| Canonical Name: | HESS J1832-085 |
| TeVCat Name: | TeV J1832-085 |
| Other Names: | PSR J1832-0836 |
| Source Type: | UNID |
| R.A.: | 18 32 30 (hh mm ss) |
| Dec.: | -08 30 41 (dd mm ss) |
| Gal Long: | 23.21 (deg) |
| Gal Lat: | 0.30 (deg) |
| Distance: | |
| Flux: | 0.008 (Crab Units) |
| Energy Threshold: | 200 GeV |
| Spectral Index: | 2.38 |
| Extended: | No |
| Discovery Date: | 2015-07 |
| 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 J1832-085 |
| Source Class: | Unid |
| Identified Object: | None |
| R.A. (J2000): | 278.13 deg (18 32 30) |
| Dec. (J2000): | -8.51 deg (-08 30 41) |
| Positional uncertainty: | 0.029 deg |
| Spatial Model: | Gaussian |
| Size: | N/A |
| Spectral Model: | power law |
| Integral Flux > 1 TeV: | 2.26e-13 +/- 3.99e-14 cm-2 s-1 |
| Pivot Energy, E0: | 1.27 TeV |
| Diff. Flux at E0: | 1.76e-13 +/- 2.86e-14 cm-2 s-1 TeV-1 |
| Spectral Index: | 2.38 +/- 0.14 |
| HGPS Source Notes: | |
| | |
The following is the text from the HGPS paper:
HESS J1832-085 is an unidentified source of VHE gamma rays. It is notable for its point-like morphology, which is measured to be less than 0.05 deg
in extension, and its scarcity of promising MWL counterparts.
An interesting object that is spatially coincident with HESS J1832-085 is the pulsar PSR J1832-0827
(Clifton & Lyne 1986), which has so far only been detected in radio wavelengths. The pulsar is likely at a distance of approx. 4.9 kpc
(Cordes & Lazio 2002), in agreement with other estimates in the range 4.4–6.1 kpc
(Frail et al. 1991) and has a spin-down luminosity Edot of 9.3 x 10e33 erg s-1
(Hobbs et al. 2004). It is one of the few pulsars with a measured braking index, n = 2.5 +/- 0.9
(Johnston & Galloway 1999), providing a characteristic age Tchar of approx. 200 kyr.
Another very intriguing object in the FoV is the energetic millisecond pulsar PSR J1832-0836, which has a 2.7 ms period
(Burgay et al. 2013). It has a spin-down luminosity Edot of 1.7 x 10e34 erg s-1, a very large characteristic age (typical of millisecond pulsars)
Tchar = 5 x 109 kyr, and distance 1.1 kpc
(Cordes & Lazio 2002).
There are no known PWNe associated with these two pulsars nor close to HESS J1832-085. If either or both of these pulsars are powering VHE PWNe, a relatively large conversion efficiency of
ConvEff(1-10 TeV) of approx. 23% would be required for PSR J1832-0827, and a more reasonable ConvEff(1-10 TeV) of approx. 0.6% for PSR J1832-0836. The older ages are at odds with the inferred
small sizes of the VHE PWNe, constrained to be less than approx. 4 (d/4.9 kpc) pc and approx. 1 (d/1.1 kpc) pc, respectively. These circumstances, plus the borderline low spin-down luminosity
of PSR J1832-0827, combine to disfavor a PSR and PWN scenario as the origin of the VHE emission in light of the known VHE PWN population
(H.E.S.S. Collaboration 2018). The millisecond pulsar scenario is even more uncertain. That
pulsar is slightly more energetic and much closer, but thus far millisecond pulsars, with ages of billions of years, are not known to produce PWNe that emit detectable levels of gamma rays at TeV energies.
Therefore, the origin of the emission from this new, enigmatic, VHE gamma-ray source is still very much unclear.
This source was moved from the "Newly Announced" to the "Default" catalogue of TeVCat on 200316.
This detection was announced by
C. Deil at the
34th ICRC.
Source position:
On 200317 the source position was updated from that in
Deil et al. (2015) to that
in the
H.E.S.S. Collaboration (2018).
From
H.E.S.S. Collaboration (2018):
- R.A. (J2000): 18h 32m 30s
- Dec. (J2000): -08d 30' 41''
- Positional uncertainty: 0.029 deg
From
Deil et al. (2015):
- Lat.: 23.21 deg
- Lon.: 0.29 deg
... Convert this position to J2000 coordinates:
- R.A. (J2000): 18h 32m 31.75s
- Dec. (J2000): -08d 30' 35.4''
... this is the position quoted in TeVCat
- no positional uncertainty is quoted
Source extent:
From
H.E.S.S. Collaboration (2018):
- this is a point source
From
Deil et al. (2015):
- an upper limit of 0.05 deg is placed on the extent
Flux:
From
Deil et al. (2015):
- 0.8% Crab
Source class:
From
Maxted et al. (2019):
The authors propose a supernova remnant counterpart for this source:
- "We examine the new Galactic supernova remnant (SNR) candidate,
G23.11+0.18, as seen by the Murchison Widefield Array radio
telescope. We describe the morphology of the candidate and find a
spectral index of -0.63 +/- 0.05 in the 70-170 MHz domain. Coincident
TeV gamma-ray detection in High Energy Stereoscopic System (HESS) data
supports the SNR nature of G23.11+0.18 and suggests that G23.11+0.18
is accelerating particles beyond TeV energies, thus making this object
a promising new cosmic-ray hadron source candidate."
From
Deil et al. (2015):
- PSR J1832-0836 lies near the source
- no further details are available in the PDF
- the source is classified as UNID in TeVCat for now
Seen by: H.E.S.S.
-
Investigation of X-ray emission from the unidentified TeV gamma-ray source HESS J1832-085 with Suzaku
Aktekin, Ebru, arXiv e-prints parXiv:2503.16908 (2025) [LINK]
-
A Supernova Remnant Counterpart for HESS J1832-085
Maxted, Nigel I. et al., ApJ 885 p129 (2019) [LINK]
-
The H.E.S.S. Galactic plane survey
H.E.S.S. Collaboration et al., A&A 612 pA1 (2018) [LINK]
-
H.E.S.S. Galactic plane survey
C. Deil for the H.E.S.S. Collaboration, ICRC 2015 [LINK]
Want a reference added? Send a bibtex entry to
the TeVCat Team
