| Canonical Name: | H 1722+119 |
| TeVCat Name: | TeV J1725+118 |
| Other Names: | |
| Source Type: | HBL |
| R.A.: | 17 25 04.3 (hh mm ss) |
| Dec.: | +11 52 15 (dd mm ss) |
| Gal Long: | 34.12 (deg) |
| Gal Lat: | 24.48 (deg) |
| Distance: | |
| Flux: | 0.02 (Crab Units) |
| Energy Threshold: | 150 GeV |
| Spectral Index: | |
| Extended: | No |
| Discovery Date: | 2013-05 |
| Discovered By: | MAGIC |
| TeVCat SubCat: | Default Catalog |
Source Notes:
160322: The source was moved from "Newly Announced" to "Default" catalogue.
Source Position:
No source position or positional uncertainty is provided.
From
NED:
- R.A. (J2000): 17h 25m 04.3s
- Dec. (J2000): +11d 52m 15s
Distance:
From
Zahoor et al. (2021):
- In this work, the effect of the absorption of the extragalactic
galactic background light was used to place constraints on the
redshifts of gamma-ray sources.
- "The very high energy (VHE) gamma-ray spectral indices of blazars
show strong correlation with the source redshift. Absence of any such
correlation in low energy gamma rays and X-rays indicate the presence
of Extragalactic Background Light (EBL) induced absorption of VHE
gamma rays. By employing a linear regression analysis, this
observational feature of blazars is used to constrain the redshift of
BL Lac objects which was unknown/uncertain earlier."
- Two different regression relations were used to constrain the source
redshift and the following values were found for H 1722+119:
- z = 0.15 +/- 0.07
- z = 0.13 +/- 0.06
From
Ahnen et al. (2016):
- "We used contemporaneous high energy gamma-ray observations from
Fermi-LAT to estimate the redshift of the source. Within the framework
of the current extragalactic background light models, we estimate the
redshift to be z = 0.34 +/- 0.15"
From
Landoni et al. (2014):
- "We secured optical and near-infrared medium-resolution spectra of
four bright BL Lac objects of unknown redshift using the spectrograph
X-Shooter at the ESO-VLT. "
- "In spite of the high quality of the spectra and the extended
spectral range of the observations, we have not detected intrisic
spectral features for these sources. However, we are able to provide
strigent lower limits to their redshift." (For two TeV sources: PG
1553+113 and H 1722+119)
- For H 1722+119 they inferred z > 0.35
From
Cortina for the MAGIC Collaboration (2013):
- " Its redshift is uncertain;
Sbarufatti et al. 2006 give z>0.17."
Spectral information:
From
Ahnen et al. (2016):
- Spectral index: 3.3 +/- 0.3(stat) +/- 0.2(syst)
Flux:
From
Ahnen et al. (2016):
- a flux at the level of 2.5 +/- 0.5 per cent of that from the Crab
Nebula above 150 GeV was detected
- no evidence for flux variability on a night-by-night basis was found
Classification
Ahnen et al. (2016) note that this source was classified as an IBL
by
Nieppola et al. (2006). The source is classified as
a HSP in the Fermi-LAT
3LAC so we classify it as a HBL here.
Additional Information:
From
Ahnen et al. (2016):
- "The results reported here are based on the observa- tions performed
during six nights between 2013 May 17 and 22, triggered by the high
optical state detected by the KVA (Kungliga Vetenskaps
Akademientelescope) located at the Observatorio del Roque de los
Muchachos, La Palma (Canary Islands, Spain), and operated by the
Tuorla Observatory, Finland"
From
Cortina for the MAGIC Collaboration (2013):
- "The MAGIC observations were triggered by the extended optical high
state of the source, reported by the
Tuorla blazar monitoring
program"
Seen by: MAGIC
-
Model-independent Redshift Estimation of BL Lac Objects through VHE Observations
Zahoor, Malik et al., arXiv e-prints parXiv:2110.15953 (2021) [LINK]
-
Investigating the peculiar emission from the new VHE gamma-ray source H1722+119
Ahnen, M.L. et al., ArXiv e-prints p (2016) [LINK]
-
Spectroscopy of BL Lacertae objects of extraordinary luminosity
Landoni et al., A&A 570 pA126 (2014) [LINK]
-
Discovery of Very High Energy Gamma-Ray Emission from BL Lac object H1722+119 by the MAGIC Telescopes
Cortina, J. for the MAGIC Collaboration, The Astronomer's Telegram 5080 p1 (2013) [LINK]
-
The BeppoSAX View of Extreme BL Lacs
Costamante, L. et al., p21 (2002) [LINK]
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