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.
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"27777 results found.
- GRB 241209D: CALET Gamma-Ray Burst Monitor detection
- GRB 241213A: SVOM/VT optical candidate
- GRB 241213B: Tiled Swift observations
- GRB 241213A: Swift/UVOT Upper Limits
- GRB 241213B: CALET Gamma-Ray Burst Monitor detection
- GRB 241213A: Swift-XRT refined Analysis
- GRB 241212A: Fermi GBM detection
- GRB 241212A: Swift ToO observations
- GRB 241213A: LCOGT Optical Upper Limits
- EP 241208A : Detection of a long soft transient by SVOM/ECLAIRs
- EP241213a/GRB241213a: Likely joint detection and INTEGRAL/SPI-ACS counterpart
- GRB 241213B: MAXI/GSC detection
- EP241213a: EP detection of An X-ray Transient
- GRB 241213A: REM optical/NIR upper limits
- GRB 241213A: Enhanced Swift-XRT position
- GRB241212A: OHP/T193 optical observations
- Swift GRB 241213A: Global MASTER-Net observations report
- GRB 241213A: Swift detection of a burst
- GRB 241212A: AstroSat CZTI detection
- GRB 241212A: SVOM detection of a bright long burst
- GRB 241212A: Fermi GBM Final Real-time Localization
- GRB 241209A: Chandra X-ray Detection
- Konus-Wind detection of GRB 241209B
- GRB 241207A: EIRSAT-1 GMOD Detection
- 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
- GRB 241209D: AstroSat CZTI detection
- GRB 241209A: EP-FXT follow-up observations
- GRB 241209B: SVOM/VT afterglow detection
- EP241208a: EP-FXT follow-up observations
- 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
- 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
- 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: Enhanced Swift-XRT position
- GRB 241114B: cubesat Avion detection
- 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
- GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
- GRB 241201A: AstroSat CZTI detection
- GRB 241206A: DDOTI Upper Limit on the Afterglow
- AT2024adec: X-ray Upper Limits from EP-FXT Observation
- EP241206a: BOOTES Global Network optical limits
- GRB 241207C: Tiled Swift observations
- GRB 241207C: MAXI/GSC detection
- GRB 241207B: Fermi GBM Final Real-time Localization
- EP241206a: EP detection of a fast X-ray transient
- GRB 241206A: Fermi GBM observation
- GRB 241207A: Fermi GBM Final Real-time Localization
- GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
- GRB 241206B: SVOM/ECLAIRs detection of a long soft transient
- EP241113a: Keck/LRIS spectroscopic observation and tentative redshift
- GRB 241206A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
- GRB 241130A: CALET Gamma-Ray Burst Monitor detection
- GRB 241201A: GRBAlpha detection
- GRB 241204A: Fermi-LAT detection
- IceCube-241127A: No transient candidates from the Zwicky Transient Facility
- EP241202b: Kinder optical counterpart candidate
- Fermi-GBM Sub-Threshold Detection of GRB 241128A
- EP241201a: EP-FXT follow-up observations
- Konus-Wind detection of GRB 241130A
- EP241201a: BOOTES-5 optical upper limit
- EP241202b: EP detection of a fast X-ray transient
- IPN triangulation of GRB 241130A
- GRB 241130A: EIRSAT-1 GMOD Detection
- GRB 241128A: Swift/UVOT Upper Limits
- GRB 241130A: Fermi GBM Detection
- GRB 241129A: Swift/BAT-GUANO localization skymap of a burst