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"1583 results found.
- SVOM GRB251211.12: Global MASTER-Net observations report
- GRB 251129A/EP251129a: AbAO and Mondy optical observations
- GRB 251208A: AstroSat CZTI detection
- GRB 251208A: Glowbug gamma-ray detection
- EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
- GRB 251208C: GECAM-B observation of a short burst
- GRB 251208A: GECAM-B observation of a short burst
- GRB 251206A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 251208D: LAST optical upper limit
- GRB 251208D: LCO analysis of the XRT sources
- GRB 251208D: Swift-XRT observations
- GRB 251208A: SVOM/GRM observation of a short burst
- GRB 251208C: SVOM/GRM observation of a short burst
- GRB 251208D: LCO optical upper limits
- SVOM GRB251208D: Global MASTER-Net observations report
- GRB 251208D: SVOM possible detection of a faint burst
- GRB 251206A: SVOM detection of a burst through offline search
- SVOM GRB251206.86: Global MASTER-Net observations report
- GRB 251203C: Swift/UVOT Upper Limit
- GRB 251203A: Insight-HXMT/HE detection
- GRB 251203C: SVOM/ECLAIRs refined analysis
- SVOM/sb25120502: SVOM detection of a faint X-ray transient candidate
- GRB 251202A / EP251202a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm and 1-m telescopes at McDonald Observatory
- GRB 251203C: SVOM/COLIBRÍ (FM-GFT) optical upper limit
- GRB 251202A: SVOM/GRM observation
- GRB 251203A: GECAM-B observation of a burst
- GRB 251203A: SVOM/GRM observation
- GRB 251203C: LCO optical afterglow confirmation
- GRB 251203C: SVOM/VT optical counterpart
- GRB 251203C: EP-FXT follow-up observation
- GRB 251129A/EP251129a : SVOM/ECLAIRs refined analysis
- GRB 251203B: Swift-XRT observations
- GRB 251203B: confirmation of a stellar flare by BOOTES-2
- GRB 251203B : SVOM trigger sb25120304 is not a GRB
- GRB 251203C: LCO optical upper limits
- GRB 251203B: LCO optical upper limits
- GRB 251203B: SVOM/VT optical observation
- GRB 251203C: SVOM detection of a burst
- SVOM GRB251203.77: Global MASTER-Net observations report
- SVOM GRB251203B: Global MASTER-Net observations report
- GRB 251203B: SVOM detection of a burst
- GRB 251129A / EP251129a: SVOM/VT optical color bluer
- GRB 251202A / EP251202a: SVOM/VT optical observation
- GRB251129A/EP251129a: Swift UVOT detection
- GRB 251201B: Kilonova-Catcher optical afterglow detection
- GRB 251201A: GECAM-B observation of a burst
- GRB 251126A: SVOM/VT optical observation
- EP251130a: SVOM/VT optical observation
- GRB 251201A: SVOM/GRM observation of a burst
- GRB 251201B: SVOM/VT optical fading
- SVOM GRB251201.19: Global MASTER-Net observations report
- GRB 251127A: SVOM/GRM observation
- EP251129a/GRB 251129A: EP-FXT follow-up observations
- GRB 251129A / EP251129a: GTC/OSIRIS+ spectroscopic redshift z = 1.460
- GRB 251129A / EP251129a: OSN and CAHA optical follow-up
- GRB 251129A / EP251129a: SAO RAS optical observations
- GRB 251128A: SVOM/GRM observation of a long burst
- SVOM GRB 251129A : MASTER optical counterpart detection
- GRB 251129A: Swift-XRT afterglow detection
- GRB 251129A: Swift ToO observations
- GRB 251129A / EP251129a: SVOM/VT optical fading
- EP251129a/GRB 251129A : Einstein Probe detection of an X-ray transient
- GRB 251129A: SVOM/VT optical counterpart confirmation with VHF data
- GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
- GRB 251129A: SVOM detection of a burst
- SVOM GRB251129A: Global MASTER-Net observations report
- GRB 251129A: SVOM detection of a burst
- EP251124a: Xinglong GWAC-F60A optical observation
- LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
- LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
- GRB 251116C: Swift-XRT confirmation of fading
- GRB 251122A/EP251122A: 1.3m DFOT optical detection
- GRB 251122A / EP251122a: Xinglong 2.16m optical observation
- GRB 251122A / EP251122a: EP-FXT counterpart detection
- EP251122a: refined analysis of the EP-WXT and EP-FXT observations
- GRB 251122A / EP251122a: WFST optical observations
- GRB 251122A/EP251122a: SVOM/VT optical observations with VHF data
- GRB 251122A/EP251122a: Additional, deeper LCO optical r band upper limit
- GRB 251122A / EP251122a: LCO optical upper limits
- EP251122a / GRB 251122A: optical counterpart candidate with Kinder observations
- GRB 251122A/EP251122a: SVOM/C-GFT upper limit
- GRB 251122A / EP251122a: SVOM detection of a long burst
- LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search
- GRB 251103A: SVOM/ECLAIRs and SVOM/GRM joint refined analysis
- EP-WXT trigger 01709248403: confirmation of a stellar flare by SVOM/VT
- LIGO/Virgo/KAGRA S251112cm: SVOM/VT optical observations and preliminary results
- EP251118a / GRB 251118C: SVOM/VT optical observation
- EP251118a / GRB 251118C: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at CTIO
- GRB 251116C: NOT optical observations
- GRB 251118C: Glowbug gamma-ray detection of the fast X-ray transient EP251118A
- GRB 251118C: Swift/BAT rates detection of a burst with a possible association with EP 251118A
- GRB 251118C: SVOM/GRM observation of a possible gamma-ray counterpart of EP251118a
- GRB 251117A: Insight-HXMT/HE detection
- GRB 251119A: SVOM trigger sb25111901 is not a GRB
- GRB 251116D: SVOM/GRM observation of a long GRB
- GRB 251119A: SVOM detection of a possible burst
- GRB 251116C: SVOM/ECLAIRs refined analysis
- GRB 251116B: SVOM/ECLAIRs refined analysis
- GRB 251117A: AstroSat CZTI detection
- GRB 251117A: Fermi GBM observation