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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').
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"
  1. GRB 090429B: Swift detection of a burst
  2. GRB 090429: Swift detection of a burst
  3. GRB 090423: pseudo burst at z=1 and its relation to GRB 080913
  4. GRB 090424 : Multiband Optical observation from Nainital
  5. IPN triangulation of very bright GRB 090427
  6. GRB 090426: R-band limit
  7. GRB 090424: Continued R-band monitoring
  8. GRB 090423: CARMA mm observations
  9. GRB 090423: millimeter detection
  10. GRB 090426: Swift/BAT spectral lag results
  11. GRB 090425: Fermi GBM detection
  12. GRB 090424: Suzaku WAM observation of the prompt emission
  13. GRB 090426: VLT spectroscopy
  14. GRB 090426: GROND Observations of the Optical/NIR Afterglow
  15. GRB 090426: Near infrared observation with ISLE at OAO
  16. GRB 090426: Okayama MITSuME optical observation
  17. GRB090426 Swift/UVOT observations
  18. GRB 090426 Keck LRIS redshift
  19. GRB 090426: Swift-BAT refined analysis
  20. GRB 090426: Swift-XRT refined analysis
  21. GRB 090423: GROND second epoch imaging and refined SED
  22. Detection of bright radio afterglow of GRB 090424 with the VLA
  23. GRB 090426: Enhanced Swift-XRT position
  24. GRB090426: Observation for Optical counterpart from MIRO
  25. GRB 090426, RIMOTS optical upper limits
  26. GRB 090426: inspection of SDSS images
  27. GRB 090426: TNT confimation of optical counterpart
  28. GRB 090426: Swift detection of a burst with an optical counterpart
  29. GRB090424: R-band detection (37.5 hrs post-burst), jet break?
  30. GRB 090424: MASTER-Net prompt optical limit
  31. GRB 090423: Fermi GBM observation (correction of isotropic equivalent energy)
  32. GRB 090424: WHT ISIS spectroscopy
  33. VLA radio observation of high-z GRB 090423
  34. GRB090424: BVRI/R-band detection after 15 hrs burst
  35. GRB 090424 : Lulin 1m telescope optical observations
  36. GRB 090424: THO optical observations
  37. GRB 090424: GROND Observations of the Optical/NIR Afterglow
  38. GRB090423: Y-band limit
  39. GRB 090424 Gemini-South Redshift
  40. GRB 090423: Y-band field calibration update/correction
  41. GRB 090423: Swift/BAT spectral lag results
  42. GRB 090424 : TAOS optical detection
  43. GRB 090424 optical observations
  44. GRB 090424: Liverpool Telescope observations
  45. GRB 090424: Swift-XRT refined analysis
  46. GRB 090424: Optical observations from 1.23m CAHA
  47. GRB 090423: energetic, luminosity and jet break
  48. Swift/UVOT observations of GRB 090424
  49. GRB 090424: MASTER-Net prompt optical observations
  50. GRB 090424: Enhanced Swift-XRT position
  51. GRB 090424: Swift-BAT refined analysis
  52. GRB 090424: Fermi GBM Observation
  53. GRB 090423: Fermi GBM observation
  54. GRB 090422: Fermi GBM observation
  55. GRB 090423: Ep,i - Eiso correlation
  56. GRB 090424: SDSS Galaxy at the Swift position
  57. GRB 090424: TNT optical observations
  58. GRB 090424: ROTSE-III Confimation of Optical Counterpart
  59. GRB 090424: Swift detection of a burst with an optical counterpart
  60. GRB 090423: Refined TNG analysis
  61. GRB090423: Y-band field calibration
  62. GRB 090423 limiting magnitudes
  63. GRB 090423: VLT/ISAAC spectroscopy
  64. GRB 090423: Near infrared observation at Okayama Observatory
  65. GRB 090423: Deep z-band upper limit and confirmation of photo-z
  66. GRB 090423: TNG Amici spectrum
  67. GRB 090423: GROND detection and preliminary photo-z
  68. GRB 090423: NOT z-band limit
  69. GRB 090423: Correction to NIR photometry
  70. GRB 090423: Swift-XRT refined analysis
  71. GRB090418A Rc-band photometry
  72. GRB090423 - Swift/UVOT upper limits.
  73. GRB 090423: NIR photometry and evidence for spectral break
  74. GRB 090422: Swift-XRT refined analysis
  75. GRB090423, RIMOTS optical upper limits
  76. GRB 090423: UKIRT data further analysis
  77. GRB 090423: Enhanced Swift-XRT position
  78. GRB 090423: Swift-BAT refined analysis
  79. GRB 090422: Swift/UVOT Upper Limits
  80. GRB 090423: UKIRT K-band observations
  81. GRB 090423: P60 Observations
  82. GRB 090423: Faulkes Telescope South observations
  83. GRB 090418A: R and I band observation
  84. GRB 090423: Swift detection of a burst
  85. GRB 090422: Liverpool Telescope possible candidate
  86. GRB 090418A: Konus-Wind and Swift/BAT joint spectral analysis
  87. GRB 090422: Swift-BAT refined analysis
  88. GRB 090422: Enhanced Swift-XRT position
  89. GRB 090410: Erratum in GCN 9189
  90. GRB 090408A: Erratum in GCN 9188
  91. GRB 090418B: RTT150 optical observations
  92. GRB 090418A: RTT150 optical observations
  93. GRB 080410: GAO 150cm telescope Optical Observation
  94. GRB 080408A: GAO 150cm telescope Optical Observation
  95. GRB 090422: Liverpool Telescope observations
  96. GRB 090418B: Suzaku WAM observation of the prompt emission
  97. GRB 090422: Swift detection of a burst
  98. GRB 090418C: Fermi GBM Detection
  99. GRB 090418A: Swift/UVOT Detection of the Neighbouring Galaxy
  100. Swift-BAT trigger 349718 is not a burst

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