Morphological and spectral measurements of 2HWC J1928+177 with HAWC - - PowerPoint PPT Presentation

▶
morphological and spectral measurements of 2hwc j1928 177
SMART_READER_LITE
LIVE PREVIEW

Morphological and spectral measurements of 2HWC J1928+177 with HAWC - - PowerPoint PPT Presentation

Dec 25, 2023 294 likes •459 views

Morphological and spectral measurements of 2HWC J1928+177 with HAWC and H.E.S.S. R. Lpez-Coto, V. Marandon, F. Brun for the HAWC and HESS collaborations ICRC 2017 - Busan - 15/07/17 High Altitude Water Cherenkov Located in Sierra Negra

slide-1
SLIDE 1
  • R. López-Coto, V. Marandon, F. Brun for the HAWC and HESS collaborations

ICRC 2017 - Busan - 15/07/17

Morphological and spectral measurements of 2HWC J1928+177 with HAWC and H.E.S.S.

slide-2
SLIDE 2

Rubén López-Coto - ICRC 2017 - 14/07/17

High Altitude Water Cherenkov

2

.

  • Located in Sierra Negra (Mexico)
  • 4100 m above sea level
  • 300 tanks
  • 200 kL water each
  • 22 000 m2 area w. 57% coverage
  • 15-20 kHz trigger rate
  • FoV ~ 2 sr
  • Energy range 0.1 - 100 TeV
  • Angular resolution ~ 0.2°-1°
  • Duty cycle > 95%
slide-3
SLIDE 3

Rubén López-Coto - ICRC 2017 - 14/07/17

High Energy Sterescopic System

3

  • Located in Namibia
  • 1800 m above sea level
  • 4 12-m diameter telescopes
  • 1 28-m diameter
  • Energy range 0.05 - 100 TeV
  • Angular resolution ~< 0.1°
slide-4
SLIDE 4

Rubén López-Coto - ICRC 2017 - 15/07/17 4

Region around SNR G054.1+00.3

Abeysekara, A.U. et al., “The 2HWC HAWC Observatory gamma-ray catalog”, arXiv:1702.02992

slide-5
SLIDE 5

Rubén López-Coto - ICRC 2017 - 15/07/17

  • 2HWC J1928+177
  • Brighter than SNR G054
  • VHE gamma-ray emission

coincident with PSR J1928+1746

  • VERITAS point-like upper limit

~1.4% of Crab (E>1 TeV) 2HWC J1930+188 (SNR G054.1+00.3) -> TeV association

Region around SNR G054.1+00.3

5

slide-6
SLIDE 6

Rubén López-Coto - ICRC 2017 - 15/07/17 6

HAWC Results (~2 years)

.

2HWC J1928+177 (PSR J1928+1746)

.

  • HAWC skymap with three? regions
  • f emission
  • Contours starting at 5 σ and

increasing by 2 σ

  • Region very complex with many

emission blobs

SNR G054.1+00.3 (PSR J1930+1852)

slide-7
SLIDE 7

Rubén López-Coto - ICRC 2017 - 15/07/17 7

HAWC-HESS comparison

  • Green: HESS 80% containment of

SNR G054.1+00.3 (HESS J1930+188).

  • Top: HAWC (~>10 TeV) with contours

in black. Compatible with the PSF

  • Bottom: HESS, Map above ~750 GeV

using 0.2 deg integration radius

  • HAWC contours in white
slide-8
SLIDE 8

Rubén López-Coto - ICRC 2017 - 15/07/17

Multiwavelength view

8

  • The source is really DARK.
  • No PWN/SNR detected at any other

wavelength Radio image from the NVSS (VLA, 1.4 GHz) Swift monitoring of 3FGL sources

slide-9
SLIDE 9

Rubén López-Coto - ICRC 2017 - 15/07/17

  • Radio pulsar discovered in the ALFA survey
  • Age = 83 kyr
  • Edot = 1.6 x 1036 erg s-1
  • Distance = 5.8 kpc
  • P = 68.7 ms, Pdot = 1.32 x 10-14 s/s
  • Observed but undetected in X-rays by Chandra -> U.L. at a 5.8x10-15 erg/s/cm2
  • No pulsed emission has been detected at gamma rays, but:
  • EGRET discovered a source coincident with the pulsar position ( 3EG

J1928+1733).

  • Fermi also reported emission from that region (3FGL J1928.9+1739).
  • > Saz Parkinson et al. (2016) associates 3FGL J1928.9+1739 emission with

that of a pulsar using Machine Learning techniques

PSR J1928+1746

9

slide-10
SLIDE 10

Rubén López-Coto - ICRC 2017 - 15/07/17

  • HAWC:
  • dN/dE = f0 (E/7 TeV)-Γ
  • f0 = (1.06±0.12)10-14 TeV-1cm-2s-1
  • Γ=2.60±0.09
  • HESS upper limits above 750 GeV

for 0.1 and 0.4 integration radius.

2HWC J1928+177

10

slide-11
SLIDE 11

Rubén López-Coto - ICRC 2017 - 15/07/17

Modeling

Electrons

  • Photon fields for IC:
  • CMB : 0.25 eV/cm3
  • FIR [20 K]: 0.3 eV/cm3
  • We need We=4.9 x 1047 erg of

electrons above 1 TeV to produce this emission.

  • Total energy injected by the

pulsar: ~ 1051 erg

11

  • Density assumed n=1 cm-3
  • The energy injected into protons
  • f E>1 TeV needs to be > 1050

erg -> Energetically challenging.

Protons

particles gammas

slide-12
SLIDE 12

Rubén López-Coto - ICRC 2017 - 15/07/17 12

TeV efficiency TeV luminosity

Comparison with PWN population

Klepser, S. et al. id 731

Characteristic age Spin-down power

slide-13
SLIDE 13

Rubén López-Coto - ICRC 2017 - 15/07/17

Comparison to SNRs

13

2HWC 1928+177

From Funk, S. 2015

slide-14
SLIDE 14

Rubén López-Coto - ICRC 2017 - 15/07/17

Conclusions

14

  • Morphology:
  • HAWC at the highest energies is compatible with the PSF -> Extension at

these energies might be up to ~0.2 deg (HAWC PSF)

  • For lower energies, the morphology is not so clear due to larger PSF and

contamination

  • Spectrum is best fit by a single power-law between ~few TeV and ~80 TeV
  • Leptonic scenario favored
  • PWN hypothesis is consistent with the rest of the PWN population
  • Comparison to SNR detected at TeV show an unseen hard spectrum at TeV

energies.

slide-15
SLIDE 15

Rubén López-Coto - ICRC 2017 - 15/07/17

Backup

15

slide-16
SLIDE 16

Rubén López-Coto - ICRC 2017 - 15/07/17

Thanks!

16