| Canonical Name: | OP 313 |
| TeVCat Name: | TeV J1310+323 |
| Other Names: | B2 1308+32 |
| Source Type: | FSRQ |
| R.A.: | 13 10 28.6638 (hh mm ss) |
| Dec.: | +32 20 43.783 (dd mm ss) |
| Gal Long: | 85.70 (deg) |
| Gal Lat: | 83.35 (deg) |
| Distance: | z=0.9973 |
| Flux: | 0.15 (Crab Units) |
| Energy Threshold: | 100 GeV |
| Spectral Index: | |
| Extended: | No |
| Discovery Date: | 2023-12 |
| Discovered By: | LST-1 |
| TeVCat SubCat: | Newly Announced |
Source Notes:
This detection was announced by the LST Collaborations in an
ATel 16381.
From
ATel 16381:
- The Large-Sized Telescope (LST-1) on La Palma has been monitoring the very
distant Flat Spectrum Radio Quasar (FSRQ) OP 313 (z=0.997,
Schneider et al. 2010)
since November 2023. Following the announcement of enhanced gamma-ray emission
by Fermi-LAT (
ATel #16356)
and several optical facilities (
ATel #16360) in early
December, the Fermi-LAT emission of OP 313 has been closely monitored using the
FlaapLUC pipeline (
Lenain et al., 2018).
- This monitoring revealed the detection of renewed activity in the
high-energy (HE, E>100 MeV) band and so, Target of Opportunity
observations with LST-1 were triggered on December 10th 2023.
- OP 313 was detected by LST-1 with a preliminary offline analysis using
data from 2023/12/11 to 2023/12/14. It was detected with a
significance greater than 5 sigma and an integrated flux, above 100
GeV, at 15% flux of the Crab Nebula.
Source Position:
The source position was taken from
NED.
- The reference for the position in NED is
Johnston et al. (1995).
- R.A. (J2000): 13h10m28.6638s
- Dec. (J2000): +32d20m43.783s
Distance:
From
Schneider et al. (2010):
- Data were taken from the fifth edition of the Sloan Digital Sky
Survey (SDSS) Quasar Catalog, which is based upon the SDSS Seventh
Data Release.
- A redshift of z = 0.9973 was determined.
- "the catalog reports the spectro1d redshifts, which have typical
quoted redshift errors of ≈0.004"
Seen by: LST-1, VERITAS, MAGIC, MACE
-
The MAGIC telescopes detect a very-high-energy gamma-ray flare from OP313
Paneque, D. et al. on behalf of the MAGIC collaboration, The Astronomer's Telegram 16977 p1 (2025) [LINK]
-
Strong multi-wavelength flaring activity from FSRQ OP 313 from optical to gamma rays
Otero-Santos, J. et al., The Astronomer's Telegram 16979 p1 (2025) [LINK]
-
VERITAS Detection of Very-High-Energy Gamma-Ray Flaring Activity from OP 313
Furniss, A. for the VERITAS Collaboration, The Astronomer's Telegram 16993 p1 (2025) [LINK]
-
Strong very-high-energy gamma-ray flaring activity from FSRQ OP313 detected with the MAGIC telescopes
Paneque, D., The Astronomer's Telegram 17000 p1 (2025) [LINK]
-
Fermi-LAT detection of renewed gamma-ray activity from the FSRQ sources PKS 0446+11 and OP 313
Casaburo, F. et al. on behalf of the Fermi Large Area Telescope Collaboration, The Astronomer's Telegram 16970 p1 (2025) [LINK]
-
Detection of gamma-ray flare from FSRQ OP 313 with MACE Telescope
Mankuzhiyil, N. on behalf of the MACE Team, The Astronomer's Telegram 17003 p1 (2025) [LINK]
-
OP 313 flare: Upper limits from a neutrino search with IceCube
Hori, S. et al., The Astronomer's Telegram 17016 p1 (2025) [LINK]
-
Signature of hadronic emission in gamma-ray spectrum of B2 1308+326
Dar, Athar A. et al., arXiv e-prints parXiv:2503.01583 (2025) [LINK]
-
Multi-band optical variability of the blazar OP 313 in the outburst state during 2024-2025
Devanand, P.U. et al., arXiv e-prints parXiv:2507.20223 (2025) [LINK]
-
A Unified Multi-Wavelength Data Analysis Workflow with gammapy. Constraining the Broadband Emission of FSRQ OP 313
Nievas Rosillo, M. et al., arXiv e-prints parXiv:2409.20487 (2024) [LINK]
-
First detection of VHE gamma-ray emission from FSRQ OP 313 with LST-1
Cortina, J. for the CTAO LST collaboration, The Astronomer's Telegram 16381 p1 (2023) [LINK]
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