TeVCat Gamma-Ray Source Summary: Geminga Pulsar

Canonical Name: Geminga Pulsar

TeVCat Name: TeV J0633+177p

Other Names: 4HWC J0634+1734

Source Type: PSR

R.A.: 06 33 54.153 (hh mm ss)

Dec.: +17 46 12.91 (dd mm ss)

Gal Long: 195.13 (deg)

Gal Lat: 4.27 (deg)

Distance: 0.25 kpc

Flux: (Crab Units)

Energy Threshold: GeV

Spectral Index: 5.62

Extended: No

Discovery Date: 2018-06

Discovered By: MAGIC

TeVCat SubCat: Default Catalog

Source Notes:

This detection was announced during the talk of Marcos Lopez at the
MAGIC 15th Anniversary Meeting in June 2018.
The source was moved from the "Newly Announced" to the "Default" catalogue
on 24 November 2020 with the publication of MAGIC Collaboration et al. (2020).

Source position:

The source position is taken from SIMBAD:
- R.A. (J2000): 06 33 54.153
- Dec. (J2000): +17 46 12.91

Distance:

From Faherty et al. (2007):
- "We find the parallax pi = 4.0 +/- 1.3 mas, corresponding to a
distance to Geminga of (250 -62 +120) pc, a result 60% larger than the
previously published value. The proper motion is 178.2 +/- 1.8 mas/year."
From Caraveo et al. (1996):
- "Using data from Hubble Space Telescope observations, we report the
first optical measurement of the annual parallax of a neutron star."
- "The resulting distance value is 157 pc (+59, -34), just consistent
with the lower end of the wide range derived from X-ray data. "

Age:

From the ATNF Pulsar catalog by Manchester et al. (2005):
- 3.42e+05 year (340 Myear)

Pulsar Period:

From MAGIC Collaboration et al. (2020):
- "From the two pulses per rotation seen by Fermi-LAT, only the second one,
P2, is detected in the MAGIC energy range, with a significance of 6.3 sigma"

From Abdo et al. (2010):
- "Geminga has a period of 237 ms and a very stable period derivative
of 1.1 x10e-14 s s-1, that characterize it as a mature pulsar with
characteristic age of 3 x10e5 yr and spin-down luminosity Edot = 3.26 x10e34 erg s-1"

From Mayer-Hasselwander et al. (1994):
- The EGRET data showed a double-peaked light curve with a peak
separation of approx. 0.5 phase.

Spectral Information:

From MAGIC Collaboration et al. (2020):
- Pulsed emission is detected between 15 GeV and 75 GeV
- "The spectrum measured by MAGIC is well-represented by a simple
power law of spectral index 5.62 +/- 0.54, which smoothly extends the
Fermi-LAT spectrum. A joint fit to MAGIC and Fermi-LAT data rules out
the existence of a sub-exponential cut-off in the combined energy
range at the 3.6 sigma significance level. The power-law tail emission
detected by MAGIC is interpreted as the transition from curvature
radiation to Inverse Compton Scattering of particles accelerated in
the northern outer gap."

	Fourth HAWC Catalog (Alfaro et al., 2026):
	A selection of information for each of the 85 sources in the Fourth HAWC Catalog is provided in TeVCat. For full details, see Alfaro et al., 2026.
	All uncertainties are purely statistical and do not include the systematics.
	The pivot energy is fixed at 2 TeV and is the value that minimizes the correlation between the flux normalization and spectral index for a Crab-like source at 0 deg zenith.
	This is one of the seven sources that was accepted as curved but for which the maximum likelihood estimation was
	unable to properly fit a log-parabola model within physically reasonable boundaries. This source likely has
	a significantly curved spectrum, but within the automated likelihood pipeline search fitting process, it was
	not able to be determined as such and a dedicated analysis is needed to confirm this morphology.

	Name:	4HWC J0634+1734^†
	R.A. (J2000):	$98.51^{+0.06}_{-0.06}$
	Dec. (J2000):	$17.57^{+0.06}_{-0.06}$
	Extension (radius):	$0.85^{+0.06}_{-0.05}$
	Flux normalisation, N0, at E0 (2TeV):	$5.5^{+0.27}_{-0.29}$
	Spectral Index:	$-2.26^{+0.031}_{-0.029}$
	Beta:	---
	Test Statistic:	417
	TeVCat Association (distance):	Geminga Pulsar (0.199)

Seen by: MAGIC, LST-1, HAWC

The Fourth HAWC Catalog of Very-High-Energy Gamma-Ray Sources
Alfaro, R. et al., arXiv e-prints parXiv:2602.00263 (2026) [LINK]
On the Contribution of the Bow Shock Pulsar Wind Nebula PSR J0437-4715 to the Observed Fluxes of GeV-TeV Positrons and Antiprotons
Petrov, A.E. and Bykov, A.M., Astronomy Letters 51 p487-497 (2025) [LINK]
Detection of the Geminga pulsar at energies down to 20 GeV with the LST-1 of CTAO
CTAO-LST Project, The et al., arXiv e-prints parXiv:2505.21632 (2025) [LINK]
Geminga contribution to the cosmic-ray positron excess according to the gamma-ray observations
Zhou, Guang-Yao et al., Communications in Theoretical Physics 74 p105403 (2022) [LINK]
New estimate for the contribution of the Geminga pulsar to the positron excess
Wu, Donglin, arXiv e-prints parXiv:2206.07621 (2022) [LINK]
Very-High-Energy Emission From Pulsars
Harding, Alice K. et al., arXiv e-prints parXiv:2110.09412 (2021) [LINK]
Detection of extended TeV emission around the Geminga pulsar with H.E.S.S
Mitchell, A.M.W. et al., arXiv e-prints parXiv:2108.02556 (2021) [LINK]
Does the Geminga gamma-ray halo imply slow diffusion around pulsars?
Recchia, Sarah et al., arXiv e-prints parXiv:2106.02275 (2021) [LINK]
Measurement of High Energy Gamma Rays from 200 MeV to 1 TeV with the Alpha Magnetic Spectrometer on the International Space Station
Beischer, Bastian, arXiv e-prints parXiv:2007.08392 (2020) [LINK]
Contribution of pulsars to cosmic-ray positrons in light of recent observation of inverse-Compton halos
Manconi, Silvia et al., Phys. Rev. D 102 p023015 (2020) [LINK]
Detection of the Geminga pulsar with MAGIC hints at a power-law tail emission beyond 15 GeV
MAGIC Collaboration et al., arXiv e-prints parXiv:2011.10412 (2020) [LINK]
Search for extended gamma-ray emission around the Geminga pulsar with H.E.S.S.
Mitchell, A. and Caroff, S. for the H.E.S.S. Collaboration, TeV Particle Astrophysics (2019) parXiv:2108.02556 (2019) [LINK]
Positron flux and gamma-ray emission from Geminga pulsar and pulsar wind nebula
Tang, X. and Piran, T., ArXiv e-prints p (2018) [LINK]
An undiscovered pulsar in the Local Bubble as an explanation of the local high energy cosmic ray electron spectrum
Lopez-Coto, R. et al., ArXiv e-prints p (2018) [LINK]
Constraints on the properties of the turbulent magnetic field around Geminga using HAWC measurements
Giacinti, G. and Lopez-Coto, R., ArXiv e-prints p (2018) [LINK]
Unveiling VHE Emission from Pulsars with MAGIC
Lopez M. et al. for the MAGIC Collaboration, Proc. MAGIC 15th Anniversary Meeting (2018) [LINK]
Search for VHE gamma-ray emission from Geminga pulsar and nebula with the MAGIC telescopes
Ahnen, M.L. et al., A&A 591 pA138 (2016) [LINK]
A Search for Pulsations from Geminga above 100 GeV with VERITAS
Aliu, E. et al., ApJ 800 p61 (2015) [LINK]
The Second Fermi Large Area Telescope Catalog of Gamma-Ray Pulsars
Abdo, A.A. et al., ApJS 208 p17 (2013) [LINK]
Fermi-LAT Observations of the Geminga Pulsar
Abdo, A.A. et al., ApJ 720 p272-283 (2010) [LINK]
Phase-resolved Studies of the High-Energy Gamma-Ray Emission from the Crab, Geminga, and VELA Pulsars
Fierro, J.M. et al., ApJ 494 p734-746 (1998) [LINK]
High-Energy Gamma Radiation from Geminga Observed by EGRET
Mayer-Hasselw et al., ApJ 421 p276 (1994) [LINK]

Want a reference added? Send a bibtex entry to the TeVCat Team

Canonical Name:	Geminga Pulsar
TeVCat Name:	TeV J0633+177p
Other Names:	4HWC J0634+1734
Source Type:	PSR
R.A.:	06 33 54.153 (hh mm ss)
Dec.:	+17 46 12.91 (dd mm ss)
Gal Long:	195.13 (deg)
Gal Lat:	4.27 (deg)
Distance:	0.25 kpc
Flux:	(Crab Units)
Energy Threshold:	GeV
Spectral Index:	5.62
Extended:	No
Discovery Date:	2018-06
Discovered By:	MAGIC
TeVCat SubCat:	Default Catalog

Observation Date (UT)	Observation Lat