| Canonical Name: | HESS J1852-000 |
| TeVCat Name: | TeV J1852-000 |
| Other Names: | Kes 78 1LHAASO J1850-004u* |
| Source Type: | UNID |
| R.A.: | 18 52 14 (hh mm ss) |
| Dec.: | 00 05 56 (dd mm ss) |
| Gal Long: | 33.11 (deg) |
| Gal Lat: | -0.13 (deg) |
| Distance: | |
| Flux: | (Crab Units) |
| Energy Threshold: | GeV |
| Spectral Index: | |
| Extended: | Yes |
| Size (X): | 0.00 (deg) |
| Size (Y): | 0.00 (deg) |
| Discovery Date: | 2011-08 |
| Discovered By: | H.E.S.S. |
| TeVCat SubCat: | Default Catalog |
| 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 J1852-000 | |
| Source Class: | Unid | |
| Identified Object: | None | |
| R.A. (J2000): | 283.06 deg (18 52 14) | |
| Dec. (J2000): | 0.10 deg (00 05 56) | |
| Positional uncertainty: | 0.111 deg | |
| Spatial Model: | Gaussian | |
| Size: | 0.278 +/- 0.042 deg | |
| Spectral Model: | power law | |
| Integral Flux > 1 TeV: | 1.21e-12 +/- 1.48e-13 cm-2 s-1 | |
| Pivot Energy, E0: | 2.06 TeV | |
| Diff. Flux at E0: | 2.96e-13 +/- 3.60e-14 cm-2 s-1 TeV-1 | |
| Spectral Index: | 2.17 +/- 0.10 | |
| 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 J1852-000 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."
For HESS J1852-000:
- "The derived spectral indices are compatible, but the integral flux above 1 TeV is about two times higher in the cross-check analysis than in the main analysis."
The following is the text from the HGPS paper:
The new source of VHE gamma-ray emission HESS J1852-000 is currently unidentified due to multiple source counterpart confusion. It is spatially associated with the partial shell-type SNR G32.8-0.1 (also known as Kes 78; Kesteven 1968; Velusamy & Kundu 1974), the incomplete shell-type SNR G33.2-0.6 (Reich 1982), and two energetic pulsars, PSR J1853-0004 and PSR J1853+0011 (Hobbs et al. 2004). Preliminary H.E.S.S. source properties were previously shown (Kosack et al. 2011) and are compatible with the HGPS results. As mentioned in Sect. 5.5, the spectral properties of HESS J1852-000 are affected by systematic uncertainties larger than nominal.
The VHE emission is located along the eastern edge of SNR Kes 78 but extends well beyond the SNR. The SNR itself is characterized by an elongated and partial nonthermal shell seen in radio and X-rays (Zhou & Chen 2011; Bamba et al. 2016). It is interacting with adjacent molecular clouds, evidenced by the detection of a shock-excited OH(1720 MHz) maser on the shell (Koralesky et al. 1998) and studies of the CO molecular environment (Zhou & Chen 2011). The distance of the SNR is estimated to be approximately 5 kpc (Koralesky et al. 1998; Zhou & Chen 2011), although approximately 8.8 kpc has also been suggested (e.g., Xu & Zhang 2009). A hadronic origin of the VHE emission has been briefly discussed (Kosack et al. 2011), involving escaped cosmic rays from Kes 78 (e.g., Aharonian 1991; Gabici et al. 2007). However, the scenario remains unconfirmed in the absence of a more detailed study of the gas environment and its potential correlation with the complex VHE morphology.
The presence of two radio pulsars, PSR J1853-0004 and PSR J1853+0011, within the VHE emission region also suggests that the VHE gamma rays could originate in one of the PWN or could even be a result of superimposed emission from two PWNe. Although there are currently no known PWNe at other energies, the pulsars' spin-down luminosities Edot of 2.1 × 10e35 erg s-1 and 2.1 × 10e34 erg s-1, respectively, and distances d = 6.6 kpc and 7.5 kpc, are reasonable in the context of other pulsars thought to be powering VHE PWNe (H.E.S.S. Collaboration 2018). The pulsars have so far only been detected in radio, although PSR J1853-0004 has been associated with the HE gamma-ray source 3FGL J1853.2+0006, which is itself a source whose existence and properties are currently uncertain (subject to analysis Flags 3 and 4 in Acero et al. 2015).
In conclusion, it is not yet clear whether the VHE emission originates from a hadronic SNR and molecular cloud interaction, previously undetected PWNe associated with one or both of the spatially coincident pulsars, or some other yet unknown source.
Five 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":
- 3FGL J1853.2+0006 (3FGL)
- G32.8-0.1 (SNR)
- J1853+0011 (PSR)
- J1853-0004 (PSR)
- G33.2-0.6 (SNR)
On 200323 this source was moved from the "Newly Announced" to the "Default" catalogue in TeVCat.
This source was added to TeVCat on 160119
Source Discovery:
- This source is the HESS Source of the Month for February 2011
Source position and its uncertainty:
On 200323 the source position was updated from that given in Kosack et al. (2011) to that
given in H.E.S.S. Collaboration (2018).
From H.E.S.S. Collaboration (2018):
- R.A. (J2000): 18h 52m 14s
- Dec. (J2000): 00d 05' 56''
- Positional uncertainty: 0.111 deg
From Kosack et al. (2011):
The PDF of this paper is available here
- It is noted that this is the approximate position
- R.A. (J2000): 18h 52m 13s
- Dec. (J2000): -00d 00' 23"
- No uncertainty is quoted for the position
Source Extent:
From Kosack et al. (2011):
- "the morphology of the peak of the emission is not consistent with
the PSF of the instrument, and can be reasonably modeled with a sum of
two elongated Gaussians, suggesting the source is not point-like
Source Association:
From Bamba et al. (2016):
- a number of source-association possibilities are proposed based on
the first dedicated X-ray study of the supernova remnant (SNR)
G32.8−0.1 (Kes 78) with Suzaku
- the possibilities described include a PWN, the SNR Kes 78 (either
diffuse emission or shock emission from the shell), a super-giant fast
x-ray transient, a low-mass x-ray binary
From Kosack et al. (2011):
- "... may be partially associated with either an interaction of the
elongated shell-type SNR Kes 78 wiah a nearby molecular cloud, or with
a previously undiscovered pulsar-wind nebula.""
A PeVatron:
From Cao et al. (2024):
- This source is listed as being a UHE source in Table 2. This means
that it has a detection above 100 TeV at a significance level
corresponding to a test statistic of greater than 20.
Seen by: H.E.S.S., LHAASO
- The First LHAASO Catalog of Gamma-Ray Sources
Cao, Zhen et al., ApJS 271 p25 (2024) [LINK]
- Using Interstellar Clouds to Search for Galactic PeVatrons: Gamma-ray Signatures from Supernova Remnants
Mitchell, A.M.W. et al., arXiv e-prints parXiv:2103.01787 (2021) [LINK]
- Search for galactic Pevatron candidates in a population of unidentified gamma-ray sources
Spengler, Gerrit, arXiv e-prints parXiv:1912.05221 (2019) [LINK]
- The H.E.S.S. Galactic plane survey
H.E.S.S. Collaboration et al., A&A 612 pA1 (2018) [LINK]
- Discovery of X-ray Emission from the Galactic Supernova Remnant G32.8-0.1 with Suzaku
Bamba, A. et al., ArXiv e-prints p (2016) [LINK]
- HESS J1852-000: A Very High Energy Gamma-ray source near Supernova Remnant Kes 78
Kosack, K. et al., International Cosmic Ray Conference 7 p76-78 (2011) [LINK]
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