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"
4714 results found.
- LAT GRB240513.31: Global MASTER-Net observations report
- Fermi trigger No 737277727: Global MASTER-Net observations report
- Fermi trigger No 737247400: Global MASTER-Net observations report
- GRB 240511A : MITSuME Akeno optical upper limits
- LIGO/Virgo/KAGRA S240511i: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240422ed: GMOS-S photometry of J-GEM24a
- Fermi trigger No 736564880: Global MASTER-Net observations report
- GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
- GRB 240503A: AstroSat CZTI detection
- Fermi trigger No 736387941: Global MASTER-Net observations report
- LXT 240402A / GRB 240402B: VLT X-shooter redshift of host
- Fermi trigger No 736379109: Global MASTER-Net observations report
- GRB 240502C: GOTO possible optical counterpart candidates
- Fermi GRB 240502B: Global MASTER-Net observations report
- Fermi GRB 240502A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
- Fermi GRB 240501A: Global MASTER-Net observations report
- Fermi trigger No 736197684: Global MASTER-Net observations report
- GRB 240408B: VZLUSAT-2 detection
- LIGO/Virgo/KAGRA S240501an: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a
- LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
- LIGO/Virgo/KAGRA S240426s: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis
- S240422ed: MeerLICHT/BlackGEM photometry on AT2024hfx and archival ZTF detection
- LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
- LIGO/Virgo/KAGRA S240422ed: Additional DECam GW-MMADS Candidates from the first two nights of observations
- LIGO/Virgo/KAGRA S240422ed: Archival BlackGEM/MeerLICHT detections of AT 2024hdr & AT 2024hdq
- LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
- LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
- LIGO/Virgo/KAGRA S240422ed: ATCA follow-up of candidate counterparts
- LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
- LIGO/Virgo/KAGRA S240422ed: DECam GW-MMADS Candidates
- IceCube Alert 240424.08: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240422ed: SAGUARO upper limits from CSS
- LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
- LIGO/Virgo/KAGRA S240422ed: No Counterparts in DDOTI/OAN Optical Observations
- LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility observations and candidates
- LIGO/Virgo/KAGRA S240422ed: GW-MMADS DECam observations
- LIGO/Virgo/KAGRA S240422ed: Magellan Observations
- LIGO/Virgo/KAGRA S240422ed: Updated NED Galaxies in the Localization Volume
- LIGO/Virgo/Kagra S240422ed: NED Galaxies in the Localization Volume
- Fermi GRB 240422A: Global MASTER-Net observations report
- Fermi trigger No 735280430: Global MASTER-Net observations report
- Fermi trigger No 735089036: Global MASTER-Net observations report
- Fermi GRB 240417A: Global MASTER-Net observations report
- Improved IPN triangulation of GRB 240411A
- GRB 240415A: SAO RAS optical observations
- Fermi GRB 240415A: Global MASTER-Net observations report
- Fermi trigger No 734754044: Global MASTER-Net observations report
- IPN triangulation of GRB 240411A
- GRB 240414A : OHP/T193 redshift determination
- LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240413p: Zwicky Transient Facility observations
- LIGO/Virgo/Kagra S240413p: NED Galaxies in the Localization Volume
- IceCube Alert 240412.23: Global MASTER-Net observations report
- GRB 240408B: GRBAlpha detection
- EP240408A: MASTER optical observations
- Swift Trigger 1220736: detection of 4U 1543-62.
- Fermi GRB 240408A: Global MASTER-Net observations report
- Fermi GRB 240407A: Global MASTER-Net observations report
- Fermi-LAT gamma-ray observations of IceCube-240327B
- Fermi-LAT gamma-ray observations of IceCube-240327A
- GRB 240331A: GRBAlpha detection
- GRB 240403B: Glowbug gamma-ray detection
- GRB 240403A: Glowbug gamma-ray detection
- IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
- GRB 240403A: Fermi GBM Detection
- LXT 240402A: MASTER optical observations with AGN in error-box
- GRB 240402B: GWAC-F50A optical upper limit
- GRB 240403A: BALROG localization (Fermi Trigger 733838255 / GRB 240403498)
- Fermi trigger No 733808041: Global MASTER-Net observations report
- Fermi GRB 240402A: Global MASTER-Net observations report
- X-ray transient EP240331A: GRANDMA-Kilonova catcher optical upper limit
- EP240331A: MASTER optical observations
- Transient EP240315a: J-band observations of AT2024eju with WIRC
- IceCube-240327B: Upper limits from a search for additional neutrino events in IceCube
- IceCube-240327A: Upper limits from a search for additional neutrino events in IceCube
- GRB 240329A: Glowbug gamma-ray detection
- GRB 240324A: AstroSat CZTI detection of a short burst
- GRB 240331A: AstroSat CZTI detection
- GRB 240329A: AstroSat CZTI detection
- GRB 240329A: GRBAlpha detection
- Fermi trigger No 733366352: Global MASTER-Net observations report
- Fermi GRB 240329A: Global MASTER-Net observations report
- Fermi GRB 240328B: Global MASTER-Net observations report
- Fermi GRB 240328A: Global MASTER-Net observations report
- X-ray transient EP240315a: continued ATCA monitoring
- IceCube-240327B: No candidates from the Zwicky Transient Facility
- GRB 240328C: Glowbug gamma-ray detection
- IceCube Alert 240327.68: Global MASTER-Net observations report
- IceCube-240327B - IceCube observation of a high-energy neutrino candidate track-like event
- IceCube-240327A - IceCube observation of a high-energy neutrino candidate track-like event
- Fermi trigger No 733097506: Global MASTER-Net observations report
- X-ray transient EP240315a: Ondrejov D50 optical limit
- Fermi trigger No 733092476: Global MASTER-Net observations report
- GRB 240320A: Glowbug gamma-ray detection
- Fermi trigger No 732937833: Global MASTER-Net observations report
- Fermi GRB 240320A: Global MASTER-Net observations report
- GRB 240315C / X-ray transient EP240315a: Swift/BAT detection