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.
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"38289 results found.
- GRB 240529A: OSN optical detection
- GRB 240529A: further SAO RAS optical observations
- GRB 240602A: Fermi GBM Final Real-time Localization
- Swift Trigger 1232465 is not a GRB
- GRB 240529A: AKO Optical Afterglow Follow-Up Observations
- LXT 240528A: GSP optical upper limit
- GRB 240529A: 1.3m DFOT Optical observations
- GRB 240531A: AstroSat CZTI detection of a short burst
- GRB 240529A : Mondy optical observations
- Konus-Wind detection of GRB 240529A
- IPN triangulation of the initial episode of GRB 240529A
- GRB 240529A: SAO RAS optical observations
- GRB 240529A: MAAO 0.7m telescope optical afterglow detection
- GRB 240529A: Insight-HXMT/HE detection
- GRB 240529A: optical photometry from Konkoly
- GRB 240529A: GROWTH-India optical follow-up
- GRB 240529A: T193/MISTRAL observations
- GRB 240529A: Redshift from GTC/OSIRIS+
- GRB 240529A: AKO Optical Afterglow Detection
- LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
- GRB 240529A: J-band detections with WINTER
- GRB 240529A: Skynet Optical Observations
- GRB 240529A: Swift-BAT refined analysis
- GRB 240529A: Swift-XRT refined Analysis
- GRB240529A: BOOTES-6/DPRT optical detection
- GRB 240529A: Swift/UVOT Detection
- GRB 240529A: NOT optical observations
- GRB 240529A: AstroSat CZTI detection
- GRB 240529A: GOTO optical afterglow detection
- GRB 240527B: Swift-XRT afterglow detection
- GRB 240529A: Enhanced Swift-XRT position
- GRB 240529A: Swift detection of a burst with an optical counterpart
- Swift GRB240529.12: Global MASTER-Net observations report
- GRB 240527B: Fermi GBM Observation
- Fermi GRB 240527A: Global MASTER-Net observations report
- GRB 240527B: Fermi-LAT detection
- LAT GRB240527.59: Global MASTER-Net observations report
- Fermi GRB 240527B: Global MASTER-Net observations report
- GRB 240527B: Fermi GBM Final Localization
- GRB 240527B: BALROG localization (Fermi Trigger 738511436 / GRB 240527586)
- GRB 240527A: Fermi GBM Final Real-time Localization
- GRB 240523A: Swift-BAT refined analysis
- Fermi trigger No 738348224: Global MASTER-Net observations report
- Fermi trigger No 738330463: Global MASTER-Net observations report
- GRB 240523A: Swift-XRT refined Analysis
- GRB 240523A: Enhanced Swift-XRT position
- GRB 240523A: Swift detection of a burst
- GRB 240521B: Fermi GBM Observation
- Fermi GBM Sub-Threshold Detection of GRB 240516B
- GRB 240513A: Swift-XRT afterglow detection
- GRB 240521B: Swift/BAT-GUANO arcminute localization of a long burst
- Fermi trigger No 737996942: Global MASTER-Net observations report
- EP240518a: GSP optical upper limit
- GRB 240521A: GECAM-B detection of a long burst
- GRB 240516B: AstroSat CZTI detection
- LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
- GRB 240514B: VZLUSAT-2 detection
- GRB 240504A: VZLUSAT-2 detection
- GRB 240502A: VZLUSAT-2 detection
- GRB 240519A: GRBAlpha detection
- GRB 240516A: Swift/UVOT Upper Limits
- GRB 240519A: AstroSat CZTI detection
- Fermi trigger No 737788024: Global MASTER-Net observations report
- EP240518a: possibly identified with a flare star by EP-FXT
- GRB 240519A: BALROG localization (Fermi Trigger 737788024 / GRB 240519213)
- GRB 240516A: Swift-BAT refined analysis
- Fermi GRB 240517A: Global MASTER-Net observations report
- GRB 240516A ATCA radio observations
- IPN triangulation of GRB 240514B (short)
- GRB 240513A: Swift ToO observations
- GRB 240517A: Fermi GBM Final Real-time Localization
- Konus-Wind detection of GRB 240513A
- GRB 240516A: AstroSat CZTI detection
- GRB 240516A: Swift-XRT refined Analysis
- GRB 240514E: A possible candidate BD-21 1074
- Fermi trigger No 737559855: Global MASTER-Net observations report
- GRB 240516A: Fermi GBM Observation
- GRB 240511A: Observations from GTC/OSIRIS+
- GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
- GRB 240516A: GOTO optical upper limit
- LIGO/Virgo/KAGRA S240422ed: GRID non-detection and upper limits
- Fermi trigger No 737523389: Global MASTER-Net observations report
- GRB 240516A: Swift detection of a burst
- Swift GRB240516.15: Global MASTER-Net observations report
- GRB 240514B: AT2024ixa/GOTO24bph is not consistent with the Fermi localisation
- Fermi trigger No 737476171: Global MASTER-Net observations report
- GRB 240511A: radio detection of afterglow candidate
- GRB 240514B: GOTO candidate optical counterpart
- MAXI GRB240514.78: Global MASTER-Net observations report
- Fermi Gamma-ray Burst Monitor list of triggers that are not a GRB
- GRB 240514E: MAXI/GSC detection of a probable afterglow
- GRB 240514B: GRBAlpha detection
- GRB 240514B: Fermi GBM Detection
- GRB 240513A: Fermi GBM observation
- GRB 240513A: Swift-XRT observations
- GRB 240514D: AstroSat CZTI detection
- GRB 240514C: Fermi GBM Final Real-time Localization