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"45442 results found.
- 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
- GRB 050306: further TAROT optical data
- GRB050309: Early optical limit from P60
- 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: R-band observations
- GRB 050306: No Swift UVOT Optical Counterpart Detected
- GRB 050306: REM optical-infrared observations
- GRB 050306: Possible X-ray Afterglow Position from the Swift
- Swift trigger 107518: optical observation
- GRB 050306: TAROT optical observations
- GRB 050306,optical observation
- GRB 050306: Swift-BAT detection of a long burst
- Ongoing activity of SGR 1806-20 after the giant flare
- GRB050215B: Late-Time Swift UVOT Observations
- GRB 050126: Confirmation of the NIR afterglow candidate
- PROMPT VRcIc Observations of GRB 050223
- XRF/GRB 050215B: Radio Observations
- XMM-Newton Images of GRB 050223
- GRB 050219b: candidate NIR afterglow
- IBAS GRB Alert #2321
- Confirmed XRF nature for GRB050215b
- GRB 050223: optical observations
- GRB050223 XMM-Newton observation
- INTEGRAL detection of GRB 050223
- GRB 050223 : Planned XMM-Newton observation
- 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
- HETE-2 Observations of GRB 050215b (=U11570): A Likely X-Ray Flash
- GRB050219b: CORRECTION to time of UVOT observations
- GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
- GRB050219b: No Swift UVOT Detection of Afterglow Emission
- GRB 050219b: CORRECTION to refined XRT position
- GRB 050219a: Optical observations from LCO
- GRB 050219b: Optical and near-IR observations from LCO
- 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: Radio Observations
- 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
- GRB 050215b, BOOTES-1B optical limit
- GRB050215B: ROTSE-III optical observations
- GRB050215A: ROTSE-III Optical Observations
- GRB050209: TAROT optical observations
- GRB 050209(=U11568): Duration and spectrum
- short/hard GRB 050202, optical observations
- GRB050209: REM optical observations
- GRB 050209 I-band observation
- GRB 050209 Optical observations
- GRB050209: P60 Optical Observations
- GRB050209 (=U11568): A Long GRB Detected by HETE
- GRB 050209: Optical observation
- GRB 050128: Radio observations
- Further analysis of the short Swift-BAT GRB 050202
- GRB 050202: Second epoch radio observations
- GRB 050129: Optical observations
- GRB050202: Radio Observations
- GRB 050202: Optical observations with LCO40
- GRB 050202: Short burst detected by Swift-BAT
- GRB 050128 Optical observation with REM
- GRB 050129: a weak long GRB detected with INTEGRAL
- SGR1806-20: Swift-BAT detection of a large normal burst
- GRB050128: Faulkes Telescope South observations
- GRB 050124: Radio Observations
- GRB 050128: near-infrared observations with REM
- GRB050128,optical observations
- GRB 050126: A NIR afterglow candidate in the revised XRT error circle
- GRB050126: Updated Swift XRT Position
- SGR 1806-20: GMRT results at 240 MHz band.
- SGR 1806-20: low frequency GMRT results of 2005 Jan 16.
- GRB 050126: Radio Observations
- GRB050128 Swift-BAT observations
- GRB 050128: Swift XRT prompt afterglow position
- HETE #3667: P60 Observations
- GRB 050124: K-band afterglow observations