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"2744 results found.
- GRB 060522: Swift detection of a burst with possible optical afterglow
- GRB 060512: reanalysis of optical spectra
- GRB 060515: NIR observation
- GRB060515: P200 NIR Observations
- GRB 060515 BAT refined analysis
- GRB 060515: Swift/XRT Team refined analysis
- GRB 060515: Swift/XRT position
- GRB 060515: TAROT optical observation
- GRB060418: optical observations
- GRB 060510B: Swift detection of a burst
- GRB060502B: improvement in the XRT afterglow position
- GRB 060505: Swift XRT Team Refined Analysis
- GRB 060502B: Refined analysis of the Swift-BAT short burst
- Short GRB 060502B: Tautenburg Observation
- GRB 060502B: Swift detection of a short burst
- GRB 060501: MDM Observations
- GRB060428B: possible detection of an optical counterpart by Swift/UVOT.
- GRB 060428: Swift detection of a burst
- GRB060425:MASTER survey observations
- Possible GRB060421: BART limits
- GRB(?) 060421: Swift detection of a burst
- GRB 060322: IAC80 optical observations
- GRB 060323: Swift/UVOT Observations
- GRB 060323: Optical Observations
- GRB 060323: Tautenburg OT candidate retraction
- GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
- GRB 060323: Swift detection of a burst with a possible optical afterglow
- GRB060206: optical observation
- GRB060218: Refined photometric calibration of comparison stars
- GRB 060319: WHT K-band candidate afterglow
- GRB060313:Gemini South Observations
- GRB 060313, SMARTS optical counterpart?
- GRB 060313: Possible optical counterpart
- GRB 060223B: Swift XRT possible afterglow
- GRB 060218/SN 2006aj: ABT observations
- GRB 060223B: Swift-BAT refined analysis
- GRB 060223: Swift-BAT refined analysis
- GRB 060218: rebrightening
- Spectral properties of GRB060218/SN2006aj
- GRB060218: VLT spectroscopy
- GRB 051221B: Swift-XRT Team Refined Analysis
- Oddball GRB 060218, transient or GRB?
- GRB060218: Swift/XRT Team preliminary analysis of the possible burst
- Brightening of the Optical Counterpart of the Possible GRB 060218
- GRB 060218: Pre-burst detection of a possible host galaxy
- GRB 060218A: ROTSE-III Possible Optical Flare
- GRB060218: Swift/XRT refined position of a possible burst
- Preliminary refined analysis of the Swift-BAT trigger 191157
- GRB 060218: Swift-BAT detection of a possible burst
- GRB060213: Swift XRT observations and possible afterglow candidate
- GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy
- GRB 060211B: Swift/BAT refined analysis
- GRB 060209(?): Swift-BAT detection of a possible burst
- Orphan GRB Afterglow candidate
- GRB 060206: Swift-BAT refined analysis
- GRB 060204B: Swift-BAT refined analysis
- GRB 060203: P60 Confirmation of Optical Afterglow
- Possible GRB 060203: candidate optical counterpart
- Swift BAT Trigger 180151: Swift XRT source detection
- Possible GRB 060203: optical observations at Asiago
- Swift-BAT trigger 180151 is unknown origin at this time
- GRB 060121: Gemini Late-time Observations
- GRB 051211A: MDM Observations
- GRB 060123: Gemini spectroscopy of the putative host galaxy
- Possible GRB 051221B: MDM Correction
- GRB060105: refined analysis of the Suzaku observation
- GRB 060117: pseudo-z from spectral parameters of the prompt emission
- GRB 060116: possible I-J dropout
- GRB 060111B: MITSuME detection of optical afterglow
- GRB060111A: RTT150 optical observations
- GRB060111B: RTT150, possible host galaxy
- GRB 060111B: Swift detection of a burst
- GRB 060111: possible UVOT counterpart
- GRB 060110: Swift-BAT refined analysis
- GRB051211B: optical observations
- GRB 051227: Swift/UVOT Upper Limits (Possible U-band
- GRB 051227: Further analysis of the Swift-BAT burst
- Possible GRB 051221B: MDM Optical Detection
- Possible GRB 051221B: Swift XRT position
- Swift-BAT detection of a possible burst
- GRB 051221: Possible nearby cluster
- GRB051211A (=H3979): Refined Analysis
- GRB051211A: possible optical candidate
- GRB 051215: near-infrared observations
- GRB 051215: Swift detection of a possible burst
- GRB051105: optical observations
- GRB 051213: Swift-BAT detection of a burst
- GRB051211b: P60 Observations
- GRB 051211A and GRB051211B: BOOTES simultaneous observations
- GRB 051211B: a possible optical detection by TAROT
- HETE SXC localization of GRB 051211 (=H3979)
- IPN observations of SGR1806-20
- Possible resuming of the SGR 1806-20 activity
- GRB 051127: Swift-BAT detection of a possible burst
- GRB 051117B: R and I observations of possible host galaxy
- GRB 051111A: ROTSE-III Detection of Possible Counterpart
- GRB 051109: ROTSE-III Detection of Possible Counterpart
- GRB051103: optical observations
- Chandra Observations of GRB 051022
- GRB 051022, J & K-band observation