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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"

12316 results found.

  1. GRB 130502A: RATIR Optical and NIR Observations
  2. GRB 130427A: MITSuME Ishigakijima Optical Observation after 5 days
  3. GRB 130502A: Swift detection of a burst
  4. GRB 130425: MASTER-Net optical observations
  5. GRB 130427B: MITSuME Ishigakijima upper limits
  6. GRB 130427B: RATIR Optical and NIR Observations
  7. GRB 130427B: MITSuME Okayama upper limits
  8. GRB 130427A: MAXI/GSC detection
  9. Trigger 554491: Swift detection of a spike possibly from Sgr A*
  10. GRB 130420A: Continued RATIR Optical and NIR Observations
  11. GRB 130420A: Continued RATIR Optical and NIR Observations
  12. GRB 130418A: Continued RATIR Optical and NIR Observations
  13. Swift Trigger 554135 is probably not a GRB or transient
  14. GRB 130420B: RATIR Optical and NIR Observations
  15. GRB 130420B: Weihai optical upper limit
  16. GRB 130420B: Swift/UVOT Upper Limits
  17. GRB 130420A: Swift/UVOT Detection
  18. GRB130420B: GMG optical upper limit
  19. GRB130420A : Xinglong TNT optical upper limit
  20. GRB 130420B: MASTER-Net optical observations
  21. GRB 130420B: Swift detection of a burst
  22. GRB 130419B (Swift trigger Trigger 553930): MASTER-Net optical observations
  23. GRB 130407A: Swift-XRT observations
  24. GRB130408A: Swift/UVOT followup observations
  25. GRB 130407A: MAXI/GSC detection
  26. Swift detection of IGR J18245-2452
  27. GRB 130306A: Confirmation of the X-ray Afterglow
  28. Swift Trigger 552142: a possible GRB
  29. GRB 130327A: Gemini Observations
  30. GRB 130327A: Swift/UVOT Upper Limits
  31. GRB 130327A: ISON-NM optical upper limit
  32. GRB 130327A: RATIR Optical and NIR Observations
  33. GRB 130305A: optical upper limit in Mondy observatory
  34. GRB 130315A: Swift/UVOT Upper Limits
  35. GRB 130313A: optical upper limit in CrAO
  36. GRB 130313A: optical upper limit in Mondy observatory
  37. GRB 130315A: SALT optical observations
  38. GRB 130313A: 5.8 GHz VLA upper limit
  39. Swift XRT observations of GRB 130310A
  40. GRB 130313A: Swift/UVOT Upper Limits
  41. GRB 130305A: PTF P48 optical upper limits
  42. GRB 130315A: Swift detection of a burst
  43. GRB 130305A: TLS Tautenburg observations
  44. GRB 130313A: RATIR Optical and NIR Observations
  45. GRB 130313A: Fading X-ray Afterglow
  46. GRB 130313A: NOT optical upper limit
  47. GRB 130313A: Weihai optical upper limit
  48. GRB 130313A: MASTER-Net optical observations
  49. GRB 130313A: Swift detection of a short burst
  50. GRB 130306A: Swift Detection of a Possible Afterglow
  51. GRB 130306A: MITSuME Ishigakijima upper limits
  52. GRB 130305A: Gemini-North upper limit
  53. GRB 130306A: MASTER-Net pre-Swift alert observation
  54. GRB 130305A: Swift/UVOT Upper Limit
  55. GRB 130305A: RATIR Observations
  56. GRB 121128A: optical upper limit in Maidanak observatory
  57. GRB 130216A: Swift/UVOT Upper Limit
  58. SGR 1806-20 outburst (trigger 549841), Swift-BAT refined analysis
  59. GRB 130216A: possible radio counterpart is steady field source
  60. GRB 130216A: Swift/XRT observations
  61. GRB 130216B: Swift/XRT observations
  62. GRB 130216B: MASTER-Net early observation
  63. GRB 130216A: MASTER-Net early observations
  64. GRB 130216A: MITSuME Ishigakijima upper limits
  65. GRB 130215A: MITSuME Okayama Optical Observation
  66. Swift GRB130206A: late XRT observations.
  67. GRB 130131B: CTIO 0.9-m optical upper-limits
  68. GRB 130211A: Swift/UVOT Upper Limits
  69. GRB 130211A: Swift detection of a burst
  70. GRB 130131A: MITSuME Akeno Optical upper limits
  71. GRB 130131B: MITSuME Akeno Optical upper limits
  72. GRB 130122A: PTF P48 optical upper limits
  73. GRB 130206A: GROND Observations
  74. GRB 130206A: Fermi LAT Observations
  75. GRB 130206A: XRT and UVOT follow-up observations.
  76. GRB 130131B: optical upper limit in Mondy observatory
  77. GRB 130131A: Swift/UVOT Upper Limits
  78. GRB 130131B: RATIR Upper Limits
  79. GRB 130131A: RATIR optical and infrared upper limits
  80. GRB 130131B: GROND Upper limits
  81. GRB 130131B: Swift/UVOT Upper Limits
  82. GRB 130131B: MITSuME Okayama optical upper limits
  83. GRB 130131A: MITSuME Okayama optical upper limits
  84. GRB 130131B: Swift detection of a burst
  85. GRB 130131A: Swift detection of a burst
  86. Swift Trigger 547142: MAXI/GSC upper limit
  87. GRB 130122A: Swift/UVOT Detection
  88. GRB 130122A: RATIR Detection
  89. GRB 130122A: Xinglong optical upper limit
  90. GRB 130102B: MASTER synchronous observations
  91. GRB 130102A: Swift/UVOT Upper Limits
  92. GRB 130102A: MASTER-Net optical observations
  93. GRB 130102B: MAXI/GSC detection
  94. GRB 130102A: Swift detection of a burst
  95. GRB 121229A: Swift/UVOT Upper Limits
  96. GRB 121229A: MAXI/GSC detection
  97. GRB 121229A: Swift detection of a burst
  98. GRB 121226A: Swift/UVOT Upper Limits
  99. GRB 121226A: NOT optical upper limit
  100. GRB 121226A: MITSuME Okayama Optical upper limits

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