GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"- 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
- LIGO/Virgo/KAGRA S241210cw: Updated Sky localization
- LIGO/Virgo/KAGRA S241210d: Updated Sky localization and EM Bright Classification
- 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
- LIGO/Virgo/KAGRA S241210fu: Identification of a GW compact binary merger candidate
- EP241208a: Optical upper limit with Kinder observations
- 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
- LIGO/Virgo/KAGRA S241210cw: Identification of a GW compact binary merger candidate
- EP241208a: Global MASTER-Net observations report
- EP241208a: EP-FXT follow-up observations
- LIGO/Virgo/KAGRA S241210d: Identification of a GW compact binary merger candidate
- Fermi trigger No 755485387: Global MASTER-Net observations report
- 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
- LIGO/Virgo/KAGRA S241102br: continued GRAWITA observations and detection of an optical transient (AT2024adip)
- 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
- EP241206a: 1.5m OSN optical limit
- GRB 241209A: Prompt enhanced Swift-XRT position
- GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
- EP241208a: EP detection of a fast X-ray transient
- GRB 241209A: Swift detection of a short burst
- Swift GRB241209.23: Global MASTER-Net observations report
- 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
- AT2024adec: X-ray Upper Limits from EP-FXT Observation
- AT2024adec: X-ray Upper Limits from EP-FXT Observation
- EP241206a: BOOTES Global Network optical limits
- GRB 241207C: MASTER optical observations
- Fermi trigger No 755225799: Global MASTER-Net observations report
- GRB 241207C: Tiled Swift observations
- GRB 241207C: MAXI/GSC detection
- GRB 241207B: Fermi GBM Final Real-time Localization
- Fermi trigger No 755277791: Global MASTER-Net observations report
- Fermi GRB 241207A: Global MASTER-Net observations report
- EP241206a: Global MASTER-Net observations report
- EP241206a: EP detection of a fast X-ray transient
- 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
- EP241113a: Keck/LRIS spectroscopic observation and tentative redshift
- Fermi GRB 241206A: Global MASTER-Net observations report
- GRB 241206A: Fermi GBM Final Real-time Localization