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"39057 results found.
- GRB 260903A: NOT optical observations and afterglow fading
- SVOM GRB260903A: Global MASTER-Net observations report
- GRB 260903A: LCO optical observations
- GRB 260903A: SVOM/VT optical candidate
- GRB 260903A: Retraction of optical counterpart of GCN 45501
- GRB 260831A: GECAM-B observation
- GRB 260903A: LCO optical counterpart detection
- GRB 260827A: Insight-HXMT/HE detection
- GRB 260903A: SVOM detection of a soft faint burst
- Konus-Wind detection of GRB 260829A
- GRB 260829A: SVOM/GRM observation
- GRB 260818A: ATCA detection of a candidate radio counterpart
- EP260901a: Global MASTER-Net observations report
- GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
- GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
- NuSTAR Transient 260828: LCO Optical Upper Limits
- SVOM trigger sb26083106 is not a GRB
- GRB 260829A: AstroSat CZTI detection
- GRB 260831B: EP-FXT follow-up observation
- GRB 260830A: NuSTAR detection of prompt emission
- GRB 260831B: LCO optical upper limits
- EP260830a: Global MASTER-Net observations report
- GRB 260827A: SVOM/GRM observation
- GRB 260831B: SVOM detection of a possible burst
- IPN triangulation of GRB 260829A
- GRB 260827A: Glowbug gamma-ray detection
- GRB 260831A: Fermi GBM Final Real-time Localization
- GRB 260829A: GECAM-B observation of a long burst
- GRB 260825A: SVOM/GRM observation of a long burst
- GRB 260825A: GECAM-B observation
- GRB 260829A: Fermi GBM Detection
- GRB 260825A: AstroSat CZTI detection
- GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
- GRB 260829A: Fermi GBM Final Real-time Localization
- Fermi GBM trigger 809666623/260829141 is not a GRB
- GRB 260818B: Further EP-FXT observation
- GRB 260818B: VLT optical and nIR observations
- GRB 260818B: TNG NIR observations
- MAXI GRB260827.40: Global MASTER-Net observations report
- IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260827A: Fermi GBM Final Real-time Localization
- GRB 260818B: 6 GHz VLA observations
- GRB 260818B: SVOM/VT optical upper limit and continuous observations
- GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
- GRB 260808B: SAO RAS observations of the optical rebrightening
- EP260822a: Global MASTER-Net observations report
- EP Alert 260820.31: Global MASTER-Net observations report
- GRB 260807A: EP-FXT follow-up observations
- GRB 260822A: SVOM/ECLAIRs refined analysis
- GRB 260809A: SVOM/ECLAIRs refined analysis
- GRB 260822A: SVOM/VT optical upper limits
- IceCube Alert 260825A: Global MASTER-Net observations report
- GRB 260825A: Fermi GBM Final Real-time Localization
- IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260822A: PRIME near-infrared upper limits from multiple epochs
- GRB 260822A: EP/FXT follow-up observations
- GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
- GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
- GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
- GRB 260822A: GOTO optical counterpart detection
- GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
- GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
- EP260822a: Einstein Probe detection of a fast X-ray transient
- GRB 260822A: LCO optical upper limits
- The EP-WXT trigger 01709287395 is likely a flaring star
- GRB260822B: Fermi GBM Final Localization
- GRB 260822A: GROWTH-India Telescope Upper Limits
- GRB 260822A: GOTO optical upper limit
- GRB 260822A: SVOM detection of a short burst
- GRB 260818B: VLA radio observations
- GRB 260818B: SVOM/C-GFT optical upper limit
- IceCube Alert 260821A: Global MASTER-Net observations report
- GRB 260820A: Insight-HXMT/HE detection
- IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
- GRB 260818B: SVOM/GRM observation
- GRB260820A: Fermi GBM Final Real-Time Localization
- GRB 260818B: Insight-HXMT detection
- GRB 260818B: EP-FXT follow-up observation
- GRB 260818A: J-band observations with WINTER
- GRB 260818B: SVOM/ECLAIRs refined analysis
- GRB 260818A: SVOM/ECLAIRs refined analysis
- GRB 260818B: NOT optical upper limits
- GRB 260810A: SVOM/GRM observation
- GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB260818A: EP-FXT follow-up observation
- GRB 260818B: LCO optical upper limits
- GRB 260818B: SVOM detection of a short burst
- SVOM trigger sb26081806 is not a GRB
- EP260806a: SAO RAS multicolor optical observations
- GRB 260818A: LCO optical upper limits
- EP260812a: AbAO optical upper limit
- GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 260810A: Insight-HXMT/HE detection
- GRB 260818A: SVOM possible detection of a long and faint GRB
- EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
- GRB 260805D: SVOM/GRM detection of a possible magnetar burst
- GRB 260808B: Liverpool Telescope further optical observations
- GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
- GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
- GRB 260813A: Fermi GBM Final Real-time Localization