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.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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"- LIGO/Virgo G299232: Khureltogot observations
- GRB 170912A: Swift/UVOT Upper-Limits
- GRB 170912B: Swift-XRT refined Analysis
- GRB 170912B: Fermi GBM observations
- LIGO/Virgo G298936: Konus-Wind observations
- LIGO/Virgo G299232: Konus-Wind observations
- GRB 170911A: Fermi GBM observation
- GRB 170912B: Enhanced Swift-XRT position
- LIGO/Virgo G299232: Pierre Auger Observatory follow-up
- LIGO/Virgo G298389: Pierre Auger Observatory neutrino follow-up
- GRB 170912B: Swift detection of a burst
- GRB 170912A: Enhanced Swift-XRT position
- GRB 170912A: Prompt enhanced Swift-XRT position
- GRB 170912A: Swift detection of a burst
- LIGO/Virgo G297595: Las Cumbres Observatory Optical Follow-Up
- Konus-Wind observation of GRB 170906A
- GRB 170911A: MAXI/GSC detection
- Konus-Wind observation of GRB 170906C
- GRB 170906A: AstroSat CZTI(Veto) detection
- GRB 170830B CALET Gamma-Ray Burst Monitor detection
- IBAS Alert nr. 7913 is not a real GRB
- Fermi-GBM GRB mis-classifications during current Solar activity
- Konus-Wind observation of GRB 170904A
- LIGO/Virgo G298048: VLA radio non-detection
- LIGO/Virgo G298048: VLBA upper limits at 8.7GHz for the GW counterpart SSS17a/DLT17ck on August 20-21 UT
- Swift Triggered on MAXI J1535-571
- LIGO/Virgo G298048: LWA Detection
- GRB 170906A: Swift/UVOT Detection
- GRB 170906B: Swift/UVOT Upper Limits
- GRB 170906B: Swift-XRT refined Analysis
- LIGO/Virgo G299232: Swift-XRT sources
- GRB 170906C: optical observations
- LIGO/Virgo G298048: ATCA observations of of SSS17a in NGC 4993
- GRB 170906B: Swift-BAT refined analysis
- GRB 170906B: Fermi GBM detection
- GRB 170906A: Fermi GBM detection
- GRB 170906A: Swift-BAT refined analysis
- GRB 170906C: COATLI Observations
- GRB 170906A: Swift-XRT refined Analysis
- GRB 170906C: Swift/UVOT Upper Limits
- GRB 170906C: Swift-XRT refined Analysis
- LIGO/Virgo G298048 GRAWITA: VST-ESO PARANAL follow up of SSS17a in NGC4993.
- GRB 170906C: Swift-BAT refined analysis
- GRB 170906C: Enhanced Swift-XRT position
- GRB 170906A: MASTER-OAFA (Argentina) early automatic OT detection
- GRB 170829A: Insight-HXMT detection
- GRB 170906C: Swift-XRT observations
- GRB 170906A: Fermi-LAT detection
- GRB 170906C: Swift detection of a burst
- GRB 170906A: REM optical/NIR observations
- GRB 170906A: Enhanced Swift-XRT position
- GRB 170906B: Enhanced Swift-XRT position
- GRB 170906B: Swift detection of a burst
- GRB 170906A: Swift detection of a burst with an optical afterglow
- IPN Triangulation of GRB 170904A (long/very bright)
- LIGO/Virgo G299232: Lulin Observations of Possible OTs
- GRB 170901B: Insight-HXMT detection
- GRB 170904A: Insight-HXMT detection
- LIGO/VIRGO G298048: Precise position of SSS17a based on HST and Gaia
- LIGO/VIRGO G298048: Radio detection of SSS17a at 6 GHz with the VLA
- LIGO/VIRGO G298048: Radio detection of SSS17a at 3GHz with the VLA/JAGWAR
- GRB 170903A: Fermi GBM observation
- LIGO/Virgo G299232: Maidanak observations of optical transient SwiftJ014008.5+343403.6
- LIGO/Virgo G298389: Fermi GBM Flux Upper Limits
- LIGO/Virgo G299232: LOFAR follow-up
- Swift Trigger on continued activity of MAXI J1535-571
- GRB 170827A: LCO Observations
- GRB 170903A: Swift/UVOT Upper Limits
- GRB 170903A: UAFO /ISON optical upper limit
- LIGO/Virgo G298048: e-MERLIN upper limits on 5 GHz compact emission from SSS17a
- LIGO/Virgo G298048: ATCA monitoring of SSS17a in NGC 4993
- LIGO/Virgo G299232: RoboPol observations of MASTER OT J033744.97+723159.0
- GRB 170903A: MITSuME Okayama upper limits
- GRB 170903A: Swift-XRT refined Analysis
- GRB 170903A: Host galaxy redshift from OSIRIS/GTC
- LIGO/Virgo G298048: Chandra X-ray Update on GW170817
- GRB 170903A: Enhanced Swift-XRT position
- GRB 170903A: Swift-BAT refined analysis
- GRB 170903A: Nanshan optical upper limit
- GRB 170903A: Swift-XRT observations
- GRB 170903A: Swift detection of a burst
- Swift Triggers on MAXI J1535-571
- Swift Trigger 770431 (GRB 170902A) is a not a GRB
- GRB 170902A: Enhanced Swift-XRT position
- LIGO/Virgo G297595: DECam observations of BBH merger region of interest
- GRB 170902A: Swift detection of a burst or possible Galactic transient
- LIGO/Virgo G298048: Chandra monitoring of the X-ray emission from SSS17a
- LIGO/Virgo G298048: Continued X-ray monitoring and X-ray detection of GW170817 [erratum]]
- LIGO/Virgo G298048: AGILE-GRID analysis of data contemporary to X-ray emission from SSS17a in NGC4993
- LIGO/Virgo G298048
- LIGO/Virgo G299232/PGWB170825.55: MASTER archive images of the SIWFT/UVOT and MASTER OT J033744.97+723159.0 in NGC1343 galaxy before 25
- LIGO/Virgo G298048: Hubble Space Telescope observations
- LIGO/Virgo G299232: XSNAOC spectral observation of MASTER OTJ033744.97+723159.0
- LIGO/Virgo G298048: Possible Plateau in Ks band revealed by continued Gemini-South observations
- LIGO/Virgo G298048: Continued Gemini South observations
- GRB 170831A: Fermi GBM detection
- GRB 170830A: Fermi GBM observation
- Konus-Wind observation of GRB 170827B
- Konus-Wind observation of GRB 170826A
- GRB 170830A: Astrosat CZTI detection