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"22059 results found.
- GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
- GRB 240819A: Swift ToO observations
- EP240816b: Liverpool Telescope optical follow-up observations
- Integral GRB240816.79: Global MASTER-Net observations report
- 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
- Fermi trigger No 745501396: Global MASTER-Net observations report
- EP240816a: EP detection of a fast X-ray transient and follow-up observation
- EP EP240816b: Global MASTER-Net observations report
- EP240816b: TRT optical upper limit
- EP240816b: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
- Fermi GRB 240814A: Global MASTER-Net observations report
- Fermi GRB 240814C: Global MASTER-Net observations report
- Fermi trigger No 745306088: Global MASTER-Net observations report
- Fermi GRB 240814B: Global MASTER-Net observations report
- EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
- Fermi trigger No 745220784: Global MASTER-Net observations report
- Konus-Wind detection of GRB 240810A
- GRB 240809A: ATA radio non-detection
- GRB 240809A : RAPAS follow-up observations
- GRB 240809A: VLA detection
- GRB 240809A: ALMA detection
- EP240807a: PRIME H-band upper limits
- 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: 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
- GRB240809A: Liverpool Telescope optical follow-up observations
- GRB 240809A: REM detection of the optical afterglow
- GRB 240809A: Bassano Bresciano Observatory optical observations
- Fermi-LAT gamma-ray observations of IceCube-240808A
- GRB 240809A: KAIT optical observations
- GRB 240809A: GIT afterglow observations
- GRB 240809A: Swift/UVOT Detection
- GRB 240809A: Tentative redshift from NOT
- 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
- EP-WXT trigger 01709018832: SVOM/C-GFT observations of the star flare
- EP240807a: STEP/T80S optical limits
- IceCube Alert 240808.27: Global MASTER-Net observations report
- EP EP240807a: Global MASTER-Net observations report
- EP EP240806a: Global MASTER-Net observations report
- GRB 240805A: ATCA Radio Upper Limits
- Fermi trigger No 744761058: Global MASTER-Net observations report
- EP-WXT trigger 01709018832: KAIT optical observations of the star flare
- EP240806A: Liverpool Telescope optical follow-up observations
- 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
- 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)
- Konus-Wind detection of GRB 240805A
- GRB 240805B Bassano Bresciano Observatory upper limit
- GRB 240805B: JinShan optical afterglow detection
- GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
- EP 240806A: LCO optical observations
- EP240806a: GSP optical counterpart detection
- EP240806a: EP-WXT detection of a fast X-ray transient
- GRB 240805B: Optical detection with 1.6m Mephisto
- GRB 240805B: NUTTelA-TAO / BSTI Optical Limits
- Fermi trigger No 744544656: Global MASTER-Net observations report
- GRB 240805B: Swift/UVOT Upper Limits
- GRB 240805A: Swift/UVOT Upper Limits
- GRB 240805B: BTA optical afterglow candidate
- Swift GRB 240805B: Global MASTER-Net observations report
- GRB 240805B: JinShan optical upper limits
- Fermi GRB 240805A: Global MASTER-Net observations report
- Swift GRB 240805A: Global MASTER-Net observations report
- EP240804a: GSP detects optical candidate counterpart
- EP240801a: Continued optical observations at ZTSh (CraO)
- EP240804a: VLT/X-shooter spectroscopic redshift
- EP240804a: LCOGT optical counterpart detection
- EP240804a: NOT optical counterpart detection
- EP240804a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
- GRB 240805A: Swift detection of a burst
- Fermi GRB 240804A: Global MASTER-Net observations report
- EP240802a: Montarrenti Observatory optical upper limit
- Fermi trigger No 744459130: Global MASTER-Net observations report
- EP240801a: Osservatorio Astronomico Nastro Verde upper limit
- EP240802A: Bassano Bresciano Observatory upper limit
- GRB 240802A: SVOM/GRM observation
- EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
- Fermi trigger No 744278264: Global MASTER-Net observations report
- EP240802a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
- EP240801a: further SAO RAS optical observations
- EP240801a: optical observations at CrAO and AbAO
- EP240801a: GRANDMA and Kilonova-Catcher optical observations
- EP240801a: Leavitt Observatory optical observations
- EP240801a: GTC spectroscopy and absorption redshift
- EP240801a: SAO RAS optical observations