| Canonical Name: | HESS J1729-345 |
| TeVCat Name: | TeV J1729-345 |
| Other Names: | |
| Source Type: | UNID |
| R.A.: | 17 29 35 (hh mm ss) |
| Dec.: | -34 32 22 (dd mm ss) |
| Gal Long: | 353.44 (deg) |
| Gal Lat: | -0.13 (deg) |
| Distance: | 3.2 kpc |
| Flux: | (Crab Units) |
| Energy Threshold: | GeV |
| Spectral Index: | 2.24 |
| Extended: | Yes |
| Size (X): | 0.14 (deg) |
| Size (Y): | 0.14 (deg) |
| Discovery Date: | 2011-05 |
| 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 J1729-345 |
| Source Class: | Unid |
| Identified Object: | None |
| R.A. (J2000): | 262.24 deg (17 28 58) |
| Dec. (J2000): | -34.53 deg (-34 31 35) |
| Positional uncertainty: | 0.082 deg |
| Spatial Model: | Gaussian |
| Size: | 0.189 +/- 0.031 deg |
| Spectral Model: | power law |
| Integral Flux > 1 TeV: | 8.20e-13 +/- 9.15e-14 cm-2 s-1 |
| Pivot Energy, E0: | 1.16 TeV |
| Diff. Flux at E0: | 8.25e-13 +/- 8.22e-14 cm-2 s-1 TeV-1 |
| Spectral Index: | 2.43 +/- 0.09 |
| HGPS Source Notes: | |
| | |
This is one of eleven HGPS sources that "do not have any associations with known physical objects, although some are associated
with HE gamma-ray sources."
- HESS J1729−345 is north of the nearby SNR HESS J1731−347
(H.E.S.S. Collaboration 2011).
An investigation into a potential connection between the two
suggests the VHE emission from the former could be from a molecular cloud illuminated by hadronic particles that escaped from the SNR
(Cui et al. 2016).
This source is one of the twelve source whose HGPS results differed from those published in previous publications.
- "For HESS J1729−345, the HGPS analysis finds a flux above 1 TeV larger than in H.E.S.S. Collaboration (2011).
Because of the HGPS morphology
modeling of the source and its procedure to define the integration radius, the spectrum of this source is derived in a region with a radius
about two times larger than in the dedicated publication, accounting for the observed difference."
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 J1729-345 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."
- "While the derived spectral indices are compatible, the integral flux above 1 TeV is about two times higher in the cross-check analysis than in the
main analysis."
Source position and its uncertainty:
From
Abramowski et al. (2011):
- RA: (J2000): 17 29 35
- Dec (J2000): -34 32 22
- statistical error of 0.035 deg
Source extent:
From
Abramowski et al. (2011):
- Gaussian of width 0.12 +/- 0.02 deg
Spectral Properties:
From
Abramowski et al. (2011):
- spectral index: 2.24 +/- 0.15stat +/- 0.2syst
- decorrelation energy: 0.780 TeV
- normalization: 0.44 +/- 0.07stat e-12 cm-2 s-1 TeV-1
- 1-10 TeV integrated flux: 0.88 +/- 0.29stat e-12 erg cm-2 s-1
- systematic error of 20% on the flux
Source association:
From
Condon et al. (2017):
- the first high-significance GeV gamma-ray detection of the TeV
source
HESS J1731-347 is reported on here. The authors also examined
the Fermi-LAT data from HESS J1729-345:
- "We also studied the second TeV source found by H.E.S.S. in this
region, HESS J1729−345. We added a gaussian source in the model
(R.A. = 262.39 deg, Dec. = −34.54deg, width = 0.14deg,
H.E.S.S. Collaboration et al. 2011) and performed a new fit. As it
resulted in a nondetection (TS < 3), we derived a 95% C.L. upper limit
(1.30 10e-12 erg cm−2 s −1 between 1 GeV and 2 TeV). This upper
limit is a factor of two above the TeV data and cannot constrain the
origin of the gamma-ray emission of HESS J1729−345. However, it
confirmed a turnover between the Fermi-LAT and H.E.S.S. data"
From
Guo et al. (2017):
- the search for GeV emission from this source using 9 years of data
from the Fermi Large Area Telescope is reported:
- "No significant GeV gamma-ray emission is found, and upper limits
are derived."
From
Maxted et al. (2017):
- Observations were carried out with the Mopra radio telescope,
targeting CO(1-0), CO(1-0) and CS(1-0) emission. The authors conclude:
- "when adopting a CO X-factor towards the mid-range of published
values, X-ray absorption column densities derived from the HESS
J1731−347 X-ray emission are consistent with column densities
foreground to the Scutum-Crux arm at a line of sight velocity of
approx. -15 km s-1 , suggesting a kinematic distance of approx. 3.2
kpc for HESS J1731−347."
- "Components of dense molecular gas at approx. 3.2 kpc are coincident
with the north of
HESS J1731−347, HESS J1729−345 and a cloud
associated with the HII region G353.43−0.37, as evidenced by CS(1-0)
emission and infrared-dark features. The detection of dense gas
towards gamma-ray emission to the north of
HESS J1731−347 is
suggestive of a runaway CR scenario and flags a new component of
target material mass to be included in future particle propagation
models."
- "This dense gas lends weight to the idea that HESS J1729−345 and
HESS J1731−347 are connected, perhaps via escaping cosmic rays."
From
Nayana et al. (2017):
- They report a possible radio counterpart of HESS J1729−345 from the
843 MHz MOST map and the 1.4 GHz SGPS map.
"The radio emission is thermal and it supports the hadronic origin of
gamma rays from HESS J1729−345."
From
Capasso et al. (2016):
- The authors examine the newly available Mopra CS radio telescope
data ( CS(1-0) intensity is an indicator of dense gas column density)
and conclude that they "seem to show a good correspondence between the
gas density for a specific distance solution and the very high energy
gamma-ray emission, suggesting that the latter could be caused by CRs
escaping the HESS J1731-347 shell and interacting with a nearby
molecular cloud."
- "... there seems to be a good spatial correspondence between the
CS(1- 0) intensity, an indicator of dense gas column density, seen at
3.2 kpc and the TeV emission in the bridge region connecting HESS
J1731-347 and HESS J1729-345. On the other hand, the limited
correspondence in the other two ranges does not seem to support the
association between gas and TeV emission for farther distances;
studies to try and quantify numerically the correlation are ongoing"
- "If confirmed, the association between TeV and gas emission in the
first velocity range would support the argument that the SNR is indeed
located at a distance of 3.2 kpc and that the TeV emission observed in
the surroundings of the source could be explained by cosmic ray
particles that escape from the SNR and illuminate a nearby molecular
cloud."
From
Cui et al. (2016):
- "The supernova remnant (SNR) HESS J1731-347 displays strong
nonthermal TeV gamma-ray and X-ray emission, thus the object is
presently accelerating particles to very high energies. A distinctive
feature of this young SNR is the nearby (~30 pc in projection)
extended source HESS J1729-345, which is currently unidentified but is
in spatial projection coinciding with known molecular clouds (MC). We
model the SNR evolution to explore whether the TeV emission from HESS
J1729-345 can be explained as emission from runaway hadronic cosmic
rays (CRs) that are illuminating these MCs. "
- "The TeV spectrum of HESS J1729-345 is satisfactorily fitted by the
emission from the highest energy CRs that have escaped the SNR, using
a standard Galactic CR diffusion coefficient in the interclump
medium. The TeV image of HESS J1729-345 can be explained with a
reasonable three-dimensional structure of MCs."
- "One of our main goals of this work was to verify whether the TeV
emission from the nearby source HESS J1729-345 can be explained with
gamma-ray emission from runaway CRs that have been accelerated in HESS
J1731-347 and are now illuminating molecular clouds near the SNR"
- "By placing HESS J1729-345 30 pc away from the center of the SNR,
its spectrum can be reproduced in scenarios with 20 solar mass and 25
solar mass progenitor masses, with a diffusion coefficient of 10e28
cm2 s−1, power-law index = 0.3 (in the expression for the Galactic
diffusion coefficient), inside the molecular cloud clumps."
From
Abramowski et al. (2011):
- in the radio, HESS J1729-345 lies near the HII region G353.381-0.114
- this HII region could be associated with a molecular cloud complex
- a Fermi source, 1FGL 1729.1-3452c (c means a confused source), lies nearby
Seen by: H.E.S.S.
-
Is the SNR HESS J1731-347 colliding with molecular clouds?
Cui, Y. et al., arXiv e-prints p (2019) [LINK]
-
325 and 610 MHz Radio Counterparts of SNR G353.6-0.7 a.k.a. HESS J1731-347
Nayana, A.J. et al., ArXiv e-prints p (2017) [LINK]
-
Dense molecular gas at 12 mm towards Galactic TeV gamma-ray sources
de Wilt, P. et al., MNRAS 468 p2093-2113 (2017) [LINK]
-
Probing The Local Environment of the Supernova Remnant HESS J1731-347 with CO and CS Observations
Maxted, N. et al., ArXiv e-prints p (2017) [LINK]
-
GeV gamma-ray emission in the direction of HESS J1731-347
Guo, X.-L. et al., ArXiv e-prints p (2017) [LINK]
-
Detection of two TeV shell-type remnants at GeV energies with Fermi-LAT: HESS J1731-347 and SN 1006
Condon, B. et al., ArXiv e-prints p (2017) [LINK]
-
The TeV supernova remnant shell HESS J1731-347 and its surroundings
Capasso, M. et al., ArXiv e-prints p (2016) [LINK]
-
A young supernova remnant illuminating nearby molecular clouds with cosmic rays
Cui, Y. et al., A&A 591 pA68 (2016) [LINK]
-
A dense gas survey of the gamma-ray sources HESS J1731-347 and HESS J1729-345
Maxted, N. et al., ArXiv e-prints p (2015) [LINK]
-
A new SNR with TeV shell-type morphology: HESS J1731-347
HESS Collaboration and Abramowski, A., ArXiv e-prints p (2011) [LINK]
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