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"27776 results found.
- GRB 240519A: AstroSat CZTI detection
- EP240518a: possibly identified with a flare star by EP-FXT
- EP240518a: EP-WXT detection of a new X-ray transient
- GRB 240516A: Swift-BAT refined analysis
- 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
- GRB 240516A: Fermi GBM Observation
- GRB 240511A: Observations from GTC/OSIRIS+
- GRB 240516A: GOTO optical upper limit
- LIGO/Virgo/KAGRA S240422ed: GRID non-detection and upper limits
- GRB 240516A: Swift detection of a burst
- Swift GRB240516.15: Global MASTER-Net observations report
- GRB 240511A: radio detection of afterglow candidate
- GRB 240514E: MAXI/GSC detection of a probable afterglow
- GRB 240514B: GRBAlpha detection
- GRB 240514B: Fermi GBM Detection
- GRB 240513A: Swift-XRT observations
- GRB 240514D: AstroSat CZTI detection
- GRB 240514C: Fermi GBM Final Real-time Localization
- transient: Xinglong Nearby Galaxy Supernova Survey detection of AT2024iss
- GRB 240514B: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
- GRB 240514A: Fermi GBM Final Real-time Localization
- GRB 240513A: Tiled Swift observations
- GRB 240513A: Fermi-LAT detection
- GRB 240511A: Fermi GBM Observation
- GRB 240511A: Swift-BAT refined analysis
- GRB 240513B: Fermi GBM Final Real-time Localization
- GRB 240513A: AstroSat CZTI detection
- GRB 240511A: J-band observations with WINTER
- GRB 240511A: Enhanced Swift-XRT position
- GRB 240511A : MITSuME Akeno optical upper limits
- GRB 240511A: Swift-XRT refined Analysis
- GRB 240511A: optical afterglow detection from the NOT
- Swift GRB 240511A: Global MASTER-Net observations report
- GRB 240511A: Prompt enhanced Swift-XRT position
- GRB 240511A: Swift detection of a burst
- GRB 240511A: Fermi GBM Final Real-time Localization
- EP240506a: Xinglong optical upper limit
- GRB 240504A: Fermi GBM Observation
- EP240506a: Archival radio searching
- EP240506a: BOOTES Network optical upper limit
- IPN triangulation of GRB 240504A
- EP240506a: EP-WXT detection of a new fast X-ray transient
- GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
- IPN triangulation of GRB 240501B and GRB 240501A - possible episodes of ultra long GRB
- GRB 240503A: AstroSat CZTI detection
- GRB 240504A: Fermi GBM Final Real-time Localization
- GRB 240415A 1.3m DFOT Optical upper limit
- GRB 240502C: Fermi GBM Final Localization
- GRB 240501B: GRBAlpha detection
- GRB 240430A: GRBAlpha detection
- GRB 240502B: Fermi GBM Final Real-time Localization
- GRB 240502A: Fermi GBM Final Real-time Localization
- GRB 240426A: VZLUSAT-2 detection
- GRB 240425A: VZLUSAT-2 detection
- GRB240430A: Fermi GBM Final Localization
- GRB 240501B: AstroSat CZTI detection
- GRB 240501A: Fermi GBM Final Real-time Localization
- GRB 240408B: VZLUSAT-2 detection
- GRB 240407A: VZLUSAT-2 detection
- X-ray transient EP240414a: Detection of associated supernova
- LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations
- GRB 240425A: GRBAlpha detection
- LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limit for EP240426a
- GRB 240429A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet ToO observations
- LIGO/Virgo/KAGRA S240429an: Retraction of GW compact binary merger candidate
- GRB 240428A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S240422ed: J-band non-detection of J-GEM24a
- LIGO/Virgo/KAGRA S240422ed: DDOTI Optical Upper Limit for J-GEM24a
- EP240426b: AST3-2 optical upper limit
- LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
- EP240426b: EP-WXT detection of a new fast X-ray transient
- LIGO/Virgo/KAGRA S240422ed: Archival radio detection of EP240426a
- LIGO/Virgo/KAGRA S240422ed: BOOTES-6/DPRT optical upper limits for EP240426a
- LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a
- GRB 240426A: AstroSat CZTI detection
- EP240426a: YAHPT optical upper limit
- LIGO/Virgo/KAGRA S240422ed: EP-FXT Detection of the Potential Opitcal Electromagnetic Counterpart AT 2024hfq Reported by DECam
- GRB 240414A: NOEMA detection
- LIGO/Virgo/KAGRA S240422ed: EP240426a possible optical detection
- EP240426a: GMG optical upper limit
- LVK S240422ed: Further Swift-XRT followup of three sources
- LIGO/Virgo/KAGRA S240422ed: EP-FXT detection of a candidate counterpart EP240426a
- LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
- LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis
- LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search update and AT2024hfx, AT2024hgl observations
- S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4
- LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
- S240422ed: MeerLICHT/BlackGEM photometry on AT2024hfx and archival ZTF detection
- LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam