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').
16007 results found.
- GRID detection of GRB 231205A
- GRB 231216A: GAD Observatory, La Spezia, Italy upper limit
- 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 231215A: Osservatorio Astronomico Nastro Verde upper limit
- GRB 231216A: REM NIR upper limits
- GRB 231216A: Swift/UVOT Upper Limits
- 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 231215A: GAD Observatory, La Spezia, Italy upper limit;
- GRB 231215A : OHP/T193 optical afterglow detection
- GRB 231215A: Swift/UVOT Detection
- GRB 231215A: BOOTES-4/MET optical detection
- GRB 231215A: AKO Optical Upper Limit
- GRB 231215A: Enhanced Swift-XRT position
- GRB 231214A: REM optical/NIR upper limits
- GRB 231215A: GROWTH-India optical follow-up
- GRB 231215A : Nanshan/HMT optical observations
- GRB 231215A : MITSuME Akeno optical afterglow candidate detection
- GRB 231215A: Mondy optical bright afterglow detection
- GRB 231215A: Swift-XRT observations
- GRB 231214A: Enhanced Swift-XRT position
- 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: Identification of a GW compact binary merger candidate
- GRB 231212A: GECAM-C detection of a likely short burst
- GRB 231210B: MeerLICHT afterglow observations
- GRB 231210B: Enhanced Swift-XRT position
- GRB 231210B: VLT/X-shooter redshift
- GRB 231210B: Swift detection of a burst with optical counterpart
- IPN triangulation of GRB 231129C
- GRB231205B: Swift/UVOT Upper Limits
- GRB 231208A: Glowbug gamma-ray detection
- GRB 231205B: 1.3m DFOT Optical upper limit
- 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: 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 231205B: Zadko observatory - Gingin optical observations
- GRB 231205B: Gaoyazi/GOT optical upper limit
- GRB 231205B: Nanshan/HMT optical upper limit
- GRB 231205B: GECAM-B detection of a long burst
- GRB 231205B: LCOGT Optical Upper Limits
- GRB 231205A: DDOTI Upper Limits on the Afterglow
- GRB 231205B: Enhanced Swift-XRT position
- GRB 231204A: Glowbug gamma-ray detection
- GRB 231204A: CALET Gamma-Ray Burst Monitor detection
- GRB 231205B: AKO Optical Upper Limit
- GRB 231205B: Swift detection of a burst
- IceCube-231202A: Upper limits from a search for additional neutrino events in IceCube
- GRB 231204A: Fermi GBM Final Real-time Localization
- 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 231129B: Swift-XRT observations
- Optical transient in the field of Messier 31, likely a new blazar: back to bright state
- GRB 231129A : MITSuME Akeno optical upper limits
- GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
- GRB 231129C: MASTER OT detection
- GRB 231129C: Fermi-LAT detection
- GRB 231129A: JinShan optical upper limit
- GRB 231129C: Glowbug gamma-ray detection
- GRB 231129C: Swift-XRT observations
- GRB 231129A: Swift/UVOT Upper Limits
- GRB 231129A: optical upper limit in Mondy observatory
- GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
- GRB 231129A: Enhanced Swift-XRT position
- LIGO/Virgo/KAGRA S231129ac: Identification of a GW compact binary merger candidate
- GRB 231129A: GECAM-C detection of a long burst
- GRB 231129A: Swift detection of a burst
- IceCube-231125A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S231127cg: Identification of a GW compact binary merger candidate
- GRB 231117A: MeerKAT 1.3GHz detection
- GRB 231125A (short): Glowbug gamma-ray detection
- GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
- GRB 231123C (short): Glowbug gamma-ray detection
- GRB 231124A: Glowbug gamma-ray detection
- GRB230728A: VIRT optical upper limit
- GRB230506C: VIRT optical upper limit
- GRB230506B: VIRT optical upper limit
- GRB 231123A: AstroSat CZTI detection
- GRB 231117A: Mondy optical observations
- LIGO/Virgo/KAGRA S231123cg: Identification of a GW compact binary merger candidate
- GRB 231118A: REM optical afterglow detection
- GRB 231122B: Glowbug gamma-ray detection
- GRB 231117A: Continued GTC Observations
- GRB 231122A: GECAM detection
- GRB 231117A: Swift/UVOT late time observations
- GRB 231117A: GTC Near-Infrared Observations