| Canonical Name: | PKS 0548-322 |
| TeVCat Name: | TeV J0550-322 |
| Other Names: | H 0548-322, 1ES 0548-322 |
| Source Type: | FRI |
| R.A.: | 05 50 38.4 (hh mm ss) |
| Dec.: | -32 16 12.9 (dd mm ss) |
| Gal Long: | 237.56 (deg) |
| Gal Lat: | -26.15 (deg) |
| Distance: | z=0.069 |
| Flux: | 0.013 (Crab Units) |
| Energy Threshold: | 200 GeV |
| Spectral Index: | 2.86 |
| Extended: | No |
| Discovery Date: | 2007-07 |
| Discovered By: | H.E.S.S. |
| TeVCat SubCat: | Default Catalog |
Source Notes:
Detection:
Presented at the
30th ICRC
Source position and its uncertainty:
From
Aharonian et al. (2010):
- R.A. (J2000): 05h 50m 38.4s +/- 3.2s
- Dec. (J2000): −32d 16' 12.9" +/-40.2"
Classification:
This source was classified as a HBL in TeVCat until 250919 when it was updated to FRI.
From
Tomar et al. (2025):
- "It was classified as a BL Lac in the 4FGL-DR4 catalog. However, it
exhibits a wide-angled tailed FR-I morphology in both RACS and VLASS
images and low core dominance. The optical spectrum shows host galaxy
absorption features (Fosbury and Disney, 1976). These observations
resulted in the reclassification of this source as an FR-I radio
galaxy (
Paliya et al., 2024)."
From
Paliya et al. (2024):
- "This source is classified as a BL Lac in the 4FGL-DR4 catalog. Its
optical spectrum consists of a blue non-thermal continuum along with
the host galaxy absorption features (
R. A. E. Fosbury & M. J. Disney 1976).
R. R. J. Antonucci & J. S. Ulvestad (1984) reported the detection of a
head-tail morphology, which was well resolved in the VLASS image
analyzed in this work. The low-frequency observations taken with RACS
also reveal this object’s WAT nature and much larger diffuse emission
toward the southern direction. The computed core dominance is low."
Spectral Properties:
From
Aharonian et al. (2010):
- Spectral Index: 2.86 +/- 0.34(stat) +/- 0.10(syst)
Distance:
- the redshift of z = 0.069 comes from
Fosbury & Disney (1976)
Seen by: H.E.S.S.
-
X-Ray Spectral Variability of 13 TeV High-energy-peaked Blazars with XMM-Newton
Devanand, P.U. et al., ApJS 278 p20 (2025) [LINK]
-
Fermi-Large Area Telescope Detection of Very High Energy (>100 GeV) Emission from Misaligned Jetted Active Galactic Nuclei
Tomar, Gunjan et al., arXiv e-prints parXiv:2508.15921 (2025) [LINK]
-
Radio Morphology of Gamma-Ray Sources: Double-lobed Radio Sources
Paliya, Vaidehi S. et al., ApJ 976 p120 (2024) [LINK]
-
X-ray Intraday Variability of HBL Blazars with XMM-Newton
Devanand, P.U. et al., arXiv e-prints parXiv:2209.05515 (2022) [LINK]
-
Constraining X-ray emission in HBL blazars using multiwavelength observations
Wierzcholska, Alicja and Wagner, Stefan, arXiv e-prints parXiv:2006.00066 (2020) [LINK]
-
Discovery of VHE gamma-rays from the BL Lacertae object PKS 0548-322
Aharonian, F. et al., A&A 521 pA69+ (2010) [LINK]
-
Detection of Intra-day Variability Timescales of Four High Energy Peaked Blazars with XMM-Newton
Gaur, H. et al., ArXiv e-prints p (2010) [LINK]
-
Discovery of VHE gamma-rays from the BL Lac object PKS 0548-322 with H.E.S.S
Superina, G. et al., Proc. 30th International Cosmic Ray Conference
Vol 3 p913-916 (2008) [LINK]
-
Intrinsic absorbers in BL Lac objects: The XMM-Newton view
Blustin, A.J. et al., A&A 417 p61-70 (2004) [LINK]
-
The BeppoSAX View of Extreme BL Lacs
Costamante, L. et al., p21 (2002) [LINK]
-
Extreme synchrotron BL Lac objects. Stretching the blazar sequence
Costamante, L. et al., A&A 371 p512-526 (2001) [LINK]
-
Looking for high energy peaked blazars
Costamante, L. et al., Mem. Soc. Astron. Italiana 72 p153-155 (2001) [LINK]
-
New extreme synchrotron BL Lac objects
Costamante, L. et al., X-ray Astronomy: Stellar Endpoints, AGN, and the Diffuse X-ray Background 599 p586-589 (2001) [LINK]
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