| Canonical Name: | HESS J1804-216 |
| TeVCat Name: | TeV J1804-217 |
| Other Names: | G8.7-0.1
W30
PSR J1803-2137 |
| Source Type: | UNID |
| R.A.: | 18 04 31.2 (hh mm ss) |
| Dec.: | -21 42 00 (dd mm ss) |
| Gal Long: | 8.40 (deg) |
| Gal Lat: | -0.03 (deg) |
| Distance: | 6 kpc |
| Flux: | 0.25 (Crab Units) |
| Energy Threshold: | 200 GeV |
| Spectral Index: | |
| Extended: | Yes |
| Size (X): | 0.16 (deg) |
| Size (Y): | 0.27 (deg) |
| Discovery Date: | 2005-03 |
| 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 J1804-216 |
| Source Class: | Unid |
| Identified Object: | None |
| R.A. (J2000): | 271.18 deg (18 04 42) |
| Dec. (J2000): | -21.74 deg (-21 44 34) |
| Positional uncertainty: | 0.090 deg |
| Spatial Model: | 2-Gaussian |
| Size: | 0.243 +/- 0.034 deg |
| Spectral Model: | power law |
| Integral Flux > 1 TeV: | 5.12e-12 +/- 2.30e-13 cm-2 s-1 |
| Pivot Energy, E0: | 0.72 TeV |
| Diff. Flux at E0: | 2.13e-11 +/- 6.20e-13 cm-2 s-1 TeV-1 |
| Spectral Index: | 2.69 +/- 0.04 |
| HGPS Source Notes: | |
| | |
Seven 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":
- G8.3-0.0 (SNR)
- B1800-21 (PSR)
- 3FGL J1805.6-2136e (3FGL)
- 2FHL J1805.6-2136e (2FHL)
- G8.7-0.1 (COMP)
- J1803-2149 (PSR)
- 3FGL J1803.1-2147 (3FGL)
Source position and its uncertainty:
From
Aharonian et al. (2006):
- l: 8.401 +/- 0.016 (deg)
- b: -0.033 +/- 0.018 (deg)
- R.A. (deg): 271.13 (Convert to HMS: 18 04 31.2)
- Dec. (deg): -21.70 (Convert to HMS: -21 42 00)
From HESS
online catalog:
- R.A. (J2000): 18:04:31
- Dec. (J2000): -21:42:00
- l: 8.40
- b: -0.03
From
Higashi et al. (2008):
- R.A. (J2000): 271.079 deg (Converts to: 18 04 18.96)
- Dec. (J2000): -21.727 deg (Converts to: -21 43 37.2)
- no positional uncertainty quoted
Source Extent:
From
Aharonian et al. (2006):
- radius: 0.200 +/- 0.010 deg
From
Higashi et al. (2008):
- extent along R.A. axis: 0.160 +/- 0.005 deg
- extent along Dec. axis: 0.274 +/- 0.011 deg
Source Association:
From
Feijen et al. (2022):
- "HESS J1804-216 is one of the brightest yet most mysterious TeV
gamma-ray sources discovered to date. Previous arc-minute scale
studies of the interstellar medium (ISM) surrounding this TeV
gamma-ray source revealed HESS J1804-216 is likely powered by a mature
supernova remnant (SNR) or pulsar, hence its origin remains uncertain."
- "In this paper, we focus on the diffusive escape of cosmic-ray
protons from potential SNR accelerators."
- "This work is the first attempt at modelling the spatial morphology
of gamma-rays towards HESS J1804-216, using arc-minute ISM
observations from both Mopra and the Southern Galactic Plane Survey."
- "The spectral and spatial distributions of gamma-rays for the two
nearby potential SNR counterparts, SNR G8.7-0.1 and the progenitor SNR
of PSR J1803-2137, are presented here."
- "We conclude that moderately slow diffusion is required for both
candidates. The most promising candidate to be powering the TeV
gamma-rays from HESS J1804-216 in a hadronic scenario is the
progenitor SNR of PSR J1803-213."
From
Feijen et al. (2020):
- The authors carried out "the most detailed study of interstellar gas
using data from the Mopra Southern Galactic Plane CO Survey, 7 and 12
mm wavelength Mopra surveys and Southern Galactic Plane Survey of HI."
- "Several components of atomic and molecular gas are found to overlap
HESS J1804-216 at various velocities along the line of sight."
- "The CS(1-0) emission clumps confirm the presence of dense gas. Both
correlation and anti-correlation between the gas and TeV gamma-ray
emission have been identified in various gas tracers, enabling several
origin scenarios for the TeV gamma-ray emission from HESS J1804-216."
- "For a hadronic scenario, SNR G8.7-0.1 and the progenitor SNR of
PSR J1803-2137 require cosmic ray (CR) enhancement factors of approx.
50 times the solar neighbour CR flux value to produce the TeV gamma-ray
emission. Assuming an isotropic diffusion model, CRs from both these
SNRs require a slow diffusion coefficient, as found for other TeV SNRs
associated with adjacent ISM gas."
- "The morphology of gas located at 3.8 kpc (the dispersion measure
distance to PSR J1803-2137) tends to anti-correlate with features of
the TeV emission from HESS J1804-216, making the leptonic scenario
possible."
- Both pure hadronic and pure leptonic scenarios thus remain
plausible."
From
Bing et al. (2019):
- The authors studied the region around W30 using a decade of
observations from the Fermi Large Area Telescope in the energy range
between 0.3 and 300 GeV.
- They suggest that the TeV emission could originate in the PWN of the
pulsar PSR J1803-2137.
- "The morphological and spectral analyses allow us to resolve the
gamma-ray emission into two extended structures from different
origins."
- "One of them mostly overlaps with the supernova remnant (SNR)
G8.7-0.1 and has a soft spectrum that resembles with the spectra of
other middle-aged SNRs interacting with molecular clouds."
- "The other shows remarkable spatial and spectral consistency with
the TeV emission from HESS J1804-216, and its spectrum could be
naturally explained by inverse Compton scattering of electrons like a
number of TeV gamma-ray emitting pulsar wind nebulae. Thus we
attribute this source to the nebula around the pulsar PSR J1803-2137."
From
Acero et al. (2013):
- this source has a relatively hard spectrum at LAT energies that
connects spectrally to the associated VHE source.
From
Yuan, Liu & Bi (2012):
- this object is treated as being associated with G8.7-0.1
From
Lin, Webb & Barret (2013):
- "We have analyzed three XMM-Newton observations of the central part
of the unidentified TeV gamma-ray source HESS J1804-216. We focus on
two X-ray sources 2XMMi J180442.0-214221 (Src 1) and 2XMMi
J180432.5-214009 (Src 2), which were suggested to be the possible
X-ray counterparts to the TeV source.
- " ... Src 1 and Src 2 are probably two magnetic cataclysmic
variables that happen to be in the direction of the TeV source, not
its X-ray counterparts."
- "HESS J1804-216 is still most likely associated with SNR G8.7-0.1 or
PSR J1803-2137, as suggested before."
Seen by: H.E.S.S., CANGAROO
-
Modelling the Gamma-Ray Morphology of HESS J1804-216 from Two Supernova Remnants in a Hadronic Scenario
Feijen, K. et al., arXiv e-prints parXiv:2201.11387 (2022) [LINK]
-
Arc-minute-scale studies of the interstellar gas towards HESS J1804-216: Still an unidentified TeV gamma-ray source
Feijen, K. et al., arXiv e-prints parXiv:2011.09021 (2020) [LINK]
-
The GeV emission in the field of the star-forming region W30 revisited
Liu, Bing et al., arXiv e-prints parXiv:1907.00180 (2019) [LINK]
-
Dense molecular gas at 12 mm towards Galactic TeV gamma-ray sources
de Wilt, P. et al., MNRAS 468 p2093-2113 (2017) [LINK]
-
A statistical study of Galactic SNR source spectra detected at >GeV energies
Mandelartz, M. et al., ArXiv e-prints p (2013) [LINK]
-
XMM-Newton Observations of the TeV $\backslash$gamma-ray Source HESS J1804-216
Lin, D. et al., ArXiv e-prints p (2013) [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]
-
Unified model for the gamma-ray emission of supernova remnants
Yuan, Q. et al., ArXiv e-prints p (2012) [LINK]
-
Fermi Large Area Telescope Observations of the Supernova Remnant G8.7-0.1
Ajello, M. et al., ApJ 744 p80 (2012) [LINK]
-
Fermi Large Area Telescope Observations of Supernova Remnants Interacting with Molecular Clouds
Castro, D. and Slane, P., ApJ 717 p372-378 (2010) [LINK]
-
Observation of Very High Energy Gamma Rays from HESS J1804-216 with CANGAROO-III Telescopes
Higashi, Y. et al., ApJ 683 p957-966 (2008) [LINK]
-
The H.E.S.S. Survey of the Inner Galaxy in Very High Energy Gamma Rays
Aharonian, F. et al., ApJ 636 p777-797 (2006) [LINK]
-
A New Population of Very High Energy Gamma-Ray Sources in the Milky Way
Aharonian, F. et al., Science 307 p1938-1942 (2005) [LINK]
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