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"5386 results found.
- GRB051103:_MASTER_optical_observations
- GRB051028:MASTER observations
- GRB051021.63
- Swift-BAT trigger 160640 is not a real GRB
- GRB051021: A GRB Localized by HETE
- GRB050925: Swift UVOT upper limits
- GRB 050916: XRT position
- Swift is in normal operation
- GRB 050906: Possible X-ray Counterpart
- GRB 050906: Radio Observations
- GRB050904: Optical Observations
- Swift-BAT triggers 153461-153465 are not GRBs
- Retraction of Swift-BAT trigger #153355
- GRB050827: Swift-BAT detection of a burst
- GRB050822: Swift/UVOT upper limits
- GRB 050822: Swift-BAT refined analysis
- GRB 050822: ROTSE-III Prompt Optical Limits
- GRB 050822: Swift detection of a long burst
- GRB050820B: Planned XMM-Newton observation
- GRB050820B: BAT-Swift detection of a bright GRB
- GRB050813, SDSS pre-burst observations
- RBO GRB 050714A and GRB 050716 observations
- GRB050730: Radio Detection
- GRB 050730, corrected photometry and break?
- GRB050801: Swift-BAT detection of a burst
- GRB 050730, spectra and optical photometry
- GRB 050730: Swift XRT afterglow observations
- GRB050730, afterglow observations
- GRB 050730 : Planned XMM-Newton observation
- GRB050730: Liverpool Telescope optical observations
- GRB 050730, optical candidate
- GRB 050724, SMARTS optical/IR afterglow observations
- GRB050726: Swift-BAT detection of a weak burst
- GRB 050715: Swift-BAT detection
- Swift detection of a long transient (GRB 050714B?)
- GRB 050712: Swift XRT afterglow position
- GRB 050712: Swift detection of a weak burst
- GRB 050626: Swift XRT observations
- H11603: An X-ray flare from V4641 Sgr, or a possible XRF
- GRB 050626 - a long GRB detected with INTEGRAL
- GRB 050603: INTEGRAL shows it is not a short GRB
- GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
- GRB 050525: MITSuME Optical Observation in VRI
- GRB 050525A: BOOTES simultaneous optical observations
- GRB050525: Optical observations
- XRF 050522: Swift XRT refined analysis
- RBO Observations of GRB050520
- GRB 050505: SARA Observations
- GRB 050502a: Swift XRT Upper Limit
- GRB 050416: Swift/UVOT detection of afterglow emission
- GRB050416: Refined Swift-XRT analysis
- GRB 050416: Swift XRT Position
- GRB050416: P60 Afterglow Candidate
- GRB 050412: Subaru observations
- GRB 050412: optical limit
- GRB 050412: Swift-BAT refined analysis
- GRB 050412: Swift XRT Position
- Swift-BAT Detection of GRB 050412: A Bright, Long Burst
- GRB 050408, SMARTS optical/IR afterglow observations
- GRB 050408: Swift XRT Position
- GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
- GRB050401, radio observation at 4.8 GHz and 8.64 GHz
- GRB050331: No Afterglow Detected
- Swift-BAT detection of a bright outburst from SGR1806-20
- Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
- GRB 050318: Swift/UVOT detection of afterglow emission
- GRB 050318: Magellan optical afterglow identification
- GRB050318: Swift XRT position
- GRB050223: analysis of the XMM-Newton observation
- GRB050316: MASTER before, simultanious and follow up optical
- GRB 050306: ROTSE-III early limits
- GRB 050315, SMARTS optical/IR afterglow observations
- GRB050309: CONCAM pre-trigger and trigger coincident optical
- GRB 050306: Confirmation of X-ray afterglow
- GRB 050306: further TAROT optical data
- GRB 050306: TAROT optical observations
- 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
- 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
- GRB 050215b: Swift XRT Observations
- GRB 050209 Optical observations
- GRB 050209: Optical observation
- GRB 050202: Short burst detected by Swift-BAT
- GRB 050129: a weak long GRB detected with INTEGRAL
- GRB050126: Burst Parameters Measured by BAT
- GRB 050126: Prompt XRT detection and localization
- GRB050124,optical observation
- GRB050124: Updated Swift XRT Position and Fluxes
- GRB050124: Swift-BAT position of a double-peaked burst
- GRB050117: Palomar WIRC Ks-band observations
- GRB050117b: Swift-BAT detection of a weak burst
- Second Epoch VLA observations of SGR 1806-20
- GRB041223: optical and NIR observations with REM
- GRB041219: Confirmed NIR Afterglow
- GRB 041218: Optical Observation