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.
Lucene Examples (click to copy):
subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
3363 results found.
- Fermi trigger No 713974668: Global MASTER-Net observations report
- Swift GRB230818.98: Global MASTER-Net observations report
- IPN triangulation of GRB 230815B
- GRB 230812B: continued SAO RAS optical observation
- GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
- Fermi trigger No 713205976: Global MASTER-Net observations report
- Fermi GRB 230807A: Global MASTER-Net observations report
- Fermi trigger No 713134237: Global MASTER-Net observations report
- Fermi trigger No 712927418: Global MASTER-Net observations report
- Fermi trigger No 712798043: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S230802aq: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
- GRB 230723B: Swift-BAT refined analysis
- IceCube-230727A: Upper limits from a search for additional neutrino events in IceCube
- IceCube-230724A: Upper limits from a search for additional neutrino events in IceCube
- IceCube Alert 230725.90: Global MASTER-Net observations report
- IceCube Alert 230724.08: Global MASTER-Net observations report
- Fermi trigger No 711805358: Global MASTER-Net observations report
- Swift GRB 230723B: Global MASTER-Net observations report
- Fermi GRB 230723A: Global MASTER-Net observations report
- IceCube-230707A : MAXI upper limit and NICER follow-up observation of Swift J1753.5-0127
- IceCube-230707A: No candidates from the Zwicky Transient Facility
- LIGO/Virgo/KAGRA S230627c: GECKO optical follow-up observations of host galaxy candidates and ZTF23aaptsuy/AT2023lxu
- Fermi trigger No 710117592: Global MASTER-Net observations report
- Konus-Wind detection of GRB 220623A
- Fermi GRB 230628C: Global MASTER-Net observations report
- Fermi GRB 230628D: Global MASTER-Net observations report
- ZTF23aaoohpy /AT2023lcr: TNG NIR detection
- LIGO/Virgo/KAGRA S230627c: Coverage and upper limits from MAXI/GSC observations
- GRB 230623A: Swift-XRT observations
- GRB 230623A: Tiled Swift observations
- MAXI GRB 230623A: MASTER optical observations
- GRB 230623A: Tiled Swift observations
- GRB 230623A: MAXI/GSC detection
- LIGO/Virgo S230621ad: Global MASTER-Net observations report
- LIGO/Virgo S230620ad: Global MASTER-Net observations report
- ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Swift/UVOT detection
- IPN triangulation of GRB 230616A (short)
- AT2023lcr: Neil Gehrels Swift Observatory X-ray detection
- LIGO/Virgo S230620al: Global MASTER-Net observations report
- LIGO/Virgo S230618s: Global MASTER-Net observations report
- LIGO/Virgo S230616aa: Global MASTER-Net observations report
- LIGO/Virgo S230615ak: Global MASTER-Net observations report
- LIGO/Virgo S230617ba: Global MASTER-Net observations report
- LIGO/Virgo S230618k: Global MASTER-Net observations report
- LIGO/Virgo S230618d: Global MASTER-Net observations report
- LIGO/Virgo S230617bc: Global MASTER-Net observations report
- LIGO/Virgo S230617aq: Global MASTER-Net observations report
- LIGO/Virgo S230617aj: Global MASTER-Net observations report
- LIGO/Virgo S230616s: Global MASTER-Net observations report
- LIGO/Virgo S230608as: Global MASTER-Net observations report
- LIGO/Virgo S230609a: Global MASTER-Net observations report
- LIGO/Virgo S230608ah: Global MASTER-Net observations report
- LIGO/Virgo S230529ay: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S230529ay: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S230525a: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S230518h: Updated Sky localization
- IceCube Alert 230524.47: Global MASTER-Net observations report
- Fermi trigger No 706610076: Global MASTER-Net observations report
- AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230523A
- LIGO/Virgo S230522a: Global MASTER-Net observations report
- LIGO/Virgo S230520ae: Global MASTER-Net observations report
- GRB 230520A: CALET Gamma-Ray Burst Monitor detection
- LIGO/Virgo/KAGRA S230520ae: Upper limits from IceCube neutrino search
- LIGO/Virgo/KAGRA S230518h: GECKO tiling observations with KMTNet
- GRB 230520A: MAXI/GSC detection
- LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S230518h: Global MASTER-Net observations report
- LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 230510B: Fermi GBM detection
- GRB 230510B: AstroSat CZTI detection
- GRB 230510B: CALET Gamma-Ray Burst Monitor detection
- GRB 230510B: MAXI/GSC detection
- GRB 230506C: TSHAO possible afterglow candidate
- GRB 230420A: Swift-BAT refined analysis
- GRB 230409B: 3.6m DOT near-infrared detection, afterglow confirmation
- GRB 230409B: Mondy optical upper limit
- Fermi trigger No 702745263: Global MASTER-Net observations report
- MAXI GRB230408.82: Global MASTER-Net observations report
- GRB 230409B: Swift detection of a burst
- Fermi trigger No 701883729: Global MASTER-Net observations report
- GRB 230328B: Swift-BAT refined analysis
- GRB 230328B: Nanshan/NEXT optical upper limit
- Fermi GRB 230328A: Global MASTER-Net observations report
- Fermi trigger No 701321709: Global MASTER-Net observations report
- Konus-Wind detection of GRB 230309A
- GRB 230322A: Fermi GBM Final Real-time Localization
- Fermi GRB 230313A: Global MASTER-Net observations report
- GRB 230307A: soft X-ray detection with LEIA
- Further improved IPN localization for GRB 230307A
- GRB 230307A: MAXI/GSC upper limit
- Fermi GRB 230308A: Global MASTER-Net observations report
- Fermi trigger No 699294715: Global MASTER-Net observations report
- Fermi trigger No 699311646: Global MASTER-Net observations report
- GRB 230220A: Correction to GCN 33352
- Fermi GRB 230220B: Global MASTER-Net observations report
- GRB 230220A: MAXI/GSC detection
- IceCube-230217A: BOOTES-4/MET Optical Observations