GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"35322 results found.
- EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart
- GRB 241213B: MAXI/GSC detection
- GRB 241213A: REM optical/NIR upper limits
- GRB 241213A: Enhanced Swift-XRT position
- GRB241212A: OHP/T193 optical observations
- GRB 241213A: SAO RAS optical upper limit
- Swift GRB 241213A: Global MASTER-Net observations report
- GRB 241213A: Swift detection of a burst
- GRB 241212A : SVOM/C-GFT optical upper limit at early phase
- GRB 241212A : SVOM/VT bright optical afterglow
- GRB 241212A: AstroSat CZTI detection
- GRB 241209B: GRANDMA/TRT upper limit
- GRB 241207A: TSHAO Zeiss-1000 optical observations
- GRB 241212A: SVOM detection of a bright long burst
- GRB 241212A: Fermi GBM Final Real-time Localization
- GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
- GRB 241209A: Chandra X-ray Detection
- Konus-Wind detection of GRB 241209B
- GRB 241207A: EIRSAT-1 GMOD Detection
- GRB 241209A: Redshift of the likely host galaxy z = 0.784 from OSIRIS+/GTC
- GRB 241209B: GRBAlpha detection
- GRB 241206C: GRBAlpha detection
- GRB 241211A: Fermi GBM Final Real-time Localization
- GRB 241129A: Fermi GBM Observation
- GRB 241209B: Swift/BAT-GUANO localization skymap of a burst
- GRB 241209D: REM optical/NIR upper limits
- Konus-Wind detection of GRB 241209D
- GRB 241209B: Swift-XRT afterglow detection
- GRB 241209C: Fermi GBM Observation
- GRB 241209A: Swift-XRT refined Analysis
- Fermi Gamma-ray Burst Monitor trigger 755485387 / 241210044 is not a GRB
- GRB 241128A: CrAO ZTSh and Mondy AZT-33IK optical observations
- GRB 241209D: AstroSat CZTI detection
- GRB 241209A: EP-FXT follow-up observations
- GRB 241209B: SVOM/VT afterglow detection
- GRB 241207B: Fermi GBM Observation
- GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits
- GRB 241209D: Swift-XRT refined Analysis
- GRB 241209D: Fermi GBM Observation
- GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
- GRB 241209D: COLIBRÍ detection of the afterglow
- GRB 241209A: COLIBRÍ Optical Upper Limit
- Fermi GRB 241209D: Global MASTER-Net observations report
- GRB 241209A: Fermi GBM Observation
- GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
- GRB 241209A: GRANDMA/TAROT upper limit
- GRB 241209B: BOOTES-5 optical upper limit
- Swift GRB 241209D: Global MASTER-Net observations report
- Fermi GRB 241209C: Global MASTER-Net observations report
- Fermi GRB 241209E: Global MASTER-Net observations report
- GRB 241209E: Fermi GBM Final Real-time Localization
- GRB 241209B: Swift ToO observations
- GRB 241209A: REM optical/NIR observations
- GRB 241209D: Enhanced Swift-XRT position
- GRB 241209C: AstroSat CZTI detection
- GRB 241209D: Swift detection of a burst
- GRB 241209D: Fermi GBM Final Real-time Localization
- GRB 241209A: VLT/X-shooter spectroscopy
- GRB 241209A: Enhanced Swift-XRT position
- GRB 241114B: cubesat Avion detection
- GRB 241209A: VLT optical observations
- Fermi GRB 241209A: Global MASTER-Net observations report
- GRB 241209C: Fermi GBM Final Real-time Localization
- GRB 241209A: GOTO optical upper limits
- GRB 241209A: Prompt enhanced Swift-XRT position
- GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
- GRB 241209A: Swift detection of a short burst
- GRB 241209A: Fermi GBM Final Real-time Localization
- Fermi GRB 241207B: Global MASTER-Net observations report
- GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
- Fermi Gamma-ray Burst Monitor trigger 755277791/241207641 is not a GRB
- GRB 241201A: AstroSat CZTI detection
- GRB 241206A: DDOTI Upper Limit on the Afterglow
- GRB 241207C: MASTER optical observations
- GRB 241207C: Tiled Swift observations
- GRB 241207C: MAXI/GSC detection
- GRB 241207B: Fermi GBM Final Real-time Localization
- Fermi GRB 241207A: Global MASTER-Net observations report
- GRB 241206A: Fermi GBM observation
- GRB 241206C: SVOM/GRM observation of a likely short burst
- GRB 241207A: Fermi GBM Final Real-time Localization
- GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
- GRB 241206B: SVOM/MXT observations: a probable flare from the QSO 1ES 1959+650
- GRB 241206B: GWAC-F50A optical upper limit
- GRB 241206B: SVOM/ECLAIRs detection of a long soft transient
- Fermi GRB 241206A: Global MASTER-Net observations report
- GRB 241206A: Fermi GBM Final Real-time Localization
- GRB 241204A: COLIBRÍ Optical Upper Limit
- EP241202b: KAIT optical upper limit
- LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
- GRB 241204A: DDOTI Upper Limits on the Afterglow
- GRB 241204A: Fermi GBM Observation
- Fermi GRB 241204A: Global MASTER-Net observations report
- GRB 241130A: CALET Gamma-Ray Burst Monitor detection
- GRB 241128A : RAPAS follow-up observations
- GRB 241201A: GRBAlpha detection
- GRB 241204A: Fermi-LAT detection
- EP241202b: Upper limits from Fermi-GBM Observations
- Fermi-GBM Sub-Threshold Detection of GRB 241128A
- GRB 241113B : RAPAS follow-up observation