GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. 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').
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"- GRB 240814A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S240813d: Updated Sky localization
- Fermi trigger No 745220784: Global MASTER-Net observations report
- Konus-Wind detection of GRB 240811A
- Konus-Wind detection of GRB 240810A
- Fermi Gamma-ray Burst Monitor trigger 745220784/240813240 is not a GRB
- 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
- GRB 240809A: Correction to the VLA source position in GCN 37158
- GRB 240810A: SVOM/GRM observation
- Fermi Gamma-ray Burst Monitor trigger 240812940/745194848 is not a GRB
- Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
- Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
- GRB 240809A: ATA radio non-detection
- GRB 240812D: Fermi GBM Final Real-time Localization
- GRB 240812C: Fermi GBM Final Real-time Localization
- GRB 240809A : RAPAS follow-up observations
- GRB 240809A: VLA detection
- GRB 240809A: ALMA detection
- IPN triangulation of GRB 240810A (short)
- GRB 240811A: Swift-BAT refined analysis
- GRB 240809A: Swift-BAT refined analysis
- EP240807a: PRIME H-band upper limits
- GRB 240812B: AstroSat CZTI detection of a long burst
- IceCube-240808A: Upper limits from a search for additional neutrino events in IceCube
- GRB 240811A: Bassano Bresciano Observatory upper limit
- GRB 240811A: Swift-XRT refined Analysis
- Fermi Gamma-ray Burst Monitor trigger 745135620/240812255 is not a GRB
- GRB 240811A: Swift/UVOT Upper Limits
- EP240801a: Assy-Turgen optical observations
- Fermi GRB 240810A: Global MASTER-Net observations report
- Fermi Gamma-ray Burst Monitor trigger 240812094/745121685 is not a GRB
- GRB 240812A: Fermi GBM Final Real-time Localization
- GRB 240811A: LCOGT Optical Upper Limit
- GRB 240811A: Enhanced Swift-XRT position
- GRB 240811A: Upper limits with Mephisto
- Konus-Wind detection of GRB 240809A
- Fermi trigger No 745057312: Global MASTER-Net observations report
- Swift GRB 240811A: Global MASTER-Net observations report
- GRB 240811A: Swift detection of a burst
- Fermi Gamma-ray Burst Monitor trigger 745050426/240811269 is not a GRB
- GRB240809A: Liverpool Telescope optical follow-up observations
- GRB 240810A: Fermi GBM Final Real-time Localization
- GRB 240809A: REM detection of the optical afterglow
- GRB 240809A: Bassano Bresciano Observatory optical observations
- Konus-Wind detection of GRB 240807A (a counterpart of EP240807a)
- GRB 240809A: Conclusive redshift from VLT
- Fermi-LAT gamma-ray observations of IceCube-240808A
- GRB 240809A: KAIT optical observations
- GRB 240808A: AstroSat CZTI detection
- GRB 240809A: GIT afterglow observations
- GRB 240809B: MAXI/GSC detection
- GRB 240809A: Swift/UVOT Detection
- GRB 240809A: Tentative redshift from NOT
- GRB 240809A: Swift-XRT refined Analysis
- IPN triangulation of GRB 240807A / EP 240807a
- LIGO/Virgo/KAGRA S240807h: Updated Sky localization and EM Bright Classification
- X-ray Transient EP240807a: PRIME near-infrared upper limits
- Swift GRB 240809A: Global MASTER-Net observations report
- GRB 240809A: JinShan optical observations
- GRB 240809A: Enhanced Swift-XRT position
- GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
- GRB 240809A: SVOM/GRM observation
- GRB 240808A: SVOM/GRM observation
- GRB 240807A: SVOM/GRM observation
- GRB 240809A: Swift detection of a burst with a bright optical counterpart
- EP-WXT trigger 01709018832: SVOM/C-GFT observations of the star flare
- EP240807a: STEP/T80S optical limits
- GRB 240807B: AstroSat CZTI detection of a short burst
- IceCube Alert 240808.27: Global MASTER-Net observations report
- EP EP240807a: Global MASTER-Net observations report
- EP EP240806a: Global MASTER-Net observations report
- IceCube-240808A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 240801A: GRBAlpha detection
- GRB 240807B: Fermi GBM Final Localization
- GRB 240710B: VZLUSAT-2 detection
- GRB 240805A: ATCA Radio Upper Limits
- Fermi trigger No 744761058: Global MASTER-Net observations report
- EP240807a/GRB 240807A: EP-FXT detection of the X-ray emission
- S240807h: Identification of a GW compact binary merger candidate
- EP-WXT trigger 01709018832: KAIT optical observations of the star flare
- EP240802a/GRB240802A: KAIT optical upper limit
- GRB 240720B: VZLUSAT-2 detection
- GRB 240710A: VZLUSAT-2 detection
- EP240806A: Liverpool Telescope optical follow-up observations
- The EP-WXT trigger 01709018832 on August 7th is likely a flaring star
- GRB 240807A: Fermi GBM Final Localization
- EP240807a: EP-WXT detection of a fast X-ray transient
- EP240806a: Gemini North-GMOS spectroscopic redshift of z = 2.818
- GRB 240805B: GIT optical upper limit
- EP240806a: KAIT optical observations
- GRB 240805B: Swift-BAT refined analysis
- GRB 240805A: Swift-BAT refined analysis
- Fermi trigger No 744629911: Global MASTER-Net observations report
- EP240804a (GRB 240804B): NOT optical observations
- EP240806a: LCOGT optical counterpart detection
- Konus-Wind detection of GRB 240802A (EP240802a)
- Improved IPN triangulation of GRB 240802A / EP 240802a
- Konus-Wind detection of GRB 240805A