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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. GRB080310, unusual slow decay in the optical
  2. GRB 080310: GAO 150cm telescope Optical Observation
  3. GRB080310 : Optical observations by LOAO and Lulin
  4. GRB 080310: ROTSE-III Observations of Optical Counterpart
  5. GRB080310: Optical observation by MITSuME telescope
  6. GRB080310, optical observations with the LBT
  7. GRB 080307: GAO 150cm telescope Optical Observation
  8. GRB 080229A: GAO 150cm telescope Optical Observation
  9. GRB 080310: PAIRITEL detection and PAIRITEL+KAIT+UVOT SED
  10. GRB 080307: NIR upper limit
  11. GRB 080229: NIR upper limit
  12. GRB 080310: early RAPTOR multicolor observations
  13. GRB 080310, Swift-BAT refined analysis
  14. GRB080210: optical observations
  15. GRB080307: optical upper limit
  16. GRB 080310: Swift-XRT refined analysis
  17. GRB 080310: Swift/UVOT Refined Analysis
  18. GRB 080310: Redshift from Keck/DEIMOS Spectra
  19. GRB 080310 - SDSS Pre-Burst Observations
  20. GRB080310 : Lulin optical observation
  21. GRB 080310: Enhanced Swift-XRT position
  22. GRB 080310: RRM optical photometry with the VLT
  23. GRB080310, detection of break in optical
  24. GRB 080310: VLT/UVES spectroscopy
  25. GRB080310, optical observations with LBT
  26. GRB 080310: Magellan redshift revision
  27. GRB 080310: Lick/Kast Spectroscopy
  28. GRB080310: Super-LOTIS suggestion of brightening
  29. GRB 080310, SMARTS optical/IR afterglow observations
  30. GRB 080310: REM observations
  31. GRB 080310: Magellan redshift
  32. GRB 080310 afterglow candidate (correction to UT time)
  33. GRB 080310: Swift detection of a burst with optical afterglow
  34. GRB 080310 afterglow candidate
  35. GRB080229, optical upper limit (Correction)
  36. GRB080307, optical upper limit
  37. GRB080307 BOAO optical afterglow observation - detection of a possible OT
  38. GRB080229, optical upper limit
  39. GRB 080307: Swift-XRT Team refined analysis
  40. GRB 080307: Swift/UVOT Upper Limits
  41. GRB 080307: Early RAPTOR Limits
  42. GRB 080307, Swift-BAT refined analysis
  43. GRB080307 - SDSS Pre-Burst Observations
  44. GRB 080307: TNT optical observation
  45. GRB080307: Optical upper limits
  46. GRB 080307: Gemini-N i-band observations - candidate afterglow
  47. GRB 080307: BOAO imaging - retraction and new limit
  48. GRB 080307: retraction of UVOT candidate
  49. GRB 080307: Enhanced Swift-XRT position
  50. GRB 080307, Preliminary Swift-BAT refined analysis
  51. GRB 080307 : BOAO optical afterglow observation
  52. GRB 080307: Optical observation with DMC/KANATA
  53. GRB 080307: Swift detection of a burst
  54. VLA possible radio detection of GRB 080229
  55. GRB 080303: Swift/UVOT follow-up of afterglow detection
  56. GRB 080303, Swift-BAT refined analysis
  57. GRB 080303: Rapid PROMPT Detections
  58. GRB080303: Swift XRT refined analysis
  59. GRB 080303: Enhanced Swift-XRT position
  60. Swift UVOT observations of GRB080229B
  61. GRB080229B: Swift XRT afterglow observation
  62. GRB 080303A: Faulkes Telescope South optical afterglow observations
  63. GRB 080303
  64. GRB 080303: Swift detection of a burst with optical afterglow
  65. GRB 080303: REM NIR afterglow candidate
  66. GRB 080303A: ROTSE-III Optical Limits
  67. GRB 080229: I-band observations from OSN
  68. GRB 080229: VLT NIR observations
  69. GRB080229: Swift XRT refined analysis
  70. GRB 080229: TNG NIR observations
  71. GRB 080229: Deep Gemini/GMOS optical observations
  72. GRB 080229: Enhanced Swift-XRT position
  73. GRB 080229: REM NIR observations
  74. GRB080229: Possible optical afterglow
  75. GRB 080229B: Gamma Ray Burst Localization by SuperAGILE
  76. UVOT analysis for GRB080229
  77. GRB 080229, Swift-BAT refined analysis
  78. GRB 080229: Faulkes Telescope South optical limit
  79. GRB 080229A: ROTSE-III Optical Limits
  80. GRB 080229: Swift detection of a bright burst
  81. Early optical shallow decay in GRB 071112C
  82. GRB080207: optical observations
  83. GRB080205: optical observations
  84. GRB080211: optical observations
  85. XRF 080109/SN2008D : GMRT upper limit at 1.28 GHz
  86. GRB 071010B : Early optical brightening detected by TAOS
  87. Swift-XRT improved positions, and new redshift limits.
  88. ESO optical and NIR observations of GRB 080218B
  89. GRB 080204: Suzaku WAM observation of the prompt emission
  90. GRB 080218B, Swift-BAT refined analysis
  91. GRB 080218B: Swift-XRT refined analysis
  92. Swift/UVOT observations of GRB080218B
  93. GRB 080218B: REM NIR early upper limits
  94. GRB 080212: Mount Abu NIR observations
  95. GRB 080218B: Enhanced Swift-XRT position
  96. GRB 080218B: GROND upper limits
  97. GRB 080218b, SMARTS optical/IR limits
  98. GRB 080218A, Swift-BAT refined analysis
  99. GRB080218B: Watcher prompt limit
  100. GRB 080211: Suzaku WAM observation of the prompt emission

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