Back to Main Page
Observation Date (UT) Observation Lat

Canonical Name:HESS J1837-069
TeVCat Name:TeV J1837-069
Other Names:1HWC J1838-060
1HWC J1836-074c
2HWC J1837-069
FGES J1836.5-0652
Source Type:PWN
R.A.:18 37 38.4 (hh mm ss)
Dec.:-06 57 00 (dd mm ss)
Gal Long: 25.18 (deg)
Gal Lat: -0.12 (deg)
Distance: 6.6 kpc
Flux:0.531 (Crab Units)
Energy Threshold:1000 GeV
Spectral Index:2.27
Extended:Yes
Size (X):0.36 (deg)
Size (Y):0.36 (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 J1837-069
Source Class: PWN
Identified Object: PSR J1838-0655
R.A. (J2000): 279.37 deg (18 37 29)
Dec. (J2000): -6.96 deg (-06 57 36)
Positional uncertainty: 0.033 deg
Spatial Model: 3-Gaussian
Size: 0.355 +/- 0.031 deg
Spectral Model: power law
Integral Flux > 1 TeV: 1.15e-11 +/- 4.94e-13 cm-2 s-1
Pivot Energy, E0: 0.95 TeV
Diff. Flux at E0: 2.00e-11 +/- 6.86e-13 cm-2 s-1 TeV-1
Spectral Index: 2.54 +/- 0.04
HGPS Source Notes:
The following is the text from the HGPS paper:

The HGPS analysis of HESS J1837-069 finds a size of 0.36 +/- 0.03 deg based on modeling the VHE gamma-ray emission as three Gaussian components. This is larger than the size previously derived using a single asymmetric Gaussian (Aharonian et al. 2006), i.e., 0.12 deg by 0.05 deg ; and using a single Gaussian (Marandon et al. 2008), i.e., 0.22 deg . The more complex modeling of the HGPS, which also takes into account more of the extended nebular emission from this identified PWN, explains the apparent discrepancy. Consequently, we used a larger region (twice the radius compared to Aharonian et al. 2006) to derive the spectrum, leading to an integral flux above 1 TeV that is larger by a factor of approximeately 3 than in the dedicated publication.

This is one of the 31 firmly-identified objects among the HGPS sources. 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":
- J1838-0655 (PSR)
- 2FHL J1836.5-0655e (2FHL)
- 3FGL J1836.5-0655e (3FGL)
- 2FHL J1837.4-0717 (2FHL)
- 3FGL J1837.6-0717 (3FGL)
- G25.2+0.3 (PWN)
- 3FGL J1838.9-0646 (3FGL)



Source position and its uncertainty:

From MAGIC Collaboration (2018):
- R.A. (J2000): 279.26 +/- 0.02 deg = 18h 37m 02.4s
- Dec. (J2000): -6.99 +/- 0.01 deg = -06 59' 24''

From Aharonian et al. (2006):
This is the position that is quoted in the TeVCat table.
- l: 25.185 +/- 0.012 (deg)
- b: -0.106 +/- 0.016 (deg)
- R.A. (deg): 279.41 (Convert to HMS: 18 37 38.4)
- Dec. (deg): -6.95 (Convert to HMS: -06 57 00)

Source Extent:

From MAGIC Collaboration (2018):
- an extension of 0.23 +/- 0.01 deg is reported

From H.E.S.S. Collaboration (2018):
- 0.36 +/- 0.03 deg based on modeling the VHE gamma- ray emission as
three Gaussian components
"This is larger than the size previously derived using a single
asymmetric Gaussian (Aharonian et al. 2006),
i.e., 0.12deg by 0.05deg ; and using a single Gaussian (Marandon et al. 2008),
i.e., 0.22deg. The more complex modeling of the HGPS, which also
takes into account more of the extended nebular emission from this
identified PWN, explains the apparent discrepancy. Consequently, we
used a larger region (twice the radius compared to Aharonian et al. 2006)
to derive the spectrum, leading to an integral flux above 1 TeV that
is larger by a factor of approx. 3 than in the dedicated publication."

From Aharonian et al. (2006):
- semi-major axis: 7 +/- 1' = 0.12 +/- 0.02 deg
- semi-minor axis: 3 +/- 1' = 0.05 +/- 0.02 deg
- angle: 149 +/- 10
...measured counter-clk wrt the positive Gal. Lat. axis

Spectral Properties:

From MAGIC Collaboration (2018):
- spectral index: 2.29 +/- 0.04
- flux normalisation at decorrelation energy: 4.4 +/ 0.2 10e-12 TeV-1 cm-2 s-1
- decorrelation energy: 1.25 TeV

From H.E.S.S. Collaboration (2018):
- spectral index: 2.54 +/- 0.04
- Flux (> 1 TeV): 11.55 +/- 0.49 10e-12 cm-2 s-1
- this corresponds to the "Flux_Spec_Int_1TeV" parameter which is defined as "power law integral flux above 1 TeV"
"... we used a larger region (twice the radius compared to Aharonian et al. 2006)
to derive the spectrum, leading to an integral flux above 1 TeV that
is larger by a factor of approx. 3 than in the dedicated publication"

Source Classification:

140702: The source classification was updated from UNID to PWN due to
some of the analyses described below.

From Cristofari (2021):
- 2HWC J1825-134 has been listed as a possible PeVatron

From Banik & Bhadra (2021):
- "Recently the MAGIC telescope observed three TeV gamma-ray extended sources
in the galactic plane in the neighborhood of radio SNR G24.7+0.6. Among them,
the PWN HESS J1837-069 was detected earlier by the HESS observatory during its
first galactic plane survey. The other two sources, MAGIC J1835-069 and
MAGIC J1837-073 are detected for the first time at such high energies. Here
we shall show that the observed gamma-rays from the SNR G24.7+0.6 and the
HESS J1837-069 can be explained in terms of hadronic interactions of the
PWN/SNR accelerated cosmic rays with the ambient matter. We shall further
demonstrate that the observed gamma-rays from the MAGIC J1837-073 can be
interpreted through hadronic interactions of runaway cosmic-rays from PWN
HESS J1837-069 with the molecular cloud at the location of MAGIC J1837-073.
No such association has been found between MAGIC J1835-069 and SNR G24.7+0.6
or PWN HESS J1837-069. We have examined the maximum energy attainable by
cosmic-ray particles in the SNR G24.7+0.6/ PWN HESS J1837-069 and the
possibility of their detection with future gamma-ray telescopes. The study
of TeV neutrino emissions from the stated sources suggests that the
HESS J1837-069 should be detected by IceCube Gen-2 neutrino telescope in a
few years of observation."

From Cao et al. (2021):
- HESS J1837-069 may be associated with LHAASO J1839-0545

From MAGIC Collaboration (2018):
The field of view of SNR G24.7+0.6 was observed and three distinct sources were detected:
- the brightest source is identified with HESS J1837-069
- an excess to the south of this source, MAGIC J1837-073, coincident with 3FGL J1837.6-0717
- MAGIC J1835-069 that is perhaps associated with SNR G24.7+0.6

From H.E.S.S. Collaboration (2018):
- this source is listed as being a PWN that is associated with PSR J1838-0655

From Katsuta et al. (2017):
- The authors describe a study of the extended emission detected by
Fermi LAT from the G25.0+0.0 region. They divide the emission into
various components comprising three main sources, each with a number
of subregions. They associate one of these subregions, G25B1, with the
TeV source HESS J1837-069.
- "G25B1 is spatially coincident with HESS J1837-069. The X-ray
observation found PSR J1838-0655 embedded in a PWN with an extent of
1.3 arcmin at the edge of HESS J1837-069 (Gotthelf & Halpern 2008).
The H.E.S.S. source is a TeV PWN powered by this PSR with a spindown
luminosity of 5.5 x 10e36 erg sāˆ’1. The SED measured by the LAT
smoothly connects to that measured by H.E.S.S., which suggests that
photons of the LAT and H.E.S.S. data have the same origin. G25B1 has a
photon index of about 1.5, which is consistent with the expected
relativistic electron distribution of PWNe ... G25B1 is most likely a
PWN powered by PSR J1838āˆ’0655."

From Abeysekara et al. (2017):
- "2HWC J1837-065 is the principal maximum of an elongated region
containing multiple known extended sources which are not resolved in
the present analysis. It may be associated with the close
by TeV source HESS J1837-069 (distance of āˆ¼0.4 deg )."

From Abeysekara et al. (2015):
- "1HWC J1838-060 is detected at 6.1sigma post trials and is located
in the middle of the known TeV sources HESS J1837-069 and HESS
J1841-055"
- "1HWCJ1836-074c has a post-trials significance of 3.2Ļƒ, with the
nearest TeV PWN, HESS J1837-069, approx. 0.5deg away with a compatible
differential flux."

From Fujita et al. (2013):
- "... we conclude that the gamma-rays detected from HESS J1837-069
are not created through proton-proton interactions, and may more
plausibly originate from the pulsar that was recently found near RSGC 1."

From Acero et al. (2013):
- Analysis of the LAT data from this source leads to its
classification as a PWN candidate

From Gotthelf & Halpern (2008):
- It is postulated that the TeV emission comes from a PWN.
- "At an assumed distance of 6.6 kpc by association with an adjacent
massive star cluster, the efficiency of PSR J1838-0655 converting
spin-down luminosity to radiation is ... ~3% for the >200 GeV emission
of HESS J1837-069, making it a plausible power source for the latter."
- "A second X-ray source adjacent to the TeV emission, AX
J1837.3-0652, is resolved into an apparent pulsar/PWN; it may also
contribute to HESS J1837-069. The star cluster RSGC 1 may have given
birth to one or both pulsars, while fueling TeV emission from the
extended PWN with target photons for inverse Compton scattering."


Seen by: H.E.S.S., HAWC, MAGIC
Want a reference added? Send a bibtex entry to the TeVCat Team
Try TevCat 2.0 Beta!