| Canonical Name: | 4C +21.35 |
| TeVCat Name: | TeV J1224+213 |
| Other Names: | PKS 1222+216 |
| Source Type: | FSRQ |
| R.A.: | 12 24 54.4 (hh mm ss) |
| Dec.: | +21 22 46 (dd mm ss) |
| Gal Long: | 255.07 (deg) |
| Gal Lat: | 81.66 (deg) |
| Distance: | z=0.432 |
| Flux: | 0.03 (Crab Units) |
| Energy Threshold: | 100 GeV |
| Spectral Index: | 3.75 |
| Extended: | No |
| Discovery Date: | 2010-06 |
| Discovered By: | MAGIC |
| TeVCat SubCat: | Default Catalog |
Source Notes:
Source position and its uncertainty:
- no information available
- the source position provided by
NED is used
Spectral Index:
From
Aleksic et al.: 3.75 +/- 0.27(stat) +/- 0.2(syst)
A preliminary spectral index of 3.77 +/- 0.27 was announced at
the
2010 Texas Symposium (
Gonzalez, P6).
Source Flux:
From
Holder J. (2014):
- The integral flux above 100 GeV corresponds to (1.4 +/- 0.3) x
10e11 ph cm-2 s-1 (equivalent to ~3% of the Crab Nebula flux). The
excess is consistent with a constant flux over the ten nights of
observation, although we note that there are limited statistics. This
is the first VHE detection of this source since the brief VHE flare
detected by
MAGIC on June 17th 2010.
From
Aleksic et al. (2011)
- "The averaged integral flux above 100 GeV is (4.6 ± 0.5) × 10e-10
cm-2 s-1 (~1 Crab Nebula flux). The VHE flux measured by MAGIC varies
significantly within the 30 minute exposure implying a flux doubling
time of about 10 minutes. "
From
Mariotti M. (2010):
- "The integral flux for gamma-rays with energies above 100 GeV is
estimated to be at >=30% of the Crab nebula flux."
Seen by: MAGIC, VERITAS
-
Multiwavelength periodicity search in a sample of gamma-ray bright blazars
Otero-Santos, J. et al., arXiv e-prints parXiv:2210.16327 (2022) [LINK]
-
Long-term optical and gamma-ray variability of the blazar PKS 1222+216
Ezhikode, Savithri H. et al., arXiv e-prints parXiv:2209.13574 (2022) [LINK]
-
Polarized Optical Emission of the Blazar PKS 1222+216: Discovery of A 420-day Quasi-Periodic Signal
Zhang, Pengfei and Wang, Zhongxiang, arXiv e-prints parXiv:2207.10824 (2022) [LINK]
-
Probing Photon-ALP Oscillations from the Flat Spectrum Radio Quasar 4C+21.35
Li, Hai-Jun, arXiv e-prints parXiv:2203.08573 (2022) [LINK]
-
Variability and Spectral Characteristics of Three Flaring Gamma-ray Quasars Observed by VERITAS and Fermi-LAT
Adams, C.B. et al., arXiv e-prints parXiv:2110.13181 (2021) [LINK]
-
Temporal and Spectral Study of PKS B1222+216 Flares in 2014
Chatterjee, Anshu et al., arXiv e-prints parXiv:2105.10891 (2021) [LINK]
-
Multiwavelength study of the quiescent states of six brightest flat-spectrum radio quasars detected by Fermi-LAT
Roy, Abhradeep et al., MNRAS 504 p1103-1114 (2021) [LINK]
-
Locating the gamma-ray emission region in the brightest Fermi-LAT Flat Spectrum Radio Quasars
Acharyya, Atreya et al., arXiv e-prints parXiv:2011.01073 (2020) [LINK]
-
Diversity of gamma-ray and Radio Variabilities of Bright Blazars and Implications for gamma-ray Emission Location
Zhang, Hai-Ming et al., arXiv e-prints parXiv:2003.11175 (2020) [LINK]
-
Recollimation shocks and radiative losses in extragalactic relativistic jets
Bodo, G. and Tavecchio, F., ArXiv e-prints p (2017) [LINK]
-
Effects of Spatial Fluctuations in the Extra Galactic Background Light on Hard Gamma Ray Spectra
Kudoda, A.M. and Faltenbacher, A., ArXiv e-prints p (2017) [LINK]
-
Orphan gamma-ray flares from relativistic blobs encountering luminous stars
Banasinski, P. et al., ArXiv e-prints p (2016) [LINK]
-
Location of gamma-ray flaring region in quasar 4C +21.35
Lei, M. and Wang, J., ArXiv e-prints p (2015) [LINK]
-
Very-high-energy blazars: updates from VERITAS observations and multi-wavelength campaigns
Cerruti, M. for the VERITAS Collaboration, ArXiv e-prints p (2015) [LINK]
-
Brightest Fermi-LAT Flares of PKS 1222+216: Implications on Emission and Acceleration Processes
Kushwaha, P. et al., ArXiv e-prints p (2014) [LINK]
-
Detection of Persistent VHE emission from PKS 1222+216 (4C +21.35) with VERITAS
Holder, J., The Astronomer's Telegram 5981 p1 (2014) [LINK]
-
Multifrequency Studies of the Peculiar Quasar 4C +21.35 during the 2010 Flaring Activity
Ackermann, M. et al., ApJ 786 p157 (2014) [LINK]
-
VHE gamma-ray emission from the FSRQs observed by the MAGIC telescopes
Lindfors, E. et al., ArXiv e-prints p (2013) [LINK]
-
Variable Gamma-ray Emission Induced by Ultra-High Energy Neutral Beams: Application to 4C +21.35
Dermer, C.D. et al., ArXiv e-prints p (2012) [LINK]
-
Evidence for an axion-like particle from PKS 1222+216?
Tavecchio, F. et al., ArXiv e-prints p (2012) [LINK]
-
Energetic Constraints on a Rapid Gamma-Ray Flare in PKS 1222+216
Nalewajko, K. et al., ArXiv e-prints p (2012) [LINK]
-
Fermi Large Area Telescope Detection of Bright Gamma-Ray Outbursts from the Peculiar Quasar 4C +21.35
Tanaka, Y.T. et al., ApJ 733 p19 (2011) [LINK]
-
Challenging the high-energy emission zone in FSRQs
Stamerra, A. et al., ArXiv e-prints p (2011) [LINK]
-
The Optical Properties of PKS 1222+216 During the Fermi Mission
Smith, P.S. et al., ArXiv e-prints p (2011) [LINK]
-
Short time scale variability at gamma rays in FSRQs and implications on the current models
Foschini, L. et al., ArXiv e-prints p (2011) [LINK]
-
Testing the emission models of blazar jets with the MAGIC telescopes
Becerra-Gonzalez, J. et al., ArXiv e-prints p (2011) [LINK]
-
On the origin of the gamma-ray emission from the flaring blazar PKS 1222+216
Tavecchio, F. et al., ArXiv e-prints p (2011) [LINK]
-
Magic Discovery of Very High Energy Emission from the FSRQ PKS 1222+21
Aleksic, J. et al., ApJ 730 pL8+ (2011) [LINK]
-
MAGIC detects a VHE flare from 4C +21.35 (PKS 1222+21)
M. Mariotti on behalf of the MAGIC Collaboration, ATel 2684 [LINK]
-
NIR Flaring of PKS1222+216
L. Carrasco et al., ATel 2626 [LINK]
-
AGILE detection of gamma-ray emission from 4C+21.35 (PKS 1222+21)
A. Bulgarelli et al., ATel 2641 [LINK]
-
Fermi LAT observed another strong GeV flare from 4C 21.35 (PKS 1222+21)
D. Donato on behalf of the Fermi Large Area Telescope Collaboration, ATel 2584 [LINK]
-
Discovery of VHE gamma-ray emission from 4C +21.35 with Fermi
A. Neronov, D. Semikoz & Ie. Vovk, ATel 2617 [LINK]
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