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Observation Date (UT) Observation Lat

Canonical Name:MAGIC J1857.2+0263
TeVCat Name:TeV J1857+026m
Other Names:HESS J1857+026
1HWC J1857+023
2HWC J1857+027
Source Type:PWN
R.A.:18 57 13.0 (hh mm ss)
Dec.:02 37 31 (dd mm ss)
Gal Long: 35.93 (deg)
Gal Lat: -0.09 (deg)
Flux: (Crab Units)
Energy Threshold:1000 GeV
Spectral Index:2.2
Size (X):0.17 (deg)
Size (Y):0.06 (deg)
Discovery Date:2014-11
Discovered By: MAGIC
TeVCat SubCat:Default Catalog

Source Notes:
This source and MAGIC J1857.6+0297 form part of a two-source scenario
that the MAGIC data favour for HESS J1857+026

Source Position:
From Aleksic et al. (2014):
- R.A. (J2000): 18h 57m 13.0s +/- 4.0s(stat) +/- 10.8s(syst)
- Dec. (J2000): 02d 37' 31" +/- 50"(stat) +/- 3'(syst)

Source extent:
From Aleksic et al. (2014):
- This elongated source was fitted by a noncircular 2D Gaussian
yielding an intrinsic extension of:
- major axis: 0.17 +/- 0.03(stat) +/- 0.02(syst) deg
- minor axis: 0.06 +/- 0.03(stat) +/- 0.02(syst) deg
- major axis has an inclination of 37 +/- 6(stat) deg counter-clockwise wrt R.A. axis

Spectral Information:
From Aleksic et al. (2014):
- Spectral index: 2.2 +/- 0.1 (stat) above 1 TeV

From Aleksic et al. (2014):
- the differential flux is approximately 45% of the total differential
flux measued by MAGIC at 1 TeV for HESS J1857+026

Source Associtaion:
From Aleksic et al. (2014):
- "... we expect MAGIC J1877.2+0263 to be associated with PSR J1856+0245"
- "We then interpret MAGIC J1857.2+0263 as the emission from the relic
PWN of PSR J1856+0245. We expect that the elongated shape of the
emission above 1 TeV as well as its offset position from the pulsar
are signatures of complex PWN evolutionary processes, which involve an
interaction with the SNR reverse shock, while the initial pulsar
velocity could also play a role."
From Abeysekara et al. (2015):
- "The source 1HWC J1857+023* is detected at 6.2sigma post trials and
is approx. 0.4deg away from both HESS J1857+026 and HESS J1858+020.
... The flux of HESS J1857+026 is approximately an order of
magnitude higher than HESS J1858+020, and the differential flux
normalization from 1HWC J1857+023 is compatible with the combined flux
of HESS J1857+026 and HESS J1858+020"
*1HWC J1857+023 is not listed under a separate entry in TeVCat. It is
listed as an associated source for HESS J1857+026, HESS J1858+020,
MAGIC J1857.2+0253 and MAGIC J1857.6+0297.

Seen by: H.E.S.S., MAGIC, HAWC
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