| Canonical Name: | Eta Carinae |
| TeVCat Name: | TeV J1045-596 |
| Other Names: | |
| Source Type: | Binary |
| R.A.: | 10 44 35 (hh mm ss) |
| Dec.: | -59 39 56.6 (dd mm ss) |
| Gal Long: | 287.53 (deg) |
| Gal Lat: | -0.64 (deg) |
| Distance: | 2.3 kpc |
| Flux: | 0 (Crab Units) |
| Energy Threshold: | 200 GeV |
| Spectral Index: | |
| Extended: | No |
| Discovery Date: | 2017-08 |
| Discovered By: | H.E.S.S. |
| TeVCat SubCat: | Default Catalog |
Source Notes:
This detection was announced by the
H.E.S.S. Collaboration
at the 2017 ICRC. It is the first detection of a colliding-wind binary
in the VHE regime. The pre-trial siginificance for the 25 hours
(total) of observations is 13.6 sigma at an energy threshold of 200 GeV.
From
Leser et al. (2017):
The observations were taken in 2014 and 2015 directly before and
shortly after periastron passage (phases 0.78-1.1).
Source position:
On 200303 the source position in TeVCat was updated from that in
Abramowski et al. to that in
H.E.S.S. Collaboration (2020).
From
H.E.S.S. Collaboration (2020):
- R.A. (J2000): 10h 44m 35s +/- 6.6s (stat) +/- 90s (syst)
- Dec. (J2000): -59d 39' 56.6'' +/- 48''(stat) +/- 288''(syst)
- "Within the statistical and systematical error, the derived best-fit
position is consistent with the optical position of eta Car."
The position reported in TeVCat was that from a previous
H.E.S.S. publication in which upper limits on this source were
published -
Abramowski et al.:
R.A. (J2000): 10h 45m 03.6s
Dec. (J2000): -59 41' 04.3''
Source Extent:
From
H.E.S.S. Collaboration (2020):
The data used in this paper were comprised of two data sets (details
in the paper) called DS-I and DS-II.
- "Assuming a spectral index of A = 3.7, consistent with the
spectral result discussed below, the morphology fit on DS-II (the data
set, which shows the lowest instrumental systematics) results in a
morphology consistent with being point-like"
HOTS J1044-5957:
- "Another complication in the determination of the source morphology
is the assumption of a single component as origin of the gamma
rays. Figure 2 suggests that a weaker emission component south of Eta
Car exists and possibly biases the 2D morphology fit. A dedicated
analysis was performed towards this emission component at:
- R.A. (J2000): 10h 44m 22.8s and
- Dec. (J2000): −59d 57' 51.8'',
... which results in a hotspot at 6.5 sigma level in DS-II – dubbed HOTS J1044−5957.
At this significance level, and given the fact that the emission is located in
the region with the highest NSB in the FoV, we do not claim a new source, but
we note that not fully understood systematics could explain at least parts of
this emission. The contribution of HOTS J1044−5957 to the Eta Car emission is
estimated to approx. 15%, based on a Gaussian fit to the 1D spatial profile
along the axis connecting Eta Car and HOTS J1044−5957."
- "We emphasise that the hotspot is not detected in the crosscheck
analysis, neither in DS-I nor in DS-II. This further supports that the
hotspot seen in the main analysis may be caused by a systematic
effect, likely the response of the classifying parameters to the
NSB. Also, at lower γ-ray energies, no counterpart is reported in the
Fermi−LAT 4FGL catalogue (
Fermi-LAT Collaboration, 2019)"
Distance:
From
Leser et al. (2017):
- the binary system of Eta Carinae is located at a distance of 2.3 kpc
Spectral Information:
From
H.E.S.S. Collaboration (2020):
The data used in this paper were comprised of two data sets (details
in the paper) called DS-I and DS-II.
- "The decorrelation energy E0 is defined as
E0 = exp ( cov(F0,A)/F0 dA^2) GeV
where cov is the covariance error matrix."
DS-I:
- spectral index (A): 3.94 +/- 0.35
- energy threshold: 190 GeV
- E0: 290 GeV
- flux normalisation at E0: 5.1 +/- 0.5 x10e-11 cm-2 s-1 TeV-1
- flux (> 200 GeV): - flux (> 200 GeV): 1.6 +/- 0.2 x10e-11 cm-2 s-1
DS-II:
- spectral index (A): 3.49 +/- 0.23
- energy threshold: 220 GeV
- E0: 360 GeV
- flux normalisation at E0: 3.2 +/- 0.3 x10e-11 cm-2 s-1 TeV-1
- flux (> 200 GeV): - flux (> 200 GeV): 2.0 +/- 0.2 x10e-11 cm-2 s-1
Flux Variability:
From
H.E.S.S. Collaboration (2020):
- "The measurement of variability, or phase-locked flux variations on
timescales of days to weeks, could help to identify the region of
gamma-ray production inside the colliding wind binary."
- "H.E.S.S. observed Eta Car shortly before the thermal X-ray maximum
at phase p approx. 0.95 and after the X-ray minimum and recovery at
phase p approx. 1.1."
- "The flux H.E.S.S. observed shows no indication of phase-locked flux
variations. Due to the sporadic sampling and limited sensitivity of
the measurement, no statement on variability on timescales shorter
than months can be made."
- "The lack of strong flux variations in the H.E.S.S. light-curve
before and after the thermal X-ray minimum is broadly consistent with
the behaviour in hard X-rays (
Hamaguchi et al. 2018) and GeV gamma
rays (e.g.
Balbo & Walter 2017). No flare similar to the one detected
with AGILE (
Tavani et al. 2009) in 2008 is seen in the H.E.S.S.
data. Within statistical and systematic uncertainties, no change in
the reconstructed source flux, nor a change in spectral index, could
be detected."
Fermi-LAT Data:
From
Ge et al. (2022):
- "We report the Fermi Large Area Telescope (Fermi-LAT) detection of
the gamma-ray emission toward the massive star forming region of
Carina Nebula Complex (CNC)."
- "Using the latest source catalog and diffuse background models, we
found that the GeV gamma-ray emission in this region can be resolved
into three different components."
- "The GeV gamma-ray emission from the central point source is
considered to originate from the Eta Carina. We further found the
diffuse GeV gamma-ray emission around the CNC which can be modelled by
two Gaussian disks with radii of 0.4deg (region A) and 0.75deg (region B,
respectively."
- "The GeV gamma-ray emission from both the regions A and B have good
spatial consistency with the derived molecular gas in projection on
the sky. The GeV gamma-ray emission of region A reveals a
characteristic spectral shape of the pion-decay process, which
indicates that the gamma rays are produced by the interactions of
hadronic cosmic rays with ambient gas. The gamma-rays spectrum of
region B has a hard photon index of 2.12 +/- 0.02, which is similar to
other young massive star clusters. We argue that the diffuse GeV
gamma-ray emission in region A and region B likely originate from the
interaction of accelerated protons in clusters with the ambient gas."
Seen by: H.E.S.S.
-
Diffuse gamma-ray emission around the massive star forming region of Carina Nebula Complex
Ge, Ting-Ting et al., arXiv e-prints parXiv:2210.01352 (2022) [LINK]
-
Eta Carinae with Fermi-LAT: Two full orbits and the third periastron
Marti-Devesa, G. and Reimer, O., arXiv e-prints parXiv:2109.05950 (2021) [LINK]
-
Modelling Eta Carinae's Great Eruption and its surrounding nebula
Hirai, Ryosuke et al., arXiv e-prints parXiv:2011.12434 (2020) [LINK]
-
The X-ray properties of Eta Carinae during its 2020 X-ray minimum
Kashi, Amit et al., arXiv e-prints parXiv:2010.03877 (2020) [LINK]
-
Eta Carinae: high angular resolution continuum, H30_alpha and He30_alpha ALMA images
Abraham, Zulema et al., MNRAS p (2020) [LINK]
-
Detection of very-high-energy gamma-ray emission from the colliding wind binary Eta Car with H.E.S.S
H.E.S.S. Collaboration et al., arXiv e-prints parXiv:2002.02336 (2020) [LINK]
-
Fast Ejecta Resulted from Jet-Wind Interaction in the Great Eruption of Eta Carinae
Akashi, Muhammad and Kashi, Amit, arXiv e-prints parXiv:2004.03993 (2020) [LINK]
-
Eta Carinae & the Homunculus: Far Infrared, Sub-millimeter Spectral Lines
Gull, T.R. et al., arXiv e-prints parXiv:2010.02351 (2020) [LINK]
-
Gamma-ray and X-ray constraints on non-thermal processes in Eta Carinae
White, R. et al., arXiv e-prints parXiv:1911.01079 (2019) [LINK]
-
Gamma-rays and positrons from Colliding Wind Binaries
Balbo, Matteo and Walter, Rol, arXiv e-prints parXiv:1909.00793 (2019) [LINK]
-
eta Carinae: particle acceleration and multi-messenger aspects
Walter, R. and Balbo, M., ArXiv e-prints p (2018) [LINK]
-
First Results of Eta Car Observations with H.E.S.S.II
Leser, E. et al., ArXiv e-prints p (2017) [LINK]
-
Fermi acceleration under control: Eta Carinae
Walter, R. et al., ArXiv e-prints p (2017) [LINK]
-
The first full orbit of Eta Carinae seen by Fermi
Reitberger, K. et al., A&A 577 pA100 (2015) [LINK]
-
HESS observations of the Carina nebula and its enigmatic colliding wind binary Eta Carinae
HESS Collaboration et al., MNRAS 424 p128-135 (2012) [LINK]
-
Eta Carinae: a very large hadron collider
Farnier, C. et al., A&A 526 pA57 (2011) [LINK]
-
Fermi Large Area Telescope Observation of a Gamma-ray Source at the Position of Eta Carinae
Abdo, A.A. et al., ApJ 723 p649-657 (2010) [LINK]
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