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"45463 results found.
- GRB050509B: Optical/Infared observations
- GRB 050509b: Swift/UVOT follow-up measurements
- GRB 050509b Milagro GeV/TeV Observations
- GRB050509B: Optical observations at the Very Large Telescope
- GRB 050509b: No Optical Variability in XRT Error Circle
- GRB050416: Afterglow detection at 188 nm with Swift UVOT
- GRB 050509a: Swift-BAT refined analysis
- GRB 050509c: ROTSE-III Optical Limits
- GRB 050509B: WSRT Radio Observations
- GRB050509c: REM NIR and Optical observations (errata corrige to GCN 3400)
- GRB 050505, early TAROT observation
- GRB050509c (=H3751): An X-Ray Flash Localized By HETE
- GRB 050509b: Further Analysis of Keck LRIS Images
- GRB050509c: REM NIR and Optical observations
- GRB 050509b: Physical Properties of the Candidate Host galaxy
- GRB 050505: SARA Observations
- Swift UVOT Follow-up Observations of GRB 050509B
- GRB 050509B, Optical Observations
- GRB 050509B: Swift/XRT refined analysis
- GRB050509a: Swift UVOT observations
- GRB 050509b: Optical observations
- GRB 050509b: Precision Astrometry
- GRB 050509b: Possible Optical Counterpart
- Keck/DEIMOS Spectrum of Possible Host Galaxy for GRB050509b
- GRB 050509A: Optical observations
- GRB 050509b: Optical Counterpart Candidate
- GRB050509b: Radio Observations
- GRB 050509b: PAIRITEL and WIYN Observations
- GRB 050509b: Swift-BAT refined analysis of the short hard burst
- GRB 050509b: optical observations
- GRB 050509b: Swift XRT Position
- GRB 050509B: ROTSE-III Optical Limits
- Swift Detection of GRB050509b: A short duration burst
- GRB 050509a: Swift XRT Position
- Swift Detection of the Burst GRB050509
- Swift-BAT detection of GRB 050507
- GRB 050505: Keck I-band Magnitude
- GRB 050505: early time observations
- GRB 050505 - Faulkes Telescope North observations
- GRB 050502a: Swift XRT Upper Limit
- GRB 050505, simultaneous optical observation
- GRB050505: Infrared observations
- GRB 050505: Further Swift UVOT observations.
- GRB050505: AAVSO observations
- GRB050416A : 1 GHz limit from GMRT
- GRB 050505: Keck absorption spectrum and redshift (z=4.27)
- GRB 050505 UVOT
- GRB050505: Optical Afterglow Candidate
- GRB 050505: Swift XRT Position
- GRB050505 Swift-BAT refined analysis
- GRB 050502a: Optical Observations
- GRB 050416b:Swift XRT afterglow upper limits
- GRB 050416b:Swift XRT afterglow upper limits
- Swift-BAT detection of GRB050505
- GRB 050504: Swift XRT position
- GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
- GRB050502b: Afterglow Confirmation
- GRB050502: P200 Observations (Correction)
- GRB050502: P200 Observations
- GRB 050504 : R band observation at Lulin observatory
- Swift UVOT observation of GRB 050504
- GRB 050504, R band Observations
- GRB050504: Faulkes North optical robotic limit
- GRB 050502b, V band Observations
- GRB050504: P60 Observations
- GRB 050504: A long GRB detected with INTEGRAL
- GRB (?) 050504: IR Observations, Intriguing Source
- GRB 050502b, Optical observations
- GRB050502a: P60 Observations (Correction)
- GRB050502a: P60 Observations
- Renewal of SGR 1806-20 activity
- GRB 050502a: RBO Observations
- GRB 050502A: WSRT Radio Observations
- GRB050502A: Optical Observations
- GRB050502B Swift-BAT refined analysis
- GRB050502B: I band source in XRT error circle
- Swift UVOT refined analysis
- Retraction of Swift-BAT trigger 116145
- GRB 050502a : R band observation at Lulin observatory
- GRB 050502b : optical observation at Lulin observatory
- GRB 050502b: Swift XRT Position
- GRB 050502A: Redshift measurement based on Keck HIRES Observations
- GRB050502B: Optical Limits from ANU 1m
- Swift Detection of the Bright Burst GRB050502b
- GRB 050502: INTEGRAL results
- GRB050502: ANU 1m optical Observations
- GRB 050502: Confirmed variability of the afterglow candidate +
- GRB 050502: PAIRITEL IR Observations
- GRB050502 - Correction on the Optical Candidate from the Liverpool
- GRB050502 - Optical Candidate from the Liverpool Telescope
- GRB 050502 - A long GRB detected with INTEGRAL
- GRB 050502: ROTSE-III Detection of Possible Counterpart
- Swift-BAT Trigger 115881 is not a real GRB
- Swift/BAT possible detection of a weak burst GRB050430
- GRB 050401: Rc observation
- GRB050416a: Radio Detection
- GRB 050422: Swift-UVOT observation
- GRB 050422: Swift-BAT refined analysis
- GRB 050422: Swift XRT Position
- Swift Detection of GRB 050422