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').
15493 results found.
- 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 231205B: AKO Optical Upper Limit
- GRB 231205B: Swift detection of a burst
- GRB 231204A: AstroSat CZTI detection
- LIGO/Virgo/KAGRA S231129ac: Upper limits from Swift/BAT-GUANO
- 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 231129A: JinShan optical upper limit
- GRB 231129C: Glowbug gamma-ray detection
- GRB 231129A: Swift/UVOT Upper Limits
- GRB 231129A: optical upper limit in Mondy observatory
- GRB 231129C: AstroSat CZTI detection
- GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
- GRB 231129C: Tiled Swift observations
- GRB 231129A: Enhanced Swift-XRT position
- GRB 231129B: Tiled Swift observations
- Fermi-LAT gamma-ray observations of IceCube-231125A
- GRB 231129A: Swift detection of a burst
- 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 231117A: Mondy optical observations
- GRB 231118A: REM optical afterglow detection
- GRB 231122B: Glowbug gamma-ray detection
- GRB 231117A: Continued GTC Observations
- GRB 231117A: Swift/UVOT late time observations
- GRB 231117A: GTC Near-Infrared Observations
- LIGO/Virgo/KAGRA S231118d: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231118an: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231114n: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S231113bb: Upper limits from Swift/BAT-GUANO
- GRB 231118A: VZLUSAT-2 detection
- GRB 231117A: AMI-LA radio observations
- 231118A: Swift-UVOT Detection
- GRB231117A: Swift-UVOT detection
- GRB 231117A : MITSuME Akeno optical afterglow candidate detection
- GRB 231118A: MeerLICHT afterglow detection
- GRB 231117A: OHP/T120 optical observations
- GRB 231118A: VLT/X-shooter redshift
- GRB 231117A: Pan-STARRS1 follow-up confirms rapid fading
- GRB 231117A: AKO Follow-Up Observation
- GRB 231118A: AstroSat CZTI detection
- GRB 231118A: Las Cumbres optical detection
- GRB 231118A: LCOGT Optical Observations
- GRB 231118A: Enhanced Swift-XRT position
- GRB 231117A: Kinder observations with Lulin observatory for AT 2023yba without fading in r band
- GRB 231118A: Skynet Optical Afterglow Discovery
- LIGO/Virgo/KAGRA S231118ab: Identification of a GW compact binary merger candidate
- GRB 231115A: Wendelstein Optical/Infrared Observations
- GRB 231115A: JinShan optical upper limits
- GRB 231117A: GIT optical follow-up
- GRB 231117A: LT observations consistent with fading
- GRB 231117A: REM optical and NIR early-time observations
- GRB 231117A: AKO Optical Upper Limit
- GRB 231117A: afterglow candidate detection from Kinder observations with Lulin observatory
- GRB 231117A (short): Glowbug gamma-ray detection
- GRB 231117A: ATLAS non-detection of an optical counterpart
- GRB 231115A : OHP/T120 optical upper limit
- GRB 231117A : MITSuME Akeno optical upper limits
- GRB 231117A: Enhanced Swift-XRT position
- GRB 231117A: Swift detection of a bright short burst
- GRB 231111A: Swift/UVOT Detection
- GRB 231115A: Swift-XRT and Swift-UVOT observations
- GRB 231115A : MITSuME Akeno and Okayama optical upper limits
- GRB 231115A: Gaoyazi/GOT follow-up and archival observations
- GRB 231115A / AT2023xvj: Updated GIT analysis
- GRB 231115A: Kinder observations with Lulin observatory
- GRB231115A: GRANDMA Observations
- GRB 231115A: GOTO pre-burst limits of AT2023xvj
- GRB 231115A: pre-burst ZTF upper limits for GRB optical counterpart candidate
- GRB 231115A (short): Glowbug gamma-ray detection
- GRB 231115A: archival HST observations
- GRB 231115A: GROWTH-India discovery of a potential optical counterpart
- GRB 231115A: Swift ToO observations
- GRB 231113A (short): Glowbug gamma-ray detection
- GRB 231114A (short): Glowbug gamma-ray detection
- LIGO/Virgo/KAGRA S231113bw: GROWTH-India coverage and upper limits
- GECAM-B observation of a short burst from SGR J1555-5402
- GRB 231106A: Glowbug gamma-ray detection
- GRB 231111A: Xinglong-2.16m optical observations
- GRB 231110A: Glowbug gamma-ray detection
- GRB 231111A: Leavitt Observatory optical observations
- GRB231111A: Optical follow-up observations with Mephisto
- GRB 231111A: GMG observation (correction)
- GRB 231111A: GMG observation upper limit
- GRB 231110A: Terskol Zeiss-2000 optical upper limit
- GRB 231111A: Mondy optical observations
- GRB 231111A: Enhanced Swift-XRT position