(SWGO) Southern Wide-field-of-view Gamma-ray Observatory - Adrián Rovero Instituto de Astronomía y Física del Espacio

Southern Wide-field-of-view
 Gamma-ray Observatory
 (SWGO)

 Adrián Rovero
Instituto de Astronomía y Física del Espacio

 Río de la Plata Ph-Exp Institute
 IFLP, march 10-11, 2020

 !1

Gamma-ray Astronomy
 Original motivation: to study cosmic-ray sources.
 Detection: power-law spectra

 How to detect gamma-rays

 Satellite

 Particle
 Detectors

 !2

Gamma-ray Astronomy
 Satellites: Fermi-LAT at HE
 (High Energy: 50MeV-50GeV)
 (LAT: Large Area Telescope, ~2m2)
 8 years: ~5000 sources
 + diffuse emission

 !3

Gamma-ray Astronomy
 Cherenkov Telescopes:
 Very High Energy (VHE)
 50GeV-50TeV
 1.5-2.5 km altitudes
 2-5 telescopes
 few degrees FoV

 VERITAS
 4x12m
 Since Arizona

 HESS ~2004 MAGIC
 1x28m 2x 17m
 4x12m La Palma
 Namibia

 !4

Gamma-ray Astronomy
 TeV Sky
 ~200 VHE sources

 !5

Gamma-ray Astronomy
 TeV Sky
 ~200 VHE sources

 Towards Anti-Center Towards Galactic Center

Background: Fermi-LAT
 !6

CTA (Cherenkov Telescope Array)
 CTA

◉A global effort to build the first true
 VHE observatory
 ✦ A user facility serving a wide

 community
 ! Data access to all scientists of
 participating countries
◉A huge improvement in all aspects of
 performance
 ✦ ~100 telescopes on two sites for

 access to the whole sky
 31 nations and >1400 scientists involved -
 Including full teams from HESS, MAGIC + VERITAS

 !7

CTA (Cherenkov Telescope Array)

 10 x Sensitivity,
 Large Collection
 Area
 Energies down to Energies up to 300
 → all topics
 20 GeV TeV
 → Cosmology++ → Pevatrons

 Rapid Slewing in 8o Field of View
 20 seconds
 → surveys,
 → transients extended objects

 10% Energy Few ‘ Angular
NASA Resolution Resolution
 → lines, features → morphology

 See ’Science with CTA’
 https://arxiv.org/abs/1709.07997 &
 https://www.cta-symposium.com/ !8

Particle Detector Arrays

 HAWC Observatory
(High Altitude Water Cherenkov)

 !9

HAWC Observatory in Mexico:
 High Energy Water Cherenkov gamma-ray observatory

 300 WCD (Water Cherenkov Detectors) =7.3m x h=5m
 4 PMTs at the bottom
 Observatory in Pico de Orizaba: 4100m, Mexico

 !10

HAWC Observatory in Mexico:
 High Energy Water Cherenkov gamma-ray observatory

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detecting air showers

HAWC Observatory in Mexico:
 Outriggers

 !13

HAWC Observatory in Mexico:
 Outriggers

 !14

HAWC Observatory in Mexico:
 Results: Second catalogue (19 months of data)

 !15

HAWC:
Galactic Plane

 !16

HAWC:
Galactic Plane

 !17

Observatorio HAWC en México:
 Results: Crab Nebula

 (preliminary)

 New source detected
 HAWC J0543+233
 Nov. 2017 (ATel #10941)

 coincident with pulsar
 PSR B0540+23

 Never detected by Cherenkov
 Telescopes (VERITAS, MAGIC)
 [¿Blinded by Crab?]

 !18

Observatorio HAWC en México:
 Resultados: SS433+W50

 SS433: microquasar:
 Supergiant + compact object

 Two jets at 90º with line of sight
 (no boosting)
 termination shock at SNR W50.

 Cherenkov Telescopes have
 never detected TeV emission
 [Energies < 10 TeV]

 !19

Observatorio HAWC en México:
 Resultados: SS433+W50

 SS433: microquasar:
 Supergiant + compact object

 Two jets at 90º with line of sight
 (no boosting)
 termination shock at SNR W50.

 Cherenkov Telescopes have
 never detected TeV emission
 [Energies < 10 TeV]

 HAWC detected two sources
 [Energies > 25 TeV]

 Nature 562, 82 (2018)

 !20

Observatorio HAWC en México:
 Resultados: SS433+W50

 SS433: microquasar:
 Supergiant + compact object

 Two jets at 90º with line of sight
 (no boosting)
 termination shock at SNR W50.

 Cherenkov Telescopes have
 never detected TeV emission
 [Energies < 10 TeV]

 HAWC detected two sources
 [Energies > 25 TeV]

 Nature 562, 82 (2018)

 Giacani
 !21

HAWC Observatory in Mexico:
 High Energy Water Cherenkov gamma-ray observatory

 A wide field-of-view gamma-ray observatory like HAWC, looking up the sky
 permanently (24hr a day all the time), provides data to address many
 scientific issues in astrophysics.

 There are strong motivations to implement it in the Southern hemisphere

 Wide-field gamma-ray observatory in the South

 !22

Next generation of high altitude
 particle detector array

 Southern Wide-field-of-view
 Gamma-ray Observatory

 SWGO

 !23

Historia:
 2005: post Milagro. Gestación de HAWC. Reunión LAGO en La Paz, búsqueda de
 sitios (en el norte y el sur). Visita sitios en Bolivia. Se hablaba de las ventajas de venir
 al sur: contactos en Argentina y Bolivia.

 2006: Primeras búsquedas en Argentina (Salta y Jujuy). Se elige México para HAWC.
 Colaboración básicamente USA-México.

 2015: Finalización de HAWC. Se intensifica la promoción de un observatorio sur.

 2016-17: Primeras propuestas de conceptos:
 • HAWC-Sur
 • ALTO
 • LATTES
 2017: Creación de la Alianza SGSO (Southern Gamma-ray Survey Observatory).
 Reunión de Buenos Aires, diciembre 2017.

 2019: Formación de la Colaboración SWGO. Reunión de Lisboa, mayo 2019:
 Colaboradores de 9 países:
 Alemania, Argentina, Brasil, EEUU, Italia, México, Reino Unido, Rep.Checa.
 Recientemente: Perú y Corea del Sur.

 White paper: febrero 2019 (arXiv:1902.08429)…. 1+ año de trabajo
 !24

SWGO Collaboration (July 2019; for 3 yr.)
 45 Institutions from 11 countries
 114 members (+19 supporting members)

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The Array: basic concept
 High altitudes and WCDs (Water Cherenkov Detectors)

 duty-cycle: ~100%
 Particle Field of view: 90º
 detector array
 North: HAWC
 South: ——
 High altitudes Future: SWGO (South)
 to detect LHASSO (North)
 shower
 particles

 duty-cycle: ~15%
 Field of view:

The Array: basic concept
 Goal: to improve HAWC sensitivity significantly at the
 Southern hemisphere (latitude 10-30 ºS)
 Higher altitudes
 to lower the
 energy threshold

 4400-5000 m

 Array area
 inproves Collection
 area

 x4

 detector density
 inproves
 reconstruction

 80%

 !27

The Array: basic concept
 Type of detector:
 (Based on WCDs)
 WCD:
 HAWC like
LATTES:
Pb plate + small WCD
RPC (gas) (Resistive plate chambers)

 Lake (pond)
 LHASSO style

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The Array: basic concept
 Type of detector:

 WCD:
 HAWC like
LATTES:
Pb plate + small WCD
RPC (gas) (Resistive plate chambers)

 + Design & Engineering Lake (pond)
 LHASSO style

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The Array: basic concept
 Sensitivity (preliminar)
 Each detecting unit has a Threshold of 50MeV (elect.) or one muon

 !30

The Array: basic concept
 Performance (preliminar)

 Resolution Sensitivity

 SWGO HAWC
 1-5 years
 Current
 Cherenkov
 Telescopes
 50 hours

 Fermi
 10 years
 SWGO
 5 years

 CTA South
 50 hours

 www.cta-observatory.org
 www.swgo.org !31

The Array: basic concept
 Performance (preliminar)

 Annual Exposure

 CTA 25 h/y
 SWGO 25% obs.

 ◉Short timescales: If CTA can get there ! more sensitivity
 ◉Steady sources: If background can be suppressed ! more sensitivity than CTA over several
 years
 www.cta-observatory.org
 www.swgo.org !32

Science with SWGO,
 few cases

advantages over HAWC
 (see white paper)
 (arXiv:1902.08429)

 !33

VHE sky with IACTs
 Galactic coordinates
 HAWC (lat. +19o) and SWGO (lat. -25o)
 Point sources (gamma-sky.net +TeVcat)

 SWGO: Souther sky more populated

 !34

Fermi bubbles:
 Extended sources at Radio and HE (Fermi-LAT)
 Controversy about its origin and nature.
 Very extended sources with diffuse borders: difficult for CTA

 !35

Origin of CR: galactic ➔ Pevatrons
 SNR: enough power to be the sources up to PeV
 SNRs are gamma-ray sources (up to ~10TeV)
 Mechanisms??: p+ (πo decay); e- (IC)
 Gamma-ray observations are not conclusive (just few cases of p+)

 Taylor A.M. (Nature 2016)

 !36

Origin of CR: galactic ➔ Pevatrons
 SNR: enough power to be the sources up to PeV
 SNRs are gamma-ray sources (up to ~10TeV)
 Mechanisms??: p+ (πo decay); e- (IC)
 Gamma-ray observations are not conclusive (just few cases of p+)

 Taylor A.M. (Nature 2016)

CR spectrum ➔ knee (~3 PeV)

PeV CR ➔ gamma ~100 TeV
(at these energies IC not efficient)

If a 100TeV gamma is detected
➔ CR

 !37

Origin of CR: galactic ➔ Pevatrons
 SNR: enough power to be the sources up to PeV
 SNRs are gamma-ray sources (up to ~10TeV)
 Mechanisms??: p+ (πo decay); e- (IC)
 Gamma-ray observations are not conclusive (just few cases of p+)

 Taylor A.M. (Nature 2016)

CR spectrum ➔ knee (~3 PeV)

PeV CR ➔ gamma ~100 TeV
(at these energies IC not efficient)

If a 100TeV gamma is detected
➔ CR

Models:
If SNR are Pevatrons ➔ only for the first few 100 yr. ➔ few candidates

SWGO ideal for the search (~10 candidates in the South)
Best candidate: G1.9+0.3 (~100yr).

 !38

Galctic Center:
 First detected Pevatron?
HESS (Nature 2016):
Detected gamma-rays at tens of TeV with no indication of cutoff..
Central BH (Sag A*)?, or a set of SNRs, massive stars and pulsars?

SWGO will be able to
follow all posible
sources simultaneously
 !39

Gamma Ray Burst (GRB):
 Previous to GRB detections at VHE:
 Difficult to observe with IACTs (alert+tracking)
 The most energetic observed at HE (Fermi-LAT): GRB 130427A
 Extrapolation showed that detection at VHE was possible

 Estimation for SWGO

 !40

Gamma Ray Burst (GRB):
 GRB detections at VHE:

GRB 180720B:
HESS: 10 hr. after alert
100-440 GeV (5.3 )
z = 0.65

GRB 190114C:
MAGIC: 1 min. after alert
200GeV - 1TeV (50 ) in the first 20 min. !!!!
z = 0.42

GRB 190829A:
HESS: 4.3 hr. after alert
3.5 hr. of data (>5 )
z = 0.078

 SWGO will be able to catch all
 these kind of events

 !41

Dark Matter: WIMP annihilation
 New generation of instruments reaches the critical sensitivity.
 Thermal relic WIMP accessible over a very wide mass range
 (Galactic Centre/Halo observations @ VHE)

 arXiv:1906.03353

 _
 bb

 i
 rm
 Fe
 Thermal
 Relic?
 SWGO
 CTA

 !42

Diffuse galactic emission:
 CRs propagating in the Galaxy produce diffuse gamma-rays.
 Measurements of this flux is relevant to study the diffusion of CRs.
 Very difficult task for IACTs (point sources, small FoV).

 Based on an
extension of the Fermi
 diffuse model

 Estimation for SWGO
 !43

Otros estudios:

 Transitorios y flares en blazares
 Ondas Gravitacionales
 Campañas multi-onda
 Nuevos fenómenos transitorios: Fast Radio Burst
 Correlación con detección de neutrinos
 Materia oscura: observación de galaxias satétiles
 Rayos Cósmicos: anisotropía
 Meteorología Espacial

 SWGO ayudará al entendimiento de todos estos fenómenos
 con su monitoreo constante en gran parte del cielo

 VER White paper: arXiv1902.08429 (feb. 2019)

 !44

Sitios

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Sitios posibles:
 Condiciones: 4400-5000 msnm; 10-30o latitud Sur.
 Solo en Sudamérica: Argentina, Bolivia, Chile, Perú

 Estudio realizado para CTA.
 Datos radar en satélite.
 Área mínima 1km2

 Elevation Key
 >2500m
 >3000m
 >3500m
 >4000m
 >4500m Dave Fegan (2005)
 >5000m

 !46

Sitios posibles:
 Condiciones: 4400-5000 msnm; 10-30o latitud Sur.
 Solo en Sudamérica: Argentina, Bolivia, Chile, Perú

 Estudio realizado para CTA.
 Datos radar en satélite.
 Área mínima 1km2

 Elevation Key
 >2500m
 >3000m
 >3500m
 >4000m
 >4500m
 >5000m

 !47

Sitios posibles:
 Condiciones: ~5000 msnm; 20-30o latitud Sur.
 Solo en Sudamérica: Argentina, Bolivia, Chile, “Perú”

 !48

Sitio argentino propuesto:
 Cerro Vecar: Sitios de LLAMA y QUBIC.
 30 km de San Antonio de los Cobres, Salta.

 !49

Sitio argentino propuesto:
 Observatorios

Comodato LLAMA
QUBIC
SGSO

 !50

Colaboración SGSO:
 Visita a Salta delegación 14 personas (dic. 2017)

 !51

Colaboración SGSO:
 Antecedentes

 Puebla (2016); Rochester (2017), en conjunto con HAWC.

 Buenos Aires, diciembre 2017: formación Alianza SGSO
 Ahora 125 personas, 18 países: Alemania, Argentina, Brasil, Chile, España,
 EEUU, Francia, Israel, Italia, Japón, México, Países Bajos, Perú, Polonia,
 Reino Unido, Suecia, Sudáfrica, Suiza.

 Visita a Salta delegación 14 personas.

 Heidelberg (2018):
 primera reunión como SGSO

 Lisboa (mayo 2019):
 discusión algún tipo de formalización

 !52

Sitio argentino propuesto:
 Vistas

 Volcan Tuzgle

 Cerro Vecar

Visita al sitio de comitiva internacional (dic. 2017)

 !53

Colaboración argentina:
 En formación

 Comunidad: Auger, CTA + Universidad Nacional de Salta
 La participación de la UNSa es muy importante por su localía.

 Motivación actual:
 • blazares:
 • origen de RC
 • meteorologia espacial
 • desarrollo de detectores, simulaciones
 • procesamiento y almacenamiento de datos

 Tareas a corto y mediano plazo:
 • Presentación a la Secretaría de CyT [hecho: oct-2019]
 • Instalación de prototipo en el sitio [PICT 2018]
 • Simulaciones del detector (empezando por el prototipo)
 • Estudios de impacto y factibilidad (agua): INTI Salta. [iniciado: ene-2020]
 • Estudios geotécnicos: INENCO, UNSa.
 • Próximo hito: elección del sitio ~2021-22

 !54

Colaboración argentina:
 En formación

 Firmantes del SoI:

 Necesitamos:
 • participación de locales: más visibilidad internacional
 • recursos: viajes, prototipo en el sitio, etc.
 • infraestructura en el sitio: electricidad, conectividad
 • determinar con certeza la disponibilidad de agua.
 Grupos de Trabajo:

 !55

Conclusions

◉Strong motivation for a southern hemisphere wide field of view high
 duty cycle detector!
 ✦ SWGO – 3 year design/preparation period ! project launch!

◉Strong complementarity between SWGO & CTA
 ✦ Triggering CTA: flares and transients

 ✦ Detecting hard spectrum sources ! CTA follow-up
 ✦ Large scale emission complementing CTAs detailed view Argentinian

 Collaboration:
 ✦ Triggering CTA: flares and transients

◉Argentinian Collaboration
 ✦ Three institution signed the SoI (Members of the Steering Committee)

 ✦ Financing is being requested

 ✦ Participation is crucial for the Argentinian site proposal.

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