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.
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 060801: Swift/XRT Astrometry Correction
- GRB 061028: Futher P200 Observations
- GRB 061028: MDM Observations
- GRB 061028: P200 Observations
- GRB 061028: SARA upper limit
- GRB 061028: z band imaging
- GRB061028: XRT refined analysis
- GRB 061028: Swift/UVOT Observations
- GRB 061028, Swift-BAT refined analysis
- GRB 061028: TAROT Calern observatory late optical observations
- GRB 061028: TAROT Calern observatory optical observations
- GRB 061028: Swift detection of a burst
- GRB 061027, Swift refined analysis of a possible burst
- GRB 061027: Swift detection of a possible burst
- GRB061025: ROTSE-III Confirmation of Optical Counterpart
- GRB061025: Swift XRT refined analysis
- GRB061025: Swift/UVOT observations
- GRB 061019: MITSuME upper limits
- GRB 061025: REM observations
- GRB 061025: Gemini-S observations
- GRB061025: Swift XRT position
- GRB 061025: ROTSE-III Optical Limits
- GRB 061025: a long GRB detected by INTEGRAL
- Swift XRT boresight update
- GRB 061021, Swift-BAT Lag analysis
- Konus-Wind observation of GRB 061021
- GRB 061021 - VLT spectrum without lines
- GRB 061021: Swift-XRT refined analysis
- GRB 061021: Swift/UVOT Observation
- GRB 061021, Swift-BAT refined analysis
- GRB 061021: Swift detection of a burst
- GRB 061019: Super-LOTIS upper limit
- GRB060904b: optical observations
- GRB061019: optical observations
- GRB061019: optical observations
- GRB 061019: SARA upper limit
- GRB 061019: dust-scattered X-ray halo detected in Swift/XRT
- GRB 060930: MARGE Optical Limits
- GRB 061019: Swift/UVOT upper limit
- GRB 061019: SMARTS afterglow confirmation
- GRB061019: Swift XRT refined analysis
- GRB 061019, Swift-BAT refined analysis
- GRB 061019: TAROT La Silla observatory optical observations
- GRB 061019: REM K-band candidate afterglow
- GRB061019: Swift/XRT position
- GRB 061019: Swift-BAT detection of a burst
- GRB 060825: GORT Observations
- GRB 061007: Second Epoch ATCA Radio Observations
- GRB 061007: RHESSI Spectral Fit
- GRB 061007: Suzaku/WAM observation of the prompt emission
- GRB 061006: astrometry-corrected XRT position
- Konus-Wind observation of GRB 061007
- GRB 060928: Confirmation of the X-ray afterglow detected by Swift
- GRB 061007: ATCA Radio Observations
- GRB061007: Swift UVOT followup observations
- GRB 061006: optical afterglow
- GRB 061006 : Suzaku/WAM observation of the prompt emission
- GRB 061007: OA fading and VLT redshift
- GRB 061007: Magellan Spectroscopy
- GRB 061007: Correction to GCN 5712
- GRB 061007: Swift-BAT refined analysis
- GRB 061007: Swift XRT refined analysis
- GRB 061006: Swift/UVOT optical observations
- Konus-Wind observation of the short hard GRB 061006
- GRB 061007 - FTS early brightening and power law decay
- GRB 061007 - Faulkes Telescope South Afterglow Confirmation
- GRB 061007: Swift detection of a burst with an optical counterpart
- GRB 061007: ROTSE-III Detection of Optical Counterpart
- GRB 061006: VLT observation
- GRB 061006: Swift-BAT refined analysis of the short-hard burst
- GRB 061006: Swift-XRT Team Refined Analysis
- GRB061006 (Swift 232585) might be a short-hard GRB
- GRB 060930: near-IR afterglow candidate retraction
- GRB061006: Faulkes Telescope South Observations
- GRB 061006: Swift detection of a burst
- GRB 061004: Optical afterglow candidate and redshift
- GRB 061004: Las Campanas Optical/NIR Observations
- GRB061004: Swift/UVOT optical observations
- GRB 061004: Swift-XRT Team Refined Analysis
- GRB 061004, Swift BAT refined analysis
- GRB 061004: Nearby 2MASS Galaxy
- GRB 060928: Correction to GCN 5690
- GRB 061004: Swift detection of a burst
- GRB 060928: 2 pseudo-z from 2 detections spectral parameters
- Konus-Wind observation of GRB 060928
- GRB 060928: Suzaku/WAM observation of the prompt emission
- IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
- GRB 060928: Swift observations
- GRB 060928: RHESSI Spectral Fit
- IPN triangulation of GRB060928 (long, exceptionally bright)
- GRB061002: Swift UVOT followup observations
- GRB 060930: near-IR afterglow candidate
- GRB 061002: Swift-XRT Team Refined Analysis
- VLA observations of GRB 060926
- GRB061002 - SDSS Pre-Burst Observations
- GRB 061002, Swift-BAT refined analysis
- GRB061002: MASTER-VWF-Kislovodsk observations
- GRB 061002: Swift detection of a burst: CORRECTED CONTENT
- GRB 061002: Swift detection of a burst
- GRB 060908: Detection of a possible host