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"- GRB 080703: UVOT Follow-Up Observation
- GRB 080703: VLT observations of the afterglow
- GRB 080703: Enhanced Swift-XRT position
- GRB 080703, Swift-BAT refined analysis
- GRB 080702B Swift-BAT refined analysis
- GRB 080703: Swift detection of a burst with optical afterglow
- GRB 080703A: ROTSE-III Detection of Optical Counterpart
- No radio detection from the short GRB 080702A
- GRB 080702b: LCO optical observations
- Swift/UVOT observation of GRB080702A
- GRB 080702B: Swift XRT and UVOT observations
- GRB 080625: Suzaku WAM observation of the prompt emission
- GRB 080702A: MITSuME Akeno optical upper limits
- GRB 080701A: Early RAPTOR optical limits
- Swift Trigger 315630: Swift/UVOT Upper Limits
- GRB 080702A, Swift-BAT refined analysis
- GRB 080702A: Swift-XRT Team refined analysis
- GRB 080702B : Burst detected in BAT during Swift slew
- GRB 080702A: Enhanced Swift-XRT position
- Swift Trigger 315630: TLS R-band observation
- Swift Trigger 315630: Probably not a GRB
- GRB 080702: Swift detection of a short burst
- GRB 080701: Swift-XRT refined analysis
- GRB 080701A, VATT optical upper limit
- TLS I-Band Observation of GRB 080701A
- GRB 080701A: Swift/UVOT Upper Limits
- GRB 080701A: Early Super-LOTIS Observations
- GRB 080701: Enhanced Swift-XRT position
- GRB 080701A, Swift-BAT refined analysis
- Trigger 315630: Swift detection of a possible burst
- GRB 080701: Swift-XRT Prompt Analysis
- GRB 080701: Swift detection of a burst
- GRB 080623: Suzaku WAM observation of the prompt emission
- GRB 080625: Swift/UVOT Follow-Up Observations
- GRB 080625: Further observations from OSN
- GRB 080625:Swift-XRT detection of the afterglow
- GRB 080625: Swift/UVOT Detection of an Optical Afterglow
- GRB 080625: Observations at OSN
- GRB 080625: Gamma Ray Burst Localization by SuperAGILE
- GRB 080623: GROND upper limits
- GRB080623: Swift UVOT followup observations
- GRB 080623: Swift-XRT refined analysis
- GRB 080623, Swift-BAT refined analysis
- GRB 080623: Enhanced Swift-XRT position
- GRB 080623: TAROT La Silla observatory optical observations
- GRB 080623: Swift/UVOT Non-Detection of an Optical Afterglow
- GRB 080623: Swift XRT prompt analysis
- GRB 080623: Swift detection of a burst
- Swift trigger 314975 is not a GRB
- Swift-BAT trigger 314975 possible burst
- GRB080607: optical observation
- GRB 080603b: optical observation
- GRB 070809: Putative host galaxy and redshift
- VLA upper limit on INTEGRAL burst GRB 080613A
- GRB 0800603A: optical observation
- GRB080613B: MITSuME upper limits
- GRB080613A: Optical upper limits with Okayama MITSuME telescope
- Konus-Wind observation of GRB 080613B
- GRB 080603A: optical observations on June 04
- GRB 080613A: Swift-XRT detection of the afterglow
- GRB080613A: Swift/UVOT Upper Limits
- GRB 080613A: GROND Confirmation of the Afterglow Candidate
- GRB 080613B: GROND Upper Limits
- GRB 080613B - NOT optical and IR nondetections
- GRB080613B: Swift/UVOT Upper Limits
- GRB 080613B, Swift-BAT refined analysis
- GRB 080613B: Swift-XRT refined analysis
- GRB 080514B: Spectroscopic constraints and probable host galaxy
- GRB 080613B: Swift detection of a burst
- GRB 080613: Faulkes Telescope North optical candidate
- GRB 080613 : a long GRB detected with INTEGRAL
- GRB 080603A: Late-time Keck imaging and spectroscopy
- GRB 080603b: optical observation
- Swift observations of BAT Slew Survey event (Trigger=010)
- GRB 080603A: final Swift-XRT observations.
- GRB 080607: AGILE-MCAL observation of the prompt emission
- GRB 080603B - TLS 2nd Epoch: Another Break
- GRB 080605: TLS 3rd Epoch - Source Confusion
- GRB080605: optical observation with the MITSuME-OAO telescope
- Konus-Wind observation of GRB 080607
- GRB080607: RTT150 optical observations
- GRB 080603A: optical observations
- GRB 080607: Swift-XRT refined analysis
- Swift/UVOT Observations of GRB080607
- GRB 080605: optical observations
- GRB 080607 KAIT observations
- VLA detection of INTEGRAL burst GRB 080603A
- Konus-Wind observation of GRB 080605
- GRB 080607: Enhanced Swift-XRT position
- GRB 080607, Swift-BAT refined analysis
- GRB 080605: GROND 2nd epoch observations
- GRB 080607 - PAIRITEL NIR detection
- GRB 080607: Keck/LRIS spectroscopy and redshift
- GRB 080607: Super-LOTIS early observations
- GRB 080607: Swift detection of a burst with optical afterglow
- GRB 080607: ROTSE-III Detection of Optical Counterpart
- GRB 080605: TLS RRM Analysis, Plateau/Rebrightening, Red OT
- GRB 080605: Swift-UVOT refined analysis
- Possible VLA radio detection on INTEGRAL burst GRB 080603A
- GRB 080604: VLA radio upper limit