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"
24598 results found.
- GRB 231216A: optical upper limits from the INAF Asiago Observatory
- GRB 231215A: AMI-LA radio detection
- GRB 231216A: Nanshan/HMT optical upper limit
- GRB 231216A: LCOGT Optical Upper Limits
- GRB 231216A: Osservatorio Astronomico Nastro Verde upper limit
- GRB 231216A: Swift-XRT refined analysis correction
- GRB 231215A: Osservatorio Astronomico Nastro Verde upper limit
- GRB 231216A: Swift-XRT refined Analysis
- GRB 231216A: REM NIR upper limits
- GRB 231216A: Swift/UVOT Upper Limits
- GRB 231216A: Swift-BAT refined analysis
- GRB 231215A: Swift-BAT refined analysis
- GRB 231214A: Swift-BAT refined analysis
- GRB 231216A: R-band observations from T120 at Observatoire de Haute-Provence
- GRB 231216A: GIT optical upper limit
- GRB 231216A: Swift detection of a burst
- Konus-Wind detection of GRB 231215A
- GRB 231214A: Swift/UVOT Upper Limits
- GRB 231205B: VZLUSAT-2 detection
- GRB 231204A: VZLUSAT-2 detection
- GRB 231215A: GAD Observatory, La Spezia, Italy upper limit;
- GRB 231215A: Fermi GBM observation
- GRB 231215A : OHP/T193 optical afterglow detection
- GRB 231215A: Swift/UVOT Detection
- LIGO/Virgo/KAGRA S231215i: 3 counterpart neutrino candidate events from an IceCube neutrino search
- GRB 231215A: Swift-XRT refined Analysis
- GRB 231215A: AKO Optical Upper Limit
- GRB 231214A: Fermi GBM observation
- GRB 231215A: Enhanced Swift-XRT position
- Fermi trigger No 724326442: Global MASTER-Net observations report
- GRB 231214A: REM optical/NIR upper limits
- GRB 231215A: GROWTH-India optical follow-up
- GRB 231215A : Nanshan/HMT optical observations
- GRB 231215A: AstroSat CZTI detection
- GRB 231215A : MITSuME Akeno optical afterglow candidate detection
- GRB 231214A: Swift-XRT refined Analysis
- GRB 231215A: Mondy optical bright afterglow detection
- GRB 231214A: AstroSat CZTI detection
- GRB 231215A: Swift-XRT observations
- GRB 231215A: Swift detection of a burst
- GRB 231214A: Enhanced Swift-XRT position
- GRB 231214B: Swift/BAT-GUANO detection of a burst
- GRB 231214A: Swift detection of a burst
- GRB 231210B: REM optical/NIR upper limits
- IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S231213ap: Updated Sky localization
- LIGO/Virgo/KAGRA S231213ap: Identification of a GW compact binary merger candidate
- Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
- LIGO/Virgo/KAGRA S231206cc: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231206ca: Upper limits from Swift/BAT-GUANO
- GRB 231212A: GECAM-C detection of a likely short burst
- GRB 231210B: MeerLICHT afterglow observations
- GRB 231210B: Swift-BAT refined analysis
- GRB 231210B: Swift-XRT refined Analysis
- GRB 231210B: Enhanced Swift-XRT position
- GRB 231210B: VLT/X-shooter redshift
- GRB 231210B: Swift detection of a burst with optical counterpart
- Swift GRB231210.90: Global MASTER-Net OT detection
- IPN triangulation of GRB 231129C
- GRB231205B: Swift/UVOT Upper Limits
- GRB 231208A: Glowbug gamma-ray detection
- LIGO/Virgo/KAGRA S231206ca: Updated Sky localization
- GRB 231205B: Swift-BAT refined analysis
- GRB 231205B: 1.3m DFOT Optical upper limit
- LIGO/Virgo/KAGRA S231206cc: Updated Sky localization and Source Classification
- GRB 231206A: joint location of multiple instruments by ETJASMIN
- GRB 231205B: optical upper limit in TSHAOand AbAO
- LIGO/Virgo/KAGRA S231206cc: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S231206ca: Identification of a GW compact binary merger candidate
- GRB231115A: TURBO Pre-Burst Optical Upper Limits
- GRB 231205B: Swift-XRT refined Analysis
- Fermi-LAT gamma-ray observations of IceCube-231202A
- GRB 231205B: REM optical/NIR upper limits
- GRB 231129C: ASIM MXGS observation and localization
- GRB 231205B: NUTTelA-TAO / BSTI Early Optical Limits
- GRB 231205B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
- GRB 231205B : MITSuME Akeno optical upper limits
- GRB 231206A: GECAM-B detection of a short burst
- GRB 231205B: Zadko observatory - Gingin optical observations
- GRB 231205B: Gaoyazi/GOT optical upper limit
- GRB 231205B: Nanshan/HMT optical upper limit
- GRB 231205B: LCOGT Optical Upper Limits
- GRB 231205A: DDOTI Upper Limits on the Afterglow
- LIGO/Virgo/KAGRA S231205c: One counterpart neutrino candidate event from an IceCube neutrino search
- GRB 231205B: Enhanced Swift-XRT position
- GRB 231204A: Glowbug gamma-ray detection
- Fermi-LAT daily aperture light curve of T CrB now available
- GRB 231205B: AKO Optical Upper Limit
- GRB 231205B: Swift detection of a burst
- GRB 231205A: joint location of multiple instruments by ETJASMIN
- GRB 231205A: GECAM-B detection of a short burst
- Fermi trigger No 723326169: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S231129ac: Upper limits from Swift/BAT-GUANO
- IceCube-231202A: Upper limits from a search for additional neutrino events in IceCube
- GRB 231203A: Fermi GBM Observation
- GRB 231203A: Swift/BAT-GUANO detection of a burst outside the coded FOV
- GRB 231129C: Swift-XRT afterglow detection
- GRB 231129C: PROMPT optical upper limits for the MAXI/GSC X-ray counterpart and the MASTER afterglow candidate
- GRB 231129A: VZLUSAT-2 detection
- GRB 231129B: Swift-XRT observations