABEL IMAGES …

PRE- BLUE NUGGET

BLUE NUGGET

POST NUGGETPROJECT THE 3D OBJECT TO GENERATE “MOCK”

IMAGES AS OBSERVED BY HUBBLE

VELA HIGH RESOLUTION

VELA HST RESOLUTION

CANDELS

MHC+18

THE OUPUT SOFTMAX PROBABILITY TRACKS THE GAS MASS

SIMULATIONDEEP LEARNINGMHC+18

COSMIC TIME COSMIC TIME

MAS

S

SOFT

MAX

PR

OBA

BILI

TIES

POST-BN CLASSBN CLASS

PRE-BN CLASS

CONSTRAINTS ON THE OBSERVABILITY TIMESCALE

POST-BN CLASSBN CLASSPRE-BN CLASS

MHC+18

CAPTURING THE MODEL UNCERTAINTY

SEVERAL OPTIONS EXIST IN THE LITTERATURE…

NO TIME TO TALK ABOUT BNNs

GENERATIVE ADVERSARIAL NETWORKS

TWO COMPETING NETWORKS

(Goodfellow+)

Every 2 iterations the generator is trained to force the discriminator

to classify as real

GENERATIVE ADVERSARIAL NETWORKS

TWO COMPETING NETWORKS

(Goodfellow+)

Every 2 iterations the discriminator is trained to force to distinguish between

real and fake

ANOMALY DETECTION WITH GANs

SIMULATIONS [EAGLE, Illustris, FIRE, VELA…]

OBSERVATIONS

A PROOF-OF-CONCEPT CASE: UNSUPERVISED DETECTION OF

MERGERS WITH GANs

ANOMALY

NORMAL

MARGALEF-BENTABOL, MHC+2019


MERGERS OCCUPY A DIFFERENT REGION IN THE GAN GENERATED LATENT SPACE


(RECONSTRUCTED - ORIGINAL)

“ANOMALY SCORE”

1. MOST OF THE PROCESSING WE DO ON IMAGES CAN BE DONE WITH AI - POSSIBLY MORE EFFICIENTLY AND MORE ACCURATELY

2. WE CAN LEARN SOME PHYSICS BY USING AI TO LINK SIMULATIONS AND OBSERVATIONS

2 TAKE HOME PROVOCATIVE ?

MESSAGES FOR TODAY

WITH SUPERVISED ML GOING BACK AND FORTH FROM SIMS TO DATA

WITH UN-SUPERVISED ML TO MEASURE SIMILARITIES

DETECTION, PHOTOMETRY, PHOTOZ’s, MORPHOMETRY …

investigating galaxy evolution with deep learning

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