| Canonical Name: | HESS J1626-490 |
| TeVCat Name: | TeV J1626-490 |
| Other Names: | SNR G335.2+00.1 |
| Source Type: | UNID |
| R.A.: | 16 26 04 (hh mm ss) |
| Dec.: | -49 05 13 (dd mm ss) |
| Gal Long: | 334.77 (deg) |
| Gal Lat: | 0.05 (deg) |
| Distance: | |
| Flux: | (Crab Units) |
| Energy Threshold: | GeV |
| Spectral Index: | 2.18 |
| Extended: | Yes |
| Size (X): | 0.07 (deg) |
| Size (Y): | 0.10 (deg) |
| Discovery Date: | 2007-07 |
| 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 J1626-490 |
| Source Class: | Unid |
| Identified Object: | None |
| R.A. (J2000): | 246.75 deg (16 27 00) |
| Dec. (J2000): | -49.17 deg (-49 10 23) |
| Positional uncertainty: | 0.083 deg |
| Spatial Model: | Gaussian |
| Size: | 0.197 +/- 0.035 deg |
| Spectral Model: | power law |
| Integral Flux > 1 TeV: | 2.13e-12 +/- 2.59e-13 cm-2 s-1 |
| Pivot Energy, E0: | 1.16 TeV |
| Diff. Flux at E0: | 2.19e-12 +/- 2.33e-13 cm-2 s-1 TeV-1 |
| Spectral Index: | 2.47 +/- 0.11 |
| HGPS Source Notes: | |
| | |
This is one of eleven HGPS sources that "do not have any associations with known physical objects, although some are associated
with HE gamma-ray sources." It "has only one association, with the HE gamma-ray source 3FGL J1626.2−4911. A dedicated XMM-Newton observation
did not reveal any compelling X-ray counterpart either (Eger et al. 2011)."
The one possible association is 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":
- 3FGL J1626.2−4911 (3FGL)
Source position and its uncertainty:
From
Aharonian et al. (2008):
- RA: (J2000): 16 26 04
- Dec (J2000): -49 05 13
- The fit position has a statistical error of 0.05 deg
Source Extent:
From
Aharonian et al. (2008):
- semi-major axis: 0.07 +/- 0.02 deg
- semi-minor axis: 0.10 +/- 0.05 deg
- angle: 3 +/- 40 deg
...measured counter-clk relative to RA axis
Source Association:
From
Acero et al. (2013):
- "With a TS of 1.5, HESS J1626−490 is not detected in our
analysis. The model presented in
Eger at al. (2011) and shown in Figure 5
reproduces the H.E.S.S. SED and predicts emission below the LAT upper
limits. A radio or/and X-ray detection of synchrotron emission from a
PWN or the detection of a pulsar could call this model into question."
From
Eger at al. (2011):
- Archival XMM Newton data were analysed: "one of the detected X-ray point
sources fulfills the energetic requirements to be considered as the synchrotron
radiation (SR) counterpart to the VHE source assuming an Inverse Compton (IC)
emission scenario". No diffuse X-ray emission was detected either. "The derived
upper limit for the total X-ray flux disfavors a purely leptonic emission scenario
for HESS J1626-490." They found "a good morphological match between molecular
and atomic gas in the -27 km/s to -18 km/s line-of-sight velocity range and HESS
J1626-490" and suggest that "the most likely origin of the VHE gamma-ray emission
observed with H.E.S.S. is the hadronic interaction of cosmic rays with a moderately
dense molecular cloud" which they detected with Nanten. SNR G335.2+00.1, which
is nearby, is suggested as the origin of the cosmic rays.
Seen by: H.E.S.S.
-
Dense molecular gas at 12 mm towards Galactic TeV gamma-ray sources
de Wilt, P. et al., MNRAS 468 p2093-2113 (2017) [LINK]
-
Constraints on the Galactic Population of TEV Pulsar Wind Nebulae Using Fermi Large Area Telescope Observations
Acero, F. et al., ArXiv e-prints p (2013) [LINK]
-
A Multi-Wavelength Study of the Unidentified TeV Gamma-ray Source HESS J1626-490
Eger, P. et al., ArXiv e-prints p (2011) [LINK]
-
HESS very-high-energy gamma-ray sources without identified counterparts
Aharonian, F. et al., A&A 477 p353-363 (2008) [LINK]
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