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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"

41627 results found.

  1. GRB 070612B: KAIT limits
  2. GRB 070612A: SARA detection of possible OT
  3. GRB 070610: TAROT Calern observatory optical observations
  4. GRB 070610: MITSuME OAO optical upper limit
  5. GRB 070612B: Swift detection of a burst
  6. GRB070612 - SDSS Pre-Burst Observations
  7. GRB 070612: Swift detection of a burst
  8. GRB 070610: OPTIMA-Burst detection of continued strong flaring activity
  9. GRB 070610: SARA upper limit
  10. GRB 070610: Swift-XRT refined analysis
  11. GRB 070610: TLS RRM sees flaring behaviour - Galactic transient?
  12. GRB 070611: Swift/UVOT Observations
  13. GRB 070611: Swift-XRT refined analysis
  14. GRB 070611, Swift-BAT refined analysis
  15. GRB 070610: Optical observations from OSN
  16. GRB 070611: VLT redshift
  17. GRB 060121 : pseudo-z = 1.9 ('intermediate-duration' burst)
  18. GRB 070611; Swift-XRT position
  19. GRB 070611: ROTSE-III Optical Limits
  20. GRB 070611: Swift detection of a burst
  21. GRB 070610: Swift-UVOT Upper Limits
  22. GRB 070610: OPTIMA-Burst high-time-resolution optical observations
  23. GRB 070610, Swift-BAT refined analysis
  24. GRB 070610; Swift-XRT position
  25. GRB 070610: Swift detection of a burst
  26. GRB 070412: TAROT Calern observatory optical observations
  27. GRB 070411: TAROT Calern observatory optical observations
  28. GRB 070419A, deep LBT photometry and possible supernova detection
  29. GRB070520B: optical observations
  30. GRB070520: optical observation
  31. GRB070518: optical observation
  32. GRB070521: optical observation
  33. Swift/UVOT refined analysis of GRB070531
  34. GRB 070531: NOT nIR observations
  35. GRB 070531: I-band observations from IAC80
  36. GRB 070531: Swift-XRT position
  37. GRB 070531: Liverpool Telescope Optical Observations
  38. GRB 070531: Swift detection of a burst
  39. GRB 070529: SARA upper limit
  40. Swift/UVOT refined analysis of GRB070529
  41. GRB 070529: MARGE Observations
  42. GRB 070529: Optical aterglow from MIRO
  43. GRB 070529: Gemini Redshift
  44. GRB 070529: Swift-XRT refined analysis
  45. GRB 070529, Swift-BAT refined analysis
  46. GRB 070529: Xinglong TNT Optical Upper Limit
  47. GRB 070529: Swift detection of a burst with an optical aterglow
  48. GRB 070412: Deep Keck imaging
  49. Swift Triggers 280447, 280450 and 280451 are invalid
  50. Swift trigger 280447 is probably a Galactic transient
  51. GRB 070518, deep LBT photometry
  52. GRB 070518: MARGE Observations
  53. Konus-Wind observation of GRB 070521
  54. GRB 070518: optical observation
  55. GRB070521: Second Epoch Gemini Imaging
  56. GRB070521: NIR observations
  57. GRB070520B: NIR observations
  58. GRB 070521: Swift/UVOT Upper Limits
  59. GRB 070521: Swift-XRT refined analysis
  60. GRB 070521: Keck imaging
  61. GRB070521: Gemini Observations
  62. GROND upper limits of GRB 070521
  63. GRB 070521 Milagro GeV/TeV Observations
  64. GRB 070520B: SARA upper limit
  65. GRB 070520A: SARA upper limit
  66. GRB 070521: SARA upper limit
  67. GRB 070521: Subaru observations and possible host detection
  68. GRB070518: Optical/NIR observation
  69. GRB 070520B: Swift/UVOT Upper Limits
  70. GRB 070520A: Subaru Observations
  71. GRB 070521, Swift-BAT refined analysis
  72. GRB 070520A: Swift UVOT Upper Limits
  73. GRB 070520B: Swift-XRT refined analysis
  74. GRB 070521: optical limit by Pi of the Sky
  75. GRB070521: P200 Observations
  76. GRB070521 : Faulkes Telescope North Observations
  77. GRB 070521: TAROT La Silla observatory optical observations
  78. GRB070521: Bright SDSS Galaxy Near XRT Error Circle
  79. GRB070521 - SDSS Pre-Burst Observations
  80. GRB 070521: Swift detection of a burst
  81. GRB 070520A: MITSuME Akeno optical upper limits
  82. GRB 070520B, Swift-BAT refined analysis
  83. GRB 070520A, Swift-BAT refined analysis
  84. GRB 070520A: Swift-XRT refined analysis
  85. GRB 070518: TNG observations
  86. GRB 070520B: Swift detection of a burst
  87. GRB 070520: Xinglong EST optical Upper Limit
  88. GRB 070520: Swift detection of a burst
  89. VLA observation of GRB 070518
  90. GRB 070518: Swift-XRT refined analysis
  91. GRB 070517: Gemini optical imaging
  92. GRB070518: UVOT refined analysis
  93. GRB070518: OSN observation
  94. GRB 070518, Swift-BAT refined analysis
  95. GRB 070518: OT confirmed form Xinglong TNT observation
  96. GRB 070518: Swift detection of a burst with optical afterglow
  97. GRB070517: Swift-XRT Refined Analysis
  98. GRB 070517: Swift detection of a burst
  99. GRB 070509: objects inside XRT error circle
  100. GRB 070512: IPN localization and Konus spectrum of a bright burst

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