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"
3821 results found.
- LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
- GRB240529A: BOOTES-6/DPRT optical detection
- GRB 240529A: NOT optical observations
- GRB 240529A: AstroSat CZTI detection
- Swift GRB240529.12: Global MASTER-Net observations report
- Fermi GRB 240527A: Global MASTER-Net observations report
- LAT GRB240527.59: Global MASTER-Net observations report
- Fermi trigger No 738348224: Global MASTER-Net observations report
- Fermi trigger No 738330463: Global MASTER-Net observations report
- Fermi trigger No 737996942: Global MASTER-Net observations report
- GRB 240516B: AstroSat CZTI detection
- GRB 240516A: Swift-BAT refined analysis
- GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
- GRB 240516A: GOTO optical upper limit
- GRB 240516A: Swift detection of a burst
- Fermi GRB 240514B: Global MASTER-Net observations report
- LAT GRB240513.31: Global MASTER-Net observations report
- Fermi GRB 240513B: Global MASTER-Net observations report
- Fermi trigger No 737277727: Global MASTER-Net observations report
- Fermi trigger No 737247400: Global MASTER-Net observations report
- Fermi trigger No 737168073: Global MASTER-Net observations report
- Fermi trigger No 737173236: Global MASTER-Net observations report
- Fermi trigger No 737105243: Global MASTER-Net observations report
- Fermi trigger No 737152719: Global MASTER-Net observations report
- Fermi trigger No 737111207: Global MASTER-Net observations report
- EP240506a: CrAO ZTSH optical upper limit
- EP240506a: Optical upper limit with Kinder observations
- IPN triangulation of GRB 240504A
- GRB 240502A: 1.3m DFOT Optical upper limit
- GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
- GRB 240415A 1.3m DFOT Optical upper limit
- Fermi GRB 240502B: Global MASTER-Net observations report
- Fermi GRB 240502A: Global MASTER-Net observations report
- Fermi trigger No 736197684: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240501an: Identification of a GW compact binary merger candidate
- GRB 240429A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S240428dr: Identification of a GW compact binary merger candidate
- LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
- LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
- LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
- LIGO/Virgo/KAGRA S240422ed: EP-FXT detection of a candidate counterpart EP240426a
- S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4
- LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
- LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
- LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
- LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
- LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam upper limits on the Swift/XRT source S240422ed_X61
- LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
- Fermi trigger No 735470374: Global MASTER-Net observations report
- Fermi GRB 240421B: Global MASTER-Net observations report
- GRB 240421B: Fermi GBM Observation
- LIGO/Virgo/KAGRA S240421ar: Identification of a GW unmodeled transient candidate
- Fermi trigger No 735280430: Global MASTER-Net observations report
- GRB 240411A: GOTO early optical upper limits
- Fermi GRB 240417A: Global MASTER-Net observations report
- Fermi GRB 240415A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240413p: No Counterparts in DDOTI/OAN Optical Observations
- IPN triangulation of GRB 240410A
- IPN triangulation of GRB 240411A
- LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
- Fermi GRB 240407A: Global MASTER-Net observations report
- GRB 240402C: Glowbug gamma-ray detection
- GRB 240402C: GRBAlpha detection
- Fermi GRB 240402A: Global MASTER-Net observations report
- GRB 240329A: Glowbug gamma-ray detection
- GRB 240329A: AstroSat CZTI detection
- GRB 240329A: GRBAlpha detection
- Fermi trigger No 733366352: Global MASTER-Net observations report
- Fermi GRB 240329A: Global MASTER-Net observations report
- GRB 240329A: BALROG localization (Fermi Trigger 733441392 / GRB 240329905)
- GRB 240329A: Fermi GBM Final Real-time Localization
- Fermi GRB 240328B: Global MASTER-Net observations report
- Fermi GRB 240328A: Global MASTER-Net observations report
- GRB 240320A: Glowbug gamma-ray detection
- Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
- Fermi trigger No 732657380: Global MASTER-Net observations report
- GRB 240320A: Fermi GBM Final Real-time Localization
- Fermi GRB 240318A: Global MASTER-Net observations report
- Fermi GRB 240317B: Global MASTER-Net observations report
- X-ray transient EP240315a: VLT/X-shooter spectroscopic redshift of z = 4.859
- Fermi trigger No 732299243: Global MASTER-Net observations report
- GRB 240315A: Fermi GBM Final Real-time Localization
- Fermi trigger No 731839490: Global MASTER-Net observations report
- Fermi GRB 240310A: Global MASTER-Net observations report
- GRB 240309A: MAXI/GSC detection
- GRID detection of GRB 240229A (Updated Report)
- GRID detection of GRB 240229A
- GRB 240229A: Glowbug gamma-ray detection
- GRB 240229A: GRBAlpha detection
- Fermi-LAT gamma-ray observations of IceCube-240229A
- GRB 240305C: AstroSat CZTI detection of a short burst
- GRB 240229A: VZLUSAT-2 detection
- Fermi trigger No 731161136: Global MASTER-Net observations report
- IceCube-240229A: Upper limits from a search for additional neutrino events in IceCube
- GRB 240229A: CALET Gamma-Ray Burst Monitor detection
- IceCube-240229A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 240225B: further SAO RAS optical observations
- Fermi GRB 240229A: Global MASTER-Net observations report
- IceCube Alert 240229.66: Global MASTER-Net observations report
- GRB 240229A: BALROG localization (Fermi Trigger 730908432 / GRB 240229588)