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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"

12054 results found.

  1. Swift Trigger 556533 is probably not an astrophysical event
  2. Swift XRT observation of GRB 130518B
  3. GRB 130514B: RATIR Optical and NIR Observations
  4. GRB 130515A: Swift/UVOT Upper Limits
  5. GRB 130514B: GROND observations
  6. GRB 130515A: GROND Observations
  7. GRB 130515A: Swift detection of a short burst
  8. GRB 130513A: Bassano Bresciano optical upper limit
  9. GRB130514B: MASTER-Net optical observations.
  10. GRB 130514A: RATIR Optical and NIR Observations
  11. GRB 130513A: RATIR Optical and NIR Observations
  12. GRB 130513A: Swift/UVOT Upper Limits
  13. GRB 130514A: Swift/UVOT Upper Limits
  14. GRB 130513A: GROND observations
  15. GRB 130514A: Swift detection of a burst
  16. GRB130508A: MASTER-Net optical observations
  17. GRB 130511A: Kanata/HOWPol optical observation
  18. GRB 130511A: MITSuME Okayama upper limits
  19. GRB 130511A: Upper limit by Xinglong TNT optical observation
  20. GRB 130508A: Swift/UVOT Upper Limits
  21. GRB 130508A: MITSuME Akeno upper limits
  22. GRB 130508A: RATIR Optical and NIR Observations
  23. GRB 130508A: MITSuME Okayama upper limits
  24. GRB 130508A: Swift detection of a probable burst
  25. GRB 130505B: Further Swift observations
  26. GRB 130505A: RATIR Optical and NIR Observations
  27. GRB 130505B: MAXI/GSC detection
  28. GRB 130502A: optical upper limit
  29. Swift/UVOT observations of GRB130505A
  30. GRB 130505A: MAXI/GSC detection
  31. GRB 130504A: MITSuME Okayama upper limits
  32. GRB 130504A: Bassano Bresciano Observatory optical upper limit
  33. GRB 130504A: Swift/UVOT Upper Limits
  34. Trigger 555096: Swift detection of a possible burst
  35. GRB130502A: MASTER-Net optical observations
  36. GRB 130502B: Swift/UVOT Upper Limits
  37. GRB 130502A: Swift/UVOT Upper Limits
  38. GRB 130502B: P60 Observations
  39. GRB 130502A: RATIR Optical and NIR Observations
  40. GRB 130427A: MITSuME Ishigakijima Optical Observation after 5 days
  41. GRB 130502A: Swift detection of a burst
  42. GRB 130425: MASTER-Net optical observations
  43. GRB 130427B: MITSuME Ishigakijima upper limits
  44. GRB 130427B: RATIR Optical and NIR Observations
  45. GRB 130427B: MITSuME Okayama upper limits
  46. GRB 130427A: MAXI/GSC detection
  47. Trigger 554491: Swift detection of a spike possibly from Sgr A*
  48. GRB 130420A: Continued RATIR Optical and NIR Observations
  49. GRB 130420A: Continued RATIR Optical and NIR Observations
  50. GRB 130418A: Continued RATIR Optical and NIR Observations
  51. Swift Trigger 554135 is probably not a GRB or transient
  52. GRB 130420B: RATIR Optical and NIR Observations
  53. GRB 130420B: Weihai optical upper limit
  54. GRB 130420B: Swift/UVOT Upper Limits
  55. GRB 130420A: Swift/UVOT Detection
  56. GRB130420B: GMG optical upper limit
  57. GRB130420A : Xinglong TNT optical upper limit
  58. GRB 130420B: MASTER-Net optical observations
  59. GRB 130420B: Swift detection of a burst
  60. GRB 130419B (Swift trigger Trigger 553930): MASTER-Net optical observations
  61. GRB 130407A: Swift-XRT observations
  62. GRB130408A: Swift/UVOT followup observations
  63. GRB 130407A: MAXI/GSC detection
  64. Swift detection of IGR J18245-2452
  65. GRB 130306A: Confirmation of the X-ray Afterglow
  66. Swift Trigger 552142: a possible GRB
  67. GRB 130327A: Gemini Observations
  68. GRB 130327A: Swift/UVOT Upper Limits
  69. GRB 130327A: ISON-NM optical upper limit
  70. GRB 130327A: RATIR Optical and NIR Observations
  71. GRB 130305A: optical upper limit in Mondy observatory
  72. GRB 130315A: Swift/UVOT Upper Limits
  73. GRB 130313A: optical upper limit in CrAO
  74. GRB 130313A: optical upper limit in Mondy observatory
  75. GRB 130315A: SALT optical observations
  76. GRB 130313A: 5.8 GHz VLA upper limit
  77. Swift XRT observations of GRB 130310A
  78. GRB 130313A: Swift/UVOT Upper Limits
  79. GRB 130305A: PTF P48 optical upper limits
  80. GRB 130315A: Swift detection of a burst
  81. GRB 130305A: TLS Tautenburg observations
  82. GRB 130313A: RATIR Optical and NIR Observations
  83. GRB 130313A: Fading X-ray Afterglow
  84. GRB 130313A: NOT optical upper limit
  85. GRB 130313A: Weihai optical upper limit
  86. GRB 130313A: MASTER-Net optical observations
  87. GRB 130313A: Swift detection of a short burst
  88. GRB 130306A: Swift Detection of a Possible Afterglow
  89. GRB 130306A: MITSuME Ishigakijima upper limits
  90. GRB 130305A: Gemini-North upper limit
  91. GRB 130306A: MASTER-Net pre-Swift alert observation
  92. GRB 130305A: Swift/UVOT Upper Limit
  93. GRB 130305A: RATIR Observations
  94. GRB 121128A: optical upper limit in Maidanak observatory
  95. GRB 130216A: Swift/UVOT Upper Limit
  96. SGR 1806-20 outburst (trigger 549841), Swift-BAT refined analysis
  97. GRB 130216A: possible radio counterpart is steady field source
  98. GRB 130216A: Swift/XRT observations
  99. GRB 130216B: Swift/XRT observations
  100. GRB 130216B: MASTER-Net early observation

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