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"- Konus-Wind observation of GRB 171112A
- FACT follow-up of IceCube20171106
- Konus-Wind observation of GRB 171108A
- GRB 171112A: MAXI/GSC detection
- IPN Triangulation of GRB 171108A (short)
- GRB 171103A: Insight-HXMT observation
- IceCube-171106A: Swift Observations
- HAWC follow-up of IceCube-171106A
- GRB 171010A: afterglow and SN 2017htp optical observations
- GRB 171108A: Fermi GBM detection
- GRB 171102A CALET Gamma-Ray Burst Monitor detection
- GRB 171101A CALET Gamma-Ray Burst Monitor detection
- INTEGRAL observation of IceCube-171106A
- GRB 171030A: MASTER OT J034412.48-263556.5 featureless continuum spectrum from Lijiang 2.4m (China) telescope and 2m the Himalayan Chandra
- GRB 171010A: possible SN component
- Fermi-GBM Trigger 531686417 / 171106778 is not related to ICECUBE-171106A
- IceCube-171106A - IceCube observation of a high-energy neutrino candidate
- AMON ICECUBE EHE 130214 (close by time to Fermi trigger): MASTER early follow-up observations
- GRB 171103A: AstroSat CZTI detection
- GRB 171030A: MASTER inspection of the IPN error box of the short GRB.
- Konus-Wind observation of GRB 171103A (short/hard)
- GRB 171103A: Fermi GBM observation
- GRB 171103A: Swift-BAT refined analysis of a short GRB
- LIGO/Virgo G298936: NOT spectroscopy of GWFUNC-17ure
- Fermi GBM detections of Swift J0243.6+6124 and modification of the GBM trigger configuration
- GRB 171010A: VLT spectroscopic identification of the associated SN 2017htp
- GRB 171103A: Swift detection of a short hard burst
- Konus-Wind observation of GRB 171102A
- GRB 171102B: AbAO optical upper limit
- GRB 171102B: TShAO optical upper limit
- IPN Triangulation of GRB 171102A
- GRB 171102B: Nanshan 0.36m and 0.60m optical upper limits
- GRB 171102B: RATIR Optical and NIR Observations
- GRB 171102B: Swift-BAT refined analysis
- GRB 171102B: MITSuME Akeno optical upper limits
- GRB 171102B: Swift/UVOT Upper Limits
- GRB 171102B: Swift-XRT refined Analysis
- GRB 171102B: Enhanced Swift-XRT position
- GRB 171102A: Fermi GBM detection
- GRB 171102B: Swift detection of a burst
- GRB 171102A: Fermi-LAT detection
- GRB 171030A: IPN error box through NSs probability merging rate map
- GRB 171030A: Fermi GBM detection
- GRB 171030A: Swift non-localization with BAT, XRT and UVOT
- GRB 171030A: Swift ToO observations
- IPN Triangulation of GRB 171030A (short)
- Fermi-GBM triggers due to Swift J0243.6+6124
- Swift Trigger 783893: KAIT Optical Observations
- GRB 171027A: KAIT Optical Upper Limit
- Swift Triggers 784159 and 784160 are not bursts
- GRB 171022A: Fermi-LAT detection retraction
- Konus-Wind observation of GRB 171027A
- AMI-LA observations of the new Be X-ray binary Swift J0243.6+6124
- Swift Trigger 783893: LCO 1-m telescope observations
- Swift Trigger 783893 is probably not a GRB
- GRB 171027A, Swift-BAT refined analysis
- Retraction of high energy neutrino candidate IceCube-171028
- GRB 171027A: Swift/UVOT Upper Limits
- GRB 171027A: Swift-XRT refined Analysis
- GRB 171027A: Enhanced Swift-XRT position
- GRB 171027A: RATIR Confirmation of Fading and Photo-z
- GRB 171027A: VLT optical upper limits
- GRB 171027A: LCO 1-m telescope observations
- GROND observations of GRB 171027A: correction
- GRB 171027A: RATIR Detection of a NIR Afterglow Candidate
- GROND observations of GRB 171027A
- GRB 171027A: MASTER-OAFA (Argentina) early prompt optical observations
- GRB 171027A: Prompt enhanced Swift-XRT position
- GRB 171027A: Swift detection of a burst
- Konus-Wind observation of GRB 171022A
- IPN Triangulation of GRB 171022A
- GRB 171013B CALET Gamma-Ray Burst Monitor detection
- Fermi GBM trigger 530617076/171025401 is not a GRB
- Swift trigger 781740: Further analysis from Swift and Fermi/GBM
- Numerous Fermi-GBM Subthreshold Notices are due to Swift J0243.6+6
- GRB 171022A: Fermi GBM detection
- GRB 171022A: Fermi-LAT detection
- Swift Trigger 781740 is not a burst
- Fermi GBM Observations of IceCube-171015A
- GRB 171020A: Continued RATIR Optical and NIR Observation
- GRB 171020A: TAROT Calern observatory optical observations
- GRB 171020A: Swift/UVOT Upper Limits
- GRB 171020A: NOT spectroscopic redshift
- GRB 171020A: Swift-BAT refined analysis
- GRB 171020A: RATIR Optical and NIR Observations
- GRB 171020A: Swift-XRT refined Analysis
- GRB 171020A: Enhanced Swift-XRT position
- GRB 171020A: LT observations
- GRB 171020A: Correction of alpha in GCN 22031
- GRB 171020A: Confirmation of OT fading
- GRB 171020A: Mini-MegaTORTORA upper limits on simultaneous optical emission
- GRB 171020A: NOT optical afterglow detection
- GRB 171020A: Swift detection of a burst
- Fermi-GBM Detection of possible burst from AXP CXOU J164710.2-455216/PSR J1647-4552
- GRB 171011B: Insight-HXMT detection
- Trigger 780207: Swift triggers again on AXP CXOU J164710.2-455216/PSR J1647-4552
- Swift Trigger on AXP CXOU J164710.2-455216/PSR J1647-4552
- GRB 171010B: Swift-XRT afterglow detection
- GRB 171011B CALET Gamma-Ray Burst Monitor detection
- Trigger 779762: Swift detection of Vela X-1