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Observation Date (UT) Observation Lat

Canonical Name:HESS J0632+057
TeVCat Name:TeV J0632+058
Other Names:
Source Type:Binary
R.A.:06 33 00.8 (hh mm ss)
Dec.:+05 47 39 (dd mm ss)
Gal Long: 205.67 (deg)
Gal Lat: -1.44 (deg)
Distance: 1.4 kpc
Flux:0.03 (Crab Units)
Energy Threshold:400 GeV
Spectral Index:2.67
Extended:No
Discovery Date:2007-07
Discovered By: H.E.S.S.
TeVCat SubCat:Default Catalog

Source Notes:

Source position and its uncertainty:
On 170919 the position in TeVCat was updated from
that given in Aharonian et al. (2007) to the
VERITAS position from Aliu et al. (2014)
From Aliu et al. (2014):
VERITAS position:
- R.A. (J2000): 06h 33m 00.8s +/- 0.5s (stat)
- Dec. (J2000): +05d 47' 39'' +/- 10'' (stat)
- Systematic uncertainty: > 50''
H.E.S.S. position:
- R.A. (J2000): 06h 32m 59.4s +/- 1.1s (stat)
- Dec. (J2000): +05d 47' 20'' +/- 16.1'' (stat)
From Aharonian et al. (2007):
- R.A. (J2000): 06h 32m 58.3s
- Dec. (J2000): +05d 48' 20''
- Uncertainty: 28'' (stat), 20'' (syst)

Period:
From Maier et al. (2019):
The authors report on very-high energy observations taken over more
than ten years with H.E.S.S., MAGIC, and VERITAS combining to produce
roughly 440 hours of observations. An unusually bright TeV outburst was
detected in January 2018.
- "The updated gamma-ray light curve now covers all phases of the orbital
period with significant detections in almost all orbital phases."
- "The orbital period from gamma-ray data is determined to be:
318.7 +/- 3.4 days (phase dispersion method)
316.3 +/- 4.3 days (Pearson correlation coefficient method)
consistent with the measurements of 317.3 +/- 0.7 days at X-ray energies."
From Moritani et al. (2018):
- they carried out high-dispersion spectroscopic monitoring over four
orbital cycles
- "The velocity is seen to increase much earlier than expected for the
orbital period of 315 days, and much more steeply than expected at
around "apastron""
- "The period of the H_alpha modulation is found to be as 308 +26-23 days"
- Swift/XRT data from 2009-2015 were also analysed and used to
conclude that the orbital period is: 313 +11 -8 days
From Malyshev et al. (2017):
- they determine the period to be: 316.2 +1.8 -2.0 d (95% c.r.)
From Aliu et al. (2014):
- the period of this binary system is: 315 +/- 5 days

Distance:
The distance quoted in TeVCat, 1.4, is the median of the estimate
from Aragona et al. (2010)
From Aliu et al. (2014):
- "The optical counterpart of HESS J0632+057 is the massive B-star MWC 148
(HD 259440=LS VI +05 11) at a distance of 1.1–1.7 kpc (Aragona et al. 2010)"

Classification:
From Moritani et al. (2018):
Using the new period that they derived and assuming that the H_alpha
velocities trace the motion of the Be star, the authors derived a new
set of orbital parameters.
- "The mass function implies that mass of the compact object
is less than 2.5 M_sun assuming that the mass of the Be star
is 13.2 - 8.2 M_sun (Aragona et al. 2010) unless the inclination
is extremely small. The photon index indicates that the spectra
becomes softer when the system is bright. These suggest that the
compact object is a pulsar."
From Malyshev et al. (2017):
- " We argue that the observed variability can be explained within a
“similar to PSR B1259-63” model in which the orbit of the compact
object is inclined to the disk of Be star. We show that the observed
X-ray to TeV emission can originate from a broken cut-off powerlaw
population of electrons and describe the way in which future X-ray/TeV
observations can distinguish between proposed and flip-flop emission
model of this system"
From Bongiorno et al. (2011):
- they have detected a 320 +/- 5 day period in XRT data taken over a
period of over two years
There is much evidence to suggest that this source is a HMXRB system:
- Bongiorno et al. (2011)
- de Naurois (2011)
- Hinton et al. (2009)
- Aharonian et al. (2007)

Flux:
From Aliu et al. (2014):
- "The phase-folded light curves reveal several important
characteristics of the high-energy emission: a clear detection of the
source in the phase range 0.2–0.4, around the maximum of the X-ray
light curve, with a flux of 2%–3% of that of the Crab Nebula; a first
detection of a gamma-ray emission component at orbital phases in the
range 0.6–0.9, in which a secondary peak in the X-ray light curve is
also observed; and a non-detected low state at all other orbital
phases."
From Aleksic et al. (2012):
- flux measured corresponds to about 4% of the Crab Nebula flux at an
orbital phase of ~0.3 after periastron

Spectral Information:
From Maier et al. (2017):
- All orbital phases (2006-2017), spectral index: 2.67 +/- 0.05
- Orbital phase 0.2-0.4 (2006-2017), spectral index: 2.70 +/- 0.06
- Orbital phase 0.4-0.6 (2006-2017), spectral index: n/a
- Orbital phase 0.6-0.8 (2006-2017), spectral index: 2.55 +/- 0.13
- Orbital phase 0.8-0.2 (2006-2017), spectral index: 2.67 +/- 0.2
From Aliu et al. (2014):
- VERITAS 2010 data (orbital phase 0.2–0.4), spectral index: 2.2 +/- 0.4
- VERITAS 2011 data (orbital phase 0.2–0.4), spectral index: 2.5 +/- 0.2
- VERITAS 2012 data (orbital phase 0.2–0.4), spectral index: 2.3 +/- 0.2
- H.E.S.S. 2004-2012 data (orbital phase 0.2–0.4), spectral index: 2.3 +/- 0.2
- VERITAS 2010-2012 data (orbital phase 0.2–0.4), spectral index: 2.6 +/- 0.1
- H.E.S.S. 2004-2012 data (orbital phase 0.6–0.9), spectral index: 2.4 +/- 0.2
- H.E.S.S. 2004/2005 data, spectral index: 2.53 +/- 0.6
- MAGIC 2012 data, spectral index: 2.6 +/- 0.3
From Aleksic et al. (2012):
- Spectral index: 2.6 +/- 0.3(stat) +/- 0.2(syst)
From Aharonian et al. (2007):
- Spectral index: 2.53 +/- 0.26(stat) +/- 0.2(syst)

Fermi results:
From Li et al.
"HESS J0632+057 is the only gamma-ray binary that has been detected at
TeV energies, but not at GeV energies yet. Based on nearly nine years
of Fermi Large Area Telescope (LAT) Pass 8 data, we report here on a
deep search for the gamma-ray emission from HESS J0632+057 in the
0.1-300 GeV energy range. We find a previously unknown gamma-ray
source, Fermi J0632.6+0548, spatially coincident with HESS J0632+057."
From Hill & Caliandro for the Fermi LAT Collaboration (2013):
- "... HESS J0632+057 remains the only known gamma-ray binary to not
be detected by the LAT."


Seen by: H.E.S.S., MAGIC, VERITAS
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