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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').
  1. GRB 070612A: Super-LOTIS observations
  2. GRB 070612A: Rapid Decay
  3. GRB 070612A: Suzaku/WAM observation of the prompt emission
  4. SWIFT J195509.6+261406 / GRB 070610: OPTIMA-Burst observations
  5. GRB070612A: MITSuME Okayama Observation
  6. GRB 070612A: continued SARA observations
  7. GRB 070612A: spectral lag
  8. GRB 070611: Watcher Observations
  9. Swift Trigger 282176 is Cygnus X-1
  10. GRB 070612A: MDM Observations
  11. GRB 070612A: P60 Confirmation of Afterglow and An Underlying, Nearby
  12. GRB 070612B: SARA upper limit
  13. GRB 070612B, Swift-BAT refined analysis
  14. GRB 070612A, Swift-BAT refined analysis
  15. GRB 070612B: Swift-XRT refined analysis
  16. SWIFT J195509.6+261406 / GRB 070610: SWIFT continued observations
  17. GRB 070612B: Swift/UVOT upper limits
  18. GRB 070612B: FRAM limit
  19. GRB070612B: P60 Observations
  20. GRB 070612B: KAIT limits
  21. GRB 070612A: SARA detection of possible OT
  22. GRB 070612B: Swift XRT position from downlink data
  23. GRB 070610: TAROT Calern observatory optical observations
  24. GRB 070610: MITSuME OAO optical upper limit
  25. GRB 070612B: Swift detection of a burst
  26. GRB070612 - SDSS Pre-Burst Observations
  27. GRB 070612: Swift detection of a burst
  28. GRB 070610: OPTIMA-Burst detection of continued strong flaring activity
  29. GRB 070610: SARA upper limit
  30. GRB 070610: Swift-XRT refined analysis
  31. GRB 070610: TLS RRM sees flaring behaviour - Galactic transient?
  32. GRB 070611: Swift/UVOT Observations
  33. GRB 070611: Swift-XRT refined analysis
  34. GRB 070611, Swift-BAT refined analysis
  35. GRB 070610: Optical observations from OSN
  36. GRB 070610: Watcher Observations
  37. GRB 070611: VLT redshift
  38. GRB 060121 : pseudo-z = 1.9 ('intermediate-duration' burst)
  39. GRB 070611: ROTSE-III Detection of Late Rising Optical Counterpart
  40. GRB 070611; Swift-XRT position
  41. GRB 070611: ROTSE-III Optical Limits
  42. GRB 070611: Swift detection of a burst
  43. GRB 070610: Swift-UVOT Upper Limits
  44. GRB 070610: OPTIMA-Burst high-time-resolution optical observations
  45. GRB 070610, Swift-BAT refined analysis
  46. GRB 070610; Swift-XRT position
  47. GRB 070610: Swift detection of a burst
  48. GRB 070412: TAROT Calern observatory optical observations
  49. GRB 070411: TAROT Calern observatory optical observations
  50. GRB 070419A, deep LBT photometry and possible supernova detection
  51. GRB070520B: optical observations
  52. GRB070520: optical observation
  53. GRB070518: optical observation
  54. GRB070521: optical observation
  55. Swift/UVOT refined analysis of GRB070531
  56. GRB 070531: NOT nIR observations
  57. GRB 070531: Swift-BAT refined analysis
  58. GRB 070531: I-band observations from IAC80
  59. GRB 070531: Swift-XRT position
  60. GRB 070531: Liverpool Telescope Optical Observations
  61. GRB 070531: Swift detection of a burst
  62. GRB 070529: SARA upper limit
  63. Swift/UVOT refined analysis of GRB070529
  64. GRB 070529: MARGE Observations
  65. GRB 070529: Optical aterglow from MIRO
  66. GRB 070529: Gemini Redshift
  67. GRB 070529: Swift-XRT refined analysis
  68. GRB 070529, Swift-BAT refined analysis
  69. GRB 070529: Xinglong TNT Optical Upper Limit
  70. GRB 070529: Swift detection of a burst with an optical aterglow
  71. GRB 070412: Deep Keck imaging
  72. Swift Triggers 280447, 280450 and 280451 are invalid
  73. Swift trigger 280447 is probably a Galactic transient
  74. GRB 070518, deep LBT photometry
  75. GRB 070518: MARGE Observations
  76. GRB 070521: pseudo-z ~ 2.28 from prompt emission spectrum
  77. Konus-Wind observation of GRB 070521
  78. GRB 070518: optical observation
  79. GRB070521: Second Epoch Gemini Imaging
  80. GRB070521: NIR observations
  81. GRB070520B: NIR observations
  82. GRB 070521: Swift/UVOT Upper Limits
  83. GRB 070521, optical observation
  84. GRB 070521: Swift-XRT refined analysis
  85. GRB 070521: Keck imaging
  86. GRB070521: Gemini Observations
  87. GROND upper limits of GRB 070521
  88. GRB 070521 Milagro GeV/TeV Observations
  89. GRB 070520B: SARA upper limit
  90. GRB 070520A: SARA upper limit
  91. GRB 070521: SARA upper limit
  92. GRB 070521: Subaru observations and possible host detection
  93. GRB070518: Optical/NIR observation
  94. GRB 070520B: Swift/UVOT Upper Limits
  95. GRB 070520A: Subaru Observations
  96. GRB 070521, Swift-BAT refined analysis
  97. GRB 070520A: Swift UVOT Upper Limits
  98. GRB 070520B: Swift-XRT refined analysis
  99. GRB 070521: optical limit by Pi of the Sky
  100. GRB070521: P200 Observations

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