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"21393 results found.
- GRB 050813: Swift-BAT refined analysis
- GRB 050813: Photometry of object in XRT error circle
- GRB050813: SWIFT/UVOT observation
- GRB 050813: Swift XRT afterglow localization
- GRB 050813: Possible Short Swift-BAT GRB
- GRB050813 (Swift 150139): P60 Observations
- Swift-BAT trigger 150131 is not a GRB
- GRB050803: CrAO optical observations, no OT candidate
- GRB 050803: PROMPT BVRcIc Observations
- GRB050805b: CrAO optical limit
- GRB050805a : Null detection report
- GRB050803, optical observations
- Swift-BAT trigger 149118 is very likely not a GRB
- Retraction of Swift Trigger 149131 (GRB 050805B)
- GRB 050805b: OHP optical limits
- GRB 050805b: TAROT optical limits
- GRB050805b: MASTER optical observations
- Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
- GRB050805a: MASTER optical candidat
- Swift-BAT trigger 149118 is probably not a GRB
- GRB 050803: RTT150 optical observations
- GRB050803: CrAO optical observations, possible OT candidate
- GRB050803: Optical/UV Upper Limits from Swift-UVOT
- GRB 050803: Keck Observations
- GRB 050803: Swift-BAT refined analysis
- GRB050803: MASTER further analys
- GRB 050803: Magellan Observations
- GRB 050803: early Swift XRT analysis results
- GRB 050803: TAROT optical limits
- GRB050803: MASTER optical observations
- GRB050803: Swift-BAT detection of a very long burst
- GCN GRB observation 050713A
- GRB 050802: Swift/UVOT optical and UV detections
- GRB050802 radio non-detection
- GRB 050730: OHP optical observations
- GRB 050802: early Swift XRT analysis results
- GRB 050802: Swift/UVOT observations
- GRB 050802: Swift-BAT refined analysis
- GRB050801: Optical photometry and decay index
- GRB 050802: XRT position
- GRB 050802: Swift Gamma-ray Burst
- GRB050801: Swift/UVOT Optical and UV detections
- GCN 050801: early Swift XRT analysis results
- GRB 050801: Swift-BAT refined analysis
- GRB 050801, afterglow observations
- GRB 050730, corrected photometry and break?
- GRB 050801: ROTSE-III Early Afterglow Break
- GRB050801: Swift-BAT detection of a burst
- GRB050801: GCN XRT position is incorrect
- GRB 050801: ROTSE-III Detection of Possible Counterpart
- GRB 050730: XRT refined analysis
- GRB 050730: early TAROT optical observations
- GRB 050726: PROMPT Rc Observations
- Swift/UVOT photometry of GRB050730
- GRB050730: Refined BAT analysis of the Swift-BAT burst
- GRB 050730: Swift XRT afterglow observations
- GRB 050730 XMM-Newton observation
- GRB050730, afterglow observations
- GRB 050730: Redshift Measurement based on Magellan/MIKE Observations
- GRB050730: Liverpool Telescope optical observations
- GRB 050730, optical candidate
- GRB050730: Swift-BAT detection of a weak burst
- GRB 050713A: Swift XRT extended light curve
- GRB050713b: Maidanak optical observations
- GRB050726: Swift UVOT observations
- GRB 050724: Chandra Observations of the X-ray Afterglow
- GRB050713: analysis of the XMM-Newton observation
- Swift-BAT trigger 147918 is not a real GRB
- GRB 050727: RTT150 optical observations
- GRB050727: KAIT optical limit
- GRB 050726: PROMPT Rc Observations
- GRB 050724: dust-scattered X-ray halo detected in SWIFT/XRT observation
- GRB050724: Further Radio Observations
- GRB 050726: early Swift XRT analysis results
- GRB050726: Swift-BAT detection of a weak burst
- GRB 050724: J-band observations
- GRB 050724: GMOS Imaging and Spectroscopy
- GRB 050724: SWIFT XRT refined position
- GRB050724: Radio Observation
- GRB 050724: spectroscopy of object in the XRT error circle
- GRB 050724: optical and near-IR observations
- GRB 050724: Optical imaging/astrometry
- GRB 050724: Swift/UVOT Upper Limit
- GRB 050724: early Swift XRT analysis results
- GRB050724: Refined analysis of the Swift-BAT possible short burst
- GRB 050724: possible host galaxy in DSS
- GRB050724: a short-burst detected by Swift
- Swift-BAT trigger 147325 is not due to a real GRB
- GRB050723: XRT distributed coordinates are not related to the burst
- GRB 050721A: Swift-BAT refined analysis
- GRB 050721A: Early Swift XRT analysis results
- GRB 050721: optical afterglow confirmed
- Swift BAT Trigger 146986 is SWIFT J1753.5-0127
- GRB 050721a: Optical Observations
- GRB050721A: Swift-BAT detection of a weak burst
- GRB 050717: PROMPT RcIc Observations
- GRB050714b: Radio Observation
- GRB 050714a: Refined XRT analysis and afterglow confirmation
- Swift-BAT trigger 146731 is not a real GRB
- Swift-BAT detection of a possible GRB