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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"

32509 results found.

  1. GRB 070610: SARA upper limit
  2. GRB 070610: Swift-XRT refined analysis
  3. GRB 070610: TLS RRM sees flaring behaviour - Galactic transient?
  4. GRB 070611: Swift/UVOT Observations
  5. GRB 070611: Swift-XRT refined analysis
  6. GRB 070611, Swift-BAT refined analysis
  7. GRB 070610: Watcher Observations
  8. GRB 070611: VLT redshift
  9. GRB 070611: ROTSE-III Detection of Late Rising Optical Counterpart
  10. GRB 070611; Swift-XRT position
  11. GRB 070611: ROTSE-III Optical Limits
  12. GRB 070610: Swift-UVOT Upper Limits
  13. GRB 070610: OPTIMA-Burst high-time-resolution optical observations
  14. GRB 070610, Swift-BAT refined analysis
  15. GRB 070610; Swift-XRT position
  16. GRB 070411: TAROT Calern observatory optical observations
  17. GRB 070419A, deep LBT photometry and possible supernova detection
  18. GRB070520B: optical observations
  19. GRB070520: optical observation
  20. GRB070518: optical observation
  21. GRB070521: optical observation
  22. Swift/UVOT refined analysis of GRB070531
  23. GRB 070531: Swift-BAT refined analysis
  24. GRB 070531: Swift-XRT position
  25. GRB 070531: Liverpool Telescope Optical Observations
  26. GRB 070529: SARA upper limit
  27. Swift/UVOT refined analysis of GRB070529
  28. GRB 070529: MARGE Observations
  29. GRB 070529: Optical aterglow from MIRO
  30. GRB 070529: Gemini Redshift
  31. GRB 070529: Swift-XRT refined analysis
  32. GRB 070529, Swift-BAT refined analysis
  33. GRB 070529: Xinglong TNT Optical Upper Limit
  34. GRB 070412: Deep Keck imaging
  35. Swift Triggers 280447, 280450 and 280451 are invalid
  36. GRB 070518, deep LBT photometry
  37. GRB 070518: MARGE Observations
  38. Konus-Wind observation of GRB 070521
  39. GRB 070518: optical observation
  40. GRB070521: Second Epoch Gemini Imaging
  41. GRB070521: NIR observations
  42. GRB070520B: NIR observations
  43. GRB 070521: Swift/UVOT Upper Limits
  44. GRB 070521, optical observation
  45. GRB 070521: Swift-XRT refined analysis
  46. GRB 070521: Keck imaging
  47. GRB070521: Gemini Observations
  48. GROND upper limits of GRB 070521
  49. GRB 070521 Milagro GeV/TeV Observations
  50. GRB 070520B: SARA upper limit
  51. GRB 070520A: SARA upper limit
  52. GRB 070521: SARA upper limit
  53. GRB 070521: Subaru observations and possible host detection
  54. GRB070518: Optical/NIR observation
  55. GRB 070520B: Swift/UVOT Upper Limits
  56. GRB 070520A: Subaru Observations
  57. GRB 070521, Swift-BAT refined analysis
  58. GRB 070520A: Swift UVOT Upper Limits
  59. GRB 070520B: Swift-XRT refined analysis
  60. GRB070521: P200 Observations
  61. GRB070521 : Faulkes Telescope North Observations
  62. GRB070521: Bright SDSS Galaxy Near XRT Error Circle
  63. GRB 070520A: MITSuME Akeno optical upper limits
  64. GRB 070520B, Swift-BAT refined analysis
  65. GRB 070520A, Swift-BAT refined analysis
  66. GRB 070520A: Swift-XRT refined analysis
  67. GRB 070518: TNG observations
  68. GRB 070520: Xinglong EST optical Upper Limit
  69. VLA observation of GRB 070518
  70. GRB 070518: Swift-XRT refined analysis
  71. GRB 070517: Gemini optical imaging
  72. GRB070518: UVOT refined analysis
  73. GRB 070518, Swift-BAT refined analysis
  74. GRB 070518: OT confirmed form Xinglong TNT observation
  75. GRB070517: Swift-XRT Refined Analysis
  76. GRB 070517, Swift-BAT refined analysis
  77. GRB 070509: objects inside XRT error circle
  78. GRB070419A: optical observations
  79. GRB 070419A, Deep LBT photometry
  80. GRB 070509: Swift/UVOT Upper Limits
  81. Konus-Wind and Konus-A observation of GRB 070508
  82. Swift-BAT trigger 278987 is not a GRB
  83. GRB070509: Swift-XRT Refined Analysis
  84. RHESSI Spectrum of GRB070508
  85. GRB 070508: OA fading and tentative redshift
  86. GRB 070509, Swift-BAT refined analysis
  87. GRB 070508: Suzaku/WAM observation of the prompt emission
  88. GRB 070509: REM observations
  89. GRB 070509: ROTSE-III Optical Limits
  90. GRB070508: Swift/UVOT Observations
  91. GRB 070508, SMARTS optical afterglow observation
  92. GRB 070508, Swift-BAT refined analysis
  93. GRB 070508: Multicolor optical observations and possible redshift limit
  94. GRB 070508: Swift-XRT refined analysis
  95. GRB 070508: Optical observation limiting magnitude
  96. GRB 070508: Optical afterglow detection
  97. GRB 070508: REM observations
  98. GRB070412: MAGIC telescope GeV observation
  99. Swift-BAT trigger 278809 is not a GRB
  100. GRB 070506: VLT redshift

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