| Canonical Name: | SNR G054.1+00.3 |
| TeVCat Name: | TeV J1930+188 |
| Other Names: | PSR J1930+1852
VER J1930+188
2HWC J1930+188
HESS J1930+188
1LHAASO J1929+1846u* |
| Source Type: | PWN |
| R.A.: | 19 30 32 (hh mm ss) |
| Dec.: | +18 52 12 (dd mm ss) |
| Gal Long: | 54.10 (deg) |
| Gal Lat: | 0.26 (deg) |
| Distance: | 6.2 kpc |
| Flux: | 0.025 (Crab Units) |
| Energy Threshold: | 1000 GeV |
| Spectral Index: | 2.39 |
| Extended: | No |
| Discovery Date: | 2009-07 |
| Discovered By: | VERITAS |
| Green's Catalog: | Link |
| 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 J1930+188 |
| Source Class: | Composite |
| Identified Object: | G54.1+0.3 |
| R.A. (J2000): | 292.61 deg (19 30 25) |
| Dec. (J2000): | 18.84 deg (18 50 10) |
| Positional uncertainty: | 0.031 deg |
| Spatial Model: | Gaussian |
| Size: | 0.120 +/- 0.019 deg |
| Spectral Model: | power law |
| Integral Flux > 1 TeV: | 3.18e-13 +/- 6.79e-14 cm-2 s-1 |
| Pivot Energy, E0: | 1.70 TeV |
| Diff. Flux at E0: | 1.28e-13 +/- 2.73e-14 cm-2 s-1 TeV-1 |
| Spectral Index: | 2.59 +/- 0.26 |
| HGPS Source Notes: | |
| | |
The following is the text from the HGPS paper:
The VHE gamma-ray source, discovered with VERITAS (with the identifier VER J1930+188,
Acciari et al. 2010), is coincident with the composite SNR
G54.1+0.3 and the pulsar PSR J1930+1852. We report on the H.E.S.S. observations of this source for the first time here. The HGPS source is found to have a slightly displaced position from the pulsar
and the VERITAS best fit (by 0.04 deg). Despite the agreement with the VERITAS spectral index, the integral flux above 1 TeV found in our
analysis is ∼40% lower than their published flux. We note, however, that the apparent discrepancy with VERITAS is not confirmed by our
cross-check analysis, which yields a flux for this source that is larger by more than the nominal 30% systematic flux uncertainty, and is in agreement with the VERITAS measurement.
This is one of the 31 firmly-identified objects among the HGPS sources. Three 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":
- G54.1+0.3 (COMP)
- J1930+1852 (PSR)
- VER J1930+188 (EXTRA)
"EXTRA associations: For completeness, in addition to the associations obtained through the catalog-based, automatic procedure, we add a list of 20 extra
associated objects that are plausible counterparts for some HGPS sources and are not covered by the limited set of catalogs we use."
Source position and its uncertainty:
From
Acciari et al. (2010):
- R.A. (J2000): 19 30 32 +/- 25s
=> 141002: R.A. uncertainty updated to 2s after communication with Acciari et al.
- Dec. (J2000): +18 52 12 +/- 20"
- Systematic uncertainty of 0.02deg
Spectral Properties:
From
Abeysekara et al. (2018):
- Spectral index (VERITAS data): 2.18 +/- 0.20 (stat) above 120 GeV
- Flux normalisation (at 1 TeV): 6.6 +/- 1.3 (stat) x10e-13 TeV-1 cm-2 s-1
- "Extrapolation of the HAWC spectrum to the VERITAS energy range
yields an integrated flux that is seven times larger than the VERITAS
flux. Although this is still in agreement with the VERITAS measurement
within 2 sigma statistical uncertainties, we tested whether the HAWC
data favor a power law distribution with a cutoff. To reduce the
number of degrees of freedom, we fixed the index of the power law with
a cutoff scenario to the index value measured by VERITAS."
"... the HAWC result can be explained with either a single power law
or a power law with a cutoff. The extrapolation of the power law with
a cutoff to VERITAS energies produces an integral flux that is only
∼50% larger than the VERITAS flux, within the 1 sigma statistical
error, providing better agreement. While all three measurements were
estimated for a point-like source, HAWC would estimate flux from a
larger area than VERITAS due to their larger PSF. Because HAWC modeled
a single source in the likelihood analysis for this study, the flux
estimation may be influenced by emission from other sources in the
region."
From
Abeysekara et al. (2017):
- Spectral index: 2.74 +/- 0.12 (stat) +/- 0.2 (syst)
- Differential flux at 7 TeV: 9.8 +/- 1.5 (stat) +/- 4.9 (syst) x10e15 TeV-1 cm-2 s-1
From
Acciari et al. (2010):
- Spectral index: 2.39 +/- 0.23(stat) +/- 0.30(syst)
Distance:
From
Ranasinghe & Leahy (2018):
- "We carry out a comprehensive study of H I 21 cm line observations
and 13CO line observations of 21 supernova remnants (SNRs). The aim of
the study is to search for H I absorption features to obtain kinematic
distances in a consistent manner."
- "Our fit of the observed HI profile including a Gaussian velocity
dispersion yields a tangent point velocity of 52.8 km s-1, very
different than that assumed by Leahy et al. (2008). The associated
13CO molecular cloud at 53.66 km s−1 (Leahy et al. (2008) Figure 3)
places the SNR at the tangent point. Therefore, the distance to the
SNR is 4.9 kpc."
- in Table 1 of the paper, which summarises the results, the distances
found in the literature for this SNR are listed as between 5.6-7.2 kpc.
whilst the distance derived from the analysis presented in this paper
is quoted as 4.9 +/- 0.8 kpc
Source Association:
From
Cao et al. (2021):
- SNR G054.1+00.3 / 2HWC J1930+188 / HESS J1930+188 / VER J1930+188 may be associated with
LHAASO J1929+1745
From
Abeysekara et al. (2018):
- "The likely astrophysical counterpart for both the newly detected
Fermi point source, VER J1930+188, and 2HWC J1930+188 is SNR G54.1+0.3,
a PWN at a distance of ∼6.5 kpc hosting a young, energetic pulsar,
PSR J1930+1852, with a spin-down luminosity of 1.2 10e37erg s−1 and a
characteristic age of 2900 years (
Camilo et al. 2002). The pulsar
powers a PWN, which is observed in radio and X-rays. The gamma-ray
emission from the PWN can be explained as resulting from inverse
Compton scattering of electrons accelerated at the PWN termination
shock on ambient photon fields."
From
Abeysekara et al. (2017):
- "Source 2HWC J1930+188 is associated with the SNR SNR G054.1+00.3,
which is a known TeV source discovered by VERITAS (
Acciari et al. 2010).
The VERITAS observation is consistent with a point-like source within
the resolution of the instrument. SNR G054.1+00.3 hosts a young,
energetic pulsar, PSR J1930+1852, at its center (E-dot: 1.2 x10e37 erg
s−1, d = 7 kpc, t = 2.9 kyr).
Lu et al. (2001) report the discovery of
a non-thermal X-ray jet that is consistent with a radio extension. It
confirms the existence of a PWN in the SNR G054.1+00.3. The spectral
indices and fluxes at 7 TeV of VERITAS and HAWC are consistent within
statistical and systematic uncertainties. The HAWC measurements
indicate that the TeV spectrum associated with SNR G054.1+00.3 extends
beyond the VERITAS measured energy range (250 GeV–4 TeV)."
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: VERITAS, HAWC, H.E.S.S., LHAASO
-
SNR G54.1+0.3, a PeVatron candidate unveiled by LHAASO
Shi, Yihan et al., arXiv e-prints parXiv:2504.04544 (2025) [LINK]
-
The First LHAASO Catalog of Gamma-Ray Sources
Cao, Zhen et al., ApJS 271 p25 (2024) [LINK]
-
Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 gamma-ray Galactic sources
Cao, Z., Aharonian, F.A., An, Q., et al., Nature 594 p33-36 (2021) [LINK]
-
Spectral Modelling of H.E.S.S.-detected Pulsar Wind Nebulae
van Rensburg, C. et al., ArXiv e-prints p (2018) [LINK]
-
Revised Distances to 21 Supernova Remnants
Ranasinghe, S. and Leahy, D.A., AJ 155 p204 (2018) [LINK]
-
VERITAS and Fermi-LAT observations of new HAWC sources
VERITAS Collaboration et al., ArXiv e-prints p (2018) [LINK]
-
The H.E.S.S. Galactic plane survey
H.E.S.S. Collaboration et al., A&A 612 pA1 (2018) [LINK]
-
A Dust Twin of Cas A: Cool Dust and Pre-Solar Grain of Silica Revealed in the Supernova Remnant G54.1+0.3
Rho, J. et al., ArXiv e-prints p (2017) [LINK]
-
The 2HWC HAWC Observatory Gamma-Ray Catalog
Abeysekara, A.U. et al., ApJ 843 p40 (2017) [LINK]
-
Pulsar Wind Nebulae from X-rays to VHE gamma-rays
Kargaltsev, O. et al., 466 p167 (2013) [LINK]
-
Discovery of Very High Energy Gamma-ray Emission from the SNR G54.1+0.3
Acciari, V.A. et al., ApJ 719 pL69-L73 (2010) [LINK]
-
Lepto-hadronic origin of gamma-rays from the G54.1+0.3 pulsar wind nebula
Li, H. et al., MNRAS 408 pL80-L84 (2010) [LINK]
-
XMM-Newton and SUZAKU detection of an X-ray emitting shell around the pulsar wind nebula G54.1+0.3
Bocchino, F. et al., A&A 520 pA71+ (2010) [LINK]
-
VERITAS Observations of Supernova Remnants and Pulsar Wind Nebulae in the Fermi Era
Humensky, T.B. and for the VERITAS Collaboration, ArXiv e-prints p (2009) [LINK]
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