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"28039 results found.
- GRB 230628E: Swift-XRT refined Analysis
- GRB 230628E: Enhanced Swift-XRT position (Correction to name in GCN 34115)
- GRB 230628A: Enhanced Swift-XRT position
- LIGO/Virgo/KAGRA S230628ax: Identification of a GW compact binary merger candidate
- GRB 230628E: LCOGT Optical Upper Limit
- GRB 230628E: Swift detection of a burst
- GRB 230628D: BALROG localization (Fermi Trigger 709676556 / GRB 230628849)
- LIGO/Virgo/KAGRA low-significance gravitational wave candidate S230628aj: one counterpart neutrino candidate from IceCube neutrino searches
- GRB 230628B: Swift/BAT-GUANO detection of a burst outside the coded FOV
- ZTF23aaoohpy /AT2023lcr: TNG NIR detection
- LIGO/Virgo/KAGRA S230527c: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo/KAGRA S230627c: ATLAS information on the ZTF candidates
- LIGO/Virgo/KAGRA S230627c: Upper limits from Fermi-GBM Observations
- GRB230626A: Fermi GBM Detection
- LIGO/Virgo/KAGRA S230627c: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S230627c: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S230627c: Identification of a GW compact binary merger candidate
- GRB 230618A: Swift-BAT refined analysis
- GRB 230625B: Swift/BAT-GUANO detection of a long burst
- LIGO/Virgo/KAGRA S230624av: Updated Sky localization
- GRB 230622A: Swift-BAT refined analysis
- GRB 230623A: Swift-XRT observations
- INTEGRAL upper limit on any GRB associated with ZTF23aaoohpy/AT2023lcr
- ZTF23aaoohpy/AT2023lcr: further SAO RAS observations
- ATLAS23msn/ZTF23aaoohpy/AT2023lcr: Zeiss-1000 of Koshka observatory optical observations
- GRB 230623B: Swift/BAT-GUANO detection of a long burst outside the coded FOV
- LIGO/Virgo/KAGRA S230624av: Identification of a GW compact binary merger candidate
- IceCube-Cascade 230622A: Upper limits from a search for additional neutrino events in IceCube
- GRB 230622A: Swift-XRT refined Analysis
- GRB 230623A: MAXI/GSC detection
- ZTF23aaoohpy/AT2023lcr: SAO RAS observations
- Fermi GBM-230619: AstroSat CZTI non-detection and upper limits for the sub-threshold candidate
- GRB 230622A: Swift detection of a burst
- IceCube-Cascade 230621A: Upper limits from a search for additional neutrino events in IceCube
- Fermi GBM-230619: A soft subthreshold candidate potentially associated with a subthreshold LIGO/Virgo compact binary merger candidate
- ZTF23aaoohpy/AT2023lcr: Montarrenti Observatory optical observations
- ZTF23aaoohpy (AT2023lcr/ATLAS23msn): Upper limits from Konus-Wind observations
- ZTF23aaoohpy/AT2023lc: Mondy optical observations
- IPN triangulation of GRB 230616A (short)
- LIGO/Virgo/KAGRA S230619bg: one counterpart neutrino candidate from IceCube neutrino searches
- AT2023lcr: Neil Gehrels Swift Observatory X-ray detection
- AT2023lcr (ATLAS23msn/ZTF23aaoohpy): Kinder observations with Lulin observatory and a probable plateau in the g-band light curve
- AT2023lcr: Pan-STARRS & ATLAS Observations
- ZTF23aaoohpy/AT2023lcr: Keck/LRIS spectroscopy and redshift
- ZTF23aaoohpy/AT2023lcr: Xinglong-2.16m optical observations
- LIGO/Virgo/KAGRA S230615az: Wendelstein observations of DESI galaxies and GIT candidates
- ZTF23aaoohpy/AT2023lcr: OHP/T193 and OHP/T120 optical follow-up observations
- ZTF23aaoohpy/AT2023lcr: GROWTH-India Telescope follow-up observations
- GRB 230618A: Osservatorio Astronomico Nastro verde upper limit
- ZTF23aaoohpy/AT2023lcr: GOTO early optical observations and constraint
- ZTF23aaoohpy/AT2023lcr: Zwicky Transient Facility discovery of a fast fading red transient
- GRB 230618A: Enhanced Swift-XRT position
- GRB 230618A: Swift/UVOT Upper Limits
- GRB 230618A: Swift-XRT refined Analysis
- GRB 230616A: Swift-XRT observations
- LIGO/Virgo S230616aa: Global MASTER-Net observations report
- LIGO/Virgo S230615an: Global MASTER-Net observations report
- GRB230618A: LCOGT Optical Observations
- GRB 230618A: Swift detection of a burst
- LIGO/Virgo/KAGRA S230615az: T80S Search and Candidate Counterpart Identification
- GRB 230616A: Swift/BAT-GUANO detection of a short burst outside the coded FOV
- LIGO/Virgo/KAGRA S230615az: Xinglong-2.16m photometric observations of GIT candidates
- LIGO/Virgo/KAGRA S230529ay: Upper limits from a two-week IceCube neutrino search
- LIGO/Virgo/KAGRA S230615az: GROWTH-India candidates
- GRB 230614B: Fermi GBM Observation
- GRB 230614C: Fermi GBM Detection
- LIGO/Virgo S230613at: Global MASTER-Net observations report
- LIGO/Virgo S230614t: Global MASTER-Net observations report
- GRB 230614B: Swift/BAT-GUANO detection outside the coded FOV
- Fermi trigger No 708426906: Global MASTER-Net observations report
- GRB 230606A: LCOGT Optical Observations
- IceCube-Cascade 230610A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S230608as: Updated Sky localization
- LIGO/Virgo/KAGRA S230606d: Updated Sky localization
- LIGO/Virgo/KAGRA S230609u: Updated Sky localization
- LIGO/Virgo/KAGRA S230609u: Identification of a GW compact binary merger candidate
- LIGO/Virgo S230608as: Global MASTER-Net observations report
- ZTF23aamxeqf/AT2023jxk: 1.3m DFOT Optical upper limit
- LIGO/Virgo/KAGRA S230608as: Identification of a GW compact binary merger candidate
- Fermi GRB 230603A: Global MASTER-Net observations report
- Fermi trigger No 707039690: Global MASTER-Net observations report
- ZTF and GIT Observations of the Candidate Optical Afterglow AT2023jxk
- GRB 230606A: Swift-BAT refined analysis
- GRB 230606A: Gaoyazi/GOT optical upper limit
- GRB 230606A: Fermi GBM Observation
- GRB 230606A: Swift-XRT refined Analysis
- GRB 230604A: GRBAlpha detection
- GRB 230606A: Swift/UVOT Upper Limits
- GRB 230606A: Enhanced Swift-XRT position
- LIGO/Virgo/KAGRA S230606d: Identification of a GW compact binary merger candidate
- Fermi-LAT gamma-ray observations of IceCube-230603A
- LIGO/Virgo/KAGRA S230605o: Updated Sky localization
- IceCube-230603A: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo/KAGRA S230601bf: Updated Sky localization
- LIGO/Virgo/KAGRA S230605o: Identification of a GW compact binary merger candidate
- LIGO/Virgo S230602ap: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S230518h: Upper limits from a two-week IceCube neutrino search
- GRB 230521A: VZLUSAT-2 detection
- GRB 230522A: GRBAlpha and VZLUSAT-2 joint detection
- LIGO/Virgo/KAGRA S230601bf: Identification of a GW compact binary merger candidate