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"19538 results found.
- GRB 050319: Detection of Possible Optical Counterpart
- GRB 050318: Swift/UVOT detection of afterglow emission
- GRB050318: Swift XRT position
- Swift-BAT detection of GRB 050318
- GRB050223: analysis of the XMM-Newton observation
- GRB 050306: ROTSE-III early limits
- GRB 050315: Swift-BAT further refined analysis
- GRB050315: Swift-BAT Refined analysis
- Non-detection of GRB050315 in ATCA Radio Observations
- GRB 050315: Swift XRT Position
- GRB 050315: Early Observations with Swift/UVOT
- Swift-BAT detection of GRB 050315
- GRB050223: No XMM-Newton OM detection of afterglow emission
- GRB050309: CONCAM pre-trigger and trigger coincident optical
- GRB 050126: Redshift determination
- Swift-BAT trigger 107873: No Swift XRT counterpart
- GRB 050306: Confirmation of X-ray afterglow
- GRB 050309, Early optical limits from RAPTOR
- Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
- GRB 050309 : Lulin R-band observation
- Swift 107873: P60 Optical Observations
- GRB 050306: CORRECTION to date of observation
- GRB 050306: No Swift UVOT Optical Counterpart Detected
- GRB 050306: Possible X-ray Afterglow Position from the Swift
- Swift trigger 107518: optical observation
- GRB 050306,optical observation
- GRB 050306: Swift-BAT detection of a long burst
- GRB050215B: Late-Time Swift UVOT Observations
- PROMPT VRcIc Observations of GRB 050223
- GRB 050223: optical observations
- GRB050223 XMM-Newton observation
- INTEGRAL detection of GRB 050223
- GRB050223: No Swift UVOT Detection of Afterglow Emission
- GRB050223: ROTSE-III Optical Observations
- GRB 050223 Swift/BAT detection of a burst
- GRB 050223: Swift XRT Position
- GRB050219b: CORRECTION to time of UVOT observations
- GRB050219b: No Swift UVOT Detection of Afterglow Emission
- GRB 050219b: CORRECTION to refined XRT position
- GRB050219b: No Swift UVOT Detection of Afterglow Emission
- GRB 050219b: Refined XRT position
- GRB 050219b: Swift-BAT detection of a burst
- GRB 050219b: CORRECTION: Swift XRT Position
- GRB 050219b: Swift XRT Position
- GRB 050219a, optical observations
- GRB 050219a: Refined XRT position
- GRB050219a: No Swift UVOT Detection of Afterglow Emission
- GRB 050219: Swift-BAT detection of a burst
- GRB050215b: Swift UVOT Detection of Afterglow Emission
- GRB 050219: Prompt X-ray position
- GRB 050215b: XRT confirmation of IR afterglow candidate
- GRB050215b: P60 Optical Observations
- GRB 050215b: Swift XRT Source Variability
- GRB 050215B: candidate afterglow
- GRB 050215b : Lulin follow-up observation
- GRB 050215b, BOOTES-2 simultaneous optical observations
- GRB 050215B: UKIRT K-band imaging
- GRB 050215b: Swift XRT Observations
- GRB050215b: No Swift UVOT Detection of Afterglow Emission
- GRB050215a: No Swift UVOT Detection of Afterglow Emission
- Swift-BAT detects two bursts: GRB050215a and GRB050215b
- GRB050215B: ROTSE-III optical observations
- GRB050215A: ROTSE-III Optical Observations
- short/hard GRB 050202, optical observations
- GRB 050128: Radio observations
- Further analysis of the short Swift-BAT GRB 050202
- GRB 050202: Second epoch radio observations
- GRB050202: Radio Observations
- GRB 050202: Short burst detected by Swift-BAT
- SGR1806-20: Swift-BAT detection of a large normal burst
- GRB050128: Faulkes Telescope South observations
- GRB050128,optical observations
- GRB050126: Updated Swift XRT Position
- GRB 050126: Radio Observations
- GRB050128 Swift-BAT observations
- GRB 050128: Swift XRT prompt afterglow position
- GRB 050124: K-band afterglow observations
- GRB050126: MASTER optical limit for KECK OT
- GRB050126: Burst Parameters Measured by BAT
- GRB050126: MASTER optical observations
- GRB 050126: Prompt XRT detection and localization
- GRB050124: No Swift UVOT Detection of Afterglow Emission
- GRB 050117a: Radio Observations
- GRB050124,optical observation
- GRB050124: Updated Swift XRT Position and Fluxes
- GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
- GRB050124: Refined BAT position, spectral and fluence information
- GRB050124: Swift-BAT position of a double-peaked burst
- GRB050117a: Radio Observations
- GRB050117a: Refined analysis
- GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
- GRB050117b: Swift-BAT detection of a weak burst
- GRB050117: optical observation
- GRB 050117, I-band observations
- GRB 050117: Optical observation
- GRB050117: Refined XRT position
- GRB050117: MASTER optical observations
- MASTER:GRB050117 SWIFT
- GRB050117: Swift-BAT detection of a long multi-peaked burst
- GRB050117: Swift XRT Position