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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. GMRT upper limit of GRB 070610/SWIFT J195509.6+261406 in 610 MHz
  2. GRB 070612A: TNG optical observations
  3. Swift/UVOT detection of GRB070616 optical afterglow.
  4. GRB070612A: Gemini Spectroscopic Redshift
  5. GRB 070612A: NOT observations
  6. GRB070616: Optical Observation by MITSuME Akeno
  7. GRB 070612B: Optical Observation by MITSuME Akeno
  8. GRB070616: Optical Observation by MITSuME Okayama
  9. GRB 070616, Swift-BAT further refined analysis
  10. GRB 070616: Swift XRT refined circular
  11. GRB 070612A: Possible WSRT Radio Detection
  12. GRB 070616: BTA astrometry and finding chart
  13. GRB 070616: BTA optical observations
  14. Swift/UVOT observations of GRB070616
  15. GRB 070616: TLS observation
  16. Swift XRT observations of the INTEGRAL burst GRB070615: Possible
  17. GRB 070616, Swift-BAT partial refined analysis
  18. GRB 070616: Swift detection of a burst
  19. GRB 070612B: optical observations
  20. UVOT Observations of INTEGRAL burst GRB070615
  21. VLA upper limit on GRB 070610
  22. GRB 070615
  23. GRB 070615: A long GRB detected by INTEGRAL
  24. SWIFT J195509.6+261406 (GRB 070610): further observations
  25. GRB 070612A: Super-LOTIS observations
  26. GRB 070612A: Rapid Decay
  27. GRB 070612A: Suzaku/WAM observation of the prompt emission
  28. SWIFT J195509.6+261406 / GRB 070610: OPTIMA-Burst observations
  29. GRB070612A: MITSuME Okayama Observation
  30. GRB 070612A: continued SARA observations
  31. GRB 070612A: spectral lag
  32. GRB 070611: Watcher Observations
  33. Swift Trigger 282176 is Cygnus X-1
  34. GRB 070612A: MDM Observations
  35. GRB 070612A: P60 Confirmation of Afterglow and An Underlying, Nearby
  36. GRB 070612B: SARA upper limit
  37. GRB 070612B, Swift-BAT refined analysis
  38. GRB 070612A, Swift-BAT refined analysis
  39. GRB 070612B: Swift-XRT refined analysis
  40. SWIFT J195509.6+261406 / GRB 070610: SWIFT continued observations
  41. GRB 070612B: Swift/UVOT upper limits
  42. GRB 070612B: FRAM limit
  43. GRB070612B: P60 Observations
  44. GRB 070612B: KAIT limits
  45. GRB 070612A: SARA detection of possible OT
  46. GRB 070612B: Swift XRT position from downlink data
  47. GRB 070610: TAROT Calern observatory optical observations
  48. GRB 070610: MITSuME OAO optical upper limit
  49. GRB 070612B: Swift detection of a burst
  50. GRB070612 - SDSS Pre-Burst Observations
  51. GRB 070612: Swift detection of a burst
  52. GRB 070610: OPTIMA-Burst detection of continued strong flaring activity
  53. GRB 070610: SARA upper limit
  54. GRB 070610: Swift-XRT refined analysis
  55. GRB 070610: TLS RRM sees flaring behaviour - Galactic transient?
  56. GRB 070611: Swift/UVOT Observations
  57. GRB 070611: Swift-XRT refined analysis
  58. GRB 070611, Swift-BAT refined analysis
  59. GRB 070610: Optical observations from OSN
  60. GRB 070610: Watcher Observations
  61. GRB 070611: VLT redshift
  62. GRB 060121 : pseudo-z = 1.9 ('intermediate-duration' burst)
  63. GRB 070611: ROTSE-III Detection of Late Rising Optical Counterpart
  64. GRB 070611; Swift-XRT position
  65. GRB 070611: ROTSE-III Optical Limits
  66. GRB 070611: Swift detection of a burst
  67. GRB 070610: Swift-UVOT Upper Limits
  68. GRB 070610: OPTIMA-Burst high-time-resolution optical observations
  69. GRB 070610, Swift-BAT refined analysis
  70. GRB 070610; Swift-XRT position
  71. GRB 070610: Swift detection of a burst
  72. GRB 070412: TAROT Calern observatory optical observations
  73. GRB 070411: TAROT Calern observatory optical observations
  74. GRB 070419A, deep LBT photometry and possible supernova detection
  75. GRB070520B: optical observations
  76. GRB070520: optical observation
  77. GRB070518: optical observation
  78. GRB070521: optical observation
  79. Swift/UVOT refined analysis of GRB070531
  80. GRB 070531: NOT nIR observations
  81. GRB 070531: Swift-BAT refined analysis
  82. GRB 070531: I-band observations from IAC80
  83. GRB 070531: Swift-XRT position
  84. GRB 070531: Liverpool Telescope Optical Observations
  85. GRB 070531: Swift detection of a burst
  86. GRB 070529: SARA upper limit
  87. Swift/UVOT refined analysis of GRB070529
  88. GRB 070529: MARGE Observations
  89. GRB 070529: Optical aterglow from MIRO
  90. GRB 070529: Gemini Redshift
  91. GRB 070529: Swift-XRT refined analysis
  92. GRB 070529, Swift-BAT refined analysis
  93. GRB 070529: Xinglong TNT Optical Upper Limit
  94. GRB 070529: Swift detection of a burst with an optical aterglow
  95. GRB 070412: Deep Keck imaging
  96. Swift Triggers 280447, 280450 and 280451 are invalid
  97. Swift trigger 280447 is probably a Galactic transient
  98. GRB 070518, deep LBT photometry
  99. GRB 070518: MARGE Observations
  100. GRB 070521: pseudo-z ~ 2.28 from prompt emission spectrum

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