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.
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"22204 results found.
- LIGO/Virgo/KAGRA S240422ed: DECam GW-MMADS Candidates
- LIGO/Virgo/KAGRA S240422ed: Potential Magellan candidates from GCN 36263 are unrelated.
- LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
- LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Three Potential Electromagnetic Counterparts Reported So Far
- IceCube Alert 240424.08: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240422ed: Magellan Detection of a Potential Electromagnetic Counterpart
- LIGO/Virgo/KAGRA S240422ed: SAGUARO upper limits from CSS
- LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
- LIGO/Virgo/KAGRA S240422ed: LAST optical observations
- LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search
- LIGO/Virgo/KAGRA S240422ed: WINTER J-band upper limits on the Swift/XRT source S240422ed_X61
- LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from Pan-STARRS observations of the skymap
- LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search
- LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations
- LXT240402A/GRB240402B: Chandra X-ray detection
- LIGO/Virgo/KAGRA S240422ed: no candidate counterparts from ATLAS observations
- GRB 240419A: Possible ATCA radio detection
- GRB 240421B: ATCA radio observations
- LIGO/Virgo/KAGRA S240422ed: WINTER near-infrared J-band observations
- LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility observations and candidates
- LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam observations
- LIGO/Virgo/KAGRA S240422ed: Magellan Observations
- LIGO/Virgo/KAGRA S240422ed: Updated NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S240422ed: Upper limits from Fermi-GBM Observations
- LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S240422ed: MeerLICHT and BlackGEM observations report
- LIGO/Virgo/Kagra S240422ed: NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S240422ed: Global MASTER-Net observations report
- Fermi trigger No 735470374: Global MASTER-Net observations report
- GRB 240414A: radio detection with the VLA
- Fermi-LAT gamma-ray observations of IceCube-240419A
- GRB 240414A: AMI-LA radio observations
- GRB 240414A: LBT optical detection
- GRB 240415B: Swift-XRT observations
- Fermi GRB 240422A: Global MASTER-Net observations report
- GRB240421B: Zadko Observations
- Fermi GRB 240421B: Global MASTER-Net observations report
- Swift GRB 240421B: Global MASTER-Net observations report
- GRB 240421B: J-band upper limits from WINTER
- GRB 240421B: Swift/UVOT Upper Limits
- Fermi GRB 240421A: Global MASTER-Net observations report
- EP240420a: TNT upper limit to its optical counterpart
- EP240420a: Xinglong decaying optical counterpart
- EP240420a: Nanshan optical counterpart observations
- EP240420a: NOT optical counterpart candidate and potential host
- Fermi trigger No 735280430: Global MASTER-Net observations report
- GRB240418A - Candidate afterglow from NIRES
- IceCube Alert 240419.98: Global MASTER-Net observations report
- GRB 240419B: Swift/UVOT Upper Limits
- GRB 240419A: Swift/UVOT Upper Limits
- GRB 240419B: optical afterglow from the NOT
- EP240414a: Near-IR observations with NIRES and WINTER
- Swift GRB 240419B: Global MASTER-Net observations report
- Swift GRB 240419A: Global MASTER-Net observations report
- GRB 240418A: Swift/UVOT Upper Limits
- GRB 240419A: REM NIR afterglow detection
- GRB 240411B: Swift/UVOT Detection
- GRB 240419A: VLT/UVES redshift of z = 5.178
- GRB 240419A: VLT optical afterglow detection
- Fermi trigger No 735089036: Global MASTER-Net observations report
- EP240416a: J-band observations with WINTER
- GRB 240418A: TSHAO Zeiss-1000 optical upper limit
- GRB 240418A: NOT optical upper limits
- GRB 240411A: GOTO early optical upper limits
- Swift GRB240418.85: Global MASTER-Net observations report
- 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
- EP240414a: GSP detects optical candidate counterpart AT2024gsa
- LIGO/Virgo/KAGRA S240413p: DECam GW-MMADS candidates
- 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
- LIGO/Virgo/KAGRA S240413p: STEP - T80S Search and Candidate Counterpart Identification
- EP240416A: MASTER optical observations
- 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
- GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
- GRB 240415A: Earliest optical followup with the Kinder observations
- 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
- Fermi GRB 240415A: Global MASTER-Net observations report
- GRB 240415A: Mondy optical transient detection
- GRB 240414A: Photometric observation from 2.2m CAHA
- GRB 240414A: Swift/UVOT Detection
- LXT 240402A/GRB 240402B: Swift follow-up observations
- GRB 240414A: Mondy optical observations
- X-ray transient EP 240414a - GTC spectroscopic observations
- GRB 240415A: Prompt Swift-XRT observations
- EP 240414a: NOT optical counterpart confirmation
- GRB240414A : J-band upper limits from WINTER
- GRB 240414A : OHP/T193 second epoch of optical follow-up and afterglow detection
- GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT