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"4055 results found.
- LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240902bq: Updated Sky localization
- LIGO/Virgo/KAGRA S240902bq: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S240830gn: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S240830gn: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
- LIGO/Virgo/KAGRA S240825ar: Updated Sky localization
- LIGO/Virgo/KAGRA S240825ar: Identification of a GW compact binary merger candidate
- GRB 240824B: Swift/BAT arcminute localization of a burst
- GRB240821A: EIRSAT-1 GMOD Detection
- GRB240821B: First GRB Detected by EIRSAT-1 GMOD
- LIGO/Virgo/KAGRA S240813d: Updated Sky localization
- LIGO/Virgo/KAGRA S240813d: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240813c: Updated Sky localization
- LIGO/Virgo/KAGRA S240813c: Identification of a GW compact binary merger candidate
- IceCube-240808A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S240807h: Updated Sky localization and EM Bright Classification
- EP240807a: STEP/T80S optical limits
- S240807h: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
- GRB 240727B: Swift/BAT-GUANO arcminute localization of a long burst
- IceCube-240725A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-240721A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240716b: Updated Sky localization
- LIGO/Virgo/KAGRA S240716b: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S240627by: Updated Sky localization and EM Bright Classification
- LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
- LIGO/Virgo/KAGRA S240705at: Updated Sky localization
- LIGO/Virgo/KAGRA S240705at: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240703ad: Updated Sky localization
- LIGO/Virgo/KAGRA S240703ad: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240422ed: Updated significance estimate
- LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240630t: Updated Sky localization
- LIGO/Virgo/KAGRA S240629by: Updated Sky localization
- LIGO/Virgo/KAGRA S240630t: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
- LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S240629by: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240627by: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240624cd: Retraction of GW unmodeled transient candidate
- LIGO/Virgo/KAGRA S240623dg: Retraction of GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240622h: Updated Sky localization and Source Classification
- LIGO/Virgo/KAGRA S240621em: Updated Sky localization and Source Classification
- LIGO/Virgo/KAGRA S240621dy: Updated Sky localization and Source Classification
- LIGO/Virgo/KAGRA S240621eb: Updated Sky localization and Source Classification
- LIGO/Virgo/KAGRA S240622h: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240621em: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240621eb: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240621dy: Identification of a GW compact binary merger candidate
- EP240617a: STEP/T80S optical limits
- LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
- LIGO/Virgo/KAGRA S240615dg: Updated Sky localization
- LIGO/Virgo/KAGRA S240618ah: Updated Sky localization
- LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
- LIGO/Virgo/KAGRA S240618ah: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240615ea: Updated Sky localization
- GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
- LIGO/Virgo/KAGRA S240615ea: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240615dg: Identification of a GW compact binary merger candidate
- GRB 240606B: Swift/BAT-GUANO arcminute localization of a burst
- LIGO/Virgo/KAGRA S240601co: Updated Sky localization
- LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240601aj: Updated Sky localization
- LIGO/Virgo/KAGRA S240601co: Identification of a GW compact binary merger candidate
- GRB 240529A: AKO Optical Afterglow Follow-Up Observations
- LIGO/Virgo/KAGRA S240530a: Updated Sky localization
- LIGO/Virgo/KAGRA S240527en: Updated Sky localization
- LIGO/Virgo/KAGRA S240601aj: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240531bp: Updated Sky localization
- LIGO/Virgo/KAGRA S240531bp: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240530a: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
- LIGO/Virgo/KAGRA S240527fv: Updated Sky localization
- LIGO/Virgo/KAGRA S240527fv: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240527en: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240525p: Updated Sky localization
- LIGO/Virgo/KAGRA S240525p: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240520cv: Updated Sky localization and EM Bright Classification
- 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
- LIGO/Virgo/KAGRA S240520cv: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240514c: Updated Sky localization
- LIGO/Virgo/KAGRA S240422ed: GRID non-detection and upper limits
- Fermi Gamma-ray Burst Monitor list of triggers that are not a GRB
- LIGO/Virgo/KAGRA S240514x: Updated Sky localization
- LIGO/Virgo/KAGRA S240515m: Identification of a GW compact binary merger candidate