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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"

22052 results found.

  1. Swift trigger 280447 is probably a Galactic transient
  2. GRB070521: Second Epoch Gemini Imaging
  3. GRB 070521: Swift/UVOT Upper Limits
  4. GRB 070521, optical observation
  5. GRB 070521: Swift-XRT refined analysis
  6. GRB 070521: Keck imaging
  7. GRB070521: Gemini Observations
  8. GROND upper limits of GRB 070521
  9. GRB 070520B: SARA upper limit
  10. GRB 070520A: SARA upper limit
  11. GRB 070521: SARA upper limit
  12. GRB 070521: Subaru observations and possible host detection
  13. GRB 070520B: Swift/UVOT Upper Limits
  14. GRB 070520A: Subaru Observations
  15. GRB 070520A: Swift UVOT Upper Limits
  16. GRB 070520B: Swift-XRT refined analysis
  17. GRB070521 : Faulkes Telescope North Observations
  18. GRB 070521: TAROT La Silla observatory optical observations
  19. GRB070521 - SDSS Pre-Burst Observations
  20. GRB 070521: Swift detection of a burst
  21. GRB 070520A: MITSuME Akeno optical upper limits
  22. GRB 070520A, Swift-BAT refined analysis
  23. GRB 070518: TNG observations
  24. GRB 070520B: Swift detection of a burst
  25. GRB 070520: Xinglong EST optical Upper Limit
  26. GRB 070520: Swift detection of a burst
  27. VLA observation of GRB 070518
  28. GRB070518: UVOT refined analysis
  29. GRB 070518: OT confirmed form Xinglong TNT observation
  30. GRB 070518: Swift detection of a burst with optical afterglow
  31. GRB 070517: Swift detection of a burst
  32. GRB 070509: objects inside XRT error circle
  33. GRB 070512: IPN localization and Konus spectrum of a bright burst
  34. GRB 070509: Swift/UVOT Upper Limits
  35. GRB 070510: Swift detection of a possible burst
  36. GRB 070508: OA fading and tentative redshift
  37. GRB 070509: REM observations
  38. GRB 070509: Swift detection of a burst
  39. GRB 070509: ROTSE-III Optical Limits
  40. GRB 070508: REM observations
  41. GRB 070508: TAROT La Silla observatory optical observations
  42. GRB 070508: Swift detection of an intense burst with an optical counterpart
  43. GRB 070507: Swift detection of a possible cosmic ray shower event or a possible burst
  44. GRB070506: Swift/UVOT Observations
  45. GRB 070506: Swift detection of a burst with optical afterglow
  46. GRB 070412, deep LBT imaging
  47. GRB070429B: VLT observations
  48. GRB070429B: position correction
  49. GRB 070309: Swift-XRT afterglow confirmation
  50. VLA observation of GRB 070429B
  51. Swift/UVOT observations of GRB070429B
  52. GRB 070429B, Swift-BAT refined analysis
  53. Swift/UVOT observations of GRB070429A
  54. GRB 070429A: optical and NIR observations
  55. GRB 070429B: ROTSE-III Optical Limits
  56. GRB 070429B: Swift detection of a short burst
  57. GRB 070429: ROTSE-III Optical Limits
  58. GRB 070429: Swift detection of a burst
  59. LT monitoring of GRB070412
  60. GRB 070427: Swift detection of a burst
  61. GRB 070411, further deep LBT photometry
  62. GRB 070411: Late-time Keck imaging
  63. GRB070419a: Swift UVOT observations
  64. GRB 070420: Swift XRT refined analysis
  65. GRB070420: Swift UVOT continuing observations
  66. GRB 070420: Faulkes Telescope South Observations
  67. GRB 070420: TAROT La Silla observatory optical observations
  68. GRB 070420: NIR and optical afterglow confirmed
  69. GRB 070420: Swift detection of a burst with optical afterglow
  70. GRB 070419A: MITSuME Okayama Observations
  71. GRB 070419B: Swift XRT refined analysis
  72. GRB070419 - SDSS Pre-Burst Observations
  73. GRB 070419A: SARA observations
  74. GRB 070419A: NAYUTA Optical Observation
  75. GRB 070419A: Optical and IR observations with KANATA
  76. GRB070419A, optical observation
  77. Infrared detection of GRB070419A with UKIRT
  78. GRB 070419A: Kiso Optical observation
  79. GRB 070419: P60 Confirmation of Optical Afterglow
  80. GRB 070419B: Swift detection of a burst
  81. GRB 070419A: ROTSE-III Optical Limits
  82. GRB 070419: Swift detection of a burst
  83. GRB 070418: Optical and IR observations with KANATA
  84. Trigger 276045: Swift detection of a possible burst
  85. GRB 070406: Swift XRT refined analysis
  86. GRB 070318, SMARTS optical/IR afterglow observations
  87. GRB070412: UKIRT-WFCAM JHK upper limits
  88. GRB070412: Swift UVOT observations
  89. GRB 070411: Swift/UVOT observations
  90. GRB 070412, Swift-BAT refined analysis
  91. GRB 070412 Liverpool Telescope optical limit
  92. GRB 070411: Optical photometry at Crni Vrh
  93. GRB 070412: Swift-XRT refined analysis
  94. GRB 070412: Optical observations at Crni Vrh
  95. GRB 070412: further NOT observations
  96. GRB 070412: IAC80 optical afterglow candidate
  97. GRB 070412: NOT observations
  98. GRB 070411, Swift-BAT refined analysis
  99. GRB 070412: Swift detection of a burst
  100. GRB 070411: IAC80 optical observations

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