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"7445 results found.
- LIGO/Virgo/KAGRA S230814r: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230812aj: two counterpart neutrino candidates from IceCube neutrino searches
- GRB 230812B: Detected Optical Afterglow Candidate
- GRB 230812: Swift/UVOT Detection
- GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
- GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
- GRB 230812B: KAIT Optical Afterglow Candidate
- GRB 230812B: Tiled Swift observations
- ZTF23aaoohpy/AT2023lcr: JWST spectroscopy confirmation of an associated type Ic-BL supernova
- LIGO/Virgo/KAGRA S230811n: Updated Sky localization
- LIGO/Virgo/KAGRA S230811n: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230810af: Retraction of GW compact binary merger candidate
- GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
- LIGO/Virgo/KAGRA S230808i: retraction of a GW unmodeled transient candidate
- LIGO/Virgo/KAGRA S230808i: Identification of a GW unmodeled transient candidate
- LIGO/Virgo/KAGRA S230807f: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S230807f: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230805x: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S230806ak: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S230806ak: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230805x: Updated Sky localization
- GRB 230805B: Swift detection of a burst
- LIGO/Virgo/KAGRA S230805x: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230802aq: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S230802aq: AstroSat CZTI non-detection and upper limits
- LIGO/Virgo/KAGRA S230802aq: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S230802aq: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S230802aq: Identification of a GW compact binary merger candidate
- GRB 230802A: Swift detection of a burst
- LIGO/Virgo/KAGRA S230731an: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S230731an: AstroSat CZTI non-detection and upper limits
- LIGO/Virgo/KAGRA S230731an: Updated Sky Localization and EM Bright Classification, and Correction to Source Classification
- LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S230731an: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230729z: Updated Sky localization
- GRB 230723A: Detection of candidate millimeter-band radiation by SPT-3G
- GRB 230723B: MITSuME Ishigaki optical observation
- IceCube-230727A: No candidates from the Zwicky Transient Facility
- LIGO/Virgo/KAGRA S230729z: Identification of a GW compact binary merger candidate
- IceCube-230724A: No counterparts from the Zwicky Transient Facility
- GRB 230728A: Swift detection of a burst
- IceCube-230727A - IceCube observation of a high-energy neutrino candidate track-like event
- LIGO/Virgo/KAGRA S230726a: Updated Sky localization
- GRB 230723B: MITSuME Akeno optical afterglow candidate detection
- LIGO/Virgo/KAGRA S230726b: one counterpart neutrino candidate from IceCube neutrino searches
- IceCube-230724A - IceCube observation of a high-energy neutrino candidate track-like event
- LIGO/Virgo/KAGRA S230726a: Identification of a GW compact binary merger candidate
- IceCube-230725A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 230723B: GAD Observatory, La Spezia, Italy upper limit
- GRB 230723B: Optical afterglow candidate from CAHA
- LIGO/Virgo/KAGRA S230723ac: Updated Sky localization
- LIGO/Virgo/KAGRA S230723ac: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230708z: Updated Sky localization
- LIGO/Virgo/KAGRA S230715bw: Retraction of GW compact binary merger candidate
- IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
- LIGO/Virgo/KAGRA S230709bi: Updated Sky localization
- LIGO/Virgo/KAGRA S230708t: Updated Sky localization
- IceCube-230708A: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S230712a: Retraction of GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230708z: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230708t: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230708cf: Updated Sky localization
- LIGO/Virgo/KAGRA S230707ai: Updated Sky localization
- IceCube-230707A: No candidates from the Zwicky Transient Facility
- LIGO/Virgo/KAGRA S230630am: Updated Sky localization
- LIGO/Virgo/KAGRA S230630am: Updated Sky localization
- LIGO/Virgo/KAGRA S230709bi: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230708cf: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230708bi: Retraction of GW compact binary merger candidate
- IceCube-230708A - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-230707B - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-230707A - IceCube observation of a high-energy neutrino candidate track-like event
- LIGO/Virgo/KAGRA S230707ai: Identification of a GW compact binary merger candidate
- GRB 230707A: Swift ToO observations
- LIGO/Virgo/KAGRA S230706ah: Updated Sky localization
- LIGO/Virgo/KAGRA S230704f: Updated Sky localization
- LIGO/Virgo/KAGRA S230630bq: Updated Sky localization
- LIGO/Virgo/KAGRA S230702an: Updated Sky localization
- LIGO/Virgo/KAGRA S230529ay: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S230706ah: Identification of a GW compact binary merger candidate
- LVK S230619bd/GBM-230619: Upper limits from a two-week IceCube neutrino search
- LIGO/Virgo/KAGRA S230704f: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230702an: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA low-significance gravitational wave candidate S230701z: one counterpart neutrino candidate from IceCube neutrino searches
- LIGO/Virgo/KAGRA S230627c: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S230630bq: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230630am: Identification of a GW compact binary merger candidate
- GRB 230628E - VLT spectroscopic observations
- GRB230628E: VLT optical identification of afterglow candidate
- LIGO/Virgo/KAGRA S230628ax: Identification of a GW compact binary merger candidate
- GRB 230628E: Swift detection of a burst
- LIGO/Virgo/KAGRA low-significance gravitational wave candidate S230628aj: one counterpart neutrino candidate from IceCube neutrino searches
- LIGO/Virgo/KAGRA S230516az: GOTO candidate counterpart GOTO23hu ruled out by Zwicky Transient Facility observations
- LIGO/Virgo/KAGRA S230527c: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo/KAGRA S230627c: ATLAS information on the ZTF candidates
- LIGO/Virgo/KAGRA S230627c: Upper limits from Fermi-GBM Observations
- LIGO/Virgo/Kagra S230627c: NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S230627c: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S230627c: Updated Sky localization and EM Bright Classification