M87 in TeV gamma rays

Daniel Mazin
ICRR U-Tokyo, Japan and MPI for Physics, Munich, Germany

Messier 87• Nearby giant radio galaxy, 16 Mpc, in theVirgo cluster• Central black hole:MBH ≃ 6.5×109 M⊙ (confirmed by EHT)
• Jet angle ≃15 - 25o, not a normal blazar• Highly structured jet, knots resolved inradio, optical and X-rays• Jet is variable: flares in radio, optical andX-rays• M87: possible source of HE neutrinos, andUHECRs
Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/20202

High energy
frontier

γ rays provide greatest
amount of direct information

DanielSketch byMazin
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Typical origin of very high energy gamma rays

and temporal variability

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Imaging Cherenkov Technique

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Imaging Cherenkov Technique
Imaging Atmospheric
Cherenkov Telescope(IACT)

rayo gamma"

Cherenkov li"≈ 10 km"ght

Huge effective area!"≈ 300 m"Adapted'from'W.'Hofmann'

Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

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Imaging Cherenkov Technique
IACT arraygamma-ray direction!

Multiple views of the same shower!
→ stereoscopic reconstruction !

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MAGIC, 2 x 17m

Current IACTs

H.E.S.S., 4 x 12m + 1 x 28m

VERITAS, 4 x 12m

Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

8Progress of the IACTs

Kifune plot: number of sources vs time

Mazin plot: sensitivity vs time

104

Asca
Fermi-4y(3FGL)

Number of sources

Ginga

103

CTATenma

Fermi-1y(1FGL)

Hakucho
Uhuru

γ-rays210

X-raysEGRETHESS-II+MAGIC-II+VERITAS

COS B

integral sensitivity (ergs / cm2 / s)

IACT sensitivities
10-10
Whipple 37 pix
MAGIC stereo

10-11

HESS-IMAGIC upgrade
HESS-II mono

HEGRA system

MAGIC stereo
MAGIC upgrade

Whipple 109 pix
CAT

10-12
MAGIC

HESS
HESS-I

VERITAS

CTA-1310

VHE γ-rays

10

HEGRAWhipple

Sensitivity above 1 TeV
Sensitivity above 0.1 TeV
Sensitivity above 0.05 TeV

SAS-2

11960

CTAWhipple

1980

2000
year

2020

10-14
1980

1985

1990

1995

2000

2005

CTA

2010

2015

2020

Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

2025
2030
Time (year)9M87 flares in the past: 2005
• First TeV detection

by HEGRA in 2003,
A&A 403, L1-L5(2003)• First TeV flare from

M87 detected by
H.E.S.S. in 2005
• Maybe actually aseries of flares• Speculation aboutorigin (core of HST1)

Science, Vol. 314, 1424 (2006)
DOI: 10.1126/science.1134408

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TeV emission localisation• Outer lobs can be excluded• core or HST-1: both possible. Slight preference to the core…

Science, Vol. 314, 1424 (2006)
DOI: 10.1126/science.1134408

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M87 flares in the past: 2008
ApJL, 685:L23-L26, 2008

Science 325:444-448,2009• 1-day scale variability• Coincident with radio brightening of

the core at 43GHz (VLBA)• Created a lot of excitement and hopes

Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

12M87 flares in the past: 2010
• Clear 1-day variability

in 2010 flare• τrise = 1.69+/-0.3 (d)• τfall = 0.61+/=0.08 (d)• No contemporaneousclear flare radio.
However, X-rays of thecore (seen byChandra) are in highstate, like in 2008

ApJ, 746:151 (18pp), 2012,
doi: 10.1088/0004-637X/746/2/151

Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/202013

10 years monitoring ofM87• No unique signature is seen

for the 3 flare activities• Core region is typically

preferred location of theTeV emission but HST-1
cannot be ruled out• Many models proposed toexplain TeV emission, which
is challenging because theDoppler boosting is milder
than in case of blazars
ApJ, 746:151 (18pp), 2012,
doi: 10.1088/0004-637X/746/2/151
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High TeV state also in 2012?
Beilicke et al., Gamma2012, arXiv:1210.7830
Hada et al., ApJ 788 (2014) 165• Hint of a high TeV activity in 2012 byVERITAS (not confirmed by MAGIC)• Contemporaneous radio brightening at

22 and 43GHz (VERA), similar to 2008
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M87 in low emission state
Data taken with MAGIC• Observations: 2012 to 2015
• Visibility: Dec/Jan to June/July• Data taking in total ~ 156 hrs (good data). It’s about 8% of theextragalactic data taken with MAGIC in that period.
• Most data taken under moderate moon light. Means special analysis andhigher energy threshold. Also means monitoring proposal has higher
chances to be accepted by TAC.
• Zenith range 15º - 50º

YearTeff [h]

2012
2013
2014

38.8
34.8
49.9

Significancefor E>300 GeV
5.4σ
8.8σ
7.3σ

2015

32.7

6.0σ

MNRAS 2020 in print, arXiv:2001.01643
Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

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M87 in low emission state
Data taken with MAGIC• Compatible witha point likesource• No significant

difference
between highstate and lowstate
localisation ofthe emissionMNRAS 2020 in print, arXiv:2001.01643
Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

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M87 in low emission state• Monitoring was notplanned as a MWL
campaign but for thepublication wegatheredcontemporaneous
data with our MWL
collaborators• As expected:

Complex behaviour,
no guarantee all WL
come from the sameemission region
MNRAS 2020 in print, arXiv:2001.01643
Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020 18

M87 in low emission state• Energy spectrum

does not significantly
deviate from asimple power law
over 5 decades inenergy(Fermi-LAT + MAGIC)• Similar spectral

shape as during thehigh state emission
MNRAS 2020 in print, arXiv:2001.01643
Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

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M87 in low emission state• Leptonic model(synchrotron selfCompton, SSC)
describes the data
OK. A tension in X-ray
slope and in the
gamma-ray slope isvisible but also themodel is simple• Hybrid model(hadrons and leptons)
also works but hasmany free parameters
Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

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M87 in low emission state

SSC model by Asano-san (ICRR)

Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

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M87 in low emission state
SSC model by Asano-san (ICRR)
Dependence on viewing angle:

particle dominanceDaniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

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M87 in 2017 (EHT campaign)
TeV coverage

Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

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M87 in 2017 (EHT campaign)
TeV shows low level flux, now significant flares

YRINAMILREP

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M87 in 2017 (EHT campaign)
TeV shows low level flux, now significant flares• Due to low signal

statistics it is hard toderive a reliableenergy spectrum• Integration: +/-1 weekaround EHT window• From what we have it

all looks like thespectral shape is as it
was in 2012-2015
MAGIC data setYRANIMILERP

Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

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M87 in 2018 (EHT campaign)• Densecoverage byHESS,MAGIC andVERITAS in2018• Stay tuned!

Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

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M87 2020 plans (EHT campaign)• MAGIC approved 25h contemporaneous with EHT in 2020

MAGIC also approved, in addition with lower priority, some 25h
general M87 monitoring• VERITAS approved 25h dark + 10h moon contemporaneouswithEHT in 2020
• H.E.S.S applied for Xh contemporaneous with EHT in 2020
• H.E.S.S, MAGIC and VERITAS coordinate TeV coverage during the2020 EHT campaign (backup sides in case of weather conditions)• (H.E.S.S - TBC),MAGIC and VERITAS coordinate TeV monitoringin 2020, January to May.

Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/202027

Cherenkov Telescope Array

Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

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CTA Consortium

as of June 2019
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Introduction: physics topics

Science with CherenkovTelescope Arraydoi:10.1142/10986, arXiv:1709.0799730

DanielSketch byMazin
R. Ong Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

CTA layout

Paranal, Chile

La Palma, Spain

4 LSTs15 MSTs

4 LSTs25 MSTs70 SSTs

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CTA telescope prototypes
SCTMSTLSTASTRI-CHEC

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CTA performance

flux sensitivity for 50h exposure

sensitivity versus exposure time

Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

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CTA performance

angular resolutionenergy resolution

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CTA status: La Palma
LST1 inauguration at ORM Oct 2018

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CTA status
CTA-South

CTA-North

LST1

MAGIC2MAGIC1

Now we will build it!
Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

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Conclusion / Outlook• M87 is brining monitored in TeV gamma rays since 2005
• 3 clear flares detected: 2015, 2008 and 2010
• + possible high state in 2012
• NEW: high state / flare in 2018 (stay tuned)• Spectral shape: hard, compatible with a power low, photon index in form dΝ/dE ~E^(-Γ) is Γ ~ 2.3 in all flux states• Modeling is challenging. Possible that electrons produce Inverse Compton radiation

in a region which is matter dominated but tension in spectral index for X-rays andgamma-rays. Alternative scenarios infer efficient hadron acceleration• Still many open questions. Looking forward to CTA for a much increased flux

sensitivity and improved angular resolution. Also more flares with correlated
variability would be important. Need good and long coverage because cooling times
are different (if the primary particles are electrons)Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

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BACKUPCTA-N phases(ALTERNATIVE POSITIONSFOR INSTRUMENTS)

NEW TECHNICALBUILDINGNORTHCEILOMETER
LIDAR
SUGGESTEDNEW HELIPADPOSITION

ALL SKYCAMERAHALLSKYCAMERAMST 9EXISTING
WORKSHOPS

MST 4MST 5LST 3CEILOMETER

NEWSTRETCH OF
PUBLIC ROAD

LIDAR

MST 10WEATHERSTATION 1LST 4MST 3MST 15

EXISTING
CONTROL
BUILDING

LST TELESCOPE3FOUNDATION.

MAGIC 2TELESCOPEMAXIMUM
ARCHRADIUS

LST 2MST 8LST 1ROAD BRIDGEOVER BARANCOMST 2SECURITYFENCELSTPLANWEATHERSTATION 2MST 6MSTPLANSECURITYFENCEMAGIC 1TELESCOPE
FOUNDATION.

MST 1FRAM
WEATHERSTATION 3TELESCOPEMAXIMUM
ARCHRADIUS

MST 11MST 1MST 7MST 12MST 13REVDESCRP
ITOINDATEP1SISUEDFOR
DS
ICUSS
O
IN

30/6
1/7

MST 14TITLE

CHERENKOVTELESCOPEARRAYNORTHERNHEMISPHERELSTANDMSTCO-ORDINATES

0125
METRES

250375500

DRAWING FOR DISCUSSION

SCALE

DATE

DRAWN

CHECKED

11:250300.61.7

SLB

DB

DRAWING NUMBER

REVISIONINFRA-DES-100-020 N

P1

ORG
IN
I ALDRAWN
I GSHEETSZ
IEA0Daniel Mazin Active Galactic Nucleus Jets in the EHT Era, Tohoku University, 21/1/2020

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Picture from LST meeting, 2018

LST sub-consortium

SwedenGermanyFranceSpain~80 FTE every year

PolandCroatiaItalyIndia

Japan

Mission 1:
Four LSTs at CTA-N

and newly joined• Switzerland• Bulgaria
Mission 2:
Four LSTs
at CTA-S
D. Mazin, LST ProjectManagerBrazil40

Large Size Telescope

Mirrors: JP
Interface plates: JP, DE, BR
Actuators: JP, CH
CMOS: JP

Tension cables: IT

calibration:
IT, HR, IN, DE

Camera Support
Structure: FR
Camera electronics: JP, IT, ES
Camera mechanics: ES
Camera safety: FR

Telescopestructure: DE

Rail: DE

Bogies: ES

Camera Access Tower: DE, ES

Foundation: ES
Drive and mainel. cabinet: FR

FlyWheels (2x300kW)
energy storage and UPS: JP

Key Science Projects of CTA• World Scientific open-access Book

(213 pages),
https://doi.org/10.1142/10986
arXiv:1709.07997• CTA Key Science Programs

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Extragalactic Survey
North: 60% of the time,
40% of the area

South: 40% of the time,
60% of the area+90°

galactic latitude (deg)Fermi/LAT 2FHL catalog
Detectable sources within CTA surveys
AGNs detected by IACTs+180°-180°
AGNs in CTA ExGal Survey: 123
Sources CTA Gal Plane Survey: 488
Sources in Fermi/LAT Catalog: 320
AGNs detected by IACTs: 59-90°

galactic longitude (deg)• Such scan would include Fermi Bubble (North), Virgo and Perseus clusters.

It can be performed in part from the South and in part from the North
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EBL density at z=0

Extragalactic Background Light

EBL evolution

Hubble constantBiteau & Williams 2015

EBL scaling factor

HESS limits
Fermi/LAT limits

2

CTA prediction

1.8
1.6
1.4
1.2
10.8
0.6
0.4
0.2000.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8
2
redshift z

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Temporal breakdown

Multiwavelength needs

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