| Canonical Name: | Cygnus X-1 |
| TeVCat Name: | TeV J1958+352 |
| Other Names: | LHAASO J1957+3517 |
| Source Type: | XRB |
| R.A.: | 19 57 55 (hh mm ss) |
| Dec.: | +35 22 12 (dd mm ss) |
| Gal Long: | 71.43 (deg) |
| Gal Lat: | 3.23 (deg) |
| Distance: | 2.22 kpc |
| Flux: | 0.01 (Crab Units) |
| Energy Threshold: | GeV |
| Spectral Index: | |
| Extended: | No |
| Discovery Date: | 2007-08 |
| Discovered By: | MAGIC |
| TeVCat SubCat: | Source Candidates |
Source Notes:
Significance of the Signal:
For objects for which a signal at 5 sigma has not been detected, the
details of the significance of the detection are provided:
From
Albert et al. (2007):
- "Searches for steady gamma-ray signals yielded no positive result,
and upper limits to the integral flux ranging between 1% and 2% of the
Crab Nebula flux, depending on the energy, have been established. We
also analyzed each observation night independently, obtaining evidence
of gamma-ray signals at the 4.0 sigma significance level (3.2 sigma
after trial correction) for 154 minutes of effective on-time (EOT) on
September 24 between 20:58 and 23:41 UTC, coinciding with an X-ray
flare seen by RXTE, Swift, and INTEGRAL. A search for faster-varying
signals within a night resulted in an excess with a significance of
4.9 sigma (4.1 sigma after trial correction) for 79 minutes EOT
between 22:17 and 23:41 UTC."
0 TeV
From
LHAASO Collaboration (2024):
- a signal with a statistical significance of 4.0 sigma was announced.
Source Position:
The position was updated on 2025-01-31 to that given in
LHAASO Collaboration (2024).
From
LHAASO Collaboration (2024):
- R.A. (J2000): 299.48 deg +/- 0.14 deg = 19h 57m 55s +/- 33.6s
- Dec. (J2000): +35.37 deg +/- 0.06 deg = +35d 22m 12s +/- 216s
The position provided in TeVCat up until 2025-01-31 was:
- R.A. (J2000): 19h 58m 21.70s +/- 33.6s
- Dec. (J2000): +35d 12m 05.08s +/- 216s
Source Extent:
From
LHAASO Collaboration (2024):
- Cygnus X-1 is associated with the point-like source LHAASO J1957+3517
- an upper limit of 0.22 deg is placed on the size of this source
- there is an offset of 0.19 deg between Cygnus X-1 and the associated LHAASO source.
Spectral Properties, Flux and Energetics:
From
LHAASO Collaboration (2024):
- Photon index: 4.07 +/- 0.35
- Energy range: 25 - 100 TeV
- Flux (Crab Units): <0.01 (at 100 TeV, 1 Crab Unit is approx. 10e-12 erg cl-2 s-1
Distance:
From
Miller-Jones et al. (2021):
- "We used radio astrometry to refine the distance to the black hole
x-ray binary Cygnus X-1, which we found to be 2.22 -0.17 +0.18
kiloparsecs."
A PeVatron:
From
LHAASO Collaboration (2024):
- "GRS 1915+105, MAXI J1820+070 and Cygnus X-1 are detected with
quasi-stable radiations up to approx. 100 TeV. The detection of UHE
gamma-rays demonstrates that accreting BHs and their environments can
operate as extremely efficient accelerators of particles out of 1
peta-electronvolt (PeV), thus contributing to Galactic cosmic rays
especially around the ‘knee’ region."
Seen by: MAGIC, LHAASO
-
Ultrahigh-Energy Gamma-ray Emission Associated with Black Hole-Jet Systems
LHAASO Collaboration, arXiv e-prints parXiv:2410.08988 (2024) [LINK]
-
HAWC Search for High-Mass Microquasars
HAWC Collaboration et al., arXiv e-prints parXiv:2101.08945 (2021) [LINK]
-
Gamma-ray binaries
Chernyakova, Maria and Malyshev, Denys, arXiv e-prints parXiv:2006.03615 (2020) [LINK]
-
Gamma rays from microquasars Cygnus X-1 and Cygnus X-3
Fernandez-Barral, A. et al., ArXiv e-prints p (2017) [LINK]
-
The Gamma-Ray Puzzle in Cygnus X: Implications for High-Energy Neutrinos
Yoast-Hull, T.M. et al., ArXiv e-prints p (2017) [LINK]
-
High-energy gamma-rays in the hard spectral state of Cyg X-1
Zdziarski, A.A. et al., ArXiv e-prints p (2016) [LINK]
-
A search for very high-energy flares from the microquasars GRS 1915+105, Circinus X-1, and V4641 Sgr using contemporaneous H.E.S.S. and RXTE observations
H.E.S.S. Collaboration et al., ArXiv e-prints p (2016) [LINK]
-
Detection of gamma rays of likely jet origin in Cygnus X-1
Zanin, R. et al., ArXiv e-prints p (2016) [LINK]
-
VHE gamma-ray observations of transient and variable stellar objects with the MAGIC Telescopes
Fernandez-Barral, A. et al., ArXiv e-prints p (2015) [LINK]
-
High-energy gamma-ray emission from Cyg X-1 measured by Fermi and its theoretical implications
Malyshev, D. et al., MNRAS 434 p2380-2389 (2013) [LINK]
-
Search for VHE signals from microquarsars with MAGIC
Zanin, R. et al., ArXiv e-prints p (2011) [LINK]
-
A search for Very High Energy gamma-ray emission from Sco X-1 with the MAGIC telescopes
MAGIC Collaboration et al., ArXiv e-prints p (2011) [LINK]
-
The termination region of high-mass microquasar jets
Bosch-Ramon, V. et al., ArXiv e-prints p (2011) [LINK]
-
Gamma-ray binaries: microquasars and binary systems with pulsar
Paredes, J.M., ArXiv e-prints p (2011) [LINK]
-
Non-thermal radiation from Cygnus X-1 corona
Vieyro, F.L. et al., ArXiv e-prints p (2010) [LINK]
-
Gamma-ray absorption and the origin of the gamma-ray flare in Cygnus X-1
Romero, G.E. et al., ArXiv e-prints p (2010) [LINK]
-
Episodic Transient Gamma-Ray Emission from the Microquasar Cygnus X-1
Sabatini, S. et al., ArXiv e-prints p (2010) [LINK]
-
High-energy emission from jet-clump interactions in microquasars
Araudo, A.T. et al., ArXiv e-prints p (2009) [LINK]
-
Suzaku Results on Cygnus X-1 in the Low/Hard State
Makishima, K. et al., ArXiv e-prints 801 p (2008) [LINK]
-
A model of the TeV flare of Cygnus X-1: electron acceleration and extended pair cascades
Zdziarski, A. A. et al., p (2008) [LINK]
-
Very High Energy Gamma-Ray Radiation from the Stellar Mass Black Hole Binary Cygnus X-1
Albert, J. et al., ApJ 665 pL51-L54 (2007) [LINK]
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