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Observation Date (UT) Observation Lat

Canonical Name:HESS J1746-308
TeVCat Name:TeV J1746-308
Other Names:SNR G358.5-0.9
PSR B1972-30
Source Type:UNID
R.A.:17 46 17.13 (hh mm ss)
Dec.:-30 50 28.0248 (dd mm ss)
Gal Long: 358.45 (deg)
Gal Lat: -1.11 (deg)
Distance:
Flux:0.03 (Crab Units)
Energy Threshold:1000 GeV
Spectral Index:3.27
Extended:Yes
Size (X):0.16 (deg)
Size (Y):0.16 (deg)
Discovery Date:2018-04
Discovered By: H.E.S.S.
TeVCat SubCat:Default Catalog

Source Notes:

H.E.S.S. Galactic Plane Survey (HGPS, 2018):
A selection of information for each of the 78 sources in the HGPS is provided in TeVCat. For full details, visit the HGPS website.

Name: HESS J1746-308
Source Class: Unid
Identified Object: None
R.A. (J2000): 266.57 deg (17 46 17)
Dec. (J2000): -30.84 deg (-30 50 28)
Positional uncertainty: 0.091 deg
Spatial Model: Gaussian
Size: 0.162 +/- 0.036 deg
Spectral Model: power law
Integral Flux > 1 TeV: 3.03e-13 +/- 8.52e-14 cm-2 s-1
Pivot Energy, E0: 0.49 TeV
Diff. Flux at E0: 7.21e-12 +/- 8.10e-13 cm-2 s-1 TeV-1
Spectral Index: 3.27 +/- 0.22
HGPS Source Notes:
The authors note: "For most sources, the spectral fit results reported in this catalog agree with those obtained from the independent cross-check analysis." HESS J1746-308 was one of the sources for which "larger differences, exceeding the systematic errors, are observed. Several factors could explain these differences, such as the lower energy threshold in the cross-check analysis, the differences in the morphology models, or the fact that the cross-check spectrum analysis is run for the positions and sizes obtained with the main analysis."
- The large spectral index derived from the main analysis could not be confirmed by the cross-check analysis. The differential flux values at 1 TeV are compatible, but the discrepancy in the obtained spectral indices leads to an integral flux above 1 TeV about two times higher in the cross-check analysis than in the main analysis.

Two possible associations are listed in Table A.9. "This is a list of astronomical objects, extracted from catalogs of plausible counterparts, which are are found to be spatially coincident with the HGPS source":
- G358.5−0.9 (SNR)
- B1742−30 (PSR)

Source Position:
From H.E.S.S. Collaboration (2018):
- R.A. (J2000): 17h 46m 17.13s (= 266.57138 deg)
- Dec. (J2000): -30d 50m 28.0248s (= -30.841118 deg)

Source Notes:
From H.E.S.S. Collaboration (2018):
- "HESS J1745-303 was studied in Aharonian et al. (2008b) with 80 h of
data. Its morphology is complex and three subregions, called A, B, and
C, were discussed. In the HGPS analysis, with more than 160 h on the
region, two distinct sources are detected: HESS J1745-303 and
HESS J1746-308. The former encloses the hotspots A and C and a
fraction of region B. A second source is now detected at b = -1.11 deg
latitude. This source contains part of hotspot B and emission at large
latitudes that was not significant before, likely due to the
additional livetime obtained since 2008."

Source Flux:
From H.E.S.S. Collaboration (2018):
These fluxes are taken from Table 10 of the above paper and correspond
to the map-based measurements for each source.
The flux above 1 TeV:
- 0.68 +/- 0.22 x 10e-12 cm-2 s-1
The flux above 1 TeV in percentage of the Crab:
- 3.0 +/- 1.0

Spectral Properties:
From H.E.S.S. Collaboration (2018):
These spectral properties were taken from Table 11 of the above paper.
- Spectral index: 3.27 +/- 0.22
- E_min: 0.2 TeV
- F (> 1 TeV): 0.30 +/- 0.09 x 10e-12 cm-2 s-1

Source Extent:
From H.E.S.S. Collaboration (2018):
- The shape of this source is best fit by a Gaussian.
- Size: 0.16 +/- 0.036 deg
- R_95: 0.15 deg

Source Association:
From H.E.S.S. Collaboration (2018):
- two possible associations ore listed in Table 12: SNR G358.5-0.9 and PSR B1972-30


Seen by: H.E.S.S.
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