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.
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"32567 results found.
- GRB 250813B: Swift-XRT afterglow detection
- GRB 250813B: SVOM/COLIBRÍ (FM-GFT) optical observations
- GRB 250813B: Ondrejov D50 fast decay
- GRB 250813B: SVOM detection of a bright long burst (Correction for GCN 41352).
- GRB 250813B: Ondrejov D50 optical afterglow detection
- LIGO/Virgo/KAGRA S250813k: Updated Sky localization
- EP250812a: Nickel optical upper limit
- GRB 250812A: VLT X-shooter spectroscopic redshift confirmation z = 2.571
- GRB 250812A: NTT spectroscopic redshift z = 2.57
- GRB250812a: STEP/T80S Indication of slow decay of afterglow
- EP250812a: NOT, NTT, and GS observations
- GRB 250812A: Swift/UVOT Detection
- EP250812a: COLIBRÍ detection of the VT candidate and evidence of flattening
- EP250812a: Liverpool Telescope upper limits
- EP250812a: SVOM/VT optical counterpart
- EP250812a: refined analysis of the EP-WXT and EP-FXT observations
- LIGO/Virgo/KAGRA S250813k: Identification of a GW compact binary merger candidate
- GRB 250812A: EP-FXT counterpart detection
- GRB 250812A: Swift ToO observations
- GRB 250807B: Swift-BAT refined analysis
- EP 250812a: GOTO optical upper limit
- GRB 250812A: Kilonova-Catcher optical afterglow detection
- EP250812a: Swift-XRT counterpart detection
- GRB 250812A: SVOM/COLIBRÍ (FM-GFT) optical observations
- GRB 250812A: SVOM/VT optical afterglow confirmation
- GRB 250812A: TRT likely optical counterpart detection
- GRB 250809A: Swift-BAT refined analysis
- Fermi-LAT Gamma-ray Observations of IceCube-250804A
- GRB 250807A: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S250810ck: Updated Sky localization and EM Bright Classification
- GRB 250809A: Swift/UVOT Detection
- LIGO/Virgo/KAGRA S250810ck: Identification of a GW compact binary merger candidate
- Corrected Swift-XRT Refined Analysis of GRB 250809A
- GRB 250807B: SVOM/VT optical observation
- EP250807a: EP-FXT follow-up observation upper limit
- GRB 250809A: LCOGT Optical Upper Limits
- GRB 250702B: Chandra X-ray Detection
- EP250807a: Global MASTER-Net observations report
- Fermi GRB 250808A: Global MASTER-Net observations report
- GRB 250808A: VLT X-shooter candidate counterpart
- GRB 250808A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 250808A: Fermi GBM Observation
- GRB 250807A: SVOM/VT optical continued observation
- EP-WXT trigger 01709195487: KAIT confirmation of the stellar flare
- GRB 250808A: SVOM detection of a long burst
- Konus-Wind detection of GRB 250807A
- GRB 250807B: Swift/UVOT Detection
- GRB 250807B: Kilonova-Catcher optical afterglow detection
- IceCube-250804A: Upper limits from a search for additional neutrino events in IceCube
- GRB 250807A: Swift/UVOT Detection
- GRB 250807B: VLT/X-Shooter spectroscopic redshift z = 1.522
- GRB 250806A: SVOM/MXT refined analysis
- GRB 250806A: SVOM/ECLAIRs refined analysis
- EP250807a: NTT z-band optical upper limit
- GRB 250806A: Mondy optical observations, and nearby bright galaxy photometry
- GRB 250804B: Insight-HXMT detection
- GRB 250807A: SVOM/GRM observation
- GRB 250807A: AstroSat CZTI detection of bright long burst
- GRB 250806A: NOT z-band upper limit and host galaxy candidate
- GRB 250807B: NTT optical observations
- EP250807a: EP-WXT detection of a fast X-ray transient
- GRB 250807A: SVOM/VT optical observation
- EP250806a: Upper limit from Fermi-GBM Observations
- GRB 250805A: Kilonova-Catcher optical upper limits
- EP250806a:SVOM/VT refined analysis
- GRB 250805A: Swift/UVOT Upper Limits
- GRB 250806A: Swift/UVOT U-band detection
- EP250806a: Liverpool telescope optical upper limit
- GRB 250806A: EP-FXT observation
- EP#01709198415/EP250806a: Swift-XRT observations
- EP250806a: Global MASTER-Net observations report
- EP250802a: EP-FXT follow-up observation
- EP250806a: refined analysis of the EP-WXT and EP-FXT observations
- EP250806a: Earlier Detection of the VT Candidate by COLIBRÍ and LS
- EP250806a: SVOM /VT optical candidate
- GRB 250806A: J-band upper limit from WINTER
- GRB 250805A: Swift-BAT refined analysis
- GRB 250806A: KAIT optical upper limit
- GRB 250806A: SVOM/VT refined analysis
- EP250806a: COLIBRÍ optical upper limit
- GRB 250806A: Kilonova-Catcher optical upper limits
- GRB 250806A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 250806A: SVOM/VT optical upper limit
- GRB 250805A: SVOM/VT optical counterpart
- GRB 250805A: ESO/VLT observations
- GRB 250805A: TRT optical upper limits
- GRB 250804B: Tiled Swift observations
- EP250802a: additional Liverpool Telescope upper limits
- EP250730a: SVOM/VT optical upper limit
- EP250802a: Liverpool Telescope optical upper limits
- EP250802a: Global MASTER-Net observations report
- EP250802a: GROWTH-India Telescope optical upper limit
- LIGO/Virgo/KAGRA S250802dn: Updated Sky localization
- LIGO/Virgo/KAGRA S250802dn: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S250727dc: GRANDMA/OPD observations of AT2025smm
- GRB 250702B: SMA observations
- LIGO/Virgo/KAGRA S250727dc: DECam GW-MMADS candidates
- LIGO/Virgo/KAGRA S250725j: GOTO pre-trigger detection of AT2025sib
- EP250711a: CrAO and Assy optical observations
- LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates