Search of dark matter in dwarf galaxies with ground-based gamma-ray - PowerPoint PPT Presentation

Search of dark matter in dwarf galaxies with ground-based gamma-ray detectors Michele Doro University and INFN Padova michele.doro@unipd.it Michele Doro - Halo Workshop - Madrid 2018 1

https://www.darkmatterwines.com/ 2 Michele Doro - Halo Workshop - Madrid 2018

Tasting dark matter with gamma rays Michele Doro - Halo Workshop - Madrid 2018 3

0/ DM is there! Michele Doro - Halo Workshop - Madrid 2018 4

1/ We do expect gamma-rays 5 Michele Doro - Halo Workshop - Madrid 2018

2/ Dark Matter mass (cutoff position) & Dark matter branching ratios (spectral shape) Bringmann, Doro, Fornasa JCAP01(2009)016 6

3/ Universality of Dark Matter Spectra 7 Michele Doro - Halo Workshop - Madrid 2018

What influences the flux on Earth • Hunting the highest J- factor • Left with huge uncertainties in the particle Particle Physics factor: Astrophysical factor: physics Annihilation: 1 Decay: t c dec Large uncertainties from Fund. Phys. Large uncertainties from DM profiles No target dependences (robust limits from less uncertain targets) (straightforward stacking analysis) S. Lombardi (INAF-OAR & ASDC), Dark Side of the Universe 2016, Bergen, 25-29 July 2016 8 Michele Doro - Halo Workshop - Madrid 2018

Where to look v Galactic halo and the halo around + Highest J-factor - Strong Astrophysical contamination - Huge uncertaintiy in core\cusp − “wrong” hemisphere for MAGIC) v Galaxy Clusters + Huge amount of DM but far distance à moderate/low J-factor − High astropysocal contamination - Large uncertainties in baryon feedback and substructure contributions − Extended v Dwarf Galaxies + DM dominated (high M/L ratios) and Free from astroph. bkg + Less uncertainties on J-factors - Low J-factor v Dark Clumps? + Free from astroph. bkg + Nearby and numerous − How to know where they are? v DM anisotropies − Bright enough? + In principle possible with IACTs although challenging S. Lombardi (INAF-OAR & ASDC), Dark Side of the Universe 2016, Bergen, 25-29 July 2016 9 Michele Doro - Halo Workshop - Madrid 2018

If you need to point, where to point? ANNIHILATING DARK MATTER Signal strength DECAY DECAYING DARK MATTER S. Lombardi (INAF-OAR & ASDC), Dark Side of the Universe 2016, Bergen, 25-29 July 2016 10 Michele Doro - Halo Workshop - Madrid 2018

What was accomplished with gamma rays Michele Doro - Halo Workshop - Madrid 2018 11

Techniques Cherenkov Compton Pair-production Shower front (ground) (in space) (in space) (ground) 10 GeV—100 TeV 10 MeV à 100 MeV—100 GeV 1 TeV—100TeV+ Bad angular pos. Modified from: Hofmann 2012 12 Michele Doro - Halo Workshop - Madrid 2018

A question of calorimeters • Calorimeter manmade: – Water Cherenkov: HAWC, LATTES, MILAGRO – Satellite pair-conversion instruments: Agile, Fermi-LAT • Calorimeter provided by nature : – Imaging experiment: IACT: MAGIC, HESS, VERITAS, CTA, • Imaging: – Showers create images in the camera whence the shower is totally contained – The image is the event – Stereoscopy is very important 13 M. Doro - Exotic needles in the gamma-ray haystack - RICAP 2016

Comparing experiments Plot from de Angelis, Mallamaci https://arxiv.org/abs/1611.02232 Sensitivity is not the only thing that matters 14 Michele Doro - Halo Workshop - Madrid 2018

Ingredients to discovery Compton: 20% • Similar information than • • Compton: 10 deg sensitivity for non-transient Lat/MeV: 20% • Lat/MeV: >1 deg • sources • Lat/GeV: 0.5 deg Lat/GeV: 10% • Do not take constant eff. • • IACT: <0.1 deg IACT: 10-20% • area • EAS: 0.5-1deg EAS: 100% • And also FOV & Duty cycle 15 Michele Doro - Halo Workshop - Madrid 2018

Steady or not 16 Michele Doro - Halo Workshop - Madrid 2018

IACTs (FOV <5x5) HESS, MAGIC and VERITAS (in 2012) 17 Michele Doro - Halo Workshop - Madrid 2018

Happy 15° birthday MAGIC Florian Goebel telescopes! First light in October 2003 18 M. Doro - MAGIC - CRIS 2018

IACTs: tested several target classes (oudated) MD, NIM A 742 (2014) 19 Michele Doro - Halo Workshop - Madrid 2018

Dark matter searches: 1000h+ in a decade About 1000 h in a decade ç MD XXV ECRS 2016 Proceedings 20 Michele Doro - Halo Workshop - Madrid 2018

Observe them all • Few hour à more than hundred hours • Classical à SDSS-ultra- faint à DES-ultra-faint UNDISCLOSED 21 Michele Doro - Halo Workshop - Madrid 2018

Segue 1 Deep Scan with MAGIC stereo • Longest • Strongest exposure on constraints above few a single hundreds GeV dSph : Segue according to 1: 160 hours . channel • Optimized • Results made statistical into the PDG treatment allowed performance boost See Aleksic+ JCAP 1210 (2012) 032 22 Michele Doro - Halo Workshop - Madrid 2018

Segue stereo stat treatment The likelihood was prepared so that results from different experiments could In all DM searches, we try to • be combined measure the same universal parameter, e.g. < !" > through gamma-ray flux: Different observations of • different targets differ in the astrophysical or J-factor Aim: combine measurements of • The instrument response functions do not need to be combined , but can < !" > from different targets and be used on individual factor of the likelihood à GREAT ADVANTAGE instruments RESULTS FROM DIFFERENT INSTRUMENTS AND DIFFERENT TARGETS CAN BE NOW COMBINED TO IMPROVE SENSITIVITY 23 Michele Doro - Halo Workshop - Madrid 2018

MAGIC + Fermi combined JCAP 02 (2016) 039 • MAGIC: Segue 1 (158 h) and Fermi-LAT: 15 dwarfs (6 years, Pass8) • Effective combination (2x stronger constraints) in the range 300-500 GeV 24 Michele Doro - Halo Workshop - Madrid 2018

«Gather them all» J.R.R. Tolkien's epigraph to The J.R.R. Tolkien’s abstract of Lord of the Rings MNRAM " Three DSPHS for the HESS " Three Rings for the Elven-kings under the sky, Seven for under the sky, Seven for the VERITAS in its halls of stone, Dwarf-lords in their halls of Nine for MAGIC doomed to rise. stone, Nine for Mortal Men • A project between MAGIC, One for the Dark MATTER Lord VERITAS, HESS and Fermi started doomed to die, One for the Dark on his dark MATTER throne. In to combine them all Lord on his dark throne. In the – 300+ h MAGIC the Land of FERMI where the Land of Mordor where the GAMMAs lie. One LKL to rule – 300+ h VERITAS Shadows lie. One Ring to rule them all, One LKL to find them, – 100+ h HESS them all, One Ring to find them, – Fermi-dSph One LKL to bring them all and One Ring to bring them all and Great expectations! • in the darkness PUBLISH in the darkness bind them. "— them. "— 25 Michele Doro - Halo Workshop - Madrid 2018

One or many? • If we find one dSph with J=10x J_Segue , in 500h we barely start to enter the holy region Leane+ 2018 MD XXV ECRS 2016 Proceedings 26 Michele Doro - Halo Workshop - Madrid 2018

MAGIC program New instruments are discovering new dSphs: some very promising. Expect follow-up from MAGIC! 27 Michele Doro - Halo Workshop - Madrid 2018

Huston: we have a problem. The case of Tri2 • In 2016, MAGIC had strong reasons to believe Triangulum 2 was the most DM dominated dSph • Discussion whether to observe it 28 Michele Doro - Halo Workshop - Madrid 2018

Hayashi • The usual “among analyzed dSphs, Triangulum 2 and Ursa Major II ultra faint dwarf galaxies are the most promising but large uncertain targets for dark matter annihilation while Draco classical dSph is the most robust and detectable target for dark matter decay.” 29 Michele Doro - Halo Workshop - Madrid 2018

Is Tri2-large J-factor real? Hutten+ 1606.04898 Calore+ 1611.03503 cumulative distribution of all known dSph galaxy objects 30 Michele Doro - Halo Workshop - Madrid 2018

Our own checks Own checks with Clumpy to investigate J-factor 31 Michele Doro - Halo Workshop - Madrid 2018

The killer paper 32 Michele Doro - Halo Workshop - Madrid 2018

Despite that 33 Michele Doro - Halo Workshop - Madrid 2018

DES, LSST, GAIA Advanced spectroscopy Remove foreground star What more? 34 Michele Doro - Halo Workshop - Madrid 2018

Do we know dSph? Eline Tolstoy, BAM workshop, Barolo 2017 35 Michele Doro - Halo Workshop - Madrid 2018

We need accurate J-factors (not precise) Chiappo+ 2012 36 Michele Doro - Halo Workshop - Madrid 2018

Another dark way • Dark clumps should exist! H. Zechlin: 37

Dark clumps in plain sight « […]we find a significant preference (TS = 40) for describing 47 Tuc’s spectrum with a two source population model, consisting of an ensemble of MSPs and annihilating dark matter (DM) with an enhanced density around the IMBH, when compared to an MSP-only explanation. The best-fit DM mass of 34 GeV.» 38 Michele Doro - Halo Workshop - Madrid 2018

Lines searches with dSphs MAGIC, JCAP 02 (2014) 008 • Limits were produced for narrow-band emissions (smoking guns) with 160 hours of Segue1 39 Michele Doro - Halo Workshop - Madrid 2018

Shower front detectors if m=10 TeV HAWC (left) à 2015 LHAASO (right) à in construction (2019?) 40 Michele Doro - Halo Workshop - Madrid 2018