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"- EP240417a: YAHPT Optical Upper Limits
- GRB240418A: YAHPT Upper Limits
- GRB 240419A: VLT/UVES redshift of z = 5.178
- GRB 240419A: VLT optical afterglow detection
- GRB 240419A: Enhanced Swift-XRT position
- Fermi trigger No 735089036: Global MASTER-Net observations report
- EP240416a: J-band observations with WINTER
- EP240414a: GMG observation
- GRB 240419A: Prompt enhanced Swift-XRT position
- GRB 240419A: Swift detection of a burst
- GRB 240418A: TSHAO Zeiss-1000 optical upper limit
- GRB 240418A: NOT optical upper limits
- GRB 240418A: Enhanced Swift-XRT position
- GRB 240418A: AKO Upper Limit
- GRB 240411A: GOTO early optical upper limits
- Swift GRB240418.85: Global MASTER-Net observations report
- GRB 240418A: Swift detection of a burst
- EP240417a: EP-WXT detection of a fast X-ray transient
- Fermi GRB 240417A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240413p: X-ray upper limits from EP-WXT for the candidate AGN counterpart
- EP240416A: Terskol Zeiss-2000 optical upper limit
- EP240416A: Khureltogoot optical upper limit
- Improved IPN triangulation of GRB 240411A
- EP240416a: BOOTES-2/TELMA Optical Upper Limit
- EP240414a: GSP detects optical candidate counterpart AT2024gsa
- LIGO/Virgo/KAGRA S240413p: DECam GW-MMADS candidates
- IceCube-Cascade 240416A: Upper limits from a search for additional neutrino events in IceCube
- GRB 240417A: Fermi GBM Final Real-time Localization
- EP240414a: Pan-STARRS detects re-brightening of the candidate counterpart AT2024gsa
- LIGO/Virgo/KAGRA S240413p: historical ATLAS and ZTF observations of the candidate AGN counterpart
- GRB 240415A: Glowbug gamma-ray detection
- GRB 240414A: Glowbug gamma-ray detection
- LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification
- GRB 240415B: GECAM-B detection
- EP 240416a: Xinglong and NOT decaying optical counterpart
- GRB 240415A: Swift-BAT refined analysis
- EP240416A: MASTER optical observations
- GRB 240411A: Glowbug gamma-ray detection
- GRB 240414A: Swift-BAT refined analysis
- EP240416a: Kinder optical counterpart candidate
- EP240416a: EP-WXT detection of a fast X-ray transient
- GRB 240414A: AbAO optical upprer limit
- GRB 240415A: Swift/UVOT Detection
- EP240413a: BOOTES-2/TELMA Optical Upper Limit
- GRB 240415A: Fermi GBM Observation
- GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
- GRB 240415A: Earliest optical followup with the Kinder observations
- GRB 240414A: GMG observation
- EP 240414a: BOOTES-4/MET Optical Upper Limits
- EP240414a: EP-FXT follow-up observation
- GRB 240415A: Enhanced Swift-XRT position
- GRB 240415B: Swift ToO observations
- GRB 240415B: Swift/BAT-GUANO Correction
- GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
- GRB 240415A: OHP/T193 optical observations
- GRB 240415A: optical afterglow detection from the INAF Asiago Observatory
- GRB 240415A: SAO RAS optical observations
- GRB 240415A: Mondy optical transient detection (photometry correction in GCN 36118 )
- GRB 240414A: Fermi GBM Observation
- Fermi GRB 240415A: Global MASTER-Net observations report
- GRB 240415A: Mondy optical transient detection
- GRB 240414A: Photometric observation from 2.2m CAHA
- IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
- GRB 240414A: Swift/UVOT Detection
- LXT 240402A/GRB 240402B: Swift follow-up observations
- GRB 240414A: Mondy optical observations
- GRB 240414B: Fermi GBM Final Real-time Localization
- GRB 240414A: AKO Optical Upper Limit
- X-ray transient EP 240414a - GTC spectroscopic observations
- GRB 240415A: Prompt Swift-XRT observations
- GRB 240415A: Swift detection of a burst
- GRB 240415A: Fermi GBM Final Real-time Localization
- EP240413a: Upper limits from GECAM-B Observation
- EP 240414a: NOT optical counterpart confirmation
- GRB 240414A: Swift-XRT refined Analysis
- GRB240414A : J-band upper limits from WINTER
- GRB 240414A: Enhanced Swift-XRT position
- GRB 240414A : OHP/T193 second epoch of optical follow-up and afterglow detection
- GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
- LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
- EP240413A: GOTO optical upper limits
- GRB 240414A: Skynet Optical Afterglow Observations
- Fermi trigger No 734754044: Global MASTER-Net observations report
- Swift GRB 240414A: Global MASTER-Net observations report
- EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
- IPN triangulation of GRB 240410A
- EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
- EP240414a: EP-WXT detection of a fast X-ray transient
- IPN triangulation of GRB 240411A
- Fermi-LAT gamma-ray observations of IceCube-240412A
- GRB 240414A : MITSuME Akeno optical upper limits
- GRB 240414A: Redshift confirmation from GTC/OSIRIS+
- EP240413a: EP-WXT detection of a fast X-ray transient
- GRB 240414A : OHP/T193 redshift determination
- GRB 240414A : OHP/T193 optical counterpart detection
- GRB 240414A: Swift detection of a burst
- LIGO/Virgo/KAGRA S240413p: Updated Sky localization
- LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240413p: Zwicky Transient Facility observations
- EP240408a: GSP optical upper limit