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"19808 results found.
- Konus-Wind observation of AXP/SGR 1E1547.0-5408 bursting activity
- GRB 090102: HST observations and host galaxy
- GRB 090118: no afterglow candidate
- GRB 090123: GROND detection
- GRB 090123: Swift/UVOT Observations
- GRB090123: Enhanced Swift-XRT position
- GRB 090123: Swift detection of a burst
- AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
- Trigger 340734: Swift detection of a possible short burst
- AXP 1E1547.0-5408 activity with SGR bursts
- GRB 090118: Subaru NIR Observation
- GRB 090118: KPNO 4m 2nd Epoch Observations
- GRB 090118 (BATSS): GRT Optical Observation
- GRB 090118: KPNO 4m Detection of Candidate Afterglow
- GRB090118 Swift/UVOT upper limits
- GRB 090118: GROND Upper Limits
- GRB 090118: Possible burst detection from Swift-BAT slew data
- GRB 090117 - Fermi GBM Observations
- GRB 090117: GROND Upper Limits
- GRB090117 Swift/UVOT upper limits
- GRB090117: Swift-XRT detection of a possible candidate afterglow
- GRB 090113: LOAO Detection Limits in R, I, z, Y-band
- GRB 090113: Swift UVOT upper limits
- GRB 090113: GROND Upper Limits
- GRB 090113: Observations from NOT
- GRB 090113: Enhanced Swift-XRT position
- GRB 090113: ROTSE-III Optical Limits
- GRB 090113: Swift detection of a burst
- GRB 090112: Fermi GBM detection
- GRB 090111: Swift UVOT Upper Limits
- GRB 090111: Swift-XRT refined analysis
- GRB 090111: Enhanced Swift-XRT position
- GRB 090111: Swift detection of a burst
- GRB 090107B: Swift XRT afterglow confirmation
- GRB 090107B: Swift/UVOT Observations
- GRB 090107B: Swift-XRT detection of possible afterglow
- VLA radio upper limit on GRB 090102
- GRB 090102: GRT Optical Observation
- Swift triggered on the HMXB 1A 1118-61
- GRB 090102: P60 Imaging and P200 Spectroscopy
- GRB 090102 Observations from IAC80
- GRB 090102: GROND observations of the optical afterglow
- GRB 090102: Swift-BAT refined analysis
- GRB 090102: NOT redshift
- GRB 090102: Enhanced Swift-XRT position
- GRB 090102: REM observations of a bright afterglow
- GRB 090102: Swift detection of a burst with an optical counterpart
- GRB 090102: TAROT Calern observatory optical observations
- GRB 081230: GROND confirmation of the afterglow
- GRB081230: Swift-XRT refined analysis
- GRB 081230 Swift/UVOT Observations
- GRB 081230: Enhanced Swift-XRT position
- GRB 081230: Swift detection of a burst
- GRB 081228, Swift-BAT refined analysis
- VLA radio detection of GRB 081221
- GRB 081228: Swift/UVOT Upper Limits
- GRB 081228: Swift-XRT Team refined analysis
- GRB 081228: detection by GROND
- GRB 081228: Enhanced Swift-XRT position
- GRB 081228: TAROT Calern observatory optical observations
- GRB 081228: Swift detection of a burst
- VLA radio observation of GRB 081221
- GRB 081226B: Swift XRT and UVOT upper limits
- GRB 081226: Swift-XRT refined analysis
- GRB 081226A: Swift UVOT Upper Limits
- GRB 081226: GROND afterglow candidate
- GRB 081226: ROTSE-III Optical Limits
- GRB 081226: Swift detection of a possible short-hard burst
- GRB 080810: optical observations
- GRB 081211B: optical observations
- GRB 081224: Swift-XRT observation
- GRB 081222: MITSuME optical observation
- GRB 081221: GROND observations
- VLA radio upper limit on GRB 081222
- GRB 081221: Probable host galaxy in Keck imaging
- GRB 081222, Swift-BAT refined analysis
- GRB081222 optical limit by "Pi of the Sky"
- Konus-Wind observation of very bright GRB 081215A
- GRB 081222: Swift XRT refined analysis
- IPN triangulation of bright GRB 081215A
- GRB 081222: Faulkes Telescope South observations
- GRB 081221: Gemini-N nIR imaging
- GRB081222, optical observation
- GRB081203A: BTA observation
- Konus-Wind observation of GRB 081221
- GRB 081222: GROND Detection of the Optical/NIR Afterglow
- GRB081222: REM candidate afterglow
- GRB 081222: Swift detection of a burst with a bright optical afterglow
- GRB 081221: Enhanced Swift-XRT position
- GRB 081221: further NOT observations
- GRB 081221: NOT observations
- GRB 081221: Swift detection of a burst
- GRB 081118: Zadko observations
- Fermi Trig Num 251059717 = SGR 0044+42: MASTER prompt optical observations
- GRB 0811215A: MASTER prompt optical observations
- GRB 081215A: Andromeda inside Fermi error box: MASTER observations
- GRB 0811215A: Andromeda inside Fermi error box: MASTER observations
- Possible GRB 081211B: Swift/UVOT Upper Limits
- Possible GRB 081211B - Swift-XRT analysis
- GRB 081207: Fermi GBM detection