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"32494 results found.
- GRB 240821A: EP-FXT follow-up observation and afterglow candidates
- Fermi GRB 240821B: Global MASTER-Net observations report
- EP240801a: Keck/LRIS spectroscopic redshift confirmation
- GRB 240821A: SVOM/GRM observation
- GRB 240821A: SVOM/GRM observation
- GRB 240821A: GRANDMA/LesMakes-T60 Upper Limit
- Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
- GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
- GRB 240819A: Swift-XRT observations
- GRB 240819A: JinShan optical upper limits on one Swift/XRT source
- EP240820a: TRT optical upper limit
- GRB 240819A: KAIT optical upper limit
- EP240816a: PRIME upper limits
- GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
- GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
- GRB 240819A: Swift ToO observations
- GRB 240814A: SVOM/GRM observation
- EP240816b: Liverpool Telescope optical follow-up observations
- GRB 240814C: SVOM/GRM observation
- IceCube-240721A: AT2023qqp and AT2024pge likely unrelated
- GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
- GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
- EP240816b: KAIT optical upper limit
- GRB 240814B: GRBAlpha detection
- EP EP240816b: Global MASTER-Net observations report
- EP240816b: TRT optical upper limit
- Fermi GRB 240814A: Global MASTER-Net observations report
- Fermi GRB 240814C: Global MASTER-Net observations report
- Fermi GRB 240814B: Global MASTER-Net observations report
- GRB 240812B: SVOM/GRM observation
- EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
- LIGO/Virgo/KAGRA S240813d: Updated Sky localization
- Konus-Wind detection of GRB 240811A
- Konus-Wind detection of GRB 240810A
- 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
- GRB 240809A: ATA radio non-detection
- 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
- IceCube-240808A: Upper limits from a search for additional neutrino events in IceCube
- GRB 240811A: Bassano Bresciano Observatory upper limit
- GRB 240811A: Swift/UVOT Upper Limits
- EP240801a: Assy-Turgen optical observations
- Fermi GRB 240810A: Global MASTER-Net observations report
- GRB 240811A: LCOGT Optical Upper Limit
- GRB 240811A: Upper limits with Mephisto
- Konus-Wind detection of GRB 240809A
- Swift GRB 240811A: Global MASTER-Net observations report
- GRB240809A: Liverpool Telescope optical follow-up observations
- 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 240809A: Swift/UVOT Detection
- GRB 240809A: Tentative redshift from NOT
- 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: Skynet & Photon Ranch Optical Afterglow Observations
- GRB 240809A: SVOM/GRM observation
- GRB 240807A: SVOM/GRM observation
- 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
- EP EP240807a: Global MASTER-Net observations report
- EP EP240806a: Global MASTER-Net observations report
- GRB 240801A: GRBAlpha detection
- GRB 240710B: VZLUSAT-2 detection
- GRB 240805A: ATCA Radio Upper Limits
- EP240807a/GRB 240807A: EP-FXT detection of the X-ray emission
- S240807h: Identification of a GW compact binary merger candidate
- EP240802a/GRB240802A: KAIT optical upper limit
- GRB 240720B: VZLUSAT-2 detection
- GRB 240710A: VZLUSAT-2 detection
- EP240806A: Liverpool Telescope optical follow-up observations
- 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
- 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
- GRB 240805B Bassano Bresciano Observatory upper limit