N. Komin, H.E.S.S. Galactic Highlights, 36th ICRC 2019, Madison, 26/07/2019. 1

Highlights from the Observationsof the Milky Way with H.E.S.S.

Nukri Komin*

for the H.E.S.S. Collaboration

*Wits University, Johannesburg, South Africa

N. Komin, H.E.S.S. Galactic Highlights, 36th ICRC 2019, Madison, 26/07/2019. 2

High Energy Stereoscopic System (H.E.S.S.)

■ array of 5 Imaging Air Cherenkov Telescopes

■ record Cherenkov light of air showers

■ 5°/3.2° field of view (CT 1–4/CT5)

■ 30 GeV ... tens of TeV, angular resolution <0.1°

■ Namibia → Southern Hemisphere is ideal for Milky Way observations

see Heike ProkophGAI1b, Thu 13:45

see Heike ProkophGAI1b, Thu 13:45

www.cta-observatory.org

N. Komin, H.E.S.S. Galactic Highlights, 36th ICRC 2019, Madison, 26/07/2019. 3

The H.E.S.S. Galactic Plane Survey

■ [A&A 612, A1 (2018)]

N. Komin, H.E.S.S. Galactic Highlights, 36th ICRC 2019, Madison, 26/07/2019. 4

The Galactic Plane with H.E.S.S. and HAWC

see Armelle Jardin-BlicqGAI2h, Thu 18:15

see Armelle Jardin-BlicqGAI2h, Thu 18:15

HAWC

H.E.S.S.

H.E.S.S.

HAWC

■ overlap of H.E.S.S. and HAWC maps■ different map generation techniques

■ HAWC large FoV■ H.E.S.S. small FoV

■ good match between both instruments

■ reveals extended H.E.S.S. counterparts to HAWC sources

N. Komin, H.E.S.S. Galactic Highlights, 36th ICRC 2019, Madison, 26/07/2019. 5

The Pulsar Wind Nebula HESS J1825–137

■ [A&A 621, A116 (2019)]■ extension out to 1.5° from pulsar → intrinsic diameter ~100pc

■ strong energy-dependent morphology: R ∝E-0.29

■ rules out pure diffusion models■ significant cut-off of spectrum at 19 TeV

Energy (TeV)-410 -310 -210 -110 1 10 210

)-1 s

-2dN

/dE

(erg

cm

2 E

-1310

-1210

-1110

-1010

IC (total)IC (CMB)IC (FIR)IC (IR)IC (VIS)

Fermi-LAT (2011)3FGL (2015)3FHL (2017)H.E.S.S. Total (38 boxes)2HWC J1825-134

PSR B1823-13:

● Ė = 2.8 10✕ 36 erg/s

● age: 21 kyrs

PSR B1823-13:

● Ė = 2.8 10✕ 36 erg/s

● age: 21 kyrs

N. Komin, H.E.S.S. Galactic Highlights, 36th ICRC 2019, Madison, 26/07/2019. 6

The Pulsar Wind Nebula Vela X■ [A&A 627, A100 (2019)]■ H.E.S.S. + Suzaku X-ray data■ magnetic field: ~6 μG

■ no constrain on turbulence■ gamma-ray cut-off between 12 and 16 TeV → electrons up to ~100 TeV

N. Komin, H.E.S.S. Galactic Highlights, 36th ICRC 2019, Madison, 26/07/2019. 7

VHE Pulsations from Pulsars: Vela

■ clear detection of P2 (10-100 GeV)■ power-law spectrum■ [A&A 620, A66 (2018)]■ pulsations at >3 TeV

characteristics:

● Ė = 6.9 10✕ 36 erg/s

● P = 89ms

● age: 11 kyrs

● distance: 280 pc

characteristics:

● Ė = 6.9 10✕ 36 erg/s

● P = 89ms

● age: 11 kyrs

● distance: 280 pc

N. Komin, H.E.S.S. Galactic Highlights, 36th ICRC 2019, Madison, 26/07/2019. 8

VHE Pulsations from Pulsars: PSR B1706-44

see Marion Spir-JacobGAI2a, Thu 16:30

see Marion Spir-JacobGAI2a, Thu 16:30

■ 4.7σ significance■ power-law spectrum■ 4th VHE pulsar

characteristics:

● Ė = 3.4 10✕ 36 erg/s

● P = 102 ms

● age: 17 kyrs

● distance: 2.6 kpc

characteristics:

● Ė = 3.4 10✕ 36 erg/s

● P = 102 ms

● age: 17 kyrs

● distance: 2.6 kpc

N. Komin, H.E.S.S. Galactic Highlights, 36th ICRC 2019, Madison, 26/07/2019. 9

Gamma-Ray Binaries: PSR B1259–63/LS 2883

■ H.E.S.S. observations of 3 periastron passages■ high flux before 1st disk crossing■ minimum at periastron■ high flux during GeV flare

■ pure power-law spectrum■ highest flux point at 45.4 TeV■ cut-off >30 TeV

CT5 mono sky map

see poster no. 82Thu, Fri

see poster no. 82Thu, Fri

characteristics:

● Oe companion star

● pulsar

● eccentricity 0.87

● period 3.4 years

characteristics:

● Oe companion star

● pulsar

● eccentricity 0.87

● period 3.4 years

N. Komin, H.E.S.S. Galactic Highlights, 36th ICRC 2019, Madison, 26/07/2019. 10

Gamma-Ray Binaries: HESS J0632+057

■ VHE observations over 15 years with H.E.S.S., VERITAS and MAGIC■ orbital period: 316-318d■ double-peaked phase-folded light-curve■ ToO observations of flare in Jan 2018

PreliminaryPreliminary

characteristics:

● B0pe companion star

● unknown compact object

● eccentricity 0.6

● period 315-320d

characteristics:

● B0pe companion star

● unknown compact object

● eccentricity 0.6

● period 315-320d

see Gernot MaierGAI6c, Mon 14:00

see Gernot MaierGAI6c, Mon 14:00

N. Komin, H.E.S.S. Galactic Highlights, 36th ICRC 2019, Madison, 26/07/2019. 11

Low-Mass X-Ray Binary MAXI J1820+70

■ outburst in 2018■ VHE observations with H.E.S.S., MAGIC and VERITAS

■ covering most of outburst■ no detection of VHE emission■ high optical activity during high state seen with

MAGIC central pixel

1−10 1Hardness (4-10 keV)/(2-4 keV)

2−10

1−10

1

10/s

in [2

-10]

keV

2co

unts

/cm

MAXI data

H.E.S.S. obs.

MAGIC obs.

VERITAS obs.

Preliminary

31/03/18 30/04/18 30/05/18 29/06/18 29/07/18 28/08/18 27/09/18 27/10/18Date

0

0.5

1

1.5

2

MAX

I/GSC

Har

dnes

s

MAXI/GSC, Hardness: ratio of counts in [4,10 keV] / [2,4 keV]Preliminary

HS HSIM IMSS

31/03/18 30/04/18 30/05/18 29/06/18 29/07/18 28/08/18 27/09/18 27/10/18Date

0

1

2

3

)-1

.s-2

erg.

cm-1

0Fl

ux (1

0

Fermi LAT, [0.1,100] GeV, index -2.5, 99% C.L.Preliminary

58200 58220 58240 58260 58280 58300 58320 58340 58360 58380 58400 58420MJD

0

1000

2000

3000

4000

Swift

/BAT

Flu

x (m

Cra

b)

SWIFT/BAT [15,50] keVH.E.S.S. obs.MAGIC obs.VERITAS obs.

Preliminary

see poster no. 69Thu, Fri

see poster no. 69Thu, Fri

characteristics:

● ~1M☉ companion star

● ~5M☉ black hole

characteristics:

● ~1M☉ companion star

● ~5M☉ black hole

N. Komin, H.E.S.S. Galactic Highlights, 36th ICRC 2019, Madison, 26/07/2019. 12

Observations of Supernovae

■ [A&A 626, A57 (2019)]■ serendipitous observations of core-collapse

supernovae in other galaxies■ distances between 4 and 54 Mpc■ ToO observations of SN2016adj

■ no detection → upper limit on fluxes■ gamma-ray emission depends on ambient

medium→ depends on mass-loss and stellar wind velocity of progenitor

■ SN 1993J like explosions could be detected with H.E.S.S. and CTA

■ strong constraint for progenitor’s mass loss rate for SN2016adj

Time since discovery (days)0 50 100 150 200 250 300 350

SN 2004cxSN 2005dnSN 2008bkSN 2008bpSN 2008hoSN 2009hfSN 2009jsSN 2011jaSN 2012ccSN 2016adj

N. Komin, H.E.S.S. Galactic Highlights, 36th ICRC 2019, Madison, 26/07/2019. 13

Large Magellanic Cloud■ 1st VHE view of LMC

■ no new sources■ N 157B: curved spectrum■ upper limits for SNR, pulsars, HMXB

σ

exposure contours: 10, 20, 50, 100, 200 h

see poster no. 64Sat, Mon

see poster no. 64Sat, Mon

N. Komin, H.E.S.S. Galactic Highlights, 36th ICRC 2019, Madison, 26/07/2019. 14

Summary

■ H.E.S.S. Galactic Plane Survey finished, source hunting over?■ comparison with HAWC reveals new extended sources■ source hunting in the LMC

■ detailed studies of extended sources■ particle transport and magnetic field in PWNe

■ time domain astronomy■ periodic emission from gamma-ray binaries■ outbursts from microquasars■ supernova explosions

■ multi-collaboration studies with VERITAS, MAGIC, HAWC■ extension for 3 more years → more results to come