Back to Main Page
Observation Date (UT) Observation Lat

Canonical Name:Galactic Centre
TeVCat Name:TeV J1745-290
Other Names:Sgr A*,
HESS J1745-290,
VER J1745-290
Source Type:UNID
R.A.:17 45 39.6 (hh mm ss)
Dec.:-29 00 22 (dd mm ss)
Gal Long: 359.94 (deg)
Gal Lat: -0.04 (deg)
Distance: 8.5 kpc
Flux:0.05 (Crab Units)
Energy Threshold:165 GeV
Spectral Index:2.1
Extended:No
Discovery Date:2004-05
Discovered By: CANGAROO
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 J1745-290
Source Class: Unid
Identified Object: None
R.A. (J2000): 266.42 deg (17 45 39)
Dec. (J2000): -29.01 deg (-29 00 21)
Positional uncertainty: 0.002 deg
Spatial Model: Point-Like
Size: N/A
Spectral Model: exponentially cutoff power law
Integral Flux > 1 TeV: 1.70e-12 +/- 7.91e-14 cm-2 s-1
Pivot Energy, E0: 1.00 TeV
Diff. Flux at E0: 2.55e-12 +/- 4.00e-14 cm-2 s-1 TeV-1
Spectral Index: 2.14 +/- 0.02
Cutoff fit param.: 0.093 +/- 0.017 TeV-1
HGPS Source Notes:
"This is one of the fourteen EXTERN sources in the HGPS catalog, i.e., VHE sources in the HGPS region previously detected by H.E.S.S. that were not reanalyzed in the paper:"
- "Given the difficulties with modeling complex source morphologies, we decided to restrict the HGPS analyses to a symmetrical Gaussian model assumption and exclude all firmly identified shell-like sources and the very complex GC region from reanalysis."

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":
- Sgr A* (EXTRA)
- J1745−2900 (PSR)
- G359.9−0.0 (PWN)
- 2FHL J1745.7−2900 (2FHL)
- 3FGL J1745.6−2859c (3FGL)
- G0.0+0.0 (COMP)
- 3FGL J1745.3−2903c (3FGL)
"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 Smith et al. (2015):
- Gal. Lon.: 359.94deg +/- 0.002deg (stat) +/- 0.013deg (syst)
- Gal. Lat.: -0.053deg +/- 0.002deg (stat) +/- 0.013deg (syst)
- Convert to R.A. / Dec.:
- R.A. (J2000): 17h 45m 41.03s
- Dec. (J2000): -29d 00' 54.0"

From Acero et al. (2010):
- This is the position that is quoted in TeVCat
- R.A. (J2000): 17h 45m 39.6s +/- 0.4s(stat) +/- 0.4s(syst)
- Dec. (J2000): -29d 00' 22" +/- 6"(stat) +/- 6"(syst)

Spectral Information:

From Ahnen et al. (2016):
- the spectral shape in the range from 300 GeV - 40 TeV was found to
be well described by a power-law with an exponential cut-off with the
following parameters:
- Spectral index: 1.85 +/- 0.13
- Ecut: 7.57 +/- 2.29 TeV
- f0 = 7.26 +/- 0.89 e-13 cm-2 s-1 TeV-1
- at E0 = 2 TeV

From Smith et al. (2015):
- Three different functional forms are fitted to the spectrum of the
source. A power law with an exponential cutoff provides the best fit,
having smaller errors on the normalization constant than the smoothly
broken power law.
- Spectral index: 2.1 +/- 0.04
- E(break): 12.8 +/- 1.9 TeV
- N0: 2.8 +/- 0.08 e-12 cm-2 s-1 TeV-1

Source Association:

From Kistler (2015):
- "HESS data now points to two plausible origins: the supermassive
black hole (perhaps with >PeV cosmic rays and neutrinos) or
high-energy electrons from the putative X-ray pulsar wind nebula
G359.95-0.04. We show that if the magnetic field experienced by PWN
electrons is near the several mG ambient field strength suggested by
radio observations of the nearby GC magnetar SGR J1745-29, synchrotron
losses constrain the TeV gamma-ray output to be far below the
data. Accounting for the peculiar geometry of GC infrared emission, we
also find that the requisite TeV flux could be reached if the PWN is
~1 pc from Sgr A* and the magnetic field is two orders of magnitude
weaker, a scenario that we discuss in relation to recent data and
theoretical developments. Otherwise, Sgr A* is left, which would then
be a PeV link to other AGN."

From Mori et al. (2015):
- "We present the first sub-arcminute images of the Galactic Center
above 10 keV, obtained with NuSTAR."
-"Above ~20 keV, hard X-ray emission in the central 10 pc region
around Sgr A* consists of the candidate PWN G359.95-0.04 and the CHXE,
(a previously unknown central component of hard X-ray emission)
possibly resulting from an unresolved population of massive CVs with
white dwarf masses M_WD approx. 0.9 solar mass. "
- "Spectral energy distribution analysis suggests that G359.95-0.04 is
likely the hard X-ray counterpart of the ultra-high gamma-ray source
HESS J1745-290, strongly favoring a leptonic origin of the GC TeV
emission."

Pevatron:

From Mitchell (2021):
- this source is included in a list of Galactic sources currently known
to produce gamma-ray emission above 100 TeV.



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